Attending physicians' annual service volume and use of virtual end-of-life care: A population-based cohort study in Ontario, Canada

IMPORTANCE

Physicians and their practice behaviors influence access to healthcare and may represent potentially modifiable targets for practice-changing interventions. Use of virtual care at the end-of-life significantly increased during the COVID-19 pandemic, but its association with physician practice behaviors, (e.g., annual service volume) is unknown.

OBJECTIVE

Measure the association of physicians' annual service volume with their use of virtual end-of-life care (EOLC) and the magnitude of physician-attributable variation in its use, before and during the pandemic.

DESIGN, SETTING AND PARTICIPANTS

Population-based cohort study using administrative data of all physicians in Ontario, Canada who cared for adults in the last 90 days of life between 01/25/2018-12/31/2021. Multivariable modified Poisson regression models measured the association between attending physicians' use of virtual EOLC and their annual service volume. We calculated the variance partition coefficients for each regression and stratified by time period before and during the pandemic.

EXPOSURE

Annual service volume of a person's attending physician in the preceding year.

MAIN OUTCOMES AND MEASURES

Delivery of ≥1 virtual EOLC visit by a person's attending physician and the proportion of variation in its use attributable to physicians.

RESULTS

Among the 35,825 unique attending physicians caring for 315,494 adults, use of virtual EOLC was associated with receiving care from a high compared to low service volume attending physician; the magnitude of this association diminished during the pandemic (adjusted RR 1.25 [95% CI 1.14, 1.37] pre-pandemic;1.10 (95% CI 1.08, 1.12) during the pandemic). Physicians accounted for 36% of the variation in virtual EOLC use pre-pandemic and 12% of this variation during the pandemic.

CONCLUSIONS AND RELEVANCE

Physicians' annual service volume was associated with use of virtual EOLC and physicians accounted for a substantial proportion of the variation in its use. Physicians may be appropriate and potentially modifiable targets for interventions to modulate use of EOLC delivery.

Hospital learning curves for robot-assisted surgeries: a population-based analysis

BACKGROUND

Robot-assisted surgery has been rapidly adopted. It is important to define the learning curve to inform credentialling requirements, training programs, identify fast and slow learners, and protect patients. This study aimed to characterize the hospital learning curve for common robot-assisted procedures.

STUDY DESIGN

This cohort study, using administrative health data for Ontario, Canada, included adult patients who underwent a robot-assisted radical prostatectomy (RARP), total robotic hysterectomy (TRH), robot-assisted partial nephrectomy (RAPN), or robotic portal lobectomy using four arms (RPL-4) between 2010 and 2021. The association between cumulative hospital volume of a robot-assisted procedure and major complications was evaluated using multivariable logistic models adjusted for patient characteristics and clustering at the hospital level.

RESULTS

A total of 6814 patients were included, with 5230, 543, 465, and 576 patients in the RARP, TRH, RAPN, and RPL-4 cohorts, respectively. There was no association between cumulative hospital volume and major complications. Visual inspection of learning curves demonstrated a transient worsening of outcomes followed by subsequent improvements with experience. Operative time decreased for all procedures with increasing volume and reached plateaus after approximately 300 RARPs, 75 TRHs, and 150 RPL-4s. The odds of a prolonged length of stay decreased with increasing volume for patients undergoing a RARP (OR 0.87; 95% CI 0.82-0.92) or RPL-4 (OR 0.77; 95% CI 0.68-0.87).

CONCLUSION

Hospitals may adopt robot-assisted surgery without significantly increasing the risk of major complications for patients early in the learning curve and with an expectation of increasing efficiency.

Ethnic differences in the association between age at diagnosis of diabetes and the risk of cardiovascular complications: a population-based cohort study

BACKGROUND

We examined ethnic differences in the association between age at diagnosis of diabetes and the risk of cardiovascular complications.

METHODS

We conducted a population-based cohort study in Ontario, Canada among individuals with diabetes and matched individuals without diabetes (2002-18). We fit Cox proportional hazards models to determine the associations of age at diagnosis and ethnicity (Chinese, South Asian, general population) with cardiovascular complications. We tested for an interaction between age at diagnosis and ethnicity.

RESULTS

There were 453,433 individuals with diabetes (49.7% women) and 453,433 matches. There was a significant interaction between age at diagnosis and ethnicity (P < 0.0001). Young-onset diabetes (age at diagnosis < 40) was associated with higher cardiovascular risk [hazard ratios: Chinese 4.25 (3.05-5.91), South Asian: 3.82 (3.19-4.57), General: 3.46 (3.26-3.66)] than usual-onset diabetes [age at diagnosis ≥ 40 years; Chinese: 2.22 (2.04-2.66), South Asian: 2.43 (2.22-2.66), General: 1.83 (1.81-1.86)] versus ethnicity-matched individuals. Among those with young-onset diabetes, Chinese ethnicity was associated with lower overall cardiovascular [0.44 (0.32-0.61)] but similar stroke risks versus the general population; while South Asian ethnicity was associated with lower overall cardiovascular [0.75 (0.64-0.89)] but similar coronary artery disease risks versus the general population. In usual-onset diabetes, Chinese ethnicity was associated with lower cardiovascular risk [0.44 (0.42-0.46)], while South Asian ethnicity was associated with lower cardiovascular [0.90 (0.86-0.95)] and higher coronary artery disease [1.08 (1.01-1.15)] risks versus the general population.

CONCLUSIONS

There are important ethnic differences in the association between age at diagnosis and risk of cardiovascular complications.

Comparison of Medical and Mental Health Sequelae Following Hospitalization for COVID-19, Influenza, and Sepsis

Importance

People who survive hospitalization for COVID-19 are at risk for developing new cardiovascular, neurological, mental health, and inflammatory autoimmune conditions. It is unclear how posthospitalization risks for COVID-19 compare with those for other serious infectious illnesses.

Objective

To compare risks of incident cardiovascular, neurological, and mental health conditions and rheumatoid arthritis in 1 year following COVID-19 hospitalization against 3 comparator groups: prepandemic hospitalization for influenza and hospitalization for sepsis before and during the COVID-19 pandemic.

Design, Setting, and Participants

This population-based cohort study included all adults hospitalized for COVID-19 between April 1, 2020, and October 31, 2021, historical comparator groups of people hospitalized for influenza or sepsis, and a contemporary comparator group of people hospitalized for sepsis in Ontario, Canada.

Exposure

Hospitalization for COVID-19, influenza, or sepsis.

Main Outcome and Measures

New occurrence of 13 prespecified conditions, including cardiovascular, neurological, and mental health conditions and rheumatoid arthritis, within 1 year of hospitalization.

Results

Of 379 366 included adults (median [IQR] age, 75 [63-85] years; 54% female), there were 26 499 people who survived hospitalization for COVID-19, 299 989 historical controls (17 516 for influenza and 282 473 for sepsis), and 52 878 contemporary controls hospitalized for sepsis. Hospitalization for COVID-19 was associated with an increased 1-year risk of venous thromboembolic disease compared with influenza (adjusted hazard ratio, 1.77; 95% CI, 1.36-2.31) but with no increased risks of developing selected ischemic and nonischemic cerebrovascular and cardiovascular disorders, neurological disorders, rheumatoid arthritis, or mental health conditions compared with influenza or sepsis cohorts.

Conclusions and Relevance

In this cohort study, apart from an elevated risk of venous thromboembolism within 1 year, the burden of postacute medical and mental health conditions among those who survived hospitalization for COVID-19 was comparable with other acute infectious illnesses. This suggests that many of the postacute consequences of COVID-19 may be related to the severity of infectious illness necessitating hospitalization rather than being direct consequences of infection with SARS-CoV-2.

Regional variation in lower extremity revascularization and amputation for peripheral artery disease

OBJECTIVE

The aim of this study was to quantify the recent and historical extent of regional variation in revascularization and amputation for peripheral artery disease (PAD).

METHODS

This was a repeated cross-sectional analysis of all Ontarians aged 40 years or greater between 2002 and 2019. The co-primary outcomes were revascularization (endovascular or open) and major (above-ankle) amputation for PAD. For each of 14 health care administrative regions, rates per 100,000 person-years (PY) were calculated for 6-year time periods from the fiscal years 2002 to 2019. Rates were directly standardized for regional demographics (age, sex, income) and comorbidities (congestive heart failure, diabetes, chronic obstructive pulmonary disease, chronic kidney disease). The extent of regional variation in revascularization and major amputation rates for each time period was quantified by the ratio of 90th over the 10th percentile (PRR).

RESULTS

In 2014 to 2019, there were large differences across regions in demographics (rural living [range, 0%-39.4%], lowest neighborhood income quintile [range, 10.1%-25.5%]) and comorbidities (diabetes [range, 14.2%-22.0%], chronic obstructive pulmonary disease [range, 7.8%-17.9%]), and chronic kidney disease [range, 2.1%-4.0%]. Standardized revascularization rates ranged across regions from 52.6 to 132.6/100,000 PY and standardized major amputation rates ranged from 10.0 to 37.7/100,000 PY. The extent of regional variation was large (PRR ≥2.0) for both revascularization and major amputation. From 2002-2004 to 2017-2019, the extent of regional variation increased from moderate to large for revascularization (standardized PRR, 1.87 to 2.04) and major amputation (standardized PRR, 1.94 to 3.07).

CONCLUSIONS

Significant regional differences in revascularization and major amputation rates related to PAD remain after standardizing for regional differences in demographics and comorbidities. These differences have not improved over time.

A183 VARIATION IN HEALTH SERVICES UTILIZATION AND RISK OF SURGERY ACROSS CHILDREN WITH INFLAMMATORY BOWEL DISEASE: A MULTIPROVINCE COHORT STUDY

Background

Marked variation in access to care and health services utilization is a marker of variation in quality of care. With the rising incidence of pediatric inflammatory bowel disease (IBD), we must understand variation in access to and outcomes of care to improve quality.

Purpose

Describe variation in care for pediatric IBD treated in 4 Canadian provinces.

Method

Incident cases of IBD diagnosed in children <16y were identified from health administrative data in Alberta (AB), Manitoba, Nova Scotia, and Ontario (ON) using validated algorithms. Children were assigned to one of 8 centres of care using a hierarchical assessment of health services use within 6 months of diagnosis. Children treated by adult gastroenterologists or community-based pediatric gastroenterologists were excluded due to small sample size. Outcomes included IBD-related hospitalizations, emergency department (ED) visits (AB/ON only), and IBD-related abdominal surgery. Hospitalizations and ED visits were counted cumulatively from 6-60 months after diagnosis. The risk of first surgery was defined during the same 6-60 month period. Mixed-effects meta-analysis was used to pool results across centres. Heterogeneity among centres was quantified using I² (variation in pooled event rates between centres) and τ (standard deviation of the true event rates). R² quantified the residual heterogeneity in outcomes not attributable to among-province variation.

