Recent Improvements in Attainment of the Hemoglobin A1c Target of ≤7.0% Among Adults with Type 1 Diabetes in Ontario: A Retrospective Cohort Study

Aims: We evaluated attainment of the hemoglobin A1c (HbA1c) target of ≤7.0%, its temporal trends, and associated factors among adults with type 1 diabetes in Ontario, Canada, using administrative data. Methods: We conducted a retrospective cohort study, including Ontarians with type 1 diabetes ≥18 years old with ≥1 HbA1c test between April 1, 2012 (fiscal year 2013), and March 31, 2023. Generalized estimating equations were used to determine probabilities of meeting the HbA1c target, as well as associations between fiscal year and individual-, physician-, and system-level factors on odds of meeting the target. Results: Among 28,827 adults with type 1 diabetes [14,385 (49.9%) female, 17,998 (62.4%) pump users], with median age at index of 25 years [interquartile range (IQR) 18-37] and median diabetes duration of 12 years [6-18], there were 474,714 HbA1c tests [median 2/individual/year (IQR: 1-3)]. The model-estimated probability of meeting the HbA1c target of ≤7.0% was 22.1% (95% confidence interval, CI: 21.6 to 22.5) in 2013, remained stable until 2020, and increased to 34.7% (95% CI: 34.3 to 35.2) in 2023. The age- and sex-adjusted odds ratio for meeting the target in 2023 versus 2013 was 1.87 (95% CI: 1.79 to 1.96). Young adults (18-25 years), diabetic ketoacidosis, greater comorbidity, and receiving diabetes care from a nonspecialist physician were associated with reduced odds of meeting the HbA1c target. Conclusions: One-third of adults with type 1 diabetes in Ontario met the recommended HbA1c target of ≤7.0% in 2023, with improvement noted since 2021, which may be due to advanced technologies or effects of the COVID-19 pandemic.

Factors Associated With Attainment of Glycemic Targets Among Adults With Type 1 and Type 2 Diabetes in Canada: A Cross-sectional Study Using Primary and Specialty Care Electronic Medical Record Data

OBJECTIVE

Using a new database combining primary and specialty care electronic medical record (EMR) data in Canada, we determined attainment of glycemic targets and associated predictors among adults with diabetes.

METHODS

We conducted a cross-sectional observational study combining primary and specialty care EMR data in Canada. Adults with diabetes whose primary care provider contributed to the National Diabetes Repository or who were assessed at a diabetes specialty clinic (LMC Diabetes and Endocrinology) between July 3, 2015, and June 30, 2019, were included. Diabetes type was categorized as type 2 diabetes (T2D) not prescribed insulin, T2D prescribed insulin, and type 1 diabetes (T1D). Covariates were age, sex, income quintile, province, rural/urban location, estimated glomerular filtration rate, medications, and insulin pump use. Associations between predictors and the outcome (glycated hemoglobin [A1C] of ≤7.0%) were assessed by multivariable logistic regressions.

RESULTS

Among 122,106 adults, consisting of 91,366 with T2D not prescribed insulin, 25,131 with T2D prescribed insulin, and 5,609 with T1D, attainment of an A1C of ≤7.0% was 60%, 25%, and 23%, respectively. Proportions with an A1C of ≤7.5% and ≤8.0% were 75% and 84% for those with T2D not prescribed insulin, 41% and 57% for those with T2D prescribed insulin, and 37% and 53% for those with T1D. Highest vs lowest income quintile was associated with greater odds of meeting the A1C target (adjusted odds ratio [95% confidence interval] for each diabetes category: 1.15 [1.10 to 1.21], 1.21 [1.10 to 1.33], and 1.29 [1.04 to 1.60], respectively). Individuals in Alberta and Manitoba had less antihyperglycemic medication use and attainment of A1C target than other provinces.

CONCLUSIONS

Attainment of glycemic targets among adults with diabetes was poor and differed by income and geographic location, which must be addressed in national diabetes strategies.

Point-of-Care Capillary Blood Ketone Measurements and the Prediction of Future Ketoacidosis Risk in Type 1 Diabetes

OBJECTIVE

Rather than during illness while diabetic ketoacidosis (DKA) is developing, we aimed to determine if levels of routine point-of-care capillary blood ketones could predict future DKA.

RESEARCH DESIGN AND METHODS

We examined previously collected data from placebo-assigned participants in an adjunct-to-insulin medication trial program that included measurement of fasted capillary blood ketone levels twice per week in a 2-month baseline period. The outcome was 6- to 12-month trial-adjudicated DKA.

RESULTS

DKA events occurred in 12 of 484 participants at a median of 105 (interquartile range 43, 199) days. Maximum ketone levels were higher in patient cases compared with in control patients (0.8 [0.6, 1.2] vs. 0.3 [0.2, 0.7] mmol/L; P = 0.002), with a nonparametric area under the receiver operating characteristic curve of 0.77 (95% CI 0.66-0.88). Ketone levels ≥0.8 mmol/L had a sensitivity of 64%, a specificity of 78%, and positive and negative likelihood ratios of 2.9 and 0.5, respectively.

CONCLUSIONS

This proof of concept that routine capillary ketone surveillance can identify individuals at high risk of future DKA implies a role for future technologies including continuous ketone monitoring.

Growing Income-Related Disparities in Cardiovascular Hospitalizations Among People With Diabetes, 1995-2019: A Population-Based Study

OBJECTIVE

Cardiovascular risk reduction is an important focus in the management of people with diabetes. Although event rates have been declining over the long term, they have been observed to plateau or reverse in recent years. Furthermore, the impact of income-related disparities in cardiovascular events is unknown. The objective of this study is to evaluate age-, sex-, and income-related trends in cardiovascular hospitalization rates among people with diagnosed diabetes.

RESEARCH DESIGN AND METHODS

We calculated rates of hospitalization for acute myocardial infarction, stroke, heart failure, and lower-extremity amputation in annual cohorts of the entire population of Ontario, Canada, with diagnosed diabetes, from 1995 to 2019. Event rates were stratified by age, sex, and income level.

RESULTS

We studied nearly 1.7 million people with diabetes. The rate of acute myocardial infarction declined throughout the 25-year study period (P < 0.0001), such that the rate in 2019 was less than half the rate in 1995. Rates of stroke (P < 0.0001), heart failure (P < 0.0001), and amputation (P < 0.0001) also changed over time, but hospitalization rates stabilized through the 2010s. This apparent stabilization concealed a growing income-related disparity: wealthier patients showed continued declines in rates of these outcomes during the decade, whereas rates for lower-income patients increased (P for interaction < 0.0001 for all four outcomes).

CONCLUSIONS

During a quarter-century of follow-up, cardiovascular hospitalization rates among people with diabetes fell. However, the apparent stabilization in rates of stroke, heart failure, and amputation in recent years masks the fact that rates have risen for lower-income individuals.

Diabetic retinopathy screening integrated in a multidisciplinary diabetes care clinic: a pilot project of cardiac and renal endocrine clinic

OBJECTIVE

To characterize patients referred for diabetic retinopathy (DR) screening in a unique multidisciplinary diabetes care clinic at a tertiary care centre.

METHODS

A retrospective study was conducted involving patients who were referred to the Cardiac and Renal Endocrine Clinic at a tertiary care centre (University Health Network) for DR screening between April 2019-March 2020 and November 2020-August 2021. Patients' demographics; micro- and macrovascular disease measurements; and visual acuity, intraocular pressure, fundus imaging, and optical coherence tomography results were collected and analyzed.

RESULTS

Of the 64 patients who attended the clinic, 21 patients (33%) with type 2 diabetes had on-site DR screening. The remaining 43 patients had DR screening within 6 months of the appointment or were under ophthalmology care with annual screening visits elsewhere. Of the 21 patients who underwent retinopathy screening, 7 patients (33%) had DR: 4 had mild nonproliferative DR, 2 had moderate nonproliferative DR, 1 had proliferative DR, and 1 had macular edema. Patients with DR had a significantly longer diabetes duration than patients without DR (24.5 ± 10.2 years vs 12.5 ± 5.8 years; p = 0.0247). No significant differences were observed in glycemic control, blood pressure, lipid profiles, kidney function, visual acuity, or intraocular pressure.

