Multicentre implementation of a quality improvement initiative to reduce delirium in adult intensive care units: An interrupted time series analysis

PURPOSE

The ABCDEF bundle may improve delirium outcomes among intensive care unit (ICU) patients, however population-based studies are lacking. In this study we evaluated effects of a quality improvement initiative based on the ABCDEF bundle in adult ICUs in Alberta, Canada.

MATERIAL AND METHODS

We conducted a pre-post, registry-based clinical trial, analysed using interrupted time series methodology. Outcomes were examined via segmented linear regression using mixed effects models. The main data source was a population-based electronic health record.

RESULTS

44,405 consecutive admissions (38,400 unique patients) admitted to 15 general medical/surgical and/or neurologic adult ICUs between 2014 and 2019 were included. The proportion of delirium days per ICU increased from 30.24% to 35.31% during the pre-intervention period. After intervention implementation it decreased significantly (bimonthly decrease of 0.34%, 95%CI 0.18-0.50%, p < 0.01) from 33.48% (95%CI 29.64-37.31%) in 2017 to 28.74% (95%CI 25.22-32.26%) in 2019. The proportion of sedation days using midazolam demonstrated an immediate decrease of 7.58% (95%CI 4.00-11.16%). There were no significant changes in duration of invasive ventilation, proportion of partial coma days, ICU mortality, or potential adverse events.

CONCLUSIONS

An ABCDEF delirium initiative was implemented on a population-basis within adult ICUs and was successful at reducing the prevalence of delirium.

Effect of Clinical Decision Support With Audit and Feedback on Prevention of Acute Kidney Injury in Patients Undergoing Coronary Angiography: A Randomized Clinical Trial

IMPORTANCE

Contrast-associated acute kidney injury (AKI) is a common complication of coronary angiography and percutaneous coronary intervention (PCI) that has been associated with high costs and adverse long-term outcomes.

OBJECTIVE

To determine whether a multifaceted intervention is effective for the prevention of AKI after coronary angiography or PCI.

DESIGN, SETTING, AND PARTICIPANTS

A stepped-wedge, cluster randomized clinical trial was conducted in Alberta, Canada, that included all invasive cardiologists at 3 cardiac catheterization laboratories who were randomized to various start dates for the intervention between January 2018 and September 2019. Eligible patients were aged 18 years or older who underwent nonemergency coronary angiography, PCI, or both; who were not undergoing dialysis; and who had a predicted AKI risk of greater than 5%. Thirty-four physicians performed 7820 procedures among 7106 patients who met the inclusion criteria. Participant follow-up ended in November 2020.

INTERVENTIONS

During the intervention period, cardiologists received educational outreach, computerized clinical decision support on contrast volume and hemodynamic-guided intravenous fluid targets, and audit and feedback. During the control (preintervention) period, cardiologists provided usual care and did not receive the intervention.

MAIN OUTCOMES AND MEASURES

The primary outcome was AKI. There were 12 secondary outcomes, including contrast volume, intravenous fluid administration, and major adverse cardiovascular and kidney events. The analyses were conducted using time-adjusted models.

RESULTS

Of the 34 participating cardiologists who were divided into 8 clusters by practice group and center, the intervention group included 31 who performed 4327 procedures among 4032 patients (mean age, 70.3 [SD, 10.7] years; 1384 were women [32.0%]) and the control group included 34 who performed 3493 procedures among 3251 patients (mean age, 70.2 [SD, 10.8] years; 1151 were women [33.0%]). The incidence of AKI was 7.2% (310 events after 4327 procedures) during the intervention period and 8.6% (299 events after 3493 procedures) during the control period (between-group difference, -2.3% [95% CI, -0.6% to -4.1%]; odds ratio [OR], 0.72 [95% CI, 0.56 to 0.93]; P = .01). Of 12 prespecified secondary outcomes, 8 showed no significant difference. The proportion of procedures in which excessive contrast volumes were used was reduced to 38.1% during the intervention period from 51.7% during the control period (between-group difference, -12.0% [95% CI, -14.4% to -9.4%]; OR, 0.77 [95% CI, 0.65 to 0.90]; P = .002). The proportion of procedures in eligible patients in whom insufficient intravenous fluid was given was reduced to 60.8% during the intervention period from 75.1% during the control period (between-group difference, -15.8% [95% CI, -19.7% to -12.0%]; OR, 0.68 [95% CI, 0.53 to 0.87]; P = .002). There were no significant between-group differences in major adverse cardiovascular events or major adverse kidney events.

CONCLUSIONS AND RELEVANCE

Among cardiologists randomized to an intervention including clinical decision support with audit and feedback, patients undergoing coronary procedures during the intervention period were less likely to develop AKI compared with those treated during the control period, with a time-adjusted absolute risk reduction of 2.3%. Whether this intervention would show efficacy outside this study setting requires further investigation.

TRIAL REGISTRATION

ClinicalTrials.gov Identifier: NCT03453996.

Variation in use of damage control laparotomy for trauma by trauma centers in the United States, Canada, and Australasia

Background

It is unknown how frequently damage control (DC) laparotomy is used across trauma centers in different countries. We conducted a cross-sectional survey of trauma centers in the United States, Canada, and Australasia to study variations in use of the procedure and predictors of more frequent use of DC laparotomy.

Methods

A self-administered, electronic, cross-sectional survey of trauma centers in the United States, Canada, and Australasia was conducted. The survey collected information about trauma center and program characteristics. It also asked how often the trauma program director estimated DC laparotomy was performed on injured patients at that center on average over the last year. Multivariable logistic regression was used to identify predictors of a higher reported frequency of use of DC laparotomy.

Results

Of the 366 potentially eligible trauma centers sent the survey, 199 (51.8%) trauma program directors or leaders responded [United States = 156 (78.4%), Canada = 26 (13.1%), and Australasia = 17 (8.5%)]. The reported frequency of use of DC laparotomy was highly variable across trauma centers. DC laparotomy was used more frequently in level-1 than level-2 or -3 trauma centers. Further, high-volume level-1 centers used DC laparotomy significantly more often than lower volume level-1 centers (p = 0.02). Nearly half (48.4%) of high-volume volume level-1 trauma centers reported using the procedure at least once weekly. Significant adjusted predictors of more frequent use of DC laparotomy included country of origin [odds ratio (OR) for the United States vs. Canada = 7.49; 95% confidence interval (CI) 1.39–40.27], level-1 verification status (OR = 6.02; 95% CI 2.01–18.06), and the assessment of a higher number of severely injured (Injury Severity Scale score > 15) patients (OR per-100 patients = 1.62; 95% CI 1.20–2.18) and patients with penetrating injuries (OR per-5% increase = 1.27; 95% CI 1.01–1.58) in the last year.

Conclusions

The reported frequency of use of DC laparotomy was highly variable across trauma centers. Those centers that most need to evaluate the benefit-to-risk ratio of using DC laparotomy in different scenarios may include high-volume, level-1 trauma centers, particularly those that often manage penetrating injuries.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13017-021-00396-7.

Evidence for use of damage control surgery and damage control interventions in civilian trauma patients: a systematic review

BACKGROUND

Although damage control (DC) surgery is widely assumed to reduce mortality in critically injured patients, survivors often suffer substantial morbidity, suggesting that it should only be used when indicated. The purpose of this systematic review was to determine which indications for DC have evidence that they are reliable and/or valid (and therefore in which clinical situations evidence supports use of DC or that DC improves outcomes).

METHODS

We searched 11 databases (1950-April 1, 2019) for studies that enrolled exclusively civilian trauma patients and reported data on the reliability (consistency of surgical decisions in a given clinical scenario) or content (surgeons would perform DC in that clinical scenario or the indication predicted use of DC in practice), construct (were associated with poor outcomes), or criterion (were associated with improved outcomes when DC was conducted instead of definitive surgery) validity for suggested indications for DC surgery or DC interventions.

RESULTS

Among 34,979 citations identified, we included 36 cohort studies and three cross-sectional surveys in the systematic review. Of the 59 unique indications for DC identified, 10 had evidence of content validity [e.g., a major abdominal vascular injury or a packed red blood cell (PRBC) volume exceeding the critical administration threshold], nine had evidence of construct validity (e.g., unstable patients with combined abdominal vascular and pancreas gunshot injuries or an iliac vessel injury and intraoperative acidosis), and six had evidence of criterion validity (e.g., penetrating trauma patients requiring > 10 U PRBCs with an abdominal vascular and multiple abdominal visceral injuries or intraoperative hypothermia, acidosis, or coagulopathy). No studies evaluated the reliability of indications.

CONCLUSIONS

Few indications for DC surgery or DC interventions have evidence supporting that they are reliable and/or valid. DC should be used with respect for the uncertainty regarding its effectiveness, and only in circumstances where definitive surgery cannot be entertained.