Result(s)

We identified 3777 incident cases of pediatric IBD, 2936 (78%) of which were treated at 8 pediatric centres. The number of hospitalizations was 0.67 (95% CI 0.56-0.79) per person with high between-centre heterogeneity (I² 84%, τ 0.1556). Provincial differences accounted for 93% of heterogeneity across centres (residual heterogeneity: I² 29%, τ 0.0412). Hospitalizations were less frequent in AB than other provinces (0.43 vs. 0.72-0.78). Children averaged 1.94 IBD-related ED visits, with significant heterogeneity (I² 99%, τ 1.33) with 99.7% of heterogeneity attributable to among-province differences (residual heterogeneity: I² 32%; τ 0.074). Mean ED visits were 1.1 visits in ON (I² 39%) and 3.7 in AB (I² 0%). Intestinal resection was required by 12% (95% CI 0.08-0.15) of Crohn’s patients with high among-centre heterogeneity (I² 81%, τ 0.042), and low (19%) heterogeneity due to provincial differences (residual heterogeneity: I² 76%; τ 0.039). Colectomy was required by 12% (95% CI 10-14) of children with ulcerative colitis (UC) with no between-centre heterogeneity (I² 0%, τ 0).

Conclusion(s)

There is a high degree of between-province (but not between-centre, within province) variability in health services utilization among children with IBD. There was significant between-centre variability in surgery rates for Crohn’s, but not colectomy for UC. Differences in patient characteristics or provincial health systems may be more important predictors of variation in care. Surgery for Crohn’s disease may be a target for inter-centre quality improvement efforts.

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Disclosure of Interest

None Declared

A189 EMERGENCY DEPARTMENT UTILIZATION AND RISK OF INTESTINAL RESECTION IS LOWER AMONG CHILDREN DIAGNOSED WITH INFLAMMATORY BOWEL DISEASE BEFORE 10 YEARS OF AGE: A MULTIPROVINCE POPULATION-BASED COHORT STUDY

Background

In Canada, the incidence of inflammatory bowel disease (IBD) is increasing faster among those <10 years (y) of age than in any other age group. Understanding the health services burden of IBD in this population is important for health system planning.

Purpose

To compare healthcare utilization and risk of surgery among children diagnosed with IBD across age groups defined by the Paris Classification (A1a: <10y; A1b: 10 to <16y) across 5 Canadian provinces.

Method

Children diagnosed with IBD <16 years of age were identified from health administrative data using validated algorithms in Alberta, Manitoba, Nova Scotia, Ontario, and Québec. Negative binomial regression models were used to compare (1) the pre-diagnosis frequency of health services utilization (outpatient, emergency department (ED), and hospitalization) using diagnostic codes suggestive of future IBD and (2) the annual post-diagnosis frequency of IBD-specific and IBD-related (signs, symptoms, and extra-intestinal manifestations of IBD) visits among children diagnosed <10y (A1a) and 10 to <16y (A1b). Cox proportional hazard models compared the risk of surgery (identified with validated procedure codes) across age groups. All regression models were adjusted for sex, rural/urban residence, and mean neighbourhood income quintile. Province-specific event counts (all ages combined) and models (comparing age groups; reference: A1b [10 to <16y]) were pooled using random-effects meta-analysis.

Result(s)

Among 5124 children with IBD (1165 [23%] were <10y at diagnosis), the mean number of pre-diagnosis healthcare encounters was 1.0 (95% CI 0.38 to 1.68, I²=99.6%). The mean annual post-diagnosis number of IBD-specific outpatient visits was 3.2 (95% CI 1.9-4.4, I²=99.6%); hospitalizations, 0.19 (95% CI 0.17-0.21, I²=74%); ED visits, 0.17 (95% CI 0.19-0.39, I²=99%). The mean annual post-diagnosis number of IBD-related outpatient visits was 3.9 (95% CI 2.3-5.5, I²=99.7%); hospitalizations, 0.21 (95% CI 0.19-0.23, I²=79%); ED visits, 0.29 (95% CI 0.19-0.39, I²=97%). Intestinal resection or colectomy within 5y of diagnosis occurred in 13% (95%CI 8-22, I²=93%) with Crohn’s disease (CD) and 16% (95% CI 14-18, I²=40%) with ulcerative colitis. IBD-specific ED visits (RR 0.70, 95% CI 0.50-0.97, I²=80) and the risk of intestinal resection in CD (HR 0.49, 95% CI 0.26-0.92, I²=40%) were significantly lower among children diagnosed <10y. There were no age-related differences in pre-diagnosis health services utilization or other post-diagnosis outcomes, including frequency of outpatient visits to a gastroenterologist.

Conclusion(s)

Health services utilization was generally similar for children diagnosed with IBD at <10y and between 10 and <16y, except for lower rates of IBD-specific ED visits and intestinal resection in children with CD. Further exploration of between-province differences, represented by the high statistical heterogeneity (I²) in the meta-analyses, is needed to understand sources of variation in care.

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Disclosure of Interest

E. Kuenzig: None Declared, H. Singh Consultant of: Amgen Canada, Bristol-Myers Squibb Canada, Sandoz Canada, Roche Canada, Takeda Canada and Guardant Health, A. Bitton: None Declared, G. Kaplan Grant / Research support from: Ferring, Consultant of: AbbVie, Janssen, Pfizer, Amgen, Sandoz, Pendophram, and Takeda, Speakers bureau of: AbbVie, Janssen, Pfizer, Amgen, Sandoz, Pendophram, and Takeda, M. Carroll: None Declared, A. Otley Grant / Research support from: Research support: AbbVie Global. Research site: AbbVie, Pfizer, Eli-Lily, Janssen, Consultant of: AbbVie Canada, T. Stukel: None Declared, S. Spruin: None Declared, A. Griffiths Grant / Research support from: Abbvie, Consultant of: Abbvie, Amgen, BristolMyersSquibb, Janssen, Lilly, Takeda, Speakers bureau of: Abbvie, Janssen, Takeda, D. Mack: None Declared, K. Jacobson Grant / Research support from: Abbvie Canada and Janssen Canada, Consultant of: Abbvie Canada, Janssen Canada, Merck Canada and Mylan Pharmaceuticals, Speakers bureau of: Abbvie Canada and Janssen Canada, G. Nguyen: None Declared, L. Targownik Grant / Research support from: Janssen Canada, Consultant of: AbbVie Canada, Sandoz Canada, Takeda Canada, Merck Canada, Pfizer Canada, Janssen Canada, and Roche Canada, W. El-Matary Consultant of: Abbvie and MERCK, Speakers bureau of: Abbvie and MERCK, E. Benchimol Consultant of: McKesson Canada, Dairy Farmers of Ontario (unrelated to medications used to treat inflammatory bowel disease)

Primary Care Clinical Volumes, Cholesterol Testing, and Cardiovascular Outcomes

BACKGROUND

It is unknown whether the annual number of primary care physician (PCP) unique outpatient assessments, which we refer to as clinical volume, translates into better cardiovascular preventive care. We examined the relationship between PCP outpatient clinical volumes and cholesterol testing and major adverse cardiovascular event rates among guideline-recommended eligible patients.

METHODS

This was a retrospective cohort study conducted as part of the Cardiovascular Health in Ambulatory Care Research Team (CANHEART) cohort, a population-based cohort of almost all adult residents of Ontario, Canada, followed from 2008 to 2012. For each clinical volume quintile, we compared cholesterol testing and major adverse cardiovascular events, defined as time to first event of cardiovascular death, nonfatal myocardial infarction, or nonfatal stroke.

RESULTS

The 10,037 PCPs evaluated had an annualized median volume of 2303 clinical encounters (IQR 1292-3680). Among 4,740,380 patients, 84% underwent guideline-concordant cholesterol testing at least once over 5 years, ranging from 73% with the lowest clinical volume quintile physicians to 86% with the highest. After multivariable adjustment, there was a 10.5% relative increase in the probability of cholesterol testing for every doubling of clinical volumes (95% CI 9.7-11.4; P < 0.001). Patients treated by the lowest volume quintile physicians had the highest rate of major adverse cardiovascular outcomes (compared with the highest volume quintile physicians: adjusted HR 1.15, 95% CI 1.10-1.21; P < 0.001).

CONCLUSIONS

Patients of physicians with the lowest clinical volumes received less frequent cholesterol testing and had the highest rate of incident cardiovascular events. Further research investigating the drivers of this relationship is warranted.

The influence of diabetes on temporal trends in lower extremity revascularisation and amputation for peripheral artery disease: A population-based repeated cross-sectional analysis

AIM/HYPOTHESIS

To describe the influence of diabetes on temporal changes in rates of lower extremity revascularisation and amputation for peripheral artery disease (PAD) in Ontario, Canada.

METHODS

In this population-based repeated cross-sectional study, we calculated annual rates of lower extremity revascularisation (open or endovascular) and amputation (toe, foot or leg) related to PAD among Ontario residents aged ≥40 years between 2002 and 2019. Annual rate ratios (relative to 2002) adjusted for changes in diabetes prevalence alone, as well as fully adjusted for changes in demographics, diabetes and other comorbidities, were estimated using generalized estimating equation models to model population-level effects while accounting for correlation within units of observation.

RESULTS

Compared with 2002, the Ontario population in 2019 exhibited a significantly higher prevalence of diabetes (18% vs. 10%). Between 2002 and 2019, the crude rate of revascularisation increased from 75.1 to 90.7/100,000 person-years (unadjusted RR = 1.10, 95% CI = 1.07-1.13). However, after adjustment, there was no longer an increase in the rate of revascularisation (diabetes-adjusted RR = 0.98, 95% CI = 0.96-1.01, fully-adjusted RR = 0.94, 95% CI = 0.91-0.96). The crude rate of amputation decreased from 2002 to 2019 from 49.5 to 45.4/100,000 person-years (unadjusted RR = 0.78, 95% CI = 0.75-0.81), but was more pronounced after adjustment (diabetes-adjusted RR = 0.62, 95% CI = 0.60-0.64; fully-adjusted RR = 0.58, 95% CI = 0.56-0.60).

CONCLUSIONS/INTERPRETATION

Diabetes prevalence rates strongly influenced rates of revascularisation and amputation related to PAD. A decrease in amputations related to PAD over time was attenuated by rising diabetes prevalence rates.

Access to diagnostic imaging and incidental detection of differentiated thyroid cancer in Ontario: A population-based retrospective cohort study

Global increases in thyroid cancer incidence (≥90% differentiated thyroid cancers; DTC) are hypothesized to be related to increased use of pre-diagnostic imaging. These procedures can detect DTC during imaging for conditions unrelated to the thyroid (incidental detection). The objectives were to evaluate incidental detection of DTC associated with standardized, regional imaging capacity and drivetime from patient residence to imaging facility (the exposures). We conducted a population-based retrospective cohort study of 32,097 DTC patients in Ontario, 2003-2017. We employed sex-specific spatial Bayesian hierarchical models to evaluate the exposures and examine the adjusted odds of incidental detection by administrative regions. Regional capacities of computed tomography and magnetic resonance imaging scanners are positively associated with incidental detection, but vary by sex. Contrary to hypothesis, drivetimes in urban areas are positively associated with incidental detection. Access to primary care may play a role in several administrative regions with higher adjusted odds of incidental detection.