CONCLUSIONS

Our analysis suggests a potential benefit of integrated DR screening in patients with long-standing diabetes as part of a multidisciplinary diabetes care clinic to diagnose and manage DR. Future work is needed to further develop such clinics and investigate their long-term effect on patient outcomes.

Improving diagnosis and treatment of knee osteoarthritis in persons with type 2 diabetes: development of a complex intervention

BACKGROUND

Symptomatic knee osteoarthritis (OA) commonly co-occurs in people with type 2 diabetes (T2DM) and increases the risk for diabetes complications, yet uptake of evidence-based treatment is low. We combined theory, stakeholder involvement and existing evidence to develop a multifaceted intervention to improve OA care in persons with T2DM. This was done in partnership with Arthritis Society Canada to leverage the existing infrastructure and provincial funding for community arthritis care.

METHODS

Each step was informed by a User Advisory Panel of stakeholder representatives, including persons with lived experience. First, we identified the target groups and behaviours through consulting stakeholders and current literature. Second, we interviewed persons living with T2DM and knee OA (n = 18), health professionals (HPs) who treat people with T2DM (n = 18) and arthritis therapists (ATs, n = 18) to identify the determinants of seeking and engaging in OA care (patients), assessing and treating OA (HPs) and considering T2DM in OA treatment (ATs), using the Theoretical Domains Framework (TDF). We mapped the content to behavioural change techniques (BCTs) to identify the potential intervention components. Third, we conducted stakeholder meetings to ascertain the acceptability and feasibility of intervention components, including content and modes of delivery. Fourth, we selected intervention components informed by prior steps and constructed a programme theory to inform the implementation of the intervention and its evaluation.

RESULTS

We identified the barriers and enablers to target behaviours across a number of TDF domains. All stakeholders identified insufficient access to resources to support OA care in people with T2DM. Core intervention components, incorporating a range of BCTs at the patient, HP and AT level, sought to identify persons with knee OA within T2DM care and refer to Arthritis Society Canada for delivery of evidence-based longitudinal OA management. Diverse stakeholder input throughout development allowed the co-creation of an intervention that appears feasible and acceptable to target users.

CONCLUSIONS

We integrated theory, evidence and stakeholder involvement to develop a multifaceted intervention to increase the identification of knee OA in persons with T2DM within diabetes care and improve the uptake and engagement in evidence-based OA management. Our partnership with Arthritis Society Canada supports future spread, scalability and sustainability. We will formally assess the intervention feasibility in a randomized pilot trial.

Formulating Knee Osteoarthritis Management Plans Taking Type 2 Diabetes Into Account: Qualitative Study of Arthritis Therapists Using Theoretical Domains Framework

OBJECTIVE

Delivering person-centered care in individuals with knee osteoarthritis (OA) necessitates consideration of other chronic conditions that frequently co-occur. We sought to understand the extent to which arthritis therapists consider type 2 diabetes mellitus (T2DM) when treating persons with knee OA and concomitant T2DM, and barriers to doing so.

METHODS

We conducted 18 semistructured telephone interviews with arthritis therapists working within a provincially funded arthritis care program (Arthritis Society Canada) in Ontario, Canada. We first analyzed interviews deductively using the Theoretical Domains Framework (TDF) to comprehensively identify barriers and enablers to health behaviors. Then, within TDF domains, we inductively developed themes.

RESULTS

We identified 5 TDF domains as prominently influencing the behavior of arthritis therapists considering concomitant T2DM when developing a knee OA management plan. These were as follows: therapists' perceived lack of specific knowledge around comorbidities including diabetes; the lack of breadth in skills in behavioral change techniques to help patients set and reach their goals, particularly when it came to physical activity; variable intention to factor a patient's comorbidity profile to influence their treatment recommendations; the perception of their professional role and identity as joint focused; and the environmental context with lack of formalized follow-up structure of the current Arthritis Society Canada program that limited sufficient patient monitoring and follow-up.

CONCLUSION

Within the context of a Canadian arthritis program, we identified several barriers to arthritis therapists considering T2DM in their management plan for persons with knee OA and T2DM. These results can help inform strategies to improve person-centered OA care and overall health outcomes.

Understanding the behavioural determinants of seeking and engaging in care for knee osteoarthritis in persons with type 2 diabetes mellitus: A qualitative study using the theoretical domains framework

Objectives

Symptomatic knee osteoarthritis (OA) frequently co-occurs in individuals with type 2 diabetes mellitus (T2DM). In the context of T2DM, OA is often underdiagnosed and undertreated. To elucidate strategies to improve OA care in persons with T2DM, we assessed their perceptions of the barriers and enablers to seeking and engaging in OA care.

Design

We conducted semi-structured interviews with 18 individuals with T2DM and symptomatic knee OA in Ontario, Canada. Transcripts were deductively coded using the Theoretical Domains Framework (TDF), an implementation science framework that incorporates theoretical domains of behaviour determinants, which can be linked to behaviour change techniques. Within each of the relevant domains, data were thematically analyzed to generate belief statements.

Results

Seven of the TDF domains prominently influenced the behaviour to seek and engage in OA care. Participants described insufficient receipt of OA knowledge to fully engage in care (knowledge), feeling incapable of participating in physical activity due to joint pain (beliefs about capabilities), uncertainty about effectiveness of therapies (optimism) and lack of guidance from health care providers and insufficient access to community programs/supports (environmental context and resources). Key enablers were strong social support (social influences), sources of accountability (behavioural regulation) and experiencing benefit from treatment (reinforcement). Participants did not see concomitant T2DM as limiting the desire to seek OA care.

Conclusions

Among individuals with symptomatic knee OA and T2DM, we identified behavioural determinants of seeking and engaging in OA care. These will be mapped to behavioural change techniques to inform development of a complex intervention.

Barriers and enablers to health care providers assessment and treatment of knee osteoarthritis in persons with type 2 diabetes mellitus: A qualitative study using the Theoretical Domains Framework

Objectives

Symptomatic knee osteoarthritis (OA) commonly co-exists in persons with Type 2 diabetes (T2DM) and may impede diabetes self-management. Yet, OA is often underdiagnosed and undertreated due to competing health care demands. We sought to determine healthcare providers' (HCPs') perceptions of the barriers and enablers to assessing and treating knee OA in persons with T2DM.

Design

We conducted 18 semi-structured telephone interviews with HCPs who manage persons with T2DM (family physicians, endocrinologists, diabetes educators). Interviews were analyzed deductively using Theoretical Domains Framework (TDF), a framework developed to comprehensively identify behavioural determinants. Within relevant domains, data were thematically analyzed to generate belief statements, and these were compared across the different HCP disciplines.

Results

Six TDF domains influenced HCPs behaviour to assess and treat knee OA in persons with T2DM. For all HCPs, important barriers included not seeing assessment/treatment of joint pain as a priority for their patients (intention), and insufficient access to required resources such as physiotherapy to treat OA (environmental context and resources). Endocrinologists and diabetes educators perceived having insufficient knowledge and skills to identify and manage OA (knowledge, skills), did not consider it within their professional role to do so (professional role and identity), and perceived other physicians would not want to receive a referral for OA care (social influences).

Conclusions

We identified barriers and enablers encountered by diabetes HCPs to assessing and treating knee OA in persons with T2DM involving multiple domains of the TDF. These will help inform development of a complex intervention to improve health outcomes.

Trends in the Association Between Diabetes and Cardiovascular Events, 1994-2019

This study uses administrative health care data from Ontario, Canada, to assess whether changes in diabetes management practices have affected trends in the association between diabetes vs prior cardiovascular disease and risk of cardiovascular events from 1994 to 2019 among adults aged 20 to 84 years.

'It's a Dance Between Managing Both': a qualitative study exploring perspectives of persons with knee osteoarthritis and type 2 diabetes mellitus on the impact of osteoarthritis on diabetes management and daily life

OBJECTIVES

Type 2 diabetes (T2DM) and knee osteoarthritis (OA) commonly co-occur and epidemiologic studies suggest concomitant symptomatic knee OA increases the risk of T2DM complications. We sought to explore the experiences and perspectives of individuals' living with both symptomatic knee OA and T2DM, with a focus on the impact of OA on T2DM management and daily life.