Pregnancy complications and risk of preterm birth according to maternal age: A population-based study of delivery hospitalizations in Alberta

INTRODUCTION

Pregnancy-related medical complications are associated with a 2- to 5-fold increased risk of preterm birth (PTB), but the nature of this etiologic relation in context with maternal factors remains poorly understood. Previous studies have generally treated maternal age as a confounder but overlooked its potential as an effect modifier, whereby the magnitude of the effect of complications on PTB could differ significantly across age groups. We investigated whether advanced maternal age (≥35 years) modified the association between pregnancy complications and PTB, and compared population-attributable fractions of PTB from complications in women older vs younger than 35 years.

MATERIAL AND METHODS

We analyzed population-based, cross-sectional data from the Alberta Discharge Abstract Database for women aged 18-50 years with singleton live births in hospital between 2014 and 2017 (n = 152 246). Complications were preeclampsia, gestational diabetes, and placental disorders identified using diagnostic codes. Outcomes were spontaneous (sPTB) or iatrogenic (iPTB) PTB before 37 weeks of gestation. We estimated risk ratios and risk differences using modified Poisson and log binomial regression, respectively, adjusting for confounders (pregnancy history, comorbidities). Population-attributable fractions estimates were calculated from risk ratios. Age modification was tested using interaction terms and Z-tests.

RESULTS

Prevalence of advanced maternal age was 19.2%. Pregnancy complications and s/iPTB were more common among women aged ≥35 years. Age modified the risk of PTB from preeclampsia only, with risk differences of 9.9% (95% CI 7.2%-12.6%) in older women vs 6.1% (95% CI 4.8%-7.4%) in younger women (P-interaction = 0.012) for sPTB, and 29.5% (95% CI 26.0%-33.1%) vs 20.8% (95% CI 18.9%-22.6%, P-interaction <0.001) for iPTB. Population-attributable fractions of s/iPTB types for all complications were consistently 2%-5% larger in women aged ≥35 years, and significantly larger for preeclampsia (sPTB: 5.1% vs 2.7%, P = 0.002; iPTB: 18.8% vs 14.0%, P < 0.001) and placental disorders (sPTB: 12.5% vs 8.7%, P < 0.001; iPTB: 13.2% vs 8.9%, P < 0.001).

CONCLUSIONS

Of the pregnancy complications studied, advanced maternal age only modified the association between PTB and preeclampsia, such that older women with preeclampsia have a higher risk for s/iPTB than younger counterparts. Pregnancy complications contribute to a sizable proportion of PTBs in Alberta, especially among women aged ≥35 years. Findings may inform clinical risk assessment and population-level policy targeting PTB.

Existing comorbidities in people with osteoarthritis: a retrospective analysis of a population-based cohort in Alberta, Canada

OBJECTIVES

The purpose of this study is to estimate the prevalence of comorbidities among people with osteoarthritis (OA) using administrative health data.

DESIGN

Retrospective cohort analysis.

SETTING

All residents in the province of Alberta, Canada registered with the Alberta Health Care Insurance Plan population registry.

PARTICIPANTS

497 362 people with OA as defined by 'having at least one OA-related hospitalization, or at least two OA-related physician visits or two ambulatory care visits within two years'.

PRIMARY OUTCOME MEASURES

We selected eight comorbidities based on literature review, clinical consultation and the availability of validated case definitions to estimate their frequencies at the time of diagnosis of OA. Sex-stratified age-standardised prevalence rates per 1000 population of eight clinically relevant comorbidities were calculated using direct standardisation with 95% CIs. We applied χ² tests of independence with a Bonferroni correction to compare the percentage of comorbid conditions in each age group.

RESULTS

54.6% (n=2 71 794) of people meeting the OA case definition had at least one of the eight selected comorbidities. Females had a significantly higher rate of comorbidities compared with males (standardised rates ratio=1.26, 95% CI 1.25 to 1.28). Depression, chronic obstructive pulmonary disease (COPD) and hypertension were the most prevalent in both females and males after age-standardisation, with 40% of all cases having any combination of these comorbidities. We observed a significant difference in the percentage of comorbidities among age groups, illustrated by the youngest age group (<45 years) having the highest percentage of cases with depression (24.6%), compared with a frequency of 16.1% in those >65 years.

CONCLUSIONS

Our findings highlight the high frequency of comorbidity in people with OA, with depression having the highest age-standardised prevalence rate. Comorbidities differentially affect females, and vary by age. These factors should inform healthcare programme and delivery.

Effect of Hearing Ability and Mild Behavioural Impairment on MoCA and Memory Index Scores

BACKGROUND

The life-course model of modifiable risk factors for dementia now recognizes managing hearing loss and addressing social isolation.

OBJECTIVE

To investigate the contribution and inter-relationship of hearing ability and behaviour change on cognitive ability.

METHODS

We present the preliminary findings from a prospective longitudinal study of 35 non-demented participants ages 60-93, recruited from community rehabilitation and acute-care programs of Geriatric Medicine, who underwent baseline hearing, behavioural, and cognitive testing.

RESULTS

After controlling for age and hearing impairment, the left ear Dichotic Digit Test (DDT) score accounted uniquely for 20% of the variance in MoCA Memory Index (p = .016 with β = .598). Mild Behavioural Impairment (MBI) was highly prevalent, with 80% of older adults reporting at least one MBI symptom. People with hearing impairment had greater global MBI burden than people with normal hearing, especially in the domains of apathy and impulse dyscontrol; however, greater severity of hearing impairment was not associated with a higher number of neuropsychiatric symptoms (NPS).

CONCLUSIONS

Low left DDT contributed to lower memory index and greater MBI burden is associated with hearing impairment. Our findings demonstrate the value of early non-invasive hearing and behavioural assessments as part of dementia risk assessment in older adults.

Challenges and potential solutions to the evaluation, monitoring, and regulation of surgical innovations

Background

As it may be argued that many surgical interventions provide obvious patient benefits, formal, staged assessment of the efficacy and safety of surgical procedures has historically been and remains uncommon. The majority of innovative surgical procedures have therefore often been developed based on anatomical and pathophysiological principles in an attempt to better manage clinical problems.

Main Body

In this manuscript, we sought to review and contrast the models for pharmaceutical and surgical innovation in North America, including their stages of development and methods of evaluation, monitoring, and regulation. We also aimed to review the present structure of academic surgery, the role of methodological experts and funding in conducting surgical research, and the current system of regulation of innovative surgical procedures. Finally, we highlight the influence that evidence and surgical history, education, training, and culture have on elective and emergency surgical decision-making. The above discussion is used to support the argument that the model used for assessment of innovative pharmaceuticals cannot be applied to that for evaluating surgical innovations. It is also used to support our position that although the evaluation and monitoring of innovative surgical procedures requires a rigorous, fit-for-purpose, and formal system of assessment to protect patient safety and prevent unexpected adverse health outcomes, it will only succeed if it is supported and championed by surgical practice leaders and respects surgical history, education, training, and culture.

Conclusion

We conclude the above debate by providing a recommended approach to the evaluation, monitoring, and regulation of surgical innovations, which we hope may be used as a guide for all stakeholders involved in interpreting and/or conducting future surgical research.

Ethical considerations in conducting surgical research in severe complicated intra-abdominal sepsis

Background

Severe complicated intra-abdominal sepsis (SCIAS) has high mortality, thought due in part to progressive bio-mediator generation, systemic inflammation, and multiple organ failure. Treatment includes early antibiotics and operative source control. At surgery, open abdomen management with negative-peritoneal-pressure therapy (NPPT) has been hypothesized to mitigate MOF and death, although clinical equipoise for this operative approach exists. The Closed or Open after Laparotomy (COOL) study (https://clinicaltrials.gov/ct2/show/NCT03163095) will prospectively randomize eligible patients intra-operatively to formal abdominal closure or OA with NPTT. We review the ethical basis for conducting research in SCIAS.

Main body

Research in critically ill incapacitated patients is important to advance care. Conducting research among SCIAS is complicated due to the severity of illness including delirium, need for emergent interventions, diagnostic criteria confirmed only at laparotomy, and obtundation from anaesthesia. In other circumstances involving critically ill patients, clinical experts have worked closely with ethicists to apply principles that balance the rights of patients whilst simultaneously permitting inclusion in research. In Canada, the Tri-Council Policy Statement-2 (TCPS-2) describes six criteria that permit study enrollment and randomization in such situations: (a) serious threat to the prospective participant requires immediate intervention; (b) either no standard efficacious care exists or the research offers realistic possibility of direct benefit; (c) risks are not greater than that involved in standard care or are clearly justified by prospect for direct benefits; (d) prospective participant is unconscious or lacks capacity to understand the complexities of the research; (e) third-party authorization cannot be secured in sufficient time; and (f) no relevant prior directives are known to exist that preclude participation. TCPS-2 criteria are in principle not dissimilar to other (inter)national criteria. The COOL study will use waiver of consent to initiate enrollment and randomization, followed by surrogate or proxy consent, and finally delayed informed consent in subjects that survive and regain capacity.

Conclusions

A delayed consent mechanism is a practical and ethical solution to challenges in research in SCIAS. The ultimate goal of consent is to balance respect for patient participants and to permit participation in new trials with a reasonable opportunity for improved outcome and minimal risk of harm.