No Time to Waste: An Appraisal of Value at the End of Life

OBJECTIVES

The use of economic evaluations of end-of-life interventions may be limited by an incomplete appreciation of how patients and society perceive value at end of life. The objective of this study was to evaluate how patients, caregivers, and society value gains in quantity of life and quality of life (QOL) at the end of life. The validity of the assumptions underlying the use of the quality-adjusted life-years (QALY) as a measure of preferences at end of life was also examined.

METHODS

MEDLINE, Embase, CINAHL, PsycINFO, and PubMed were searched from inception to February 22, 2021. Original research studies reporting empirical data on healthcare priority setting at end of life were included. There was no restriction on the use of either quantitative or qualitative methods. Two reviewers independently screened, selected, and extracted data from studies. Narrative synthesis was conducted for all included studies. The primary outcomes were the value of gains in quantity of life and the value of gains in QOL at end of life.

RESULTS

A total of 51 studies involving 53 981 participants reported that gains in QOL were generally preferred over quantity of life at the end of life across stakeholder groups. Several violations of the underlying assumptions of the QALY to measure preferences at the end of life were observed.

CONCLUSIONS

Most patients, caregivers, and members of the general public prioritize gains in QOL over marginal gains in life prolongation at the end of life. These findings suggest that policy evaluations of end-of-life interventions should favor those that improve QOL. QALYs may be an inadequate measure of preferences for end-of-life care thereby limiting their use in formal economic evaluations of end-of-life interventions.

Acute Care Visits for Eating Disorders Among Children and Adolescents After the Onset of the COVID-19 Pandemic

PURPOSE

Anecdotal reports suggest a significant increase in acute presentations of eating disorders among children and adolescents. Our objective was to compare the rates of emergency department visits and hospitalizations for pediatric eating disorders before and during the first 10 months of the COVID-19 pandemic.

METHODS

Using linked health administrative databases, we conducted a population-based repeated cross-sectional study of emergency department visits and hospitalizations for eating disorders among all children and adolescents aged 3-17 years, residing in Ontario, Canada. We defined the pre-COVID period from January 1, 2017, to February 29, 2020, and the post-COVID period from March 1, 2020, to December 26, 2020. Poisson generalized estimating equations were used to model 3-year pre-COVID trends to predict expected post-COVID trends and estimate the relative change from expected rates.

RESULTS

In our population of almost 2.5 million children and adolescents, acute care visits for eating disorders increased immediately after the onset of the pandemic, reaching a 4-week peak annualized rate of 34.6 (emergency department visits) and 43.2 per 100,000 population (hospitalizations) in October 2020. Overall, we observed a 66% (adjusted relative rate: 1.66, 95% confidence interval: 1.41-1.96) and 37% (adjusted relative rate: 1.37, 95% confidence interval: 1.25-1.50) increase in risk for emergency department visit and hospitalization, respectively.

CONCLUSIONS

Acute care visits for pediatric eating disorders increased significantly in Ontario after the onset of COVID-19 pandemic and remained well above expected levels during the first 10 months of the pandemic. Further research is needed to understand the social and neurobiological mechanisms underlying the observed changes in health system utilization.

Association of Hypertension and Diabetes with Ischemic Heart Disease and Stroke Mortality in India: The Million Death Study

Background

The cardiovascular outcomes of hypertension and diabetes in India have never been studied at the national level.

Objectives

We conducted a nationally-representative proportional mortality study to measure the associations of hypertension and diabetes with premature mortality due to ischemic heart disease (IHD) and stroke among Indian adults.

Methods

We determined causes of death by verbal autopsy from 2001-14 among 2.4 million households. We defined cases as those who died of the study outcomes and controls as those who died of injuries, respiratory causes, or cancer. We used multivariable logistic regression models to compute adjusted odds ratios (OR) measuring the association of hypertension and diabetes with IHD or stroke mortality, population-attributable fractions (PAF), and time trends.

Results

The mean age at death was 55.6 (standard deviation 9.9) years for IHD, 58.2 (9.0) years for stroke, and 46.8 (injury) to 59.8 (respiratory) years for controls. There were more men among both the cases (IHD: 70.1%; stroke: 59.0%) and controls (injury: 76.6%; cancer: 55.4%; respiratory: 59.8%). Hypertension was associated with six- to eight-fold increases in the odds of IHD (OR 5.9, 99% CI 5.6-6.2) and stroke mortality (7.9, 7.4-8.5). Diabetes was associated with double the odds (1.9, 1.7-2.0) of IHD mortality and increased odds of stroke mortality (1.6, 1.4-1.7). Hypertension accounted for an increasing PAF of IHD mortality and decreasing PAF of stroke mortality. Diabetes was associated with relatively lower PAFs and variable time trends.

Conclusions

Hypertension is associated with an unexpectedly high burden of cardiovascular mortality, and contributes to an increasing proportion of IHD deaths and a decreasing proportion of stroke deaths. Better management of hypertension and diabetes is urgently required to reduce premature cardiovascular mortality.

Renin-angiotensin-aldosterone system inhibitors and major cardiovascular events and acute kidney injury in patients with coronary artery disease

BACKGROUND

Renin-angiotensin-aldosterone system inhibitors (RAASIs) are recommended for most patients with coronary artery disease (CAD). However, there is debate across guidelines as to which patients with CAD benefit the most from these agents. This study investigated the association between RAASIs and cardiovascular outcomes and acute kidney injury in a contemporary cohort of patients with CAD.

METHODS

Patients ≥65 years of age with CAD alive on April 1, 2012 in Ontario, Canada were included. Outcomes included major adverse cardiovascular events (MACE: cardiovascular death, myocardial infarction (MI), unstable angina, stroke, or coronary revascularization), and acute kidney injury (AKI) hospitalizations at 4 years. Inverse probability of treatment-weighted Cox proportional hazards regression models was used to compare the rates of each outcome in patients treated with and without RAASIs (angiotensin-converting enzyme inhibitors or angiotensin II receptor blockers).

RESULTS

There were 165,058 patients with CAD identified (mean age 75 years, 65.5% male, 64.7% prescribed RAASIs). After inverse-probability weighting, treatment with RAASIs was associated with a lower rate of MACE compared with treatment without RAASIs (17.6% vs 18.2%, hazard ratio [HR]: 0.96, 95% CI: 0.93-0.99, respectively). However, treatment with RAASIs was associated with a higher rate of AKI compared with treatment without RAASIs (1.7% vs 1.5%, HR: 1.14, 95% CI: 1.02-1.29, respectively). The reduction in MACE was greater in patients with prior MI (HR: 0.87, 95% CI: 0.82-0.92) compared with patients without prior MI (HR: 1.00, 95% CI: 0.97-1.04, interaction p < 0.01). The increase in AKI was lower in patients with prior MI (HR: 0.82, 95% CI: 0.66-1.00) compared with patients without prior MI (HR: 1.37, 95% CI: 1.19-1.57, interaction p < 0.01).

CONCLUSIONS

This study supports the continued use of RAASIs in patients with CAD, although the benefit appears smaller in magnitude than observed in prior trials. High-risk patients, particularly those with prior MI, appear to benefit the most from RAASIs.

Temporal Trends in Hospitalization for Lower Extremity Peripheral Artery Disease in Ontario: The Importance of Diabetes

We sought to assess temporal trends in peripheral artery disease (PAD)-related hospitalization rates in Ontario. Trends in quarterly rates of PAD hospitalization per 100,000 Ontarians between 2006 and 2019 were assessed using autocorrelated linear regression. Stratified analyses according to age, sex, and most responsible diagnosis code type (with vs without diabetes-specific PAD codes) were performed. From 2006 to 2019, overall PAD hospitalizations did not decrease significantly when diabetes-specific codes were included. A significant decrease was observed among women and those older than 65 years old. Future studies of PAD epidemiology and outcomes using administrative data should include diabetic angiopathy.

Validation of Diagnosis and Procedure Codes for Revascularization for Peripheral Artery Disease in Ontario Administrative Databases

PURPOSE

To estimate the positive predictive value of diagnosis and procedure codes for open and endovascular revascularization for peripheral artery disease (PAD) in Ontario administrative databases.

METHODS

We conducted a retrospective validation study using population-based Ontario administrative databases (2005-2019) to identify a random sample of 600 patients who underwent revascularization for PAD at two academic centres, based on ICD-10 diagnosis codes and Canada Classification of Health Intervention procedure codes. Administrative data coding was compared to the gold standard diagnosis (PAD vs. non-PAD) and revascularization approach (open vs. endovascular) extracted through blinded hospital chart re-abstraction. Positive predictive values and 95% confidence intervals were calculated. Combinations of procedure codes with or without supplemental physician claims codes were evaluated to optimize the positive predictive value.

RESULTS

The overall positive predictive value of PAD diagnosis codes was 87.5% (84.6%-90.0%). The overall positive predictive value of revascularization procedure codes was 94.3% (92.2%-96.0%), which improved through supplementation with physician fee claim codes to 98.1% (96.6%-99.0%). Algorithms to identify individuals revascularized for PAD had combined positive predictive values ranging from 82.8% (79.6%-85.8%) to 95.7% (93.5%-97.3%).

CONCLUSION

Diagnosis and procedure codes with or without physician claims codes allow for accurate identifi-cation of individuals revascularized for PAD in Ontario administrative databases.

Family and Child Risk Factors for Early-Life RSV Illness

BACKGROUND AND OBJECTIVES

Most infants hospitalized with respiratory syncytial virus (RSV) do not meet common "high-risk" criteria and are otherwise healthy. The objective of this study was to quantify the risks and relative importance of socioeconomic factors for severe, early-life RSV-related illness. We hypothesized several of these factors, particularly those indicating severe social vulnerability, would have statistically significant associations with increased RSV hospitalization rates and may offer impactful targets for population-based RSV prevention strategies, such as prophylaxis programs.

METHODS

We used linked health, laboratory, and sociodemographic administrative data for all children born in Ontario (2012-2018) to identify all RSV-related hospitalizations occurring before the third birthday or end of follow-up (March 31, 2019). We estimated rate ratios and population attributable fractions using a fully adjusted model.

RESULTS

A total of 11 782 RSV-related hospitalizations were identified among 789 484 children. Multiple socioeconomic factors were independently associated with increased RSV-related admissions, including young maternal age, maternal criminal involvement, and maternal history of serious mental health and/or addiction concerns. For example, an estimated 4.1% (95% confidence interval: 2.2 to 5.9) of RSV-related admissions could be prevented by eliminating the increased admissions risks among children whose mothers used welfare-based drug insurance. Notably, 41.6% (95% confidence interval: 39.6 to 43.5) of admissions may be prevented by targeting older siblings (eg, through vaccination).