DESIGN

We conducted qualitative semistructured telephone interviews with persons living with T2DM and knee OA. We inductively coded and analysed interview transcripts, informed by interpretative description.

SETTING

We recruited participants from a community arthritis self-management programme and an academic hospital's family medicine clinic in Ontario, Canada.

PARTICIPANTS

We included 18 participants who had a physician diagnosis of both T2DM and knee OA, with variation age, gender, and duration of T2DM and knee OA.

RESULTS

Participants with T2DM described how concomitant painful and disabling knee OA made it difficult to engage in physical activity, negatively impacting blood glucose control. Joint pain itself, associated sleep disturbance and emotional distress were also seen to affect blood glucose control. Beyond diabetes management, the impact of OA-related pain and functional limitations on nearly all aspects of daily life led participants to view their OA as important. Despite this, many participants described that their health professionals paid little attention to their OA, which left them to self-manage. Balancing both conditions also required navigating a medical system that provided piecemeal care.

CONCLUSIONS

Individuals with T2DM view symptomatic knee OA as an important barrier to both T2DM management and overall well-being, yet are frequently met with insufficient support from health professionals. Greater recognition and management of knee OA in persons with T2DM could help improve patient-centred care and potentially disease outcomes.

Renal hemodynamic dysfunction and neuropathy in longstanding type 1 diabetes: Results from the Canadian study of longevity in type 1 diabetes

AIMS

To determine the relationship between renal hemodynamic function and neuropathy in adults with ≥50-years of type 1 diabetes (T1D) compared to nondiabetic controls.

METHODS

Glomerular filtration rate (GFR, inulin), effective renal plasma flow (ERPF, p-aminohippurate), modified Toronto Clinical Neuropathy Score (mTCNS), corneal confocal microscopy, nerve conduction, and heart rate variability (autonomic function) were measured; afferent (RA) and efferent (RE) arteriolar resistances were estimated using the Gomez equations in 74 participants with T1D and in 75 controls. Diabetic kidney disease (DKD) non-resistors were defined by eGFRMDRD < 60 ml/min/1.73 m2 or 24-h urine albumin excretion >30 mg/day. Linear regression was applied to examine the relationships between renal function (dependent variable) and neuropathy measures (independent variable), adjusted for age, sex, HbA1c, systolic blood pressure, low density lipoprotein cholesterol, and 24-h urine albumin to creatinine ratio.

RESULTS

Higher mTCNS associated with lower renal blood flow (β ± SE:-9.29 ± 4.20, p = 0.03) and greater RE (β ± SE:32.97 ± 15.43, p = 0.04) in participants with T1D, but not in controls. DKD non-resistors had a higher mTCNS and worse measures of corneal nerve morphology compared to those without DKD. Renal hemodynamic parameters did not associate with autonomic nerve function.

CONCLUSIONS

Although neurological dysfunction in the presence of diabetes may contribute to impaired renal blood flow resulting in ischemic injury in patients with T1D, early autonomic dysfunction does not appear to be associated with kidney function changes.

A Unique Multi- and Interdisciplinary Cardiology-Renal-Endocrine Clinic: A Description and Assessment of Outcomes

Background:

Patients with diabetes and co-existing chronic kidney disease and/or cardiovascular disease have complex medical needs with multiple indications for different guideline-directed medical therapies and require high health care resource utilization. The Cardiac and Renal Endocrine Clinic (C.a.R.E. Clinic) is a multi- and interdisciplinary clinic offering a unique care model to this population to overcome barriers to optimal care.

Objective:

To describe the patient characteristics and clinical data of consecutive patients seen in the C.a.R.E. Clinic between 2014 and 2020, with a focus on the feasibility, strengths, and challenges of this outpatient care model.

Design:

Single-center retrospective cohort study.

Setting:

The C.a.R.E. Clinic is a multi- and interdisciplinary clinic at Toronto General Hospital in Toronto, Canada.

Patients:

We reviewed the charts of all 118 patients who had been referred to the C.a.R.E. Clinic with type 2 diabetes mellitus, co-existing renal disease, and/or cardiovascular disease.

Measurements:

Demographic data, medication data, clinic blood pressure measurements, and laboratory data were assessed at the first and last available clinic visit.

Methods:

Data were extracted via manual chart review of paper and electronic medical records.

Results:

First and last attended clinic visit data were available for descriptive analysis in 74 patients. There was a significant improvement in low-density lipoprotein (LDL) cholesterol (1.9 mmol/L vs 1.5 mmol/L, P < .01), hemoglobin A1C (7.5% vs 7.1%, P = .02), and the proportion of patients with blood pressure at target (52.7% vs 36.5%, P = .04), but not body mass index (29.7 kg/m² vs 29.6 kg/m², P = .15) between the last and first available clinic visits. There was higher uptake in evidence-based medication use including statins (93.2% vs 81.1%, P = .01), SGLT-2i (35.1% vs 4.1%, P < .01), and GLP-1 receptor agonists (13.5% vs 4.1%, P = .02), while RAAS inhibitor use was already high at baseline (81.8% vs 78.4%, P = .56). There remains a significant opportunity for therapy with sodium-glucose cotransporter-2 inhibitors and glucagon-like peptide-1 receptor agonists.

Limitations:

This is a retrospective chart review lacking a control group, therefore clinical improvements cannot be causally attributed to the clinic alone. New evidence and changes to guideline-recommended therapies also contributed to practice changes during this time period.

Conclusions:

A multi- and interdisciplinary clinic is a feasible and potentially effective way to improve evidence-based and patient-centered care for patients with diabetes, kidney, and cardiovascular disease.

The association between physical activity time and neuropathy in longstanding type 1 diabetes: A cross-sectional analysis of the Canadian study of longevity in type 1 diabetes

AIM

Physical activity (PA) is recommended to improve glycemic control in T1D; however, the effect of PA on distal symmetric polyneuropathy (DSPN) and cardiac autonomic function in longstanding T1D is unknown.

METHODS

Data from 75 participants were collected as part of the Canadian Study of Longevity in T1D. Participants completed a physical exam, medical history, extensive complications phenotyping and reported their daily PA from the preceding 12-months. Pearson and Spearman correlations were used to assess PA time and complications variables. Linear regression was used to test associations between PA time, neurological and electrophysiological measures. Univariable regression was used to indicate the change in the given independent variables associated with a 30-min increase in PA per week.

RESULTS

Participants were 66 ± 8 years old with diabetes duration of 54 [52,58] years, HbA_1c was 7.3 ± 0.8, 65(89%) had DSPN. Weekly PA time was 156 ± 132 min, and 35(47%) reported ≧150 min/week. Participants with DSPN reported lower PA time compared to individuals without DSPN (141 ± 124 min/week vs. 258 ± 129 min/week; p = 0.015). PA time was associated with better cooling detection threshold (r = 0.24; p = 0.043), peroneal and sural amplitude (r = 0.36; p = 0.0017, r_s = 0.26; p = 0.024) and conduction velocity (r_s = 0.28; p = 0.015, r = 0.23; p = 0.050). Linear regression adjusting for age and HbA1c, showed that for each 30-min of PA there was a 0.09mv higher peroneal amplitude (p = 0.032) and 0.048 ms lower peroneal F-wave latency (p = 0.022).

CONCLUSION

In longstanding T1D, PA time is associated with superior large nerve fibre function in the lower limbs and some better measures of small nerve fibre function.

Glycaemic control in transition-aged versus early adults with type 1 diabetes and the effect of a government-funded insulin pump programme

AIM

To compare glycaemic control and adverse outcomes between transition-aged and early adults with type 1 diabetes, and the impact of continuous subcutaneous insulin infusion (CSII) therapy funded through a government Assisted Devices Program.

METHODS

This retrospective cohort study using healthcare administrative databases from Ontario, Canada included adults aged 18-35 with type 1 diabetes between 1 April 2011 and 31 March 2014. Mean HbA_1c was compared between transition-aged (18-24 years) and early adults (25-35 years), overall and stratified by whether or not they received government-funded CSII therapy (CSII vs. non-CSII). Secondary outcomes included rates of hospitalizations/emergency department visits for hyperglycaemia and hypoglycaemia over a 3-year follow-up. Comparisons were adjusted for relevant covariates.