A Clinical Risk Prediction Tool for 6-Month Mortality After Dialysis Initiation Among Older Adults

BACKGROUND

Information on an individual's risk for death following dialysis therapy initiation may inform the decision to initiate maintenance dialysis for older adults. We derived and validated a clinical risk prediction tool for all-cause mortality among older adults during the first 6 months of maintenance dialysis treatment.

STUDY DESIGN

Prediction model using retrospective administrative and clinical data.

SETTING & PARTICIPANTS

We linked administrative and clinical data to define a cohort of 2,199 older adults (age ≥ 65 years) in Alberta, Canada, who initiated maintenance dialysis therapy (excluding acute kidney injury) in May 2003 to March 2012.

CANDIDATE PREDICTORS

Demographics, laboratory data, comorbid conditions, and measures of health system use.

OUTCOMES

All-cause mortality within 6 months of dialysis therapy initiation.

ANALYTICAL APPROACH

Predicted mortality by logistic regression with 10-fold cross-validation.

RESULTS

375 (17.1%) older adults died within 6 months. We developed a 19-point risk score for 6-month mortality that included age 80 years or older (2 points), glomerular filtration rate of 10 to 14.9mL/min/1.73m² (1 point) or ≥15mL/min/1.73m² (3 points), atrial fibrillation (2 points), lymphoma (5 points), congestive heart failure (2 points), hospitalization in the prior 6 months (2 points), and metastatic cancer (3 points). Model discrimination (C statistic = 0.72) and calibration (Hosmer-Lemeshow χ²=10.36; P=0.2) were reasonable. As examples, a score < 5 equated to <25% of individuals dying in 6 months, whereas a score > 12 predicted that more than half the individuals would die in the first 6 months.

LIMITATIONS

The tool has not been externally validated; thus, generalizability cannot be assessed.

CONCLUSIONS

We used readily available clinical information to derive and internally validate a 7-variable tool to predict early mortality among older adults after dialysis therapy initiation. Following successful external validation, the tool may be useful as a clinical decision tool to aid decision making for older adults with kidney failure.

Opinions of Practicing Surgeons on the Appropriateness of Published Indications for Use of Damage Control Surgery in Trauma Patients: An International Cross-Sectional Survey

BACKGROUND

Variation in use of damage control (DC) surgery across trauma centers may be partially driven by surgeon uncertainty as to when it is appropriately indicated. We sought to determine opinions of practicing surgeons on the appropriateness of published indications for trauma DC surgery.

STUDY DESIGN

We asked 384 trauma centers in the United States, Canada, and Australasia to nominate 1 to 3 surgeons at their center to participate in a survey about DC surgery. We then asked nominated surgeons their opinions on the appropriateness (benefit-to-harm ratio) of 43 literature-derived indications for use of DC surgery in adult civilian trauma patients.

RESULTS

In total, 232 (64.8%) trauma centers nominated 366 surgeons, of whom 201 (56.0%) responded. Respondents rated 15 (78.9%) preoperative and 23 (95.8%) intraoperative indications to be appropriate. Indications respondents agreed had the greatest expected benefit included a temperature <34°C, arterial pH <7.2, and laboratory-confirmed (international normalized ratio/prothrombin time and/or partial thromboplastin time >1.5 times normal) or clinically observed coagulopathy in the pre- or intraoperative setting; administration of >10 units of packed red blood cells; requirement for a resuscitative thoracotomy in the emergency department; and identification of a juxtahepatic venous injury or devascularized or destroyed pancreas, duodenum, or pancreaticoduodenal complex during operation. Ratings were consistent across subgroups of surgeons with different training, experience, and practice settings.

CONCLUSIONS

We identified 38 indications that practicing surgeons agreed appropriately justified the use of DC surgery. Until further studies become available, these indications constitute a consensus opinion that can be used to guide practice in the current era of changing trauma resuscitation practices.

Rationale for the Assessment of Metoprolol in the Prevention of Vasovagal Syncope in Aging Subjects Trial (POST5)

BACKGROUND

Vasovagal syncope (VVS) is a common problem associated with a poor quality of life, which improves when syncope frequency is reduced. Effective pharmacological therapies for VVS are lacking. Metoprolol is a β-adrenergic receptor antagonist that is ineffective in younger patients, but may benefit older (≥40 years) VVS patients. Given the limited therapeutic options, a placebo-controlled clinical trial of metoprolol for the prevention of VVS in older patients is needed.

STRUCTURE OF STUDY

The POST5 is a multicenter, international, randomized, placebo-controlled study of metoprolol in the prevention of VVS in patients ≥40 years old. The primary endpoint is the time to first recurrence of syncope. Patients will be randomized 1:1 to receive metoprolol 25 to 100 mg BID or matching placebo, and followed up for 1 year. Secondary end points include syncope frequency, presyncope, quality of life, and cost analysis. Primary analysis will be intention to treat, with a secondary on-treatment analysis.

POWER CALCULATIONS

A sample size of 222, split equally between the groups achieves 85% power to detect a hazard rate of 0.3561 when the event rates are 50% and 30% in the placebo and metoprolol arms. Allowing for 10% dropout, we propose to enroll 248 patients.

IMPLICATIONS

This study will be the first adequately powered trial to determine whether metoprolol is effective in preventing VVS in patients ≥40 years. If effective, metoprolol may become the first line pharmacological therapy for these patients.

Kaplan-Meier Survival Analysis Overestimates the Risk of Revision Arthroplasty: A Meta-analysis

BACKGROUND

Although Kaplan-Meier survival analysis is commonly used to estimate the cumulative incidence of revision after joint arthroplasty, it theoretically overestimates the risk of revision in the presence of competing risks (such as death). Because the magnitude of overestimation is not well documented, the potential associated impact on clinical and policy decision-making remains unknown.

QUESTIONS/PURPOSES

We performed a meta-analysis to answer the following questions: (1) To what extent does the Kaplan-Meier method overestimate the cumulative incidence of revision after joint replacement compared with alternative competing-risks methods? (2) Is the extent of overestimation influenced by followup time or rate of competing risks?

METHODS

We searched Ovid MEDLINE, EMBASE, BIOSIS Previews, and Web of Science (1946, 1980, 1980, and 1899, respectively, to October 26, 2013) and included article bibliographies for studies comparing estimated cumulative incidence of revision after hip or knee arthroplasty obtained using both Kaplan-Meier and competing-risks methods. We excluded conference abstracts, unpublished studies, or studies using simulated data sets. Two reviewers independently extracted data and evaluated the quality of reporting of the included studies. Among 1160 abstracts identified, six studies were included in our meta-analysis. The principal reason for the steep attrition (1160 to six) was that the initial search was for studies in any clinical area that compared the cumulative incidence estimated using the Kaplan-Meier versus competing-risks methods for any event (not just the cumulative incidence of hip or knee revision); we did this to minimize the likelihood of missing any relevant studies. We calculated risk ratios (RRs) comparing the cumulative incidence estimated using the Kaplan-Meier method with the competing-risks method for each study and used DerSimonian and Laird random effects models to pool these RRs. Heterogeneity was explored using stratified meta-analyses and metaregression.

RESULTS

The pooled cumulative incidence of revision after hip or knee arthroplasty obtained using the Kaplan-Meier method was 1.55 times higher (95% confidence interval, 1.43-1.68; p < 0.001) than that obtained using the competing-risks method. Longer followup times and higher proportions of competing risks were not associated with increases in the amount of overestimation of revision risk by the Kaplan-Meier method (all p > 0.10). This may be due to the small number of studies that met the inclusion criteria and conservative variance approximation.

CONCLUSIONS

The Kaplan-Meier method overestimates risk of revision after hip or knee arthroplasty in populations where competing risks (such as death) might preclude the occurrence of the event of interest (revision). Competing-risks methods should be used to more accurately estimate the cumulative incidence of revision when the goal is to plan healthcare services and resource allocation for revisions.

Assessing the association between occupancy and outcome in critically Ill hospitalized patients with sepsis

BACKGROUND

Sepsis has a high prevalence, mortality-rate and cost. Sepsis patients usually enter the hospital through the Emergency Department (ED). Process or structural issues related to care may affect outcome.

METHODS

Multi-centered retrospective observational cohort study using administrative databases to identify adult patients (> = 18 years) with sepsis and severe sepsis admitted to Alberta Health Services Calgary zone adult multisystem intensive care units (ICU) through the ED between January 1, 2006 and September 30, 2009. We examined the association between ICU occupancy and hospital outcome. We explored other associations of hospital outcome including the effect of ED wait time, admission from ED during weekdays versus weekends and ED admission during the day versus at night.

RESULTS

One thousand and seven hundred seventy patients were admitted to hospital via ED, 1036 (58.5 %) with sepsis and 734 (41.5 %) with severe sepsis. In patients with sepsis, ICU occupancy > 90 % was associated with an increase in hospital mortality even after adjusting for age, sex, triage level, Charlson index, time of first ED physician assessment and ICU admission. No differences in hospital mortality were found for patients who waited more than 7 h, were admitted during the day versus night or weekdays versus weekends.

CONCLUSIONS

In patients with sepsis admitted via the ED, increased ICU occupancy was associated with higher in-hospital mortality.