CONCLUSIONS

Many social factors were independently associated with early-life RSV-related hospitalization. Existing RSV prophylaxis and emerging vaccination programs should consider the importance of both clinical and social risk factors when determining eligibility and promoting compliance.

Primary care physician volume and quality of care for older adults with dementia: a retrospective cohort study

Background

Some jurisdictions restrict primary care physicians’ daily patient volume to safeguard quality of care for complex patients. Our objective was to determine whether people with dementia receive lower-quality care if their primary care physician sees many patients daily.

Methods

Population-based retrospective cohort study using health administrative data from 100,256 community-living adults with dementia aged 66 years or older, and the 8,368 primary care physicians who cared for them in Ontario, Canada. Multivariable Poisson GEE regression models tested whether physicians’ daily patient volume was associated with the adjusted likelihood of people with dementia receiving vaccinations, prescriptions for cholinesterase inhibitors, benzodiazepines, and antipsychotics from their primary care physician.

Results

People with dementia whose primary care physicians saw ≥ 30 patients daily were 32% (95% CI: 23% to 41%, p < 0.0001) and 25% (95% CI: 17% to 33%, p < 0.0001) more likely to be prescribed benzodiazepines and antipsychotic medications, respectively, than patients of primary care physicians who saw < 20 patients daily. Patients were 3% (95% CI: 0.4% to 6%, p = 0.02) less likely to receive influenza vaccination and 8% (95% CI: 4% to 13%, p = 0.0001) more likely to be prescribed cholinesterase inhibitors if their primary care physician saw ≥ 30 versus < 20 patients daily.

Conclusions

People with dementia were more likely to receive both potentially harmful and potentially beneficial medications, and slightly less likely to be vaccinated by high-volume primary care physicians.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12875-021-01398-9.

Incidental detection, imaging modalities and temporal trends of differentiated thyroid cancer in Ontario: a population-based retrospective cohort study

BACKGROUND

Incidence rates of thyroid cancer in Ontario have increased more rapidly than those of any other cancer, whereas mortality rates have remained relatively stable. We evaluated the extent to which incidental detection of differentiated thyroid cancer during unrelated prediagnostic imaging procedures contributed to Ontario's incidence rates.

METHODS

We conducted a retrospective cohort study involving Ontarians who received a diagnosis of differentiated thyroid cancer from 1998 to 2017 using linked health care administrative databases. We classified cases as incidentally detected if a nonthyroid diagnostic imaging test (e.g., computed tomography [CT]) preceded an index event (e.g., prediagnostic fine-needle aspiration biopsy); all other cases were nonincidentally detected cases. We used Joinpoint and negative binomial regressions to characterize sex-specific rates of differentiated thyroid cancer by incidentally detected status and to quantify potential age, diagnosis period and birth cohort effects.

RESULTS

The study included 36 531 patients with differentiated thyroid cancer, of which 78.7% were female. Incidentally detected cases increased from 7.0% to 11.0% of female patients and from 13.5% to 18.2% of male patients over the study period. Age-standardized incidence rates increased more rapidly for incidentally detected cases (4.2-fold for female and 3.7-fold for male patients) than for nonincidentally detected cases (2.6-fold for female and 3.0-fold for male patients; p < 0.001). Diagnosis period was the primary factor associated with increased incidence rates of differentiated thyroid cancer, adjusting for other factors. Within each period, incidentally detected rates increased faster than nonincidentally detected rates, adjusting for age. Our results showed that CT was the most common imaging procedure preceding incidentally detected diagnoses.

INTERPRETATION

Incidentally detected cases represent a large and increasing component of the observed increases in differentiated thyroid cancer in Ontario over the past 20 years, and CT scans are primarily associated with these cases despite the modality having similar, increasing rates of use compared with magnetic resonance imaging (1993-2004). Recent increases in rates of differentiated thyroid cancer among males and incidentally detected cases among females in Ontario appear to be unrelated to birth cohort effects.

Age at diagnosis, glycemic trajectories, and responses to oral glucose-lowering drugs in type 2 diabetes in Hong Kong: A population-based observational study

BACKGROUND

Lifetime glycemic exposure and its relationship with age at diagnosis in type 2 diabetes (T2D) are unknown. Pharmacologic glycemic management strategies for young-onset T2D (age at diagnosis <40 years) are poorly defined. We studied how age at diagnosis affects glycemic exposure, glycemic deterioration, and responses to oral glucose-lowering drugs (OGLDs).

METHODS AND FINDINGS

In a population-based cohort (n = 328,199; 47.2% women; mean age 34.6 and 59.3 years, respectively, for young-onset and usual-onset [age at diagnosis ≥40 years] T2D; 2002-2016), we used linear mixed-effects models to estimate the association between age at diagnosis and A1C slope (glycemic deterioration) and tested for an interaction between age at diagnosis and responses to various combinations of OGLDs during the first decade after diagnosis. In a register-based cohort (n = 21,016; 47.1% women; mean age 43.8 and 58.9 years, respectively, for young- and usual-onset T2D; 2000-2015), we estimated the glycemic exposure from diagnosis until age 75 years. People with young-onset T2D had a higher mean A1C (8.0% [standard deviation 0.15%]) versus usual-onset T2D (7.6% [0.03%]) throughout the life span (p < 0.001). The cumulative glycemic exposure was >3 times higher for young-onset versus usual-onset T2D (41.0 [95% confidence interval 39.1-42.8] versus 12.1 [11.8-12.3] A1C-years [1 A1C-year = 1 year with 8% average A1C]). Younger age at diagnosis was associated with faster glycemic deterioration (A1C slope over time +0.08% [0.078-0.084%] per year for age at diagnosis 20 years versus +0.02% [0.016-0.018%] per year for age at diagnosis 50 years; p-value for interaction <0.001). Age at diagnosis ≥60 years was associated with glycemic improvement (-0.004% [-0.005 to -0.004%] and -0.02% [-0.027 to -0.0244%] per year for ages 60 and 70 years at diagnosis, respectively; p-value for interaction <0.001). Responses to OGLDs differed by age at diagnosis (p-value for interaction <0.001). Those with young-onset T2D had smaller A1C decrements for metformin-based combinations versus usual-onset T2D (metformin alone: young-onset -0.15% [-0.105 to -0.080%], usual-onset -0.17% [-0.179 to -0.169%]; metformin, sulfonylurea, and dipeptidyl peptidase-4 inhibitor: young-onset -0.44% [-0.476 to -0.405%], usual-onset -0.48% [-0.498 to -0.459%]; metformin and α-glucosidase inhibitor: young-onset -0.40% [-0.660 to -0.144%], usual-onset -0.25% [-0.420 to -0.077%]) but greater responses to other combinations containing sulfonylureas (sulfonylurea alone: young-onset -0.08% [-0.099 to -0.065%], usual-onset +0.06% [+0.059 to +0.072%]; sulfonylurea and α-glucosidase inhibitor: young-onset -0.10% [-0.266 to 0.064%], usual-onset: 0.25% [+0.196% to +0.312%]). Limitations include possible residual confounding and unknown generalizability outside Hong Kong.

CONCLUSIONS

In this study, we observed excess glycemic exposure and rapid glycemic deterioration in young-onset T2D, indicating that improved treatment strategies are needed in this setting. The differential responses to OGLDs between young- and usual-onset T2D suggest that better disease classification could guide personalized therapy.

A26 PEDIATRIC-ONSET INFLAMMATORY BOWEL DISEASE INCREASES THE RISK OF VENOUS THROMBOEMBOLISM: A CANGIEC POPULATION-BASED STUDY

Background

Inflammatory bowel disease (IBD) increases the risk of venous thromboembolism (VTE) in patients of all ages but the risk of VTE among Canadian children with IBD has not previously been investigated.

Aims

Report the incidence of VTE and subtypes pulmonary embolism (PE) and deep vein thrombosis (DVT) in children with and without IBD.

Methods

Children diagnosed with IBD &lt;16y were identified from health administrative data in Ontario (2002–2014), Alberta (2007–2015), and Nova Scotia (2002–2012) using validated algorithms and matched by age and sex to children without IBD (1:5 ratio). Validated ICD-10 codes identified hospitalizations for incident VTE (DVT, PE, and sinovenous thrombosis). Province-specific 5-year cumulative incidence per 1000 person-years (PY) of VTEs were pooled using fixed-effects generalized linear mixed models with a Freeman-Tukey double arcsine transformation. Incidence rate ratios (IRR) within 5 years of diagnosis were pooled using fixed-effects generalized linear mixed models to compare children with and without IBD, and children with Crohn’s disease (CD) and ulcerative colitis (UC).

Results

3127 children with IBD (1826 CD; 1045 UC) were matched to 15,635 children without IBD. The cumulative incidence of VTE within 5 years of IBD diagnosis was 2.8 (95% CI 2.1–3.8) per 1000 PYs compared to 0.13 (95% CI 0.07–0.24) per 1000 PYs in children without IBD (Table). The 5-year cumulative incidences of VTE, DVT, and PE were significantly higher in children with IBD than in children without IBD (VTE: IRR 21.44, 95% CI 10.73–42.82; DVT: IRR 25.15, 95% CI 11.12–56.89; PE: IRR 4.01, 95% CI 1.22–13.18). Compared to UC patients, children with CD were at lower risk of VTE (IRR 0.53, 95% CI 0.29–0.96) and numerically, but not statistically, lower risk of DVT (IRR 0.59, 95% CI 0.30–1.14).

Conclusions

Although VTEs are relatively rare among children with IBD, these children are at much greater risk than children without IBD. Gastroenterologists caring for these patients should be cognizant of VTE risk and provide appropriate prophylaxis to those at high risk of VTE.

Funding Agencies

CCC

Development and validation of algorithms to classify type 1 and 2 diabetes according to age at diagnosis using electronic health records

BACKGROUND

Validated algorithms to classify type 1 and 2 diabetes (T1D, T2D) are mostly limited to white pediatric populations. We conducted a large study in Hong Kong among children and adults with diabetes to develop and validate algorithms using electronic health records (EHRs) to classify diabetes type against clinical assessment as the reference standard, and to evaluate performance by age at diagnosis.

METHODS

We included all people with diabetes (age at diagnosis 1.5-100 years during 2002-15) in the Hong Kong Diabetes Register and randomized them to derivation and validation cohorts. We developed candidate algorithms to identify diabetes types using encounter codes, prescriptions, and combinations of these criteria ("combination algorithms"). We identified 3 algorithms with the highest sensitivity, positive predictive value (PPV), and kappa coefficient, and evaluated performance by age at diagnosis in the validation cohort.

