Characteristics of new users of recent antidiabetic drugs in Canada and the United Kingdom.

BACKGROUND: Characteristics of patients using newer 2nd and 3rd line antidiabetic drugs in a real-world setting are poorly understood. We described the characteristics of new users of sodium-glucose co-transporter-2 inhibitors (SGLT-2i), dipeptidyl peptidase-4 inhibitors (DPP-4i), and glucagon-like peptide-1 receptor agonists (GLP-1 RA) in Canada and the United Kingdom (UK) between 2016 and 2018. METHODS: We conducted a multi-database cohort study using administrative health databases from 7 Canadian provinces and the UK Clinical Practice Research Datalink. We assembled a base cohort of antidiabetic drug users between 2006 and 2018, from which we constructed 3 cohorts of new users of SGLT-2i, DPP-4i, and GLP-1 RA between 2016 and 2018. RESULTS: Our cohorts included 194,070 new users of DPP-4i, 166,722 new users of SGLT-2i, and 27,719 new users of GLP-1 RA. New users of GLP-1 RA were more likely to be younger (mean ± SD: 56.7 ± 12.2 years) than new users of DPP-4i (67.8 ± 12.3 years) or SGLT-2i (64.4 ± 11.1 years). In Canada, new users of DPP-4i were more likely to have a history of coronary artery disease (22%) than new users of SGLT-2i (20%) or GLP-1 RA (15%). CONCLUSION: Although SGLT-2i, DPP-4i, and GLP-1 RAs are recommended as 2nd or 3rd line therapy for type 2 diabetes, important differences exist in the characteristics of users of these drugs. Contrary to existing guidelines, new users of DPP-4i had a higher prevalence of cardiovascular disease at baseline than new users of SGLT2i or GLP-1RA.

Validity of an algorithm to identify cardiovascular deaths from administrative health records: a multi-database population-based cohort study.

BACKGROUND: Cardiovascular death is a common outcome in population-based studies about new healthcare interventions or treatments, such as new prescription medications. Vital statistics registration systems are often the preferred source of information about cause-specific mortality because they capture verified information about the deceased, but they may not always be accessible for linkage with other sources of population-based data. We assessed the validity of an algorithm applied to administrative health records for identifying cardiovascular deaths in population-based data. METHODS: Administrative health records were from an existing multi-database cohort study about sodium-glucose cotransporter-2 (SGLT2) inhibitors, a new class of antidiabetic medications. Data were from 2013 to 2018 for five Canadian provinces (Alberta, British Columbia, Manitoba, Ontario, Quebec) and the United Kingdom (UK) Clinical Practice Research Datalink (CPRD). The cardiovascular mortality algorithm was based on in-hospital cardiovascular deaths identified from diagnosis codes and select out-of-hospital deaths. Sensitivity, specificity, and positive and negative predictive values (PPV, NPV) were calculated for the cardiovascular mortality algorithm using vital statistics registrations as the reference standard. Overall and stratified estimates and 95% confidence intervals (CIs) were computed; the latter were produced by site, location of death, sex, and age. RESULTS: The cohort included 20,607 individuals (58.3% male; 77.2% ≥70 years). When compared to vital statistics registrations, the cardiovascular mortality algorithm had overall sensitivity of 64.8% (95% CI 63.6, 66.0); site-specific estimates ranged from 54.8 to 87.3%. Overall specificity was 74.9% (95% CI 74.1, 75.6) and overall PPV was 54.5% (95% CI 53.7, 55.3), while site-specific PPV ranged from 33.9 to 72.8%. The cardiovascular mortality algorithm had sensitivity of 57.1% (95% CI 55.4, 58.8) for in-hospital deaths and 72.3% (95% CI 70.8, 73.9) for out-of-hospital deaths; specificity was 88.8% (95% CI 88.1, 89.5) for in-hospital deaths and 58.5% (95% CI 57.3, 59.7) for out-of-hospital deaths. CONCLUSIONS: A cardiovascular mortality algorithm applied to administrative health records had moderate validity when compared to vital statistics data. Substantial variation existed across study sites representing different geographic locations and two healthcare systems. These variations may reflect different diagnostic coding practices and healthcare utilization patterns.

Sodium-Glucose Cotransporter-2 Inhibitors and the Risk for Diabetic Ketoacidosis : A Multicenter Cohort Study.