A protocol for a scoping and qualitative study to identify and evaluate indications for damage control surgery and damage control interventions in civilian trauma patients

INTRODUCTION

Initial abbreviated surgery with planned reoperation (damage control surgery) is frequently used for major trauma patients to rapidly control haemorrhage while limiting surgical stress. Although damage control surgery may decrease mortality risk among the severely injured, it may also be associated with several complications when inappropriately applied. We seek to scope the literature on trauma damage control surgery, identify its proposed indications, map and clarify their definitions, and examine the content and evidence on which they are based. We also seek to generate a comprehensive list of unique indications to inform an appropriateness rating process.

METHODS AND ANALYSIS

We will search 11 electronic bibliographic databases, included article bibliographies and grey literature sources for citations involving civilian trauma patients that proposed one or more indications for damage control surgery or a damage control intervention. Indications will be classified into a predefined conceptual framework and categorised and described using qualitative content analysis. Constant comparative methodology will be used to create, modify and test codes describing principal findings or injuries (eg, bilobar liver injury) and associated decision variables (eg, coagulopathy) that comprise the reported indications. After a unique list of codes have been developed, we will use the organisational system recommended by the RAND/University of California, Los Angeles (RAND-UCLA) Appropriateness Rating Method to group principal findings or injuries into chapters (subdivided by associated decision variables) according to broader clinical findings encountered during surgical practice (eg, major liver injury).

ETHICS AND DISSEMINATION

This study will constitute the first step in a multistep research programme aimed at developing appropriate, evidence-informed indications for damage control in civilian trauma patients. With use of an integrated knowledge translation intervention that includes collaboration with surgical practice leaders, this research may allow for development of indications that are more likely to be relevant to and used by surgeons. Ethics approval is not required for this study.

Clinical manifestations of tension pneumothorax: protocol for a systematic review and meta-analysis

BACKGROUND

Although health care providers utilize classically described signs and symptoms to diagnose tension pneumothorax, available literature sources differ in their descriptions of its clinical manifestations. Moreover, while the clinical manifestations of tension pneumothorax have been suggested to differ among subjects of varying respiratory status, it remains unknown if these differences are supported by clinical evidence. Thus, the primary objective of this study is to systematically describe and contrast the clinical manifestations of tension pneumothorax among patients receiving positive pressure ventilation versus those who are breathing unassisted.

METHODS/DESIGN

We will search electronic bibliographic databases (MEDLINE, PubMed, EMBASE, and the Cochrane Database of Systematic Reviews) and clinical trial registries from their first available date as well as personal files, identified review articles, and included article bibliographies. Two investigators will independently screen identified article titles and abstracts and select observational (cohort, case-control, and cross-sectional) studies and case reports and series that report original data on clinical manifestations of tension pneumothorax. These investigators will also independently assess risk of bias and extract data. Identified data on the clinical manifestations of tension pneumothorax will be stratified according to whether adult or pediatric study patients were receiving positive pressure ventilation or were breathing unassisted, as well as whether the two investigators independently agreed that the clinical condition of the study patient(s) aligned with a previously published tension pneumothorax working definition. These data will then be summarized using a formal narrative synthesis alongside a meta-analysis of observational studies and then case reports and series where possible. Pooled or combined estimates of the occurrence rate of clinical manifestations will be calculated using random effects models (for observational studies) and generalized estimating equations adjusted for reported potential confounding factors (for case reports and series).

DISCUSSION

This study will compile the world literature on tension pneumothorax and provide the first systematic description of the clinical manifestations of the disorder according to presenting patient respiratory status. It will also demonstrate a series of methods that may be used to address difficulties likely to be encountered during the conduct of a meta-analysis of data contained in published case reports and series. PROSPERO registration number: CRD42013005826.

Efficacy and safety of active negative pressure peritoneal therapy for reducing the systemic inflammatory response after damage control laparotomy (the Intra-peritoneal Vacuum Trial): study protocol for a randomized controlled trial

Background

Damage control laparotomy, or abbreviated initial laparotomy followed by temporary abdominal closure (TAC), intensive care unit resuscitation, and planned re-laparotomy, is frequently used to manage intra-abdominal bleeding and contamination among critically ill or injured adults. Animal data suggest that TAC techniques that employ negative pressure to the peritoneal cavity may reduce the systemic inflammatory response and associated organ injury. The primary objective of this study is to determine if use of a TAC dressing that affords active negative pressure peritoneal therapy, the ABThera Open Abdomen Negative Pressure Therapy System, reduces the extent of the systemic inflammatory response after damage control laparotomy for intra-abdominal sepsis or injury as compared to a commonly used TAC method that provides potentially less efficient peritoneal negative pressure, the Barker’s vacuum pack.

Methods/Design

The Intra-peritoneal Vacuum Trial will be a single-center, randomized controlled trial. Adults will be intraoperatively allocated to TAC with either the ABThera or Barker’s vacuum pack after the decision has been made by the attending surgeon to perform a damage control laparotomy. The study will use variable block size randomization. On study days 1, 2, 3, 7, and 28, blood will be collected. Whenever possible, peritoneal fluid will also be collected at these time points from the patient’s abdomen or TAC device. Luminex technology will be used to quantify the concentrations of 65 mediators relevant to the inflammatory response in peritoneal fluid and plasma. The primary endpoint is the difference in the plasma concentration of the pro-inflammatory cytokine IL-6 at 24 and 48 h after TAC dressing application. Secondary endpoints include the differential effects of these dressings on the systemic concentration of other pro-inflammatory cytokines, collective peritoneal and systemic inflammatory mediator profiles, postoperative fluid balance, intra-abdominal pressure, and several patient-important outcomes, including organ dysfunction measures and mortality.

Discussion

Results from this study will improve understanding of the effect of active negative pressure peritoneal therapy after damage control laparotomy on the inflammatory response. It will also gather necessary pilot information needed to inform design of a multicenter trial comparing clinical outcomes among patients randomized to TAC with the ABThera versus Barker’s vacuum pack.

Trial registration

ClinicalTrials.gov identifier http://www.clicaltrials.gov/ct2/show/NCT01355094

Comparative effectiveness of alternative clinical pathways for primary hip and knee joint replacement patients: a pragmatic randomized, controlled trial

OBJECTIVE

Total hip replacement (THR) and total knee replacement (TKR) (arthroplasty) surgery for end-stage osteoarthritis (OA) are ideal candidates for optimization through an algorithmic care pathway. Using a comparative effectiveness study design, we compared the effectiveness of a new clinical pathway (NCP) featuring central intake clinics, dedicated inpatient resources, care guidelines and efficiency benchmarks vs. the standard of care (SOC) for THR or TKR.

METHODS

We compared patients undergoing primary THR and TKR who received surgery in NCP vs. SOC in a randomised controlled trial within the trial timeframe. 1,570 patients (1,066 SOC and 504 NCP patients) that underwent surgery within the study timeframe from urban and rural practice settings were included. The primary endpoint was improvement in Western Ontario and McMaster University osteoarthritis index (WOMAC) overall score over 12 months post-surgery. Secondary endpoints were improvements in the physical function (PF) and bodily pain (BP) domains of the Short Form 36 (SF-36).

RESULTS

NCP patients had significantly greater improvements from baseline WOMAC scores compared to SOC patients after adjusting for covariates (treatment effect=2.56; 95% confidence interval (CI) [1.10-4.01]). SF-36 BP scores were significantly improved for both hip and knee patients in the NCP (treatment effect=3.01, 95% CI [0.70-5.32]), but SF-36 PF scores were not. Effects of the NCP were more pronounced in knee patients.

CONCLUSION

While effect sizes were small compared with major effects of the surgery itself, an evidence-informed clinical pathway can improve health related quality of life (HRQoL) of hip and knee arthroplasty patients with degenerative joint disorder in routine clinical practice for up to 12 months post-operatively. CLINICALTRIALS.GOV IDENTIFIER: NCT00277186.

Rationale for the prevention of syncope trial IV: assessment of midodrine

BACKGROUND

Vasovagal syncope is a common problem associated with a poor quality of life, which improves when the frequency of syncope is reduced. Effective pharmacological therapies for vasovagal syncope have been elusive. Midodrine is a pro-drug whose primary metabolite is an alpha-1 adrenoreceptor agonist. A few studies have suggested that it may be beneficial in syncope, but all have had significant methodological limitations. A placebo-controlled clinical trial of midodrine for the prevention of vasovagal syncope is needed.

STRUCTURE OF STUDY

The prevention of syncope trial IV (POST 4) is a multicenter, international, randomized, placebo-controlled study of midodrine in the prevention of vasovagal syncope. The primary end point is the time to first recurrence of syncope. Patients will be randomized 1:1 to receive midodrine 10-30 mg/day or matching placebo, and followed for 1 year. Secondary end points include syncope frequency, presyncope, and quality of life. Primary analysis will be performed with an intention-to-treat approach, with a secondary on-treatment analysis.