RESULTS

Among 7157 participants with type 1 diabetes, mean HbA_1c was significantly higher for transition-aged compared to early adults (71 mmol/mol [8.68%] vs. 64 mmol/mol [8.04%], p < 0.0001). This difference was smaller among CSII compared to non-CSII users (p = 0.02 for interaction between age group and CSII use). The transition-age group were more likely to experience a hyperglycaemic event compared to early adults (adjusted risk ratio, aRR: 1.56, 95% confidence interval [CI]: 1.25-1.96), which was attenuated by CSII use (aRR: 1.13, 95% CI: 0.7-1.69).

CONCLUSIONS

Transition-aged adults with type 1 diabetes had a significantly higher mean HbA_1c and risk of hyperglycaemic events compared to early adults. This difference was attenuated for CSII users, indicating that a government-funded CSII programme is associated with narrowing of the gap in glycaemic control and associated adverse outcomes for this population.

Tattoo artists and dental workers have similar musculoskeletal pain patterns

BACKGROUND

Tattoo artists are an understudied population with regards to musculoskeletal (MSK) pain.

AIMS

To explore the characteristics of MSK pain among Israeli tattoo artists and determine whether they are similar to those of dental workers.

METHODS

An online survey including demographics and the Hebrew version of the Extended Nordic Musculoskeletal Questionnaire was disseminated via Israeli social media groups. We directly compared tattoo artists, dental workers and office workers as a reference group.

RESULTS

Altogether, 114 tattoo artists, 161 dental workers and 296 office workers responded. The most prevalent pain sites were lower back (56%), neck (47%) and hand (36%) among office workers; neck (67%), lower back (62%) and upper back (42%) among the dental workers; and lower back (72%), neck (66%) and hand (55%) among tattoo artists. Contrast analysis suggested office workers were less likely to report pain in the previous 12 months compared with dental workers and tattoo artists (adjusted odds ratios [95% confidence intervals]: ORs [95% CIs] for upper limb pain: 1.13 [1.01-1.28], neck pain: 1.3 [1.15-1.47], upper back pain: 1.27 [1.12-1.43] and low back pain: 1.15 [1.02-1.3]). No significant differences were observed between dental workers and tattoo artists (upper limb pain: 1.18 [0.9-1.54], neck pain: 1.06 [0.81-1.4], upper back pain: 1.22 [0.94-1.58] and low back pain: 1.24 [0.95-1.64]).

CONCLUSIONS

Tattoo artists and dental workers have similar MSK pain characteristics and are different from those of office workers. These characteristics are seemingly a direct result of the physical demands associated with their line of work.

Impact of government-funded insulin pump programs on insulin pump use in Canada: a cross-sectional study using the National Diabetes Repository

INTRODUCTION

Insulin pump access in type 1 diabetes may be inequitable. We studied the association between government funding programs for insulin pumps and rates of insulin pump use and disparities between pump users and non-users.

RESEARCH DESIGN AND METHODS

Adults with type 1 diabetes were identified in the National Diabetes Repository, a primary care electronic medical record database of individuals with diabetes from five Canadian provinces. Proportions of individuals using insulin pumps were compared between provinces with and without pump funding programs. Multivariable logistic regression models were used to estimate the odds of insulin pump use adjusting for confounders. Univariate logistic regression models were used to estimate the odds of insulin pump use according to each predictor, according to pump funding program status.

RESULTS

Of 1559 adults with type 1 diabetes, proportions using insulin pumps were 47.8% (95% CI 45.1% to 50.5%) and 37.7% (95% CI 31.5% to 44.1%) in provinces with and without pump funding programs (p=0.0038). Adjusting for age, sex, HbA1c, income quintile, and rural/urban location, the OR for insulin pump use was 1.45 (1.08-1.94) for provinces with pump funding programs compared with provinces without. Higher income was associated with a greater odds of insulin pump use in provinces with pump funding programs, and rural/urban location was not associated with insulin pump use.

CONCLUSIONS

Insulin pump use is more common in regions with government funding programs. Further research is required to best understand and comprehensively address persistent income disparities between pump users and non-users despite the availability of reimbursement programs.

Allopurinol adherence, persistence and patterns of use in individuals with diabetes and gout: A retrospective, population-based cohort analysis

OBJECTIVE

There has been growing interest in the potential role for allopurinol to reduce cardiovascular events in people with diabetes. While adherence to allopurinol is poor in those with gout, our aim was to characterize persistence, patterns of use, and predictors of allopurinol use in a population-based cohort of individuals with diabetes and gout.

METHODS

Individuals with diabetes older than 66 (thus eligible for prescription medication coverage) and newly prescribed allopurinol were followed for up to three years in a retrospective cohort study. Allopurinol use patterns were categorized as adherer (used continuously throughout follow-up), interrupter (non-persistent but subsequently resumed), or discontinuer (non-persistent with no subsequent resumption). Main outcomes were allopurinol non-persistence (no subsequent prescription accounting for a grace period), and indicators of gout severity throughout follow-up (prescriptions for prednisone or colchicine, outpatient gout visits, hospitalization/emergency department visits for gout). Outcome frequencies were determined, a multivariable Cox proportional hazards model evaluated associations between predictors and non-persistence, and zero-inflated negative binomial (ZINB) models evaluated associations between allopurinol use pattern and indicators of gout severity.

RESULTS

22,056 individuals were followed for a maximum of 3.0 years (17,410 with 3 years of follow-up). 9092 (41.2%) were non-persistent with allopurinol. Higher risks of non-persistence were associated with female sex (HR, 95% CI: 1.28, 1.23-1.33), dementia (1.23, 1.11-1.35), and an outpatient visit for gout in the prior year (1.19, 1.09-1.29). There were 12,964 (58.8%) allopurinol adherers, 4618 interrupters (20.9%), and 4474 (20.3%) discontinuers. Allopurinol interrupters and discontinuers had indicators of more severe gout over time compared to adherers, including greater odds of being prescribed prednisone.

CONCLUSION

Allopurinol non-persistence and interruptions were frequent in individuals with diabetes and gout and were associated with prescriptions for prednisone. Suboptimal allopurinol adherence may not only increase the risk of gout complications in this population but also potentially diabetes complications through greater prednisone use and its negative effects on glycemic control.

Response to: 'Effectiveness of allopurinol on reducing mortality: Time-related biases in observational studies'

We read with great interest the manuscript by Suissa et al that reviewed observational studies of the association between allopurinol and mortality in individuals with gout (1). Suissa describes immeasurable time bias as time periods during which prescription medication records are not available (e.g. hospitalizations), leading to at-risk time being potentially misclassified as unexposed-time. Suissa recommends accounting for the possibility of immeasurable time bias by evaluating hospitalizations during follow-up or using an analytic approach that is weighted by measurable time (2).

Allopurinol and Renal Outcomes in Adults With and Without Type 2 Diabetes: A Retrospective, Population-Based Cohort Study and Propensity Score Analysis

OBJECTIVES

Elevated uric acid (UA) is common in diabetes and is implicated in the pathogenesis of chronic kidney disease (CKD). Lowering UA with allopurinol may delay CKD progression. We assessed the association between allopurinol and renal outcomes in older adults both with and without diabetes, and whether this differed by diabetes status.

METHODS

We conducted a population-based, retrospective cohort study of older adults ≥66 years of age with a gout flare using administrative data from Ontario, Canada. The primary outcome was doubling of creatinine or kidney failure. Secondary outcomes were a composite of death or kidney failure, decline in estimated glomerular filtration rate by >30%, death and kidney failure. New allopurinol users were compared with nonusers using Cox proportional hazards models and inverse probability of treatment weighting (IPTW). An interaction between allopurinol use and presence or absence of diabetes was assessed.

RESULTS

Among 5,937 older adults with a gout flare (1,911 with diabetes), 1,304 (22%) were newly treated with allopurinol. Median follow-up time was 1.11 (interquartile range, 0.33 to 3.21) years for allopurinol users and 3.38 (interquartile range, 1.42 to 4.43) years for nonusers. There was no association between allopurinol use and the primary outcome (IPTW-adjusted hazard ratio, 0.97; 95% confidence interval, 0.72 to 1.31), and this did not differ by diabetes status. Allopurinol use was not associated with any of the secondary outcomes.