BACKGROUND: Sodium-glucose cotransporter-2 (SGLT-2) inhibitors could increase the risk for diabetic ketoacidosis (DKA). OBJECTIVE: To assess whether SGLT-2 inhibitors, compared with dipeptidyl peptidase-4 (DPP-4) inhibitors, are associated with an increased risk for DKA in patients with type 2 diabetes. DESIGN: Population-based cohort study; prevalent new-user design between 2013 and 2018. (ClinicalTrials.gov: NCT04017221). SETTING: Electronic health care databases from 7 Canadian provinces and the United Kingdom. PATIENTS: 208 757 new users of SGLT-2 inhibitors were matched by using time-conditional propensity scores to 208 757 recipients of DPP-4 inhibitors. MEASUREMENTS: Cox proportional hazards models estimated site-specific hazard ratios (HRs) with 95% CIs of DKA comparing receipt of SGLT-2 inhibitors with receipt of DPP-4 inhibitors, which were pooled by using random-effects models. Secondary analyses were stratified by molecule, age, sex, and prior receipt of insulin. RESULTS: Overall, 521 patients were diagnosed with DKA during 370 454 person-years of follow-up (incidence rate per 1000 person-years, 1.40 [95% CI, 1.29 to 1.53]). Compared with DPP-4 inhibitors, SGLT-2 inhibitors were associated with an increased risk for DKA (incidence rate, 2.03 [CI, 1.83 to 2.25] versus 0.75 [CI, 0.63 to 0.89], respectively; HR, 2.85 [CI, 1.99 to 4.08]). Molecule-specific HRs were 1.86 (CI, 1.11 to 3.10) for dapagliflozin, 2.52 (CI, 1.23 to 5.14) for empagliflozin, and 3.58 (CI, 2.13 to 6.03) for canagliflozin. Age and sex did not modify the association; prior receipt of insulin appeared to decrease the risk. LIMITATIONS: There was unmeasured confounding and no laboratory data were available for the majority of patients, and molecule-specific analyses were conducted at a limited number of sites. CONCLUSION: SGLT-2 inhibitors were associated with an almost 3-fold increased risk for DKA, with molecule-specific analyses suggesting a class effect. PRIMARY FUNDING SOURCE: Canadian Institutes of Health Research.

Sodium-glucose co-transporter-2 inhibitors and the risk of urosepsis: A multi-site, prevalent new-user cohort study.

AIM: To compare urosepsis rates in patients with type 2 diabetes treated using sodium-glucose co-transporter-2 inhibitors (SGLT2i) with dipeptidyl peptidase-4 inhibitors (DPP4i) in a real-world setting. METHODS: We conducted a matched cohort study using a prevalent new-user design with time-conditional propensity scores. New users of SGLT2i from seven Canadian provinces and the UK were matched to DPP4i users. The primary outcome was hospitalization with a diagnosis of urosepsis and the secondary outcome was Fournier's gangrene. Site-specific hazard ratios for urosepsis comparing SGLT2i with DPP4i were estimated using Cox proportional hazards models and pooled using a random effects meta-analysis. RESULTS: We included 208 244 users of SGLT2i and 208 244 users of DPP4i. Among SGLT2i users, 42% initiated canagliflozin, 31% dapagliflozin and 27% empagliflozin. During a mean follow-up of 0.9 years, patients initiating SGLT2i had a lower rate of urosepsis compared with those receiving DPP4i. The pooled adjusted hazard ratio was 0.58 (95% confidence interval [CI]: 0.42-0.80). The incidence rates of Fournier's gangrene were numerically similar in SGLT2i (0.08 per 1000 person-years; 95% CI: 0.05-0.13) and DPP4i users (0.14; 95% CI: 0.09-0.21). CONCLUSIONS: In this large, multi-site study, we did not observe an increased risk for urosepsis associated with SGLT2i compared with DPP4i among patients with type 2 diabetes in a real-world setting.

Sodium glucose cotransporter 2 inhibitors and risk of major adverse cardiovascular events: multi-database retrospective cohort study.

OBJECTIVE: To compare the risk of cardiovascular events between sodium glucose cotransporter 2 (SGLT2) inhibitors and dipeptidyl peptidase-4 (DPP-4) inhibitors among people with type 2 diabetes in a real world context of clinical practice. DESIGN: Multi-database retrospective cohort study using a prevalent new user design with subsequent meta-analysis. SETTING: Canadian Network for Observational Drug Effect Studies (CNODES), with administrative healthcare databases from seven Canadian provinces and the United Kingdom, 2013-18. POPULATION: 209 867 new users of a SGLT2 inhibitor matched to 209 867 users of a DPP-4 inhibitor on time conditional propensity score and followed for a mean of 0.9 years. MAIN OUTCOME MEASURES: The primary outcome was major adverse cardiovascular events (MACE, a composite of myocardial infarction, ischaemic stroke, or cardiovascular death). Secondary outcomes were the individual components of MACE, heart failure, and all cause mortality. Cox proportional hazards models were used to estimate site specific adjusted hazards ratios and 95% confidence intervals, comparing use of SGLT2 inhibitors with use of DPP-4 inhibitors in an as treated approach. Site specific results were pooled using random effects meta-analysis. RESULTS: Compared with DPP-4 inhibitors, SGLT2 inhibitors were associated with decreased risks of MACE (incidence rate per 1000 person years: 11.4 v 16.5; hazard ratio 0.76, 95% confidence interval 0.69 to 0.84), myocardial infarction (5.1 v 6.4; 0.82, 0.70 to 0.96), cardiovascular death (3.9 v 7.7; 0.60, 0.54 to 0.67), heart failure (3.1 v 7.7; 0.43, 0.37 to 0.51), and all cause mortality (8.7 v 17.3; 0.60, 0.54 to 0.67). SGLT2 inhibitors had more modest benefits for ischaemic stroke (2.6 v 3.5; 0.85, 0.72 to 1.01). Similar benefits for MACE were observed with canagliflozin (0.79, 0.66 to 0.94), dapagliflozin (0.73, 0.63 to 0.85), and empagliflozin (0.77, 0.68 to 0.87). CONCLUSIONS: In this large observational study conducted in a real world clinical practice context, the short term use of SGLT2 inhibitors was associated with a decreased risk of cardiovascular events compared with the use of DPP-4 inhibitors. TRIAL REGISTRATION: ClinicalTrials.gov NCT03939624.