POWER CALCULATIONS

A total sample size of 112, split equally between the two groups, achieves 85 % power to detect a 50 % relative risk reduction when the event rates are 55 and 27.5 % in the placebo and midodrine arms. Allowing for 20 % dropout, we propose to enroll 140 patients.

REGISTRATION

POST 4 is registered with http://www.clinicaltrials.gov (NCT01456481).

IMPLICATIONS

This study will be the first adequately powered trial to determine whether midodrine is effective in preventing vasovagal syncope. If it is effective, then midodrine may become the first-line pharmacological therapy for this condition.

Functional outcomes for 2 years comparing hip resurfacing and total hip arthroplasty

This prospective observational study of 499 patients with hip resurfacing and 255 patients with total hip arthroplasty compared outcomes for 2 years. We used propensity scores to identify matched cohorts of 118 patients with hip resurfacing and 118 patients with total hip arthroplasty. We used these cohorts to compare improvements in the Western Ontario and McMaster University (WOMAC) osteoarthritis index and Medical Outcomes Short-Form 36 physical function component (SF-36 PF) scores at 3 months and at 1 and 2 years postsurgery. Both groups demonstrated significant improvements from baseline in WOMAC and SF-36 PF. Improvements in SF-36 PF were greater for patients with hip resurfacing than for patients with total hip arthroplasty 1 and 2 years postsurgery; improvements in WOMAC were similar for both groups. The clinical significance of this observation needs further investigation.

A multi-region assessment of population rates of cardiac catheterization and yield of high-risk coronary artery disease

Background

There is variation in cardiac catheterization utilization across jurisdictions. Previous work from Alberta, Canada, showed no evidence of a plateau in the yield of high-risk disease at cardiac catheterization rates as high as 600 per 100,000 population suggesting that the optimal rate is higher. This work aims 1) To determine if a previously demonstrated linear relationship between the yield of high-risk coronary disease and cardiac catheterization rates persists with contemporary data and 2) to explore whether the linear relationship exists in other jurisdictions.

Methods

Detailed clinical information on all patients undergoing cardiac catheterization in 3 Canadian provinces was available through the Alberta Provincial Project for Outcomes Assessment in Coronary Heart (APPROACH) disease and partner initiatives in British Columbia and Nova Scotia. Population rates of catheterization and high-risk coronary disease detection for each health region in these three provinces, and age-adjusted rates produced using direct standardization. A mixed effects regression analysis was performed to assess the relationship between catheterization rate and high-risk coronary disease detection.

Results

In the contemporary Alberta data, we found a linear relationship between the population catheterization rate and the high-risk yield. Although the yield was slightly less in time period 2 (2002-2006) than in time period 1(1995-2001), there was no statistical evidence of a plateau. The linear relationship between catheterization rate and high-risk yield was similarly demonstrated in British Columbia and Nova Scotia and appears to extend, without a plateau in yield, to rates over 800 procedures per 100,000 population.

Conclusions

Our study demonstrates a consistent finding, over time and across jurisdictions, of linearly increasing detection of high-risk CAD as population rates of cardiac catheterization increase. This internationally-relevant finding can inform country-level planning of invasive cardiac care services.

Do coder characteristics influence validity of ICD-10 hospital discharge data?

Background

Administrative data are widely used to study health systems and make important health policy decisions. Yet little is known about the influence of coder characteristics on administrative data validity in these studies. Our goal was to describe the relationship between several measures of validity in coded hospital discharge data and 1) coders' volume of coding (≥13,000 vs. <13,000 records), 2) coders' employment status (full- vs. part-time), and 3) hospital type.

Methods

This descriptive study examined 6 indicators of face validity in ICD-10 coded discharge records from 4 hospitals in Calgary, Canada between April 2002 and March 2007. Specifically, mean number of coded diagnoses, procedures, complications, Z-codes, and codes ending in 8 or 9 were compared by coding volume and employment status, as well as hospital type. The mean number of diagnoses was also compared across coder characteristics for 6 major conditions of varying complexity. Next, kappa statistics were computed to assess agreement between discharge data and linked chart data reabstracted by nursing chart reviewers. Kappas were compared across coder characteristics.

Results

422,618 discharge records were coded by 59 coders during the study period. The mean number of diagnoses per record decreased from 5.2 in 2002/2003 to 3.9 in 2006/2007, while the number of records coded annually increased from 69,613 to 102,842. Coders at the tertiary hospital coded the most diagnoses (5.0 compared with 3.9 and 3.8 at other sites). There was no variation by coder or site characteristics for any other face validity indicator. The mean number of diagnoses increased from 1.5 to 7.9 with increasing complexity of the major diagnosis, but did not vary with coder characteristics. Agreement (kappa) between coded data and chart review did not show any consistent pattern with respect to coder characteristics.

Conclusions

This large study suggests that coder characteristics do not influence the validity of hospital discharge data. Other jurisdictions might benefit from implementing similar employment programs to ours, e.g.: a requirement for a 2-year college training program, a single management structure across sites, and rotation of coders between sites. Limitations include few coder characteristics available for study due to privacy concerns.

Obstructive sleep apnoea is associated with diabetes in sleepy subjects

BACKGROUND

Although obstructive sleep apnoea (OSA) has been linked to insulin resistance and glucose intolerance, it is unclear whether there is an independent association between OSA and diabetes mellitus (DM) and whether all patients with OSA are at risk. The objective of this study was to determine the association between OSA and DM in a large cohort of patients referred for sleep diagnostic testing.

METHODS

A cross-sectional analysis of participants in a clinic-based study was conducted between July 2005 and August 2007. DM was defined by self-report and concurrent use of diabetic medications (oral hypoglycaemics and/or insulin). Sensitivity analysis was performed using a validated administrative definition of diabetes. OSA was defined by the respiratory disturbance index (RDI) using polysomnography or ambulatory monitoring. Severe OSA was defined as an RDI > or = 30/h. Subjective sleepiness was defined as an Epworth Sleepiness Scale score > or = 10.

RESULTS

Complete data were available for 2149 patients. The prevalence of DM increased with increasing OSA severity (p<0.001). Severe OSA was associated with DM following adjustment for patient demographics, weight and neck circumference (odds ratio (OR) 2.18; 95% CI 1.22 to 3.89; p<0.01). Following a stratified analysis, this relationship was observed exclusively in sleepy patients (OR 2.59 (95% CI 1.35 to 4.97) vs 1.16 (95% CI 0.31 to 4.37) in non-sleepy patients).

CONCLUSIONS

Severe OSA is independently associated with DM in patients who report excessive sleepiness. Future studies investigating the impact of OSA treatment on DM may wish to focus on this patient population.

Active smoking and the risk of type 2 diabetes: a systematic review and meta-analysis

CONTEXT

Observational studies have suggested an association between active smoking and the incidence of type 2 diabetes.

OBJECTIVE

To conduct a systematic review with meta-analysis of studies assessing the association between active smoking and incidence of type 2 diabetes.

DATA SOURCES

A search of MEDLINE (1966 to May 2007) and EMBASE (1980 to May 2007) databases was supplemented by manual searches of bibliographies of key retrieved articles, reviews of abstracts from scientific meetings, and contact with experts.

STUDY SELECTION

Studies were included if they reported risk of impaired fasting glucose, impaired glucose tolerance, or type 2 diabetes in relationship to smoking status at baseline; had a cohort design; and excluded persons with diabetes at baseline.

DATA EXTRACTION AND DATA SYNTHESIS

Two authors independently extracted the data, including the presence or absence of active smoking at baseline, the risk of diabetes, methods used to detect diabetes, and key criteria of study quality. Relative risks (RRs) were pooled using a random-effects model. Associations were tested in subgroups representing different patient characteristics and study quality criteria.

RESULTS

The search yielded 25 prospective cohort studies (N = 1.2 million participants) that reported 45 844 incident cases of diabetes during a study follow-up period ranging from 5 to 30 years. Of the 25 studies, 24 reported adjusted RRs greater than 1 (range for all studies, 0.82-3.74). The pooled adjusted RR was 1.44 (95% confidence interval [CI], 1.31-1.58). Results were consistent and statistically significant in all subgroups. The risk of diabetes was greater for heavy smokers (> or =20 cigarettes/day; RR, 1.61; 95% CI, 1.43-1.80) than for lighter smokers (RR,1.29; 95% CI, 1.13-1.48) and lower for former smokers (RR, 1.23; 95% CI, 1.14-1.33) compared with active smokers, consistent with a dose-response phenomenon.

CONCLUSION

Active smoking is associated with an increased risk of type 2 diabetes. Future research should attempt to establish whether this association is causal and to clarify its mechanisms.

Kaplan–Meier methods yielded misleading results in competing risk scenarios

BACKGROUND AND OBJECTIVE

Time-to-event curves are routinely presented in the medical literature. The most widely used method is the Kaplan-Meier (K-M) method, but this analysis approach may not be appropriate when an analysis focuses on time-to-first event in scenarios where there are competing events. We compared K-M methods applying various censoring approaches with the lesser-known "cumulative incidence competing risks" (CICR) method in an analysis of competing events.