CONCLUSIONS

Allopurinol use was not associated with renal outcomes in older adults with or without diabetes. This supports the interpretation of UA as a biomarker of CKD risk rather than a modifiable target for prevention or treatment of CKD.

Reporting and variability of constructing medication treatment episodes in pharmacoepidemiology studies: A methodologic systematic review using the case study of DPP-4 inhibitors and cardiovascular outcomes

PURPOSE

In pharmacoepidemiologic studies, estimating medication adherence, persistence, and exposure patterns is critical. Constructing medication treatment episodes from prescription claims data involves assumptions related to grace period, carry-over, and lag effect, but there are no guidelines for these assumptions. We evaluated reporting and variability of these parameters in pharmacoepidemiology studies, using a case study of antihyperglycemic medications and major adverse cardiovascular events (MACE).

METHODS

We conducted a systemic review using MEDLINE and EMBASE for studies published prior to January 2, 2020 comparing the risk of MACE between dipeptidyl peptidase 4 (DPP-4) inhibitors and active comparators. We extracted study characteristics and results, including grace period, carry-over, and lag effect. Risk of bias was assessed by the Newcastle-Ottawa scale, and assessments for prevalent user, immortal time, time lag, and time window biases.

RESULTS

A total of 14/1850 studies identified were included. Grace period was not reported in 5 (35.7%) studies and ranged from 0 days to 180 days when reported. Carry-over was not reported in 10 studies (71.4%). Lag effect was not reported in nine (71.4%) studies and ranged from 0 days to 180 days when reported. No studies conducted sensitivity analyses examining the effects of these assumptions on study findings. Predominant biases were inadequate follow-up time, comparability of cohorts, prevalent use, and lag time bias.

CONCLUSIONS

Use of grace period, carry-over, and lag effect were poorly reported and highly variable. Future pharmacoepidemiology studies should improve reporting, justify ranges for these parameters, and conduct sensitivity analyses to evaluate effects of these assumptions.

Validation of a type 1 diabetes algorithm using electronic medical records and administrative healthcare data to study the population incidence and prevalence of type 1 diabetes in Ontario, Canada

INTRODUCTION

We aimed to develop algorithms distinguishing type 1 diabetes (T1D) from type 2 diabetes in adults ≥18 years old using primary care electronic medical record (EMRPC) and administrative healthcare data from Ontario, Canada, and to estimate T1D prevalence and incidence.

RESEARCH DESIGN AND METHODS

The reference population was a random sample of patients with diabetes in EMRPC whose charts were manually abstracted (n=5402). Algorithms were developed using classification trees, random forests, and rule-based methods, using electronic medical record (EMR) data, administrative data, or both. Algorithm performance was assessed in EMRPC. Administrative data algorithms were additionally evaluated using a diabetes clinic registry with endocrinologist-assigned diabetes type (n=29 371). Three algorithms were applied to the Ontario population to evaluate the minimum, moderate and maximum estimates of T1D prevalence and incidence rates between 2010 and 2017, and trends were analyzed using negative binomial regressions.

RESULTS

Of 5402 individuals with diabetes in EMRPC, 195 had T1D. Sensitivity, specificity, positive predictive value and negative predictive value for the best performing algorithms were 80.6% (75.9-87.2), 99.8% (99.7-100), 94.9% (92.3-98.7), and 99.3% (99.1-99.5) for EMR, 51.3% (44.0-58.5), 99.5% (99.3-99.7), 79.4% (71.2-86.1), and 98.2% (97.8-98.5) for administrative data, and 87.2% (81.7-91.5), 99.9% (99.7-100), 96.6% (92.7-98.7) and 99.5% (99.3-99.7) for combined EMR and administrative data. Administrative data algorithms had similar sensitivity and specificity in the diabetes clinic registry. Of 11 499 711 adults in Ontario in 2017, there were 24 789 (0.22%, minimum estimate) to 102 140 (0.89%, maximum estimate) with T1D. Between 2010 and 2017, the age-standardized and sex-standardized prevalence rates per 1000 person-years increased (minimum estimate 1.7 to 2.56, maximum estimate 7.48 to 9.86, p<0.0001). In contrast, incidence rates decreased (minimum estimate 0.1 to 0.04, maximum estimate 0.47 to 0.09, p<0.0001).

CONCLUSIONS

Primary care EMR and administrative data algorithms performed well in identifying T1D and demonstrated increasing T1D prevalence in Ontario. These algorithms may permit the development of large, population-based cohort studies of T1D.

Bone mineral density in patients with longstanding type 1 diabetes: Results from the Canadian Study of Longevity in Type 1 Diabetes

AIM

It is currently unclear if longstanding type 1 diabetes (T1D) affects bone mineral density (BMD).

METHODS

BMD measured by dual-energy X-ray absorptiometry and history of fragility fracture was determined in 75 T1D participants with ≥50 years of diabetes duration and 75 age- and sex-matched non-diabetic controls. BMD T-scores were determined for the lumbar spine (LS), total hip (TH) and femoral neck (FN).

RESULTS

T1D participants had median diabetes duration of 54 [52, 58] years, 41 (55%) were females, and mean A_1c was 7.3 ± 0.8%. T1D females had higher LS T-scores compared to female controls (-0.3 ± 1.2 vs. -1.1 ± 1.4, p = 0.014), lower FN T-scores (-1.5 ± 1.0 vs. -1.2 ± 0.9, p = 0.042) and more fragility fractures (7 (17%) vs. 1 (2%), p = 0.021). In T1D, higher A1c was associated with higher adjusted odds of fragility fracture (p = 0.006). T1D males and controls showed no difference in BMD or fractures.

CONCLUSIONS

There were no substantial differences in T-score between T1D and matched controls; however, T1D females showed higher BMD at the LS and possibly paradoxically higher fragility fractures compared to matched controls. These findings suggest that lower T-scores may not be associated with a history of fragility fracture in females with longstanding T1D and that other factors should be investigated.

Analysis of Prevalence, Magnitude and Timing of the Dawn Phenomenon in Adults and Adolescents With Type 1 Diabetes: Descriptive Analysis of 2 Insulin Pump Trials

OBJECTIVES

To better understand the dawn phenomenon in type 1 diabetes, we sought to determine its prevalence, timing and magnitude in studies specifically designed to assess basal insulin requirements in patients using insulin pumps.

METHODS

Thirty-three participants from 2 sensor-augmented insulin pump studies were analyzed. Twenty participants were obtained from a methodologically ideal semiautomated basal analysis trial in which basal rates were determined from repeated fasting tests (the derivation set) and 13 from an artificial pancreas trial in which duration of fasting was variable (the "confirmation" set). Prevalence was determined for the total cohort and for individual trials using the standard definition of an increase in insulin exceeding 20% and lasting ≥90 minutes. Among cases, time of onset and percent change in the magnitude of basal delivery were determined.

RESULTS

Seventeen participants (52%) experienced the dawn phenomenon (11 of 20 [55%] in the derivation set and 6 of 13 [46%] in the confirmation set). Time of onset was 3 AM (interquartile range [IQR], 3 to 4:15 AM) in the derivation set and 3 AM (IQR, 3 to 4 AM) in the confirmation set. The magnitude of the dawn phenomenon was a 58.1% (IQR, 28.8% to 110.6%) increase in insulin requirements in the derivation set and 65.5% (IQR, 45.6% to 87.4%) in the confirmation set.

CONCLUSIONS

The dawn phenomenon occurs in approximately half of patients with type 1 diabetes; when present, it has predictable timing of onset (generally 3 AM) and a substantial, but highly variable, magnitude. These findings imply that optimization of glycemic control requires clinical emphasis on fasted overnight basal insulin assessment.

Elevated plasma cyclic guanosine monophosphate may explain greater efferent arteriolar tone in adults with longstanding type 1 diabetes: A brief report

Cyclic guanosine monophosphate (cGMP) influences intrarenal hemodynamics in animal models, but the relationship between cGMP and renal function in adults with type 1 diabetes (T1D) remains unclear. In this study, plasma cGMP correlated with efferent arteriolar resistance, effective renal plasma flow, and renal vascular resistance in adults with T1D.