RESULTS

There were 10,196 (T1D n = 60, T2D n = 10,136) and 5101 (T1D n = 43, T2D n = 5058) people in the derivation and validation cohorts (mean age at diagnosis 22.7, 55.9 years; 53.3, 43.9% female; for T1D and T2D respectively). Algorithms using codes or prescriptions classified T1D well for age at diagnosis < 20 years, but sensitivity and PPV dropped for older ages at diagnosis. Combination algorithms maximized sensitivity or PPV, but not both. The "high sensitivity for type 1" algorithm (ratio of type 1 to type 2 codes ≥ 4, or at least 1 insulin prescription within 90 days) had a sensitivity of 95.3% (95% confidence interval 84.2-99.4%; PPV 12.8%, 9.3-16.9%), while the "high PPV for type 1" algorithm (ratio of type 1 to type 2 codes ≥ 4, and multiple daily injections with no other glucose-lowering medication prescription) had a PPV of 100.0% (79.4-100.0%; sensitivity 37.2%, 23.0-53.3%), and the "optimized" algorithm (ratio of type 1 to type 2 codes ≥ 4, and at least 1 insulin prescription within 90 days) had a sensitivity of 65.1% (49.1-79.0%) and PPV of 75.7% (58.8-88.2%) across all ages. Accuracy of T2D classification was high for all algorithms.

CONCLUSIONS

Our validated set of algorithms accurately classifies T1D and T2D using EHRs for Hong Kong residents enrolled in a diabetes register. The choice of algorithm should be tailored to the unique requirements of each study question.

Long-Term Care Residents' Geriatric Syndromes at Admission and Disablement Over Time: An Observational Cohort Study

Background

Disablement occurs when people lose their ability to perform activities of daily living (ADLs) like bathing and dressing, and is measured as the rate of increasing disability over time. We examined whether balance impairment, cognitive impairment, or pain among residents at admission to long-term care homes were predictive of their rate of disablement over the subsequent 2 years.

Methods

Linked administrative databases were used to conduct a longitudinal cohort study of 12,334 residents admitted to 633 long-term care (LTC) homes between April 1, 2011 and March 31, 2012, in Ontario, Canada. Residents received an admission assessment of disability upon admission to LTC using the RAI-MDS 2.0 ADL long-form score (ADL LFS, range 0–28) and at least two subsequent disability assessments. Multivariable regression models estimated the adjusted association between balance impairment, cognitive impairment, and pain present at admission and residents’ subsequent disablement over 2 years.

Results

This population sample of newly admitted Ontario long-term care residents had a median disability score of 13 (interquartile range [IQR] = 7, 19) at admission. Greater balance impairment and cognitive impairment at admission were significantly associated with faster resident disablement over 2 years in adjusted models, while daily pain was not.

Conclusions

Balance impairment and cognitive impairment among newly admitted long-term care home residents are associated with increased rate of disablement over the following 2 years. Further research should examine the mechanisms driving this association and identify whether they are amenable to intervention.

Association of Primary Care Continuity With Outcomes Following Transition to Adult Care for Adolescents With Severe Mental Illness

IMPORTANCE

Adolescents with severe mental illness often age out of pediatric care without a clear transfer of care to adult services. The extent to which primary care provides stability during this vulnerable transition period is not known.

OBJECTIVE

To analyze the association between primary care continuity during the transition from pediatric to adult care and need for acute mental health services in young adulthood.

DESIGN, SETTING, AND PARTICIPANTS

This population-based cohort study used linked health and demographic administrative data for all adolescents aged 12 to 16 years with severe mental illness ascertained by hospitalization for schizophrenia, eating disorder, or mood disorder between April 1, 2002, and April 1, 2014, in Ontario, Canada. Participants were followed up through March 31, 2017. Data were analyzed from July 2018 to January 2019.

EXPOSURES

Continuous primary care (same physician as baseline [age 12-16 years] always or sometimes), discontinuous primary care (visits to a primary care physician during the transition period who was not the patient's usual physician), and no primary care during the transition period (age 17-18 years).

MAIN OUTCOMES AND MEASURES

Mental health-related hospitalizations and emergency department visits in young adulthood (age 19-26 years) adjusted for sex, rurality, neighborhood income, mental illness type, and health service use before transition.

RESULTS

Among 8409 adolescents with severe mental illness (5720 [68.0%] female; mean [SD] age, 14.8 [1.2] years), 5478 (65.1%) had continuous primary care, 2391 (28.4%) had discontinuous primary care, and 540 (6.4%) had no primary care during the transition period. Youths with no primary care during transition were more likely to be male (57.2%), have lower socioeconomic status (31.5%), and have no usual primary care practitioner at baseline (25.6%). Compared with continuous care, patients with discontinuous and no primary care had an increased rate of mental health-related hospitalization in young adulthood (adjusted relative rate, 1.20; 95% CI, 1.10-1.30; and adjusted relative rate, 1.30; 95% CI, 1.08-1.56, respectively).

CONCLUSIONS AND RELEVANCE

In the context of decreasing outpatient specialist mental health visit rates following transition to adult care, ensuring adequate access to primary care during this vulnerable period may improve mental health outcomes in young adulthood.

Excess Burden of Mental Illness and Hospitalization in Young-Onset Type 2 Diabetes: A Population-Based Cohort Study

BACKGROUND

Type 2 diabetes (T2D) increases hospitalization risk. Young-onset T2D (YOD) (defined as onset before age 40 years) is associated with excess morbidity and mortality, but its effect on hospitalizations is unknown.

OBJECTIVE

To determine hospitalization rates among persons with YOD and to examine the effect of age at onset on hospitalization risk.

DESIGN

Prospective cohort study.

SETTING

Hong Kong.

PARTICIPANTS

Adults aged 20 to 75 years in population-based (2002 to 2014; n = 422 908) and registry-based (2000 to 2014; n = 20 886) T2D cohorts.

MEASUREMENTS

All-cause and cause-specific hospitalization rates. Negative binomial regression models estimated effect of age at onset on hospitalization rate and cumulative bed-days from onset to age 75 years for YOD.

RESULTS

Patients with YOD had the highest hospitalization rates by attained age. In the registry cohort, 36.8% of YOD bed-days before age 40 years were due to mental illness. The adjusted rate ratios showed increased hospitalization in YOD versus usual-onset T2D (onset at age ≥40 years) (all-cause, 1.8 [95% CI, 1.7 to 2.0]; renal, 6.7 [CI, 4.2 to 10.6]; diabetes, 3.7 [CI, 3.0 to 4.6]; cardiovascular, 2.1 [CI, 1.8 to 2.5]; infection, 1.7 [CI, 1.4 to 2.1]; P < 0.001 for all). Models estimated that intensified risk factor control in YOD (hemoglobin A1c level <6.2%, systolic blood pressure <120 mm Hg, low-density lipoprotein cholesterol level <2.0 mmol/L [<77.3 mg/dL], triglyceride level <1.3 mmol/L [<115.1 mg/dL], waist circumference of 85 cm [men] or 80 cm [women], and smoking cessation) was associated with a one-third reduction in cumulative bed-days from onset to age 75 years (97 to 65 bed-days).

LIMITATION

Possible residual confounding.

CONCLUSION

Adults with YOD have excess hospitalizations across their lifespan compared with persons with usual-onset T2D, including an unexpectedly large burden of mental illness in young adulthood. Efforts to prevent YOD and intensify cardiometabolic risk factor control while focusing on mental health are urgently needed.

PRIMARY FUNDING SOURCE

Asia Diabetes Foundation.

Factors associated with door-in to door-out delays among ST-segment elevation myocardial infarction (STEMI) patients transferred for primary percutaneous coronary intervention: a population-based cohort study in Ontario, Canada

BACKGROUND

Compared to ST-segment elevation myocardial infarction (STEMI) patients who present at centres with catheterization facilities, those transferred for primary percutaneous coronary intervention (PCI) have substantially longer door-in to door-out (DIDO) times, where DIDO is defined as the time interval from arrival at a non-PCI hospital, to transfer to a PCI hospital. We aimed to identify potentially modifiable factors to improve DIDO times in Ontario, Canada and to assess the impact of DIDO times on 30-day mortality.

METHODS

A population-based, retrospective cohort study of 966 STEMI patients transferred for primary PCI in Ontario in 2012 was conducted. Baseline factors were examined across timely DIDO status. Multivariate logistic regression was used to examine independent predictors of timely DIDO as well as the association between DIDO times and 30-day mortality.

RESULTS

The median DIDO time was 55 min, with 20.1% of patients achieving the recommended DIDO benchmark of ≤30 min. Age (OR> 75 vs 18-55 0.30, 95% CI: 0.16-0.56), symptom-to-first medical contact (FMC) time (OR61-120mins vs < 60mins 0.60, 95% CI: 0.39-0.90; OR>120mins vs < 60mins 0.53, 95% CI:0.35-0.81) and emergency medical services transport with a pre-hospital electrocardiogram (ECG) (OREMS transport + ECG vs self-transport 2.63, 95% CI:1.59-4.35) were the strongest predictors of timely DIDO. Patients with timely ECG were more likely to have recommended DIDO times (33.0% vs 12.3%; P < 0.001). A significantly higher proportion of those who met the DIDO benchmark had timely FMC-to-balloon times (78.7% vs 27.4%; P < 0.001). Compared to patients with DIDO time ≤ 30 min, those with DIDO times > 90 min had significantly higher adjusted 30-day mortality rates (OR 2.82, 95% CI:1.10-7.19).

CONCLUSIONS

While benchmark DIDO times were still rarely achieved in the province, we identified several potentially modifiable factors in the STEMI system that might be targeted to improve DIDO times. Our findings that patients who received a pre-hospital ECG were still being transferred to non-PCI capable centres suggest strategies addressing this gap may improve patient outcomes.

Primary Care Physician Volume and Quality of Diabetes Care: A Population-Based Cohort Study

BACKGROUND

A relationship between higher patient volume and both better quality of care and better outcomes has been shown for many acute care conditions. Whether a volume-quality relationship exists for the outpatient management of chronic diseases is uncertain.

OBJECTIVE

To explore the association between primary care physician volume and quality of diabetes care.

DESIGN

Cohort study.

SETTING

The study was conducted using linked population-based health care administrative data in Ontario, Canada.

PATIENTS

1 018 647 adults with diabetes in 2011 who received care from 9014 primary care physicians. Two measures of volume were ascertained for each physician: overall ambulatory volume (representing time available to devote to chronic disease management during patient encounters) and diabetes-specific volume (representing disease-specific expertise).

MEASUREMENTS

Quality of care was measured over a 2-year period using 6 indicators: disease monitoring (eye examination, hemoglobin A1c testing, and low-density lipoprotein cholesterol testing), prescribing appropriate medications (angiotensin-converting enzyme inhibitors or angiotensin-receptor blockers and statins), and adverse clinical outcomes (emergency department visits for hypoglycemia or hyperglycemia).