METHODS

A registry containing data on 21,624 patients undergoing cardiac catheterization was analyzed. Time to coronary artery bypass grafting (CABG) was assessed in an analysis for which percutaneous coronary intervention and death were competing events. Time-to-CABG curves were calculated using the "K-M censor all method," "K-M censor death only method," "K-M ignore all method," and the CICR method.

RESULTS

One-year CABG rates calculated for the K-M "censor all," "censor death only," and "ignore all" methods were 28.8%, 22.8%, and 22.4%, respectively compared to the "actual" rate of 20.8%. For the CICR method, the corresponding 1-year rate was identical to the "actual" rate.

CONCLUSION

In situations with competing risks, and where an analysis focuses on first events, the CICR method is most appropriate, as K-M methods will tend to overestimate event rates.

Prognostic relevance of census-derived individual respondent incomes versus household incomes

BACKGROUND

Census-based measures of income derived from median income of a geographic area are often used in health research. Many national census surveys gather information on both the respondent's individual income and the income for the entire household, giving researchers a choice of census income measures. We compared the extent to which individual respondent income and household income (both obtained from census data) are associated with outcomes in a cohort of patients with cardiac disease.

METHODS

We used data from the Alberta Provincial Project for Outcome Assessment in Coronary Heart Disease (APPROACH), where postal codes were linked to the Postal Code Conversion File (PCCF) to determine each patient's census Dissemination Areas (DA). DA-derived median household income and median individual income were obtained from the 2001 Canadian Census and survival outcomes were then directly determined for income groupings defined by quintile. Two-year survival adjusted for age and sex was described with a proportional hazards analysis.

RESULTS

There were 9,397 patients undergoing cardiac catheterization between January 1, 2001 and March 31, 2002, with complete DA-level median income measures. Household income quintiles yielded a wider spread of survival across quintiles (range of 2-year estimated survival, 91.8% to 95.9% for household income versus 92.8% to 95.6% for respondent income), as well as a more progressive decline in survival as income decreased. This progressive decline was not seen for the respondent income measure.

CONCLUSIONS

The greater spread and progressive decline of survival for household income relative to respondent income leads us to conclude that household income is the better socio-economic determinant of health in our data and for the outcome measure we studied.

Population rates of cardiac catheterization and yield of high-risk coronary artery disease

BACKGROUND

The optimal population rate of cardiac catheterization is unknown. One potential way to determine it would be to examine whether there is a population rate beyond which the yield of high-risk coronary artery disease (CAD) does not rise.

METHODS

Using a detailed clinical registry that captures all patients undergoing cardiac catheterization in Alberta, we determined annual population rates of cardiac catheterization and the corresponding yield of cases of high-risk CAD in each of Alberta's 17 health regions from 1995 to 2002. Least squares linear regression analysis and hierarchical modelling methods were then used to assess the linear relation between catheterization rates and rates of high-risk CAD.

RESULTS

The age-adjusted average rate of cardiac catheterization among men ranged from 404.9 to 638.1 per 100,000 population aged over 20 years. Among women, the average rate ranged from 171.8 to 314.0 per 100,000. For both sexes, increased regional rates of catheterization were associated with a linearly increasing yield of high-risk CAD, with no evidence of a plateau in yield when more procedures were performed. One additional case of high-risk CAD was identified for every 2.5 additional cardiac catheterization procedures performed among men, and for every 3.7 additional procedures performed among women.

INTERPRETATION

The increasing yield of patients with high-risk CAD associated with increased regional population rates of cardiac catheterization, together with the absence of a plateau in yield, suggests that Alberta's population rates of cardiac catheterization are suboptimal to detect people with high-risk CAD.

Absence of bias against smokers in access to coronary revascularization after cardiac catheterization

OBJECTIVE

Many consider smoking to be a personal choice for which individuals should be held accountable. We assessed whether there is any evidence of bias against smokers in cardiac care decision-making by determining whether smokers were as likely as non-smokers to undergo revascularization procedures after cardiac catheterization.

DESIGN

Prospective cohort study. Subjects and setting. All patients undergoing cardiac catheterization in Alberta, Canada.

MAIN MEASURE

Patients were categorized as current smokers, former smokers, or never smokers, and then compared for their risk-adjusted likelihood of undergoing revascularization procedures (percutaneous coronary intervention or coronary artery bypass grafting) after cardiac catheterization.

RESULTS

Among 20406 patients undergoing catheterization, 25.4% were current smokers at the time of catheterization, 36.6% were former smokers, and 38.0% had never smoked. When compared with never smokers (reference group), the hazard ratio for undergoing any revascularization procedure after catheterization was 0.98 (95% CI 0.93-1.03) for current smokers and 0.98 (0.94-1.03) for former smokers. The hazard ratio for undergoing coronary artery bypass grafting was 1.09 (1.00-1.19) for current smokers and 1.00 (0.93-1.08) for former smokers. For percutaneous coronary intervention, the hazard ratios were 0.93 (0.87-0.99) for current smokers and 1.00 (0.94-1.06) for former smokers.

CONCLUSION

Despite potential for discrimination on the basis of smoking status, current and former smokers undergoing cardiac catheterization in Alberta, Canada were as likely to undergo revascularization procedures as catheterization patients who had never smoked.

Geographical location of residence and uniformity of access to cardiac revascularization services after catheterization

BACKGROUND

The centralization of health care services has numerous potential benefits but April compromise access for individuals living in remote areas.

OBJECTIVES

To examine the association between a patient's place of residence and the likelihood of undergoing a coronary revascularization procedure within one year after cardiac catheterization.

METHODS

All Alberta residents undergoing cardiac catheterization between 1995 and 1998 were examined. Geographical distance from patient place of residence to a centralized catheterization facility was calculated. The adjusted odds of undergoing cardiac revascularization within one year of catheterization was determined as a function of distance, controlling for differences in patient age, clinical factors and economic status.

RESULTS

Of 21816 residents who underwent cardiac catheterization in the province, 10997 had a revascularization procedure. Graphical examination of distance revealed a change in revascularization rates in patients living more than 450 km from revascularization centres. Further analysis was conducted using this cutpoint. Patients living in these remote areas were more likely to undergo a coronary revascularization procedure within the next year (adjusted odds ratio 1.65, 95% CI 1.05 to 2.59). However, these same residents were also less likely to undergo catheterization in the first place when compared with other Albertans (270 versus 398 procedures per 100000 population).

CONCLUSION

Only a small proportion of the population living in Alberta's most remote areas were more likely to undergo a revascularization procedure, indicating a remarkable uniformity of access to revascularization after coronary cardiac catheterization has occurred. This study examines the use of an existing database to gain further insights into the relationship between geography and access to cardiac care, and the distance-access relationship for coronary revascularization in Alberta.

Accuracy of city postal code coordinates as a proxy for location of residence

BACKGROUND: Health studies sometimes rely on postal code location as a proxy for the location of residence. This study compares the postal code location to that of the street address using a database from the Alberta Provincial Project for Outcome Assessment in Coronary Heart Disease (APPROACHCopyright ). Cardiac catheterization cases in an urban Canadian City were used for calendar year 1999. We determined location in meters for both the address (using the City of Calgary Street Network File in ArcView 3.2) and postal code location (using Statistic Canada's Postal Code Conversion File). RESULTS: The distance between the two estimates of location for each case were measured and it was found that 87.9% of the postal code locations were within 200 meters of the true address location (straight line distances) and 96.5% were within 500 meters of the address location (straight line distances). CONCLUSIONS: We conclude that postal code locations are a reasonably accurate proxy for address location. However, there may be research questions for which a more accurate description of location is required.

Diagnostic cardiac catheterization and revascularization rates for coronary heart disease

BACKGROUND

Despite evidence of regional variation across North America, there have been no comprehensive studies of cardiac procedure rates for coronary heart disease in Canada.

OBJECTIVES

To use available administrative data and a survey of catheterization facilities to examine regional and demographic variations in cardiovascular procedure rates.

METHODS

A survey of all cardiac catheterization facilities in Canada was conducted, and the procedure counts from these facilities were used to determine provincial catheterization rates from 1997/1998 to 2001/2002. Procedure counts for 1997/1998 to 1999/2000 for coronary artery bypass graft (CABG) surgery and percutaneous coronary intervention (PCI) were provided by the Canadian Institute for Health Information and used to calculate revascularization procedure rates. Population projections provided by Statistics Canada were used as denominators for calculating the rates, and direct standardization was used to obtain age- and sex-adjusted rates.

RESULTS AND CONCLUSIONS

The crude rate of cardiac catheterization in Canada increased from 359.9 to 471.5 per 100,000 population across the five years studied. There was considerable variation in revascularization procedure rates across health regions and provinces. Between 1997/1998 and 1999/2000, there was little increase in the rate of CABGs performed in Canada but a marked increase in the rate of PCIs. For both CABG and PCI, rates were higher for men than women, and highest in the 65- to 74-year-old age category. This study provides a valuable 'snapshot' of cardiac procedure use rates but indicates a clear need for more comprehensive collection of cardiac care data in Canada.