Association between allopurinol and cardiovascular outcomes and all-cause mortality in diabetes: A retrospective, population-based cohort study

AIM

To assess the association between allopurinol and mortality and cardiovascular outcomes in an allopurinol-treated diabetes cohort.

MATERIALS AND METHODS

We conducted a population-based retrospective cohort study in Ontario, Canada. Eligible subjects were ≥ 66 years old with diabetes and a first prescription for allopurinol between 1 April, 2002 and 31 March, 2012 and were followed until 31 March, 2016. The primary outcome was a composite: all-cause mortality, non-fatal cardiovascular event (myocardial infarction, revascularization procedure, or stroke) or congestive heart failure (CHF). Secondary outcomes were components of the primary outcome and pneumonia as a negative tracer. Allopurinol was modelled as time-varying exposed versus unexposed, daily dose category and cumulative dose using sex-specific multivariable Cox proportional hazards models.

RESULTS

Over a median follow-up of 4.65 years (interquartile range 1.79-7.81), 16 266/23 103 males and 10 571/15 313 females experienced the primary outcome. Allopurinol was associated with a reduction in the primary outcome [adjusted hazard ratios (aHR) 0.77 (95% confidence interval 0.75-0.80) and 0.81 (0.78-0.84) for males and females, respectively], driven by marked reductions in all-cause mortality and modest reductions in cardiovascular events/CHF. There was no effect of cumulative allopurinol dose on any outcome, and allopurinol was also associated with reduced risk of pneumonia in males [aHR 0.88 (0.83, 0.93)].

CONCLUSIONS

Allopurinol was associated with reduced mortality and cardiovascular outcomes. However, lack of cumulative dose effect and a positive tracer outcome in males suggests residual bias. Future research assessing whether allopurinol prevents vascular complications in diabetes requires a clinical trial.

Association between uric acid, renal haemodynamics and arterial stiffness over the natural history of type 1 diabetes

AIMS

To examine the relationship between normal plasma uric acid (PUA) levels, renal haemodynamic function, arterial stiffness and plasma renin and aldosterone over a wide range of type 1 diabetes (T1D) durations in adolescents, young adults and older adults.

MATERIALS AND METHODS

PUA, glomerular filtration rate (GFR), effective renal plasma flow (ERPF), vascular stiffness parameters (aortic augmentation index [AIx], carotid AIx, carotid femoral pulse wave velocity [cfPWV]), and plasma renin and aldosterone were measured during a euglycaemic clamp in people with T1D: 27 adolescents (mean ± SD age 16.8 ± 1.9 years), 52 young adults (mean ± SD age 25.6 ± 5.5 years) and 66 older adults (mean ± SD age 65.7 ± 7.5 years).

RESULTS

PUA was highest in patients with the longest T1D duration: 197 ± 44 μmol/L in adolescents versus 264 ± 82 μmol/L in older adults (P < 0.001). Higher PUA correlated with lower GFR only in older adults, even after correcting for age, glycated haemoglobin and sex (β = -2.12 ± 0.56; P = 0.0003), but not in adolescents or young adults. Higher PUA correlated with lower carotid AIx (β = -1.90, P = 0.02) in adolescents. In contrast, PUA correlated with higher cfPWV (P = 0.02) and higher plasma renin (P = 0.01) in older adults with T1D.

CONCLUSIONS

The relationship between higher PUA with lower GFR, increased arterial stiffness and renin angiotensin aldosterone system (RAAS) activation was observed only in older adults with longstanding T1D. T1D duration may modify the association between PUA, renal haemodynamic function and RAAS activation, leading to renal vasoconstriction and ischaemia. Further work must determine whether pharmacological PUA-lowering prevents or reverses injurious haemodynamic and neurohormonal sequelae of longstanding T1D, thereby improving clinical outcomes.

The relationships between markers of tubular injury and intrarenal haemodynamic function in adults with and without type 1 diabetes: Results from the Canadian Study of Longevity in Type 1 Diabetes

OBJECTIVE

Our aim was to define the relationships between plasma biomarkers of kidney injury and intrarenal haemodynamic function (glomerular filtration rate [GFR], effective renal plasma flow [ERPF], renal vascular resistance [RVR]) in adults with type 1 diabetes (T1D).

METHODS

The study sample comprised patients with longstanding T1D (duration ≥50 years), among whom 44 were diabetic kidney disease (DKD) resistors (eGFR >60 mL/min/1.73 m² and <30 mg/d urine albumin excretion) and 22 had DKD, in addition to 73 control participants. GFR_INULIN and ERPF_PAH were measured, RVR was calculated, and afferent (R_A )/efferent (R_E ) areteriolar resistances were derived from Gomez equations. Plasma neutrophil gelatinase-associated lipocalin (NGAL), β2 microglobulin (B2M), osteopontin (OPN) and uromodulin (UMOD) were measured using immunoassay kits from Meso Scale Discovery.

RESULTS

Plasma NGAL, B2M and OPN were higher and UMOD was lower in DKD patients vs DKD resistors and non-diabetic controls. In participants with T1D, plasma NGAL inversely correlated with GFR (r = -0.33; P = 0.006) and ERPF (r = -0.34; P = 0.006), and correlated positively with R_A (r = 0.26; P = 0.03) and RVR (r = 0.31; P = 0.01). In participants without T1D, NGAL and B2M inversely correlated with GFR (NGAL r = -0.18; P = 0.13 and B2M r = -0.49; P < 0.0001) and with ERPF (NGAL r = -0.19; P = 0.1 and B2M r = -0.42; P = 0.0003), and correlated positively with R_A (NGAL r = 0.19; P = 0.10 and B2M r = 0.3; P = 0.01) and with RVR (NGAL r = 0.20; P = 0.09 and B2M r = 0.34; P = 0.003). Differences were significant after adjusting for age, sex, HbA1c, SBP and LDL. There were statistical interactions between T1D status, B2M and intrarenal haemodynamic function (P < 0.05).

CONCLUSIONS

Elevated NGAL relates to intrarenal haemodynamic dysfunction in T1D, whereas elevated NGAL and B2M relate to intrarenal haemodynamic dysfunction in adults without T1D. These data may define a diabetes-specific interplay between tubular injury and intrarenal haemodynamic dysfunction.

Renal Hemodynamic Function and RAAS Activation Over the Natural History of Type 1 Diabetes

RATIONALE & OBJECTIVE

The renin-angiotensin-aldosterone system (RAAS) is associated with renal and cardiovascular disease in diabetes. Unfortunately, early RAAS blockade in patients with type 1 diabetes mellitus (T1DM) does not prevent the development of complications. We sought to examine the role of hyperfiltration and RAAS activation across a wide range of T1DM duration to better understand renal hemodynamic status in patients with T1DM.

STUDY DESIGN

Post hoc analysis of blood samples.

SETTING & PARTICIPANTS

148 Canadian patients with T1DM: 28 adolescents (aged 16.2±2.0 years), 54 young adults (25.4±5.6 years), and 66 older adults (65.7±7.5 years) studied in a clinical investigation unit.

EXPOSURE

Angiotensin II infusion (1ng/kg/min; a measure of RAAS activation) during a euglycemic clamp.

OUTCOMES

Glomerular filtration rate measured using inulin clearance, effective renal plasma flow measured using para-aminohippurate, afferent (R_A) and efferent (R_E) arteriolar resistances, and glomerular hydrostatic pressure estimated using the Gomez equations.

RESULTS

In a stepwise fashion, glomerular filtration rate, effective renal plasma flow, and glomerular hydrostatic pressure were higher, while renal vascular resistance and R_A were lower in adolescents versus young adults versus older adults. R_E was similar in adolescents versus young adults but was higher in older adults. Angiotensin II resulted in blunted renal hemodynamic responses in older adults (renal vascular resistance increase of 3.3% ± 1.6% vs 4.9% ± 1.9% in adolescents; P<0.001), suggesting a state of enhanced RAAS activation.

LIMITATIONS

Homogeneous study participants limit the generalizability of findings to other populations. Studying older adult participants with T1DM may be associated with a survivorship bias.