RESULTS

Higher overall ambulatory volume was associated with lower rates of appropriate disease monitoring and medication prescription. In contrast, higher diabetes-specific volume was associated with better quality of care across all 6 indicators.

LIMITATION

Only a select set of quality indicators and potential confounders could be ascertained from available data.

CONCLUSION

Primary care physicians with busier ambulatory patient practices delivered lower-quality diabetes care, but those with greater diabetes-specific experience delivered higher-quality care. These findings show that relationships between physician volume and quality can be extended from acute care to outpatient chronic disease care. Health policies or programs to support physicians with a low volume of patients with diabetes may improve care.

PRIMARY FUNDING SOURCE

Canadian Institutes of Health Research.

Disability in long-term care residents explained by prevalent geriatric syndromes, not long-term care home characteristics: a cross-sectional study

Background

Self-care disability is dependence on others to conduct activities of daily living, such as bathing, eating and dressing. Among long-term care residents, self-care disability lowers quality of life and increases health care costs. Understanding the correlates of self-care disability in this population is critical to guide clinical care and ongoing research in Geriatrics. This study examines which resident geriatric syndromes and chronic conditions are associated with residents’ self-care disability and whether these relationships vary across strata of age, sex and cognitive status. It also describes the proportion of variance in residents’ self-care disability that is explained by residents’ geriatric syndromes versus long-term care home characteristics.

Methods

We conducted a cross-sectional study using a health administrative cohort of 77,165 long-term care home residents residing in 614 Ontario long-term care homes. Eligible residents had their self-care disability assessed using the RAI-MDS 2.0 activities of daily living long-form score (range: 0–28) within 90 days of April 1st, 2011. Hierarchical multivariable regression models with random effects for long-term care homes were used to estimate the association between self-care disability and resident geriatric syndromes, chronic conditions and long-term care home characteristics. Differences in findings across strata of sex, age and cognitive status (cognitively intact versus cognitively impaired) were examined.

Results

Geriatric syndromes were much more strongly associated with self-care disability than chronic conditions in multivariable models. The direction and size of some of these effects were different for cognitively impaired versus cognitively intact residents. Residents’ geriatric syndromes explained 50% of the variation in their self-care disability scores, while characteristics of long-term care homes explained an additional 2% of variation.

Conclusion

Differences in long-term care residents’ self-care disability are largely explained by prevalent geriatric syndromes. After adjusting for resident characteristics, there is little variation in self-care disability associated with long-term care home characteristics. This suggests that residents’ geriatric syndromes—not the homes in which they live—may be the appropriate target of interventions to reduce self-care disability, and that such interventions may need to differ for cognitively impaired versus unimpaired residents.

Electronic supplementary material

The online version of this article (doi:10.1186/s12877-017-0444-1) contains supplementary material, which is available to authorized users.

Pediatric Insulin Pump Therapy: Reflecting on the First 10 Years of a Universal Funding Program in Ontario

We evaluated the universal funding program for pediatric insulin pumps in Ontario by examining the dynamics underlying patterns of pump use and adverse events using population-based health administrative data available at the Institute for Clinical Evaluative Sciences (ICES), supplemented by other data. We found that (1) pump use has increased steadily since 2006 with variation across centres and disparity in use by socioeconomic status; (2) pump discontinuation is uncommon; (3) physicians value pump therapy in numerous ways that provide important insights into patterns of uptake; and (4) the safety profile of pump therapy is, in general, very good; however, individuals of lower socioeconomic status are at an increased risk of acute diabetes complications, most frequently diabetic ketoacidosis. This comprehensive mixed-methods evaluation reveals the need to understand and intervene to reduce social disparities in the use and adverse outcomes of technologies used for diabetes management.

Socioeconomic Status, Sex, Age and Access to Medications for COPD in Ontario, Canada

Disparities in COPD health outcomes have been found with older individuals, men and those of lower socioeconomic status doing worse. We sought to determine if this was due to differences in access to COPD medications. We conducted a retrospective cohort study using population health administrative data from Ontario, Canada, a province with universal prescription drug coverage for older adults. All individuals with COPD aged 67 years and older in 2008 who were not taking inhaled long-acting bronchodilators or inhaled corticosteroids were followed for 2 years. Poisson regression was used to determine the effects of age, sex, and socioeconomic status on the likelihood of initiating one of these medications, after adjusting for potential confounders. Over the study period, 54,050 of 185,698 (29.1%) older individuals with COPD not previously taking any inhaled long-acting bronchodilators or corticosteroids were initiated on one or more of these medications. After adjustment, individuals of low socioeconomic status, measured using neighborhood income level quintiles, were slightly more likely to initiate COPD medications than those of high socioeconomic status (relative risk (RR) 1.05; 95% confidence interval (95% CI) 1.02-1.08). While men received COPD medication at a consistent rate across all age groups, the likelihood that a woman received medication decreased with increasing age. With the exception of older women, there was minimal disparity in prescription for COPD medications. Disparity in health outcomes among Ontario COPD patients is not clearly explained by differences in medication access by socioeconomic status, sex or age.

Recurrence of inguinal hernias repaired in a large hernia surgical specialty hospital and general hospitals in Ontario, Canada

BACKGROUND

The effect of hospital specialization on the risk of hernia recurrence after inguinal hernia repair is not well described.

METHODS

We studied Ontario residents who had primary elective inguinal hernia repair at an Ontario hospital between 1993 and 2007 using population-based, administrative health data. We compared patients from a large hernia specialty hospital (Shouldice Hospital) with those from general hospitals to determine the risk of recurrence.

RESULTS

We studied 235 192 patients, 27.7% of whom had surgery at Shouldice hospital. The age-standardized proportion of patients who had a recurrence ranged from 5.21% (95% confidence interval [CI] 4.94%-5.49%) among patients who had surgery at the lowest volume general hospitals to 4.79% (95% CI 4.54%-5.04%) who had surgery at the highest volume general hospitals. In contrast, patients who had surgery at the Shouldice Hospital had an age-standardized recurrence risk of 1.15% (95% CI 1.05%-1.25%). Compared with patients who had surgery at the lowest volume hospitals, hernia recurrence among those treated at the Shouldice Hospital was significantly lower after adjustment for the effects of age, sex, comorbidity and income level (adjusted hazard ratio 0.21, 95% CI 0.19-0.23, p < 0.001).

CONCLUSION

Inguinal hernia repair at Shouldice Hospital was associated with a significantly lower risk of subsequent surgery for recurrence than repair at a general hospital. While specialty hospitals may have better outcomes for treatment of common surgical conditions than general hospitals, these benefits must be weighed against potential negative impacts on clinical care and the financial sustainability of general hospitals.

Impact of diabetes on healthcare costs in a population-based cohort: a cost analysis

AIMS

To estimate the healthcare costs attributable to diabetes in Ontario, Canada using a propensity-matched control design and health administrative data from the perspective of a single-payer healthcare system.

METHODS

Incident diabetes cases among adults in Ontario were identified from the Ontario Diabetes Database between 2004 and 2012 and matched 1:3 to control subjects without diabetes identified in health administrative databases on the basis of sociodemographics and propensity score. Using a comprehensive source of administrative databases, direct per-person costs (Canadian dollars 2012) were calculated. A cost analysis was performed to calculate the attributable costs of diabetes; i.e. the difference of costs between patients with diabetes and control subjects without diabetes.

RESULTS

The study sample included 699 042 incident diabetes cases. The costs attributable to diabetes were greatest in the year after diagnosis [C$3,785 (95% CI 3708, 3862) per person for women and C$3,826 (95% CI 3751, 3901) for men], increasing substantially for older age groups and patients who died during follow-up. After accounting for baseline comorbidities, attributable costs were primarily incurred through inpatient acute hospitalizations, physician visits and prescription medications and assistive devices.

CONCLUSIONS

The excess healthcare costs attributable to diabetes are substantial and pose a significant clinical and public health challenge. This burden is an important consideration for decision-makers, particularly given increasing concern over the sustainability of the healthcare system, aging population structure and increasing prevalence of diabetic risk factors, such as obesity.

Patterns of diagnostic imaging and associated radiation exposure among long-term survivors of young adult cancer: a population-based cohort study

BACKGROUND

Survivors of young adult malignancies are at risk of accumulated exposures to radiation from repetitive diagnostic imaging. We designed a population-based cohort study to describe patterns of diagnostic imaging and cumulative diagnostic radiation exposure among survivors of young adult cancer during a survivorship time period where surveillance imaging is not typically warranted.

METHODS

Young adults aged 20-44 diagnosed with invasive malignancy in Ontario from 1992-1999 who lived at least 5 years from diagnosis were identified using the Ontario Cancer Registry and matched 5 to 1 to randomly selected cancer-free persons. We determined receipt of 5 modalities of diagnostic imaging and associated radiation dose received by survivors and controls from years 5-15 after diagnosis or matched referent date through administrative data. Matched pairs were censored six months prior to evidence of recurrence.

RESULTS

20,911 survivors and 104,524 controls had a median of 13.5 years observation. Survivors received all modalities of diagnostic imaging at significantly higher rates than controls. Survivors received CT at a 3.49-fold higher rate (95% Confidence Interval [CI]:3.37, 3.62) than controls in years 5 to 15 after diagnosis. Survivors received a mean radiation dose of 26 miliSieverts solely from diagnostic imaging in the same time period, a 4.57-fold higher dose than matched controls (95% CI: 4.39, 4.81).

CONCLUSIONS

Long-term survivors of young adult cancer have a markedly higher rate of diagnostic imaging over time than matched controls, imaging associated with substantial radiation exposure, during a time period when surveillance is not routinely recommended.

The association of hospital prevention processes and patient risk factors with the risk of Clostridium difficile infection: a population-based cohort study

BACKGROUND

Clostridium difficile is the most common cause of healthcare-acquired infection; the real-world impacts of some proposed C. difficile prevention processes are unknown.

METHODS

We conducted a population-based retrospective cohort study of all patients admitted to acute care hospitals between April 2011 and March 2012 in Ontario, Canada. Hospital prevention practices were determined by survey of infection control programmes; responses were linked to patient-level risk factors and C. difficile outcomes in Ontario administrative databases. Multivariable generalised estimating equation (GEE) regression models were used to assess the impact of selected understudied hospital prevention processes on the patient-level risk of C. difficile infection, accounting for patient risk factors, baseline C. difficile rates and structural hospital characteristics.

RESULTS

C. difficile infections complicated 2341 of 653 896 admissions (3.6 per 1000 admissions). Implementation of the selected C. difficile prevention practices was variable across the 159 hospitals with isolation of all patients at onset of diarrhoea reported by 43 (27%), auditing of antibiotic stewardship compliance by 26 (16%), auditing of cleaning practices by 115 (72%), on-site diagnostic testing by 74 (47%), vancomycin as first-line treatment by 24 (15%) and reporting rates to senior leadership by 52 (33%). None of these processes were associated with a significantly reduced risk of C. difficile after adjustment for baseline C. difficile rates, structural hospital characteristics and patient-level factors. Patient-level factors were strongly associated with C. difficile risk, including age, comorbidities, non-elective and medical admissions.