Sex differences in outcomes after cardiac catheterization: effect modification by treatment strategy and time

CONTEXT

Studies comparing outcomes of cardiac care in women vs men yield various results, with some suggesting worse outcomes for women and others suggesting equivalent outcomes.

OBJECTIVE

To determine whether extent of coronary disease, treatment strategy, and follow-up time influence the risk of death in women vs men among patients who have had cardiac catheterization.

DESIGN, SETTING, AND PATIENTS

We studied a large inception cohort by using detailed clinical data from a registry of 37 401 patients undergoing cardiac catheterization in Alberta, Canada, from 1995-2000, with follow-up through December 31, 2001.

MAIN OUTCOME MEASURES

The risk of death for women vs men was assessed for all patients combined and then in analyses stratified by degree of coronary anatomic risk and by treatment strategy (no revascularization, percutaneous coronary intervention [PCI], coronary artery bypass graft [CABG] surgery). The latter analysis included a graphic assessment of the changing relative risk over time for women vs men.

RESULTS

Women had higher 1-year mortality than men did (5.6% vs 4.6%; P<.001). However, stratified analyses demonstrated that sex differences in risk occurred only early after catheterization and were most apparent among patients undergoing revascularization. The early risk-adjusted relative risks for women vs men were elevated at 3.49 (95% confidence interval [CI], 1.95-6.24) for CABG surgery and 2.38 (95% CI, 1.48-3.83) for PCI on day 1 after catheterization, with a subsequent decrease in relative risk over time to equivalence in risk between sexes before 1 year.

CONCLUSIONS

Sex-based differences in death rates after cardiac catheterization are time- and treatment-specific. This finding may at least partially explain the discrepancies in results from earlier studies on sex differences in outcomes of cardiac care.

Sex differences in the prognostic importance of diabetes in patients with ischemic heart disease undergoing coronary angiography

OBJECTIVE

Women with ischemic heart disease have poorer outcomes than men and are suggested to have greater risk associated with diabetes. We evaluated the prognosis associated with diabetes, in analyses stratified by sex, to determine whether similar differences are seen in a large unselected cohort of patients.

RESEARCH DESIGN AND METHODS

Using the Alberta Provincial Project for Outcomes Assessment in Coronary Heart Disease (APPROACH), a clinical data collection and follow-up initiative capturing all patients undergoing cardiac catheterization in Alberta, Canada, the relative significance of diabetes on long-term survival in 13152 men and 4249 women was evaluated in patients presenting with or without myocardial infarction and according to first treatment received.

RESULTS

The 1-year mortality rates were 4.7% and 6.8% in men and women (P < 0.001), 4.1% and 7.4% in nondiabetic and diabetic men (P < 0.001), and 5.8% and 9.6% in nondiabetic and diabetic women, respectively (P < 0.001). The risk-adjusted Cox proportional hazard ratios associated with diabetes in myocardial infarction were 1.03 in men and 1.20 in women. The diabetes hazard ratios for percutaneous coronary intervention were 1.28 in men and 1.40 in women, 1.23 in men and 1.32 in women for bypass surgery, and 1.26 in men and 1.31 in women for medical therapy (P = NS for all diabetes hazard ratio comparisons between men and women).

CONCLUSIONS

Hazard ratios quantifying the adverse prognosis associated with diabetes in patients undergoing angiography are consistently higher among women than men, but the differences across sexes are not statistically significant. These slight sex differences noted in the APPROACH registry are similar to previously reported findings and may be clinically important.

Bias in estimates of confidence intervals for health outcome report cards

Health researchers commonly use logistic regression when profiling health providers. Data from the patients treated by the providers are used to construct models predicting the expected number of outcomes for providers and the ratio of observed to expected outcomes (O/E ratio) used as a risk-adjusted measure of provider performance. Typically, when calculating the standard deviation (SD) of O/E ratios, only O is treated as a random variable. We used the propagation of errors (Pe) to derive a SD estimate that accounted for variability in O and the estimate of E. Using data previously used to profile Canadian cardiac surgery providers, we compared Pe-SD estimates with typical SD (SDT) estimates. The SDT estimates and confidence intervals were always larger than the Pe estimates, most notably when one or more providers treated a large proportion of the patients. This was confirmed using computer simulations. SDT estimates should be abandoned in favor of more sophisticated estimates.

Misclassification of income quintiles derived from area-based measures. A comparison of enumeration area and forward sortation area

BACKGROUND

Census-based methods are often used to estimate socioeconomic status. We assessed the agreement between Forward Sortation Area (FSA) and Enumeration Area (EA) derived income levels for all patients undergoing cardiac catheterization in Alberta, Canada, from 1995-1998.

METHODS

Income quintiles were calculated from census data for FSA and EA level. FSA- and EA-derived income measures were compared for misclassification. Both methods were then applied to the data to determine 4-year survival by income grouping in 21,446 patients following catheterization.

RESULTS

The variability in EA-derived incomes for any given FSA-derived income is large. Only 40% of income quintiles are in agreement between the methods. For EA-based analyses, there is a linear relationship between higher income and lower mortality across all quintiles, while for FSA-based analyses, only the lowest income quintile had significantly higher mortality.

DISCUSSION

Assuming that FSA-based methods are more likely to misclassify income compared to EA-based measures, the results for the FSA-based analyses are more likely to be erroneous. EA-derived measures should therefore be used when individual data are not available.

Survival after coronary revascularization in the elderly

BACKGROUND

Elderly patients with ischemic heart disease are increasingly referred for coronary artery bypass grafting (CABG) or percutaneous coronary intervention (PCI). However, reports of poor outcomes in the elderly have led to questions about the benefit of these strategies. We studied survival by prescribed treatment (CABG, PCI, or medical therapy) for patients in 3 age categories: <70 years, 70 to 79 years, and > or =80 years of age.

METHODS AND RESULTS

The Alberta Provincial Project for Outcomes Assessment in Coronary Heart Disease (APPROACH) is a clinical data collection and outcome monitoring initiative capturing all patients undergoing cardiac catheterization and revascularization in the province of Alberta, Canada, since 1995. Characteristics and long-term outcomes of a cohort of >6000 elderly patients with ischemic heart disease were compared with younger patients. In 15 392 patients >70 years of age, 4-year adjusted actuarial survival rates for CABG, PCI, and medical therapy were 95.0%, 93.8%, and 90.5%, respectively. In 5198 patients 70 to 79 years of age, survival rates were 87.3%, 83.9%, and 79.1%, respectively. In 983 patients > or = 80 years of age, survival was 77.4% for CABG, 71.6% for PCI, and 60.3% for medical therapy. Absolute risk differences in comparison to medical therapy for CABG (17.0%) and PCI (11.3%) were greater for patients > or =80 years of age than for younger patients.

CONCLUSIONS

Elderly patients paradoxically have greater absolute risk reductions associated with surgical or percutaneous revascularization than do younger patients. The combination of these results with a recent randomized trial suggests that the benefits of aggressive revascularization therapies may extend to subsets of patients in older age groups.

Sex differences in access to coronary revascularization after cardiac catheterization: importance of detailed clinical data

BACKGROUND

Although some studies suggest that access to cardiac procedures may differ by sex, others have found no evidence of gender bias in cardiac care.

OBJECTIVE

To study rates of percutaneous coronary intervention (PCI) or coronary artery bypass graft (CABG) surgery in men and women after cardiac catheterization.

DESIGN

Cohort study with prospective data collection.

SETTING

Alberta, Canada.

PATIENTS

Persons undergoing cardiac catheterization between 1 January 1995 and 31 December 1998 (n = 21 816).

MEASUREMENTS

The occurrence of revascularization procedures (PCI or CABG) in the year after cardiac catheterization was measured. Unadjusted revascularization rates, partially adjusted rates (adjusted for clinical variables available in most databases, including administrative databases), and fully adjusted rates (additionally adjusted for extent of coronary artery disease and ejection fraction) were also evaluated.

RESULTS

The unadjusted relative risk was 0.67 (95% CI, 0.65 to 0.71) for the end point of any revascularization in women relative to men. The relative risk increased to 0.69 (CI, 0.66 to 0.72) with partial adjustment and to 0.98 (CI, 0.94 to 1.03) with full adjustment, indicating equivalent access to revascularization for men and women. For PCI, the corresponding relative risks were 0.77 (CI, 0.73 to 0.82), 0.84 (CI, 0.80 to 0.89), and 1.02 (CI, 0.96 to 1.08). For CABG surgery, the relative risks were 0.54 (CI, 0.51 to 0.58), 0.51 (CI, 0.48 to 0.55), and 0.93 (CI, 0.87 to 1.01).

CONCLUSIONS

In Alberta, Canada, clinical variables fully explain sex differences in rates of revascularization after cardiac catheterization, and misleading conclusions would arise without full adjustment for clinical differences between men and women. Extreme caution is needed in interpreting reports on access to care that use sparsely detailed clinical data sources.