Sodium-Glucose Cotransporter 2 Inhibitors and the Risk of Below-Knee Amputation: A Multicenter Observational Study.

OBJECTIVE: Reports of amputations associated with sodium-glucose cotransporter 2 (SGLT2) inhibitors have been inconsistent. We aimed to compare the risk of below-knee amputation with SGLT2 inhibitors versus dipeptidyl peptidase 4 (DPP-4) inhibitors among patients with type 2 diabetes. RESEARCH DESIGN AND METHODS: This multicenter observational study used administrative health care databases from seven Canadian provinces and the U.K. Incident SGLT2 inhibitor users were matched to DPP-4 inhibitor users using a prevalent new-user design and time-conditional propensity scores. Cox proportional hazards models were used to estimate site-specific adjusted hazard ratios (HR) and corresponding 95% CIs of incident below-knee amputation for SGLT2 inhibitor versus DPP-4 inhibitor users. Random effects meta-analyses were used to pool the site-specific results. RESULTS: The study cohort included 207,817 incident SGLT2 inhibitor users matched to 207,817 DPP-4 inhibitor users. During a mean exposed follow-up time of 11 months, the amputation rate was 1.3 per 1,000 person-years among SGLT2 inhibitor users and 1.5 per 1,000 person-years among DPP-4 inhibitor users. The adjusted HR of below-knee amputations associated with SGLT2 inhibitor use compared with DPP-4 inhibitor use was 0.88 (95% CI 0.71-1.09). Similar results were obtained in stratified analyses by specific SGLT2 inhibitor molecule. CONCLUSIONS: In this large multicenter observational study, there was no association between SGLT2 inhibitor use and incident below-knee amputations among patients with type 2 diabetes compared with DPP-4 inhibitor use. While these findings provide some reassurance, studies with a longer duration of follow-up are needed to assess potential long-term effects.

The effectiveness and limitations of regulatory warnings for the safe prescribing of citalopram.

BACKGROUND: Citalopram is the most commonly prescribed antidepressant in Canada. Concerns have been raised about its cardiac safety, and a dose-dependent prolongation of the QT interval has been documented. Drug interactions involving concomitant use of other medications that prolong the QT interval or increase citalopram levels by interfering with its metabolism increase the cardiac risk. Regulatory bodies (Health Canada and the US Food and Drug Administration) issued warnings and required labeling changes in 2011/2012, suggesting maximum citalopram doses (<40 mg for those <65 years; <20 mg for those ≥65 years) and avoiding drug interactions that increase cardiac risk. The purpose of this study is to assess the impact of these warnings on citalopram prescribing practices. METHODS: A quasi-experimental interrupted time series analysis was conducted using all citalopram prescribing data from the population of Manitoba, Canada from 1999 to 2014. This allowed for the examination of high-dose prescribing (above regulatory warning levels) and the number of interacting medications per citalopram prescription. RESULTS: There was a dramatic decline in the prescribing of high doses in both age groups, with a 64.8% decline in those <65 years and 33.6% in those ≥65 years. Segmented regression models indicated significant breakpoints in the third quarter of 2011 for both age groups (P<0.0001), corresponding to the time the regulatory warnings were issued. There appeared to be no impact of the warnings on the prescribing of interacting medications. The number of interacting medications actually increased in the postwarning period (<65, 0.78-0.81 interactions per citalopram prescription; ≥65, 0.93-0.94, P<0.001). CONCLUSION: Regulatory changes appear to have produced an important reduction in the high-dose prescribing of citalopram. In contrast to this relatively simple dosage change, there was no indication that the more complex issue of resolving drug-drug interactions was impacted by regulatory warnings.