CONCLUSIONS

In the largest study to date, selected hospital prevention strategies were not associated with a statistically significant reduction in patients' risk of C. difficile infection. These prevention strategies have either limited effectiveness or were ineffectively implemented during the study period.

The Cardiovascular Health in Ambulatory Care Research Team (CANHEART): using big data to measure and improve cardiovascular health and healthcare services

BACKGROUND

The CArdiovascular HEalth in Ambulatory care Research Team (CANHEART) is conducting a unique, population-based observational research initiative aimed at measuring and improving cardiovascular health and the quality of ambulatory cardiovascular care provided in Ontario, Canada. A particular focus will be on identifying opportunities to improve the primary and secondary prevention of cardiovascular events in Ontario's diverse multiethnic population.

METHODS AND RESULTS

A population-based cohort comprising 9.8 million Ontario adults ≥20 years in 2008 was assembled by linking multiple electronic survey, health administrative, clinical, laboratory, drug, and electronic medical record databases using encoded personal identifiers. The cohort includes ≈9.4 million primary prevention patients and ≈400,000 secondary prevention patients. Follow-up on clinical events is achieved through record linkage to comprehensive hospitalization, emergency department, and vital statistics administrative databases. Profiles of cardiovascular health and preventive care will be developed at the health region level, and the cohort will be used to study the causes of regional variation in the incidence of major cardiovascular events and other important research questions.

CONCLUSIONS

Linkage of multiple databases will enable the CANHEART study cohort to serve as a powerful big data resource for scientific research aimed at improving cardiovascular health and health services delivery. Study findings will be shared with clinicians, policy makers, and the public to facilitate population health interventions and quality improvement initiatives.

Combination long-acting β-agonists and inhaled corticosteroids compared with long-acting β-agonists alone in older adults with chronic obstructive pulmonary disease

IMPORTANCE

Chronic obstructive pulmonary disease (COPD), a manageable respiratory condition, is the third leading cause of death worldwide. Knowing which prescription medications are the most effective in improving health outcomes for people with COPD is essential to maximizing health outcomes.

OBJECTIVE

To estimate the long-term benefits of combination long-acting β-agonists (LABAs) and inhaled corticosteroids compared with LABAs alone in a real-world setting.

DESIGN, SETTING, AND PATIENTS

Population-based, longitudinal cohort study conducted in Ontario, Canada, from 2003 to 2011. All individuals aged 66 years or older who met a validated case definition of COPD on the basis of health administrative data were included. After propensity score matching, there were 8712 new users of LABA-inhaled corticosteroid combination therapy and 3160 new users of LABAs alone who were followed up for median times of 2.7 years and 2.5 years, respectively.

EXPOSURES

Newly prescribed combination LABAs and inhaled corticosteroids or LABAs alone.

MAIN OUTCOMES AND MEASURES

Composite outcome of death and COPD hospitalization.

RESULTS

The main outcome was observed among 5594 new users of LABAs and inhaled corticosteroids (3174 deaths [36.4%]; 2420 COPD hospitalizations [27.8%]) and 2129 new users of LABAs alone (1179 deaths [37.3%]; 950 COPD hospitalizations [30.1%]). New use of LABAs and inhaled corticosteroids was associated with a modestly reduced risk of death or COPD hospitalization compared with new use of LABAs alone (difference in composite outcome at 5 years, -3.7%; 95% CI, -5.7% to -1.7%; hazard ratio [HR], 0.92; 95% CI, 0.88-0.96). The greatest difference was among COPD patients with a codiagnosis of asthma (difference in composite at 5 years, -6.5%; 95% CI, -10.3% to -2.7%; HR, 0.84; 95% CI, 0.77-0.91) and those who were not receiving inhaled long-acting anticholinergic medication (difference in composite at 5 years, -8.4%; 95% CI, -11.9% to -4.9%; HR, 0.79; 95% CI, 0.73-0.86).

CONCLUSIONS AND RELEVANCE

Among older adults with COPD, particularly those with asthma and those not receiving a long-acting anticholinergic medication, newly prescribed LABA and inhaled corticosteroid combination therapy, compared with newly prescribed LABAs alone, was associated with a significantly lower risk of the composite outcome of death or COPD hospitalization.

Universal coverage without universal access: a study of psychiatrist supply and practice patterns in Ontario

BACKGROUND

We studied the relationships among psychiatrist supply, practice patterns, and access to psychiatrists in Ontario Local Health Integration Networks (LHINs) with differing levels of psychiatrist supply.

METHODS

We analyzed practice patterns of full-time psychiatrists (n = 1379) and postdischarge care to patients who had been admitted to hospital for psychiatric care, according to LHIN psychiatrist supply in 2009. We measured the characteristics of psychiatrists' patient panels, including sociodemographic characteristics, outpatient panel size, number of new patients, inpatient and outpatient visits per psychiatrist, and percentages of psychiatrists seeing fewer than 40 and fewer than 100 unique patients. Among patients admitted to hospital with schizophrenia, bipolar disorder, or major depression (n = 21,123), we measured rates of psychiatrist visits, readmissions, and visits to the emergency department within 30 and 180 days after discharge.

RESULTS

Psychiatrist supply varied from 7.2 per 100 000 residents in LHINs with below-average supply to 62.7 per 100 000 in the Toronto Central LHIN. Population-based outpatient and inpatient visit rates and psychiatric admission rates increased with LHIN psychiatrist supply. However, as the supply of psychiatrists increased, outpatient panel size for full-time psychiatrists decreased, with Toronto psychiatrists having 58% smaller outpatient panels and seeing 57% fewer new outpatients relative to LHINs with the lowest psychiatrist supply. Similar patterns were found for inpatient practice. Moreover, as supply increased, annual outpatient visit frequency increased: the average visit frequency was 7 visits per outpatient for Toronto psychiatrists and 3.9 visits per outpatient in low-supply LHINs. One-quarter of Toronto psychiatrists and 2% of psychiatrists in the lowest-supply LHINs saw their outpatients more than 16 times per year. Of full-time psychiatrists in Toronto, 10% saw fewer than 40 unique patients and 40% saw fewer than 100 unique patients annually; the corresponding proportions were 4% and 10%, respectively, in the lowest-supply LHINs. Overall, follow-up visits after psychiatric discharge were low, with slightly higher rates in LHINs with a high psychiatrist supply.

INTERPRETATION

Full-time psychiatrists who practised in Ontario LHINs with high psychiatrist supply saw fewer patients, but they saw those patients more frequently than was the case for psychiatrists in low-supply LHINs. Increasing the supply of psychiatrists while funding unlimited frequency and duration of psychotherapy care may not improve access for patients who need psychiatric services.

Defining hospitalist physicians using clinical practice data: a systems-level pilot study of Ontario physicians

BACKGROUND

Hospitalists have become dominant providers of inpatient care in many North American hospitals. Despite the global growth of hospital medicine, no objective method has been proposed for defining the hospitalist discipline and delineating among inpatient practices on the basis of physicians' clinical volumes. We propose a functional method of identifying hospital-based physicians using aggregated measures of inpatient volume and apply this method to a retrospective, population-based cohort to describe the growth of the hospitalist movement, as well as the prevalence and practice characteristics of hospital-based generalists in one Canadian province.

METHODS

We used human resource databases and financial insurance claims to identify all active fee-for-service physicians working in Ontario, Canada, between fiscal year 1996/1997 and fiscal year 2010/2011. We constructed 3 measures of inpatient volume from the insurance claims to reflect the time that physicians spent delivering inpatient care in each fiscal year. We then examined how inpatient volumes have changed for Ontario physicians over time and described the prevalence of full-time and part-time hospital-based generalists working in acute care hospitals in fiscal year 2010/2011.

RESULTS

Our analyses showed a significant increase since fiscal year 2000/2001 in the number of high-volume hospital-based family physicians practising in Ontario (p < 0.001) and associated decreases in the numbers of high-volume internists and specialists (p = 0.03), where high volume was defined as ≥ 2000 inpatient services/ year. We estimated that 620 full-time and 520 part-time hospital-based physicians were working in Ontario hospitals in 2010/2011, accounting for 4.5% of the active physician workforce (n = 25 434). Hospital-based generalists, consisting of 207 family physicians and 130 general internists, were prevalent in all geographic regions and hospital types and collectively delivered 10% of all inpatient evaluation and care coordination for Ontario residents who had been admitted to hospital.

INTERPRETATION

These analyses confirmed a substantial increase in the prevalence of general hospitalists in Ontario from 1996 to 2011. Systems-level analyses of clinical practice data represent a practical and valid method for defining and identifying hospital-based physicians.

Cardiovascular safety of inhaled long-acting bronchodilators in individuals with chronic obstructive pulmonary disease

IMPORTANCE

Chronic obstructive pulmonary disease (COPD) is a common and deadly disease. Long-acting inhaled β-agonists and anticholinergics, first-line medications for COPD, have been associated with increased risk of cardiovascular outcomes. When choosing between the medications, patients and physicians would benefit from knowing which has the least risk.

OBJECTIVE

To assess the association of these classes of medications with the risk of hospitalizations and emergency department visits for cardiovascular events.

DESIGN

We conducted a nested case-control analysis of a retrospective cohort study. We compared the risk of events between patients newly prescribed inhaled long-acting β-agonists and anticholinergics, after matching and adjusting for prognostic factors.

SETTING

Health care databases from Ontario, the largest province of Canada, with a multicultural population of approximately 13 million.

PARTICIPANTS

All individuals 66 years or older meeting a validated case definition of COPD, based on health administrative data, and treated for COPD from September 1, 2003, through March 31, 2009.

EXPOSURE

New use of an inhaled long-acting β-agonist or long-acting anticholinergic.

MAIN OUTCOME AND MEASURES

An emergency department visit or a hospitalization for a cardiovascular event.

RESULTS

Of 191 005 eligible patients, 53 532 (28.0%) had a hospitalization or an emergency department visit for a cardiovascular event. Newly prescribed long-acting inhaled β-agonists and anticholinergics were associated with a higher risk of an event compared with nonuse of those medications (respective adjusted odds ratios, 1.31 [95% CI, 1.12-1.52; P < .001] and 1.14 [1.01-1.28; P = .03]). We found no significant difference in events between the 2 medications (adjusted odds ratio of long-acting inhaled β-agonists compared with anticholinergics, 1.15 [95% CI, 0.95-1.38; P = .16]).

CONCLUSIONS AND RELEVANCE

Among older individuals with COPD, new use of long-acting β-agonists and anticholinergics is associated with similar increased risks of cardiovascular events. Close monitoring of COPD patients requiring long-acting bronchodilators is needed regardless of drug class.