Multiple imputation versus data enhancement for dealing with missing data in observational health care outcome analyses

The problem of missing data is frequently encountered in observational studies. We compared approaches to dealing with missing data. Three multiple imputation methods were compared with a method of enhancing a clinical database through merging with administrative data. The clinical database used for comparison contained information collected from 6,065 cardiac care patients in 1995 in the province of Alberta, Canada. The effectiveness of the different strategies was evaluated using measures of discrimination and goodness of fit for the 1995 data. The strategies were further evaluated by examining how well the models predicted outcomes in data collected from patients in 1996. In general, the different methods produced similar results, with one of the multiple imputation methods demonstrating a slight advantage. It is concluded that the choice of missing data strategy should be guided by statistical expertise and data resources.

Comparison of 2 methods for calculating adjusted survival curves from proportional hazards models

CONTEXT

Adjusted survival curves are often presented in medical research articles. The most commonly used method for calculating such curves is the mean of covariates method, in which average values of covariates are entered into a proportional hazards regression equation. Use of this method is widespread despite published concerns regarding the validity of resulting curves.

OBJECTIVE

To compare the mean of covariates method to the less widely used corrected group prognosis method in an analysis evaluating survival in patients with and without diabetes. In the latter method, a survival curve is calculated for each level of covariates, after which an average survival curve is calculated as a weighted average of the survival curves for each level of covariates.

DESIGN, SETTING, AND PATIENTS

Analysis of cohort study data from 11 468 Alberta residents undergoing cardiac catheterization between January 1, 1995, and December 31, 1996.

MAIN OUTCOME MEASURES

Crude and risk-adjusted survival for up to 3 years after cardiac catheterization in patients with vs without diabetes, analyzed by the mean of covariates method vs the corrected group prognosis method.

RESULTS

According to the mean of covariates method, adjusted survival at 1044 days was 94.1% and 94.9% for patients with and without diabetes, respectively, with misleading adjusted survival curves that fell above the unadjusted curves. With the corrected group prognosis method, the corresponding survival values were 91.3% and 92.4%, with curves that fell more appropriately between the unadjusted curves.

CONCLUSIONS

Misleading adjusted survival curves resulted from using the mean of covariates method of analysis for our data. We recommend using the corrected group prognosis method for calculating risk-adjusted curves.

Validation of three myocardial jeopardy scores in a population-based cardiac catheterization cohort

BACKGROUND

The Jeopardy Score from Duke University and the Myocardial Jeopardy Index from the Bypass Angioplasty Revascularization Investigation (BARI) have been validated but never applied to a large unselected cohort. We assessed the prognostic value of these existing jeopardy scores, along with that of a new Lesion Score developed for the Alberta Provincial Project for Outcome Assessment in Coronary Heart Disease (APPROACH), a clinical data collection initiative capturing all patients undergoing cardiac catheterization in the province of Alberta.

METHODS

The predictive value of these three scores were compared in a cohort of >20,000 patients (9922 treated medically, 6334 treated with percutaneous intervention, and 3811 treated with bypass surgery). Scores were considered individually in logistic regression models for their ability to predict outcome and then added to models containing sociodemographic data, comorbidities, ejection fraction, indication for procedure, and descriptors of coronary anatomy.

RESULTS

All scores were found to be predictive of 1-year mortality, especially when patients are treated medically or with percutaneous intervention. In these patients, the APPROACH Lesion Score performed slightly better than the other jeopardy scores. The Duke Jeopardy Score was most predictive in those patients undergoing coronary bypass surgery.

CONCLUSIONS

Myocardial jeopardy scores provide independent prognostic information for patients with ischemic heart disease, especially if those patients are treated medically or with percutaneous intervention. These scores represent potentially valuable tools in cardiovascular outcome studies. The APPROACH Lesion Score may perform slightly better than previously developed jeopardy scores.

Psychoeducational group increases vaginal dilation for younger women and reduces sexual fears for women of all ages with gynecological carcinoma treated with radiotherapy

PURPOSE

The association between radiotherapy for gynecological carcinoma and sexual dysfunction is well established. Regular vaginal dilation is widely recommended to these women as a way for them to maintain vaginal health and good sexual functioning. However, the compliance rate with this recommendation is low. The purpose of this study was to test the effectiveness of a group psychoeducational program based on the "information-motivation-behavioral skills" model of behavior change in increasing the rate of compliance.

METHODS AND MATERIALS

Thirty-two women with Stage I or II cervical or endometrial carcinoma who were being treated with radiotherapy were randomized and received either the experimental group program or the control intervention that consisted of written information and brief counseling. Outcome measures included global sexual health, knowledge about sexuality and cancer, fears about sexuality after cancer, and vaginal dilation compliance.

RESULTS

Younger women attending the experimental program (44.4%) were significantly more likely to follow recommendations for vaginal dilation than those who received the control intervention (5.6%). Women, regardless of age, who received the experimental intervention reported less fear about sex after cancer treatment. The older women who received the experimental intervention gained more sexual knowledge. There was no evidence that the experimental intervention improved global sexual health.

CONCLUSIONS

This is the first controlled study to provide evidence of an intervention's effectiveness 1. in increasing women's vaginal dilation following radiotherapy for gynecological carcinoma and 2. in reducing their fears about sex after cancer. Most women, particularly younger women, are unlikely to follow the recommendation to dilate unless they are given assistance in overcoming their fears and taught behavioral skills.

Reexamination of sensory integration treatment: a combination of two efficacy studies

Little empirical support exists for the application of sensory integration treatment (SIT) to assist children with learning problems. Treatment efficacy studies are expensive and difficult to carry out, and they have necessarily employed small samples that are inevitably heterogeneous. We have reanalyzed the efficacy of SIT by combining the data from one study involving 29 children in Alberta and a second study involving 67 children in Ontario. The results from each individual study, and now the results from the combined study, lead one to the conclusion that the therapeutic effect of SIT on children with learning deficits is not greater than other, more traditional methods of intervention.

Health behaviours in a Canadian community college sample: prevalence of drug use and interrelationships among behaviours

This study investigated the prevalence of drug use among a Canadian college sample and the covariation of drug taking and other health-related behaviours. A representative sample of students at a community college in Alberta were interviewed using telephone surveys, mail-in questionnaires and face-to-face interviews. Data was collected on drug, alcohol and caffeine use, cigarette smoking, eating habits, sleep habits and exercise. While use of illicit drugs did not appear to be widespread, alcohol appeared to be a primary substance abuse problem for a minority of subjects. Factor analysis indicated that the various health habits did not form one dimension of health-related behaviours. Four separate factors emerged: abusive drinking, eating habits, a drug use factor (caffeine intake, smoking, cannabis and hallucinogen use), and exercise levels. Findings are discussed in terms of their implications for future research, treatment and intervention.

The role of the pontis oralis in the generation of RSA activity in the hippocampus of the guinea pig

The relationship between field activity in the nucleus pontis oralis (PnO) and the hippocampus was examined in the guinea pig. Rhythmical slow activity (RSA or theta activity) could be recorded from both the pontis oralis and the hippocampus. RSA recorded in the pontis oralis was of the same principal frequency as that found in the hippocampus, but had a much lower amplitude. Behavioral correlates of PnO RSA were the same as the behavioral correlates of hippocampal RSA. The effects of atropine sulfate on RSA were the same at each site. Stimulation of the PnO produced RSA in the hippocampus. Lesions of the PnO had no effect on RSA recorded from the hippocampus or on the behavioral correlates of this RSA. Lesions of the medial septum abolished RSA in both sites. Cross-correlations between field activity recorded from both the hippocampus and PnO showed the same time lag before and after septal lesions. These results indicate that while the PnO is not instrumental in the production of hippocampal RSA, an intact septum is necessary for the production of RSA in both sites. They also indicate that there is a common projection to these sites which does not pass through the medial septum.

Modality specific type 2 theta production in the immobile rat

The purpose of the present study was to compare the relative effectiveness of stimulation of different sensory modalities in eliciting Type 2 theta in the rat in the presence or absence of a ferret. Visual, auditory, and tactile stimuli were presented to rats in both conditions. Tactile stimulation produced more movement than either visual or auditory stimuli when the ferret was present. In both conditions, however, more Type 2 theta was observed in response to tactile or visual stimulation than to auditory stimulation. In the arousal condition, stimulation of tactile and auditory modalities resulted in significant increases in the amount of Type 2 theta produced. Input to the visual modality produced high levels of Type 2 theta production in both low- and high-arousal conditions. It is argued that Type 2 theta is not necessarily a precursor to movement but rather sensory processing while in a high state of arousal.

Modality specific Type 2 theta production in the immobile rat

The purpose of the present study was to compare the relative effectiveness of stimulation of different sensory modalities in eliciting Type 2 theta in the rat in the presence or absence of a ferret. Visual, auditory, and tactile stimuli were presented to rats in both conditions. Tactile stimulation produced more movement than either visual or auditory stimuli when the ferret was present. In both conditions, however, more Type 2 theta was observed in response to tactile or visual stimulation than to auditory stimulation. In the arousal condition, stimulation of tactile and auditory modalities resulted in significant increases in the amount of Type 2 theta produced. Input to the visual modality produced high levels of Type 2 theta production in both low- and high-arousal conditions. It is argued that Type 2 theta is not necessarily a precursor to movement but rather sensory processing while in a high state of arousal.