CONCLUSIONS

A state of relatively low RAAS activity and predominant afferent dilation rather than efferent constriction characterize early adolescents and young adults with T1DM. This state of endogenous RAAS inactivity in early T1DM may explain why pharmacologic blockade of this neurohormonal system is often ineffective in reducing kidney disease progression in this setting. Older adults with long-standing T1DM who have predominant afferent constriction and RAAS activation may experience renoprotection from therapies that target the afferent arteriole. Further work is required to understand the potential role of non-RAAS pharmacologic agents that target R_A in patients with early and long-standing T1DM.

Estimating GFR by Serum Creatinine, Cystatin C, and β2-Microglobulin in Older Adults: Results From the Canadian Study of Longevity in Type 1 Diabetes

Introduction

Glomerular filtration rate (GFR) is routinely used for clinical assessment of kidney function. However, the accuracy of estimating equations in older adults is uncertain.

Methods

In 66 adults with ≥50 years type 1 diabetes (T1D) duration and 73 nondiabetic controls from age/sex-matched subgroups (65 ± 8 years old and 77[55%] were women) we evaluated the performance of estimated GFR (eGFR) by creatinine (Modification of Diet and Renal Disease [MDRD], Chronic Kidney Disease–Epidemiology [CKD-EPI]_cr), cystatin C (CKD-EPI_cys, CKD-EPI_cr-cys), and β₂-microglobulin (β2M) compared with measured GFR by inulin clearance (mGFR). Performance was evaluated using metrics of bias (mean difference), precision (SD), and accuracy (proportion of eGFR that differed by >20% of mGFR).

Results

Mean mGFR was 104 ± 18 ml/min per 1.73 m² (range: 70–154 ml/min per 1.73 m²) and was not different between T1D and controls (103 ± 17 vs. 105 ± 19 ml/min per 1.73 m², P = 0.39). All equations significantly underestimated mGFR (bias: −15 to −30 ml/min per 1.73 m², P < 0.001 for all comparisons) except for β2M, which had bias of 1.9 ml/min per 1.73 m² (P = 0.61). Bias was greatest in cystatin C–based equations. Precision was lowest for β2M (SD: 43.5 ml/min per 1.73 m², P < 0.001 for each comparison). Accuracy was lowest for CKD-EPI_cysC (69.1%, P < 0.001 for each comparison). Cystatin C–based equations demonstrated greater bias and lower accuracy in older age subgroups (<60, 60–69, ≥70 years). All equations demonstrated greater bias across higher ranges of mGFR (60–89, 90–119, ≥120 ml/min per 1.73 m²). Results were similar between T1D and controls except that β2M had lower performance in T1D.

Conclusion

Better estimates of GFR in older adults are needed for research and clinical practice, as this subgroup of the population has an amplified risk for the development of chronic kidney disease (CKD) that requires accurate GFR estimation methods.

Old Drugs for New Indications in Cardiovascular Medicine

Inflammation participates in the initiation and progression of atherosclerotic cardiovascular disease, and it is a critical inciting factor leading to acute ischemic events. Evidence has shown that certain anti-inflammatory medications used to treat non-atherosclerotic inflammatory diseases reduce cardiovascular events. This article reviews evidence that commonly used anti-inflammatory therapies (colchicine, allopurinol, methotrexate), reduce cardiovascular events. We discuss potential mechanisms of action, efficacy, and safety of these therapies and propose a clinical trials design to investigate their efficacy.

Atherosclerosis and Microvascular Complications: Results From the Canadian Study of Longevity in Type 1 Diabetes

OBJECTIVE

Type 1 diabetes carries a significant risk for cardiovascular mortality, but it is unclear how atherosclerosis associates with microvascular complications. We aimed to determine the relationships between atherosclerotic burden and neuropathy, retinopathy, and diabetic kidney disease (DKD) in adults with a ≥50-year history of type 1 diabetes.

RESEARCH DESIGN AND METHODS

Adults with type 1 diabetes (n = 69) underwent coronary artery calcification (CAC) volume scoring by wide-volume computerized tomography. Microvascular complications were graded as follows: neuropathy by clinical assessment, electrophysiology, vibration and cooling detection thresholds, heart rate variability, and corneal confocal microscopy; retinopathy by ultra-wide-field retinal imaging; and DKD by renal hemodynamic function measured by inulin and para-aminohippurate clearance at baseline and after intravenous infusion of angiotensin II. The cohort was dichotomized to high (≥300 Agatston units [AU]) or low (<300 AU) CAC and was stratified by diabetes status. A comparator group without diabetes (n = 73) matched for age and sex also underwent all study procedures except for retinal imaging.

RESULTS

CAC scores were higher in participants with type 1 diabetes (median Agatston score 1,000 [interquartile range = 222, 2,373] AU vs. 1 [0.75] AU in comparators, P < 0.001). In participants with type 1 diabetes, high CAC scores associated with markers of neuropathy and retinopathy, but not with DKD, or renal hemodynamic function at baseline or in response to angiotensin II.

CONCLUSIONS

The presence of high CAC in adults with longstanding type 1 diabetes was associated with large nerve fiber neuropathy and retinopathy but not with renal hemodynamic function, suggesting that neuropathy, retinopathy, and macrovascular calcification share common risk factors.

Sex differences in neuropathic pain in longstanding diabetes: Results from the Canadian Study of Longevity in Type 1 Diabetes

AIM

Neuropathy and neuropathic pain are common complications of type 1 diabetes (T1D). We aimed to determine if sex-specific differences in neuropathic pain are present in adults with longstanding T1D.

METHODS

Canadians with ≥50 years of T1D (n = 361) completed health history questionnaires that included assessment of neuropathy (defined by Michigan Neuropathy Screening Instrument questionnaire components ≥3; NEUROPATHY_MNSI-Q) and neuropathic pain. Multivariable logistic regression was used to determine sex-differences in neuropathic pain controlling for neuropathy.

RESULTS

Participants had mean age 66 ± 9 years, median diabetes duration 53[51,58] years, mean HbA1c 7.5 ± 1.0%, and 207(57%) were female. Neuropathic pain was present in 128(36%) of all participants, more prevalent among those with NEUROPATHY_MNSI-Q compared to those without [96(63%) vs. 31(15%), p < 0.001], and more prevalent in females compared to males [87(42%) vs. 41(27%), p = 0.003]. Independent of the presence of NEUROPATHY_MNSI-Q and other factors, female sex was associated with the presence of neuropathic pain [OR 2.68 (95% CI 1.4-5.0), p = 0.002].

CONCLUSIONS

We demonstrated a novel sex-specific difference in neuropathic pain in females compared to males with longstanding T1D, independent of the presence of neuropathy. Further research using more objective measures of neuropathy than the MNSI is justified to further understand this sex-specific difference.

Validity of a point-of-care nerve conduction device for polyneuropathy identification in older adults with diabetes: Results from the Canadian Study of Longevity in Type 1 Diabetes

Objective

Point-of-care nerve conduction devices (POCD) have been studied in younger patients and may facilitate screening for polyneuropathy in non-specialized clinical settings. However, performance may be impaired with advanced age owing to age-related changes in nerve conduction. We aimed to evaluate the validity of a POCD as a proxy for standard nerve conduction studies (NCS) in older adults with type 1 diabetes (T1D).

Methods

Sural nerve amplitude potential (AMP) and sural nerve conduction velocity (CV) was measured in 68 participants with ≥ 50 years T1D duration and 71 controls (from age/sex-matched subgroups) using POCD and NCS protocols. Agreement was determined by the Bland-Altman method, and validity was determined by receiver operating characteristic curves.

Results

T1D were 53% female, aged 66±8yr and had diabetes duration 54yr[52,58]. Controls were 56%(p = 0.69) female and aged 65±8yr(p = 0.36). Mean AMP_POCD and CV_POCD for the 139 participants was 7.4±5.8μV and 45.7±11.2m/s and mean AMP_NCS and CV_NCS was 7.2±6.1μV and 43.3±8.3m/s. Mean difference of AMP_POCD−AMP_NCS was 0.3±3.8μV and was 2.3±8.5m/s for CV_POCD−CV_NCS. A AMP_POCD of ≤6μV had 80% sensitivity and 80% specificity for identifying abnormal AMP_NCS, while a CV_POCD of ≤44m/s had 81% sensitivity and 82% specificity to identify abnormal CV_NCS. Abnormality in AMP_POCD or CV_POCD was associated with 87% sensitivity, while abnormality in both measures was associated with 97% specificity for polyneuropathy identification.