Effectiveness of community-wide and individual high-risk strategies to prevent diabetes: a modelling study

BACKGROUND

Diabetes has been described as one of the most important threats to the health of developed countries. Effective population strategies to prevent diabetes have not been determined but two broad strategies have been proposed: "high-risk" and "community-wide" strategies.

METHODS

We modelled the potential effectiveness of two strategies to prevent 10% of new cases of diabetes in Ontario, Canada over a 5-year period. The 5-year risk of developing physician-diagnosed diabetes was estimated for respondents to the Canadian Community Health Survey 2003 (CCHS 2.1, N = 26 232) using a validated and calibrated diabetes risk tool (Diabetes Population Risk Tool [DPoRT]). We estimated how many cases of diabetes could be prevented using two different strategies: a) a community-wide strategy that would uniformly reduce body mass index (BMI) in the entire population; and b) a high baseline risk strategy using either pharmacotherapy or lifestyle counselling to treat people who have an increased risk of developing diabetes.

RESULTS

In 2003, the 5-year risk of developing diabetes was 4.7% (383 600 new diagnosed cases of diabetes in 8 189 000 Ontarians aged 20+) and risk was moderately diffused (0.5%, 3.1% and 17.9% risk in the 1(st), 5(th) (median) and 10(th) deciles of risk). A 10% reduction in new cases of diabetes would have been achieved under any of the following scenarios: if BMI was 3.5% lower in the entire population; if lifestyle counselling covered 32.2% of high-risk people (371 900 of 1 155 000 people with 5 year diabetes risk greater than 10%); or, if pharmacotherapy covered 65.2% of high-risk people.

CONCLUSIONS

Prevention using pharmacotherapy alone requires unrealistically high coverage levels to achieve modest population reduction in new diabetes cases. On the other hand, in recent years few jurisdictions have been able to achieve a reduction in BMI at the population level, let alone a reduction of BMI of 3.5%.

Estimating influenza vaccine effectiveness in community-dwelling elderly patients using the instrumental variable analysis method

BACKGROUND

Estimates of influenza vaccine effectiveness in elderly individuals are largely from observational studies, which are susceptible to bias. Instrumental variable (IV) methods control for overt and hidden biases in observational studies.

METHODS

We used linked health administrative databases in Ontario to examine the association between influenza vaccination and all-cause mortality among community-dwelling individuals older than 65 years for 9 influenza seasons (2000-2001 to 2008-2009). We examined the composite of hospitalization for pneumonia and influenza and all-cause mortality as a secondary outcome. We used logistic regression modeling and IV analysis to remove the effect of selection bias.

RESULTS

We included 12 621 806 person-influenza seasons of observation. Logistic regression produced adjusted odds ratios of 0.67 (95% CI, 0.62-0.72) for all-cause mortality during influenza seasons and 0.85 (0.83-0.86) during post-influenza seasons when influenza is not circulating, suggesting the presence of bias. In contrast, IV analysis yielded adjusted odds ratios of 0.94 (95% CI, 0.84-1.03) during influenza seasons and 1.13 (1.07-1.19) during post-influenza seasons. For the composite of hospitalization for pneumonia and influenza and death, logistic regression produced adjusted odds ratios of 0.74 (95% CI, 0.70-0.78) during influenza seasons and 0.88 (0.87-0.90) during post-influenza seasons, whereas IV analysis produced adjusted odds ratios of 0.86 (95% CI, 0.79-0.92) and 1.02 (0.97-1.06), respectively.

CONCLUSIONS

Influenza vaccination is associated with reductions in the composite of hospitalizations for pneumonia and influenza and all-cause mortality during the influenza season but not mortality alone. Compared with standard modeling, IV analysis appears to produce less-biased estimates of vaccine effectiveness.

Prediction of emergent heart failure death by semi-quantitative triage risk stratification

OBJECTIVES

Generic triage risk assessments are widely used in the emergency department (ED), but have not been validated for prediction of short-term risk among patients with acute heart failure (HF). Our objective was to evaluate the Canadian Triage Acuity Scale (CTAS) for prediction of early death among HF patients.

METHODS

We included patients presenting with HF to an ED in Ontario from Apr 2003 to Mar 2007. We used the National Ambulatory Care Reporting System and vital statistics databases to examine care and outcomes.

RESULTS

Among 68,380 patients (76±12 years, 49.4% men), early mortality was stratified with death rates of 9.9%, 1.9%, 0.9%, and 0.5% at 1-day, and 17.2%, 5.9%, 3.8%, and 2.5% at 7-days, for CTAS 1, 2, 3, and 4-5, respectively. Compared to lower acuity (CTAS 4-5) patients, adjusted odds ratios (aOR) for 1-day death were 1.32 (95%CI; 0.93-1.88; p = 0.12) for CTAS 3, 2.41 (95%CI; 1.71-3.40; p<0.001) for CTAS 2, and highest for CTAS 1: 9.06 (95%CI; 6.28-13.06; p<0.001). Predictors of triage-critical (CTAS 1) status included oxygen saturation <90% (aOR 5.92, 95%CI; 3.09-11.81; p<0.001), respiratory rate >24 breaths/minute (aOR 1.96, 95%CI; 1.05-3.67; p = 0.034), and arrival by paramedic (aOR 3.52, 95%CI; 1.70-8.02; p = 0.001). While age/sex-adjusted CTAS score provided good discrimination for ED (c-statistic = 0.817) and 1-day (c-statistic = 0.724) death, mortality prediction was improved further after accounting for cardiac and non-cardiac co-morbidities (c-statistics 0.882 and 0.810, respectively; both p<0.001).

CONCLUSIONS

A semi-quantitative triage acuity scale assigned at ED presentation and based largely on respiratory factors predicted emergent death among HF patients.

A population-based risk algorithm for the development of diabetes: development and validation of the Diabetes Population Risk Tool (DPoRT)

BACKGROUND

National estimates of the upcoming diabetes epidemic are needed to understand the distribution of diabetes risk in the population and to inform health policy.

OBJECTIVE

To create and validate a population-based risk prediction tool for incident diabetes using commonly collected national survey data.

METHODS

With the use of a cohort design that links baseline risk factors to a validated population-based diabetes registry, a model (Diabetes Population Risk Tool (DPoRT)) was developed to predict 9-year risk for diabetes. The probability of developing diabetes was modelled using sex-specific Weibull survival functions for people > 20 years of age without diabetes (N=19,861). The model was validated in two external cohorts in Ontario (N=26,465) and Manitoba (N=9899). Predictive accuracy and model performance were assessed by comparing observed diabetes rates with predicted estimates. Discrimination and calibration were measured using a C statistic and Hosmer-Lemeshow χ² statistic (χ²(H-L)).

RESULTS

Predictive factors included were body mass index, age, ethnicity, hypertension, immigrant status, smoking, education status and heart disease. DPoRT showed good discrimination (C=0.77-0.80) and calibration (χ²(H-L) < 20) in both external validation cohorts.

CONCLUSIONS

This algorithm can be used to estimate diabetes incidence and quantify the effect of interventions using routinely collected survey data.

Estimating gestational age at birth: a population-based derivation-validation study

Introduction

Information on newborn gestational age (GA) is essential in research on perinatal and infant health, but it is not always available from administrative databases. We developed and validated a GA prediction model for singleton births for use in epidemiological studies.

Methods

Derivation of estimated GA was calculated based on 130 328 newborn infants born in Ontario hospitals between 2007 and 2009, using linear regression analysis, with several infant and maternal characteristics as the predictor (independent) variables. The model was validated in a separate sample of 130 329 newborns.

Results

The discriminative ability of the linear model based on infant birth weight and sex was reasonably approximate for infants born before the 37th week of gestation (r2 = 0.67; 95% CI: 0.65–0.68), but not for term births (37–42 weeks; r2 = 0.12; 95% CI: 0.12–0.13). Adding other infant and maternal characteristics did not improve the model discrimination.

Conclusion

Newborn gestational age before 37 weeks can be reasonably approximated using locally available data on birth weight and sex.

Estimating gestational age at birth: a population-based derivation-validation study

INTRODUCTION

Information on newborn gestational age (GA) is essential in research on perinatal and infant health, but it is not always available from administrative databases. We developed and validated a GA prediction model for singleton births for use in epidemiological studies.

METHODS

Derivation of estimated GA was calculated based on 130 328 newborn infants born in Ontario hospitals between 2007 and 2009, using linear regression analysis, with several infant and maternal characteristics as the predictor (independent) variables. The model was validated in a separate sample of 130 329 newborns.

RESULTS

The discriminative ability of the linear model based on infant birth weight and sex was reasonably approximate for infants born before the 37th week of gestation (r2 = 0.67; 95% CI: 0.65-0.68), but not for term births (37-42 weeks; r2 = 0.12; 95% CI: 0.12-0.13). Adding other infant and maternal characteristics did not improve the model discrimination.

CONCLUSION

Newborn gestational age before 37 weeks can be reasonably approximated using locally available data on birth weight and sex.

Improved outcomes with early collaborative care of ambulatory heart failure patients discharged from the emergency department

BACKGROUND

The type of outpatient physician care after an emergency department visit for heart failure may affect patients' outcomes.

METHODS AND RESULTS

Using the National Ambulatory Care Reporting System, we examined the care and outcomes of heart failure patients who visited and were discharged from the emergency department in Ontario, Canada (April 2004 to March 2007). Early collaborative care by a cardiologist and primary care (PC) physician within 30 days after discharge was compared with PC alone. Care for 10 599 patients (age, 74.9±11.9 years; 50.2% male) was provided by PC alone (n=6596), cardiologist alone (n=535), or concurrently by both cardiologist and PC (n=1478); 1990 did not visit a physician. Collaborative care patients were more likely to undergo assessment of left ventricular function (57.4% versus 28.7%), noninvasive stress testing (20.1% versus 7.8%), and cardiac catheterization (11.6% versus 2.7%) compared with PC. Drug prescriptions (patients ≥65 years of age) demonstrated higher use of angiotensin-converting enzyme inhibitors (58.8% versus 54.6%), angiotensin receptor blockers (22.7% versus 18.1%), β-adrenoceptor antagonists (63.4% versus 48.0%), loop diuretics (84.2% versus 79.6%), metolazone (4.8% versus 3.4%), and spironolactone (19.8% versus 12.7%) within 100 days after emergency department discharge for collaborative care compared with PC. In a propensity-matched model, mortality was lower with PC compared with no physician visit (hazard ratio, 0.75; 95% confidence interval, 0.64 to 0.87; P<0.001). Collaborative care reduced mortality compared with PC (hazard ratio, 0.79; 95% confidence interval, 0.63 to 1.00; P=0.045). Sole cardiology care conferred a trend to increased mortality (hazard ratio, 1.41 versus collaborative care; 95% confidence interval, 0.98 to 2.03; P=0.067).

CONCLUSIONS

Early collaborative heart failure care was associated with increased use of drug therapies and cardiovascular diagnostic tests and better outcomes compared with PC alone.