Conclusions

The POCD has strong agreement and diagnostic accuracy for identification of polyneuropathy in a high-risk subgroup and thus may represent a sufficiently accurate and rapid test for routinely detecting those with electrophysiological dysfunction.

Adiposity Impacts Intrarenal Hemodynamic Function in Adults With Long-standing Type 1 Diabetes With and Without Diabetic Nephropathy: Results From the Canadian Study of Longevity in Type 1 Diabetes

OBJECTIVE

Central adiposity is considered to be an important cardiorenal risk factor in the general population and in type 1 diabetes. We sought to determine the relationship between central adiposity and intrarenal hemodynamic function in adults with long-standing type 1 diabetes with and without diabetic nephropathy (DN).

RESEARCH DESIGN AND METHODS

Patients with type 1 diabetes (n = 66, duration ≥50 years) and age-/sex-matched control subjects (n = 73) were studied. The cohort was stratified into 44 DN Resistors (estimated glomerular filtration rate [eGFR] >60 mL/min/1.73 m² and <30 mg/day urine albumin) and 22 patients with DN (eGFR ≤60 mL/min/1.73 m² or ≥30 mg/day urine albumin). Intrarenal hemodynamic function (glomerular filtration rate for inulin [GFR_INULIN], effective renal plasma flow for p-aminohippuric acid [ERPF_PAH]) was measured. Afferent arteriolar resistance, efferent arteriolar resistance, renal blood flow, renal vascular resistance [RVR], filtration fraction, and glomerular pressure were derived from the Gomez equations. Fat and lean mass were quantified by DXA.

RESULTS

Whereas measures of adiposity did not associate with GFR_INULIN or ERPF_PAH in healthy control subjects, trunk fat mass inversely correlated with GFR_INULIN (r = -0.46, P < 0.0001) and ERPF_PAH (r = -0.31, P = 0.01) and positively correlated with RVR (r = 0.53, P = 0.0003) in type 1 diabetes. In analyses stratified by DN status, greater central adiposity related to lower GFR_INULIN values in DN and DN Resistors, but the relationships between central adiposity and ERPF_PAH and RVR were attenuated and/or reversed in patients with DN compared with DN Resistors.

CONCLUSIONS

The adiposity-intrarenal hemodynamic function relationship may be modified by the presence of type 1 diabetes and DN, requiring further study of the mechanisms by which adiposity influences renal hemodynamic function.

Evolving Trends in the Epidemiology, Risk Factors, and Prevention of Type 2 Diabetes: A Review

Currently, the global prevalence of diabetes is 8.8%. This figure is expected to increase worldwide, with the largest changes projected to occur in low- and middle-income countries. The aging of the world's population and substantial increases in obesity have contributed to the rise in diabetes. Global shifts in lifestyles have led to the adoption of unhealthy behaviours such as physical inactivity and poorer-quality diets. Correspondingly, diabetes is a rapidly-increasing problem in higher- as well as lower-income countries. In Canada, the prevalence of diabetes increased approximately 70% in the past decade. Although diabetes-related mortality rates have decreased in Canada, the number of people affected by diabetes has continued to grow because of a surge in the number of new diabetes cases. Non-European ethnic groups and individuals of lower socioeconomic status have been disproportionately affected by diabetes and its risk factors. Clinical trials have proven efficacy in reducing the onset of diabetes in high-risk populations through diet and physical activity interventions. However, these findings have not been broadly implemented into the Canadian health care context. In this article we review the evolving epidemiology of type 2 diabetes, with regard to trends in occurrence rates and prevalence; the role of risk factors including those related to ethnicity, obesity, diet, physical activity, socioeconomic status, prediabetes, and pregnancy; and the identification of critical windows for lifestyle intervention. Identifying high-risk populations and addressing the upstream determinants and risk factors of diabetes might prove to be effective diabetes prevention strategies to curb the current diabetes epidemic.

Renin-angiotensin-aldosterone system activation in long-standing type 1 diabetes

BACKGROUND

In type 1 diabetes (T1D), adjuvant treatment with inhibitors of the renin-angiotensin-aldosterone system (RAAS), which dilate the efferent arteriole, is associated with prevention of progressive albuminuria and renal dysfunction. Uncertainty still exists as to why some individuals with long-standing T1D develop diabetic kidney disease (DKD) while others do not (DKD resistors). We hypothesized that those with DKD would be distinguished from DKD resistors by the presence of RAAS activation.

METHODS

Renal and systemic hemodynamic function was measured before and after exogenous RAAS stimulation by intravenous infusion of angiotensin II (ANGII) in 75 patients with prolonged T1D durations and in equal numbers of nondiabetic controls. The primary outcome was change in renal vascular resistance (RVR) in response to RAAS stimulation, a measure of endogenous RAAS activation.

RESULTS

Those with DKD had less change in RVR following exogenous RAAS stimulation compared with DKD resistors or controls (19%, 29%, 31%, P = 0.008, DKD vs. DKD resistors), reflecting exaggerated endogenous renal RAAS activation. All T1D participants had similar changes in renal efferent arteroilar resistance (9% vs. 13%, P = 0.37) irrespective of DKD status, which reflected less change versus controls (20%, P = 0.03). In contrast, those with DKD exhibited comparatively less change in afferent arteriolar vascular resistance compared with DKD resistors or controls (33%, 48%, 48%, P = 0.031, DKD vs. DKD resistors), indicating higher endogenous RAAS activity.

CONCLUSION

In long-standing T1D, the intrarenal RAAS is exaggerated in DKD, which unexpectedly predominates at the afferent rather than the efferent arteriole, stimulating vasoconstriction.

FUNDING

JDRF operating grant 17-2013-312.

Diabetes Care Disparities in Long-standing Type 1 Diabetes in Canada and the U.S.: A Cross-sectional Comparison

OBJECTIVE

To assess national differences in diabetes care and quality of life (QOL) between individuals with long-standing type 1 diabetes (≥50 years) in Canada and the U.S.

RESEARCH DESIGN AND METHODS

Cross-sectional data from identical surveys administered in the Canadian Study of Longevity in Diabetes and the Joslin Medalist Study, collected in 2013-2016 and 2005-2011, respectively, were compared. Laboratory values and ophthalmic examination were completed by clinical care physicians for Canadians and the Joslin Clinic for Americans. Univariate comparisons and multivariable regression for HbA_1c, QOL, insulin pump use, and coronary artery disease (CAD) were performed. Nephropathy, CAD, and peripheral arterial disease (PAD) were self-reported; neuropathy was defined by a Michigan Neuropathy Screening Instrument (Questionnaire component) score ≥3, and proliferative retinopathy was documented from ophthalmic examination. QOL was self-reported on an ordinal scale.

RESULTS

Three hundred sixty-one Canadians and 668 Americans had similar ages (mean 65.78 years [SD 8.67] vs. 66.38 years [7.66], P = 0.27) and durations of diabetes (median 53.00 years [interquartile range 51.00, 58.00] vs. 53.00 years [51.00, 57.00], P = 0.51). Canadians had higher HbA_1c (mean 7.53% [SD 1.03] [59 mmol/mol] vs. 7.22% [0.98] [55 mmol/mol], P < 0.0001), lower QOL (36.9% vs. 48.7% with "excellent" QOL, P = 0.0002), and less CAD (29.7% vs. 41.2%, P = 0.0003) and insulin pump use (43.3% vs. 55.6%, P = 0.0002). Other complication rates were similar. Residual differences for Canadians compared with Americans remained after adjustment for age, sex, CAD, PAD, education, and relevant a priori selected variables: 0.28% higher HbA_1c (P = 0.0004); and odds ratios of 0.68 (95% CI 0.51, 0.90), 0.46 (0.31, 0.68), and 0.71 (0.52, 0.96) for higher QOL, CAD, and insulin pump use, respectively.

CONCLUSIONS

Although Canadians and Americans have similar rates of complications other than CAD, further research is required to understand why Canadians have higher HbA_1c levels, lower QOL, and less insulin pump use.