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

Grace periods and exposure misclassification in self-controlled case-series studies of drug-drug interactions

The self-controlled case-series (SCCS) research design is increasingly used in pharmacoepidemiologic studies of drug-drug interactions (DDIs), with the target of inference being the incidence rate ratio (IRR) associated with concomitant exposure to the object plus precipitant drug vs the object drug alone. While day-level drug exposure can be inferred from dispensing claims, these inferences may be inaccurate, leading to biased IRRs. Grace periods (periods assuming continued treatment impact after days' supply exhaustion) are frequently used by researchers, but the impact of grace period decisions on bias from exposure misclassification remains unclear. Motivated by an SCCS study examining the potential DDI between clopidogrel (object) and warfarin (precipitant), we investigated bias due to precipitant or object exposure misclassification using simulations. We show that misclassified precipitant treatment always biases the estimated IRR toward the null, whereas misclassified object treatment may lead to bias in either direction or no bias, depending on the scenario. Further, including a grace period for each object dispensing may unintentionally increase the risk of misclassification bias. To minimize such bias, we recommend (1) avoiding the use of grace periods when specifying object drug exposure episodes and (2) including a washout period following each precipitant exposed period. This article is part of a Special Collection on Pharmacoepidemiology.

Comparative safety and cardiovascular effectiveness of sodium-glucose cotransporter-2 inhibitors and glucagon-like peptide-1 receptor agonists in nursing homes

AIM

Studies examining the safety and effectiveness of sodium-glucose cotransporter-2 inhibitors (SGLT2is) versus glucagon-like peptide-1 receptor agonists (GLP-1RAs) among community-dwelling adults may not generalize to nursing home (NH) residents, who are typically older and more multimorbid. We compared the safety and cardiovascular effectiveness of SGLT2is and GLP-1RAs among US NH residents.

MATERIALS AND METHODS

Eligible individuals were aged ≥66 years with type 2 diabetes mellitus and initiated an SGLT2i or GLP-1RA in an NH between 2013 and 2018. Safety outcomes included fall-related injuries, hypoglycaemia, diabetic ketoacidosis (DKA), urinary tract infection or genital infection, and acute kidney injury in the year following treatment initiation. Cardiovascular effectiveness outcomes included death, major adverse cardiovascular events and hospitalization for heart failure. Per-protocol adjusted hazard ratios (HR) were calculated using stabilized inverse probability of treatment and censoring weighted cause-specific hazard regression models accounting for 127 covariates.

RESULTS

The study population included 7710 residents (31.08% SGLT2i, 68.92% GLP-1RA). Compared with GLP-1RA initiators, SGLT2i initiators had higher rates of DKA (HR 1.95, 95% confidence limits 1.27, 2.99) and death (HR 1.18, 95% confidence limits 1.02, 1.36). Rates of urinary tract infection or genital infection, acute kidney injury, major adverse cardiovascular events, and heart failure were also elevated, while rates of fall-related injuries and hypoglycaemia were reduced, but all estimates were imprecise and highly compatible with no difference.

CONCLUSIONS

SGLT2is do not have superior, and may have inferior, effectiveness compared with GLP-1RAs for cardiovascular and mortality outcomes in NH residents. Residents initiating SGLT2is should be monitored closely for DKA.

Empagliflozin is associated with lower cardiovascular risk compared with dipeptidyl peptidase-4 inhibitors in adults with and without cardiovascular disease: EMPagliflozin compaRative effectIveness and SafEty (EMPRISE) study results from Europe and Asia

BACKGROUND

Studies that have reported lower risk for cardiovascular outcomes in users of Sodium-Glucose Cotransporter-2 Inhibitors (SGLT-2i) are limited by residual cofounding and lack of information on prior cardiovascular disease (CVD). This study compared risk of cardiovascular events in patients within routine care settings in Europe and Asia with type 2 diabetes (T2D) initiating empagliflozin compared to dipeptidyl peptidase-4 inhibitors (DPP-4i) stratified by pre-existing CVD and history of heart failure (HF).

METHODS AND RESULTS

Adults initiating empagliflozin and DPP-4i in 2014-2018/19 from 11 countries in Europe and Asia were compared using propensity score matching and Cox proportional hazards regression to assess differences in rates of primary outcomes: hospitalisation for heart failure (HHF), myocardial infarction (MI), stroke; and secondary outcomes: cardiovascular mortality (CVM), coronary revascularisation procedure, composite outcome including HHF or CVM, and 3-point major adverse cardiovascular events (MACE: MI, stroke and CVM). Country-specific results were meta-analysed and pooled hazard ratios (HR) with 95% confidence intervals (CI) from random-effects models are presented. In total, 85,244 empagliflozin/DPP4i PS-matched patient pairs were included with overall mean follow-up of 0.7 years. Among those with pre-existing CVD, lower risk was observed for HHF (HR 0.74; 95% CI 0.64-0.86), CVM (HR 0.55; 95% CI 0.38-0.80), HHF or CVM (HR 0.57; 95% CI 0.48-0.67) and stroke (HR 0.79; 95% CI 0.67-0.94) in patients initiating empagliflozin vs DPP-4i. Similar patterns were observed among patients without pre-existing CVD and those with and without pre-existing HF.

CONCLUSION

These results from diverse patient populations in routine care settings across Europe and Asia demonstrate that initiation of empagliflozin compared to DPP-4i results in favourable cardioprotective effects regardless of pre-existing CVD or HF status.

A data-informed approach using individualised dispensing patterns to estimate medicine exposure periods and dose from pharmaceutical claims data

Pharmaceutical claims data are often used as the primary information source to define medicine exposure periods in pharmacoepidemiological studies. However, often critical information on directions for use and the intended duration of medicine supply are not available. In the absence of this information, alternative approaches are needed to support the assignment of exposure periods. This study summarises the key methods commonly used to estimate medicine exposure periods and dose from pharmaceutical claims data; and describes a method using individualised dispensing patterns to define time-dependent estimates of medicine exposure and dose. This method extends on important features of existing methods and also accounts for recent changes in an individual's medicine use. Specifically, this method constructs medicine exposure periods and estimates the dose used by considering characteristics from an individual's prior dispensings, accounting for the time between prior dispensings and the amount supplied at prior dispensings. Guidance on the practical applications of this method is also provided. Although developed primarily for application to databases, which do not contain duration of supply or dose information, use of this method may also facilitate investigations when such information is available and there is a need to consider individualised and/or changing dosing regimens. By shifting the reliance on prescribed duration and dose to determine exposure and dose estimates, individualised dispensing information is used to estimate patterns of exposure and dose for an individual. Reflecting real-world individualised use of medicines with complex and variable dosing regimens, this method offers a pragmatic approach that can be applied to all medicine classes.

The concomitant use of proton pump inhibitors and BRAF/MEK inhibitors in metastatic melanoma

BACKGROUND

Proton-pump inhibitors (PPIs) are commonly used by patients with cancer, although they could reduce the absorption of oral anticancer targeted therapies. The US Food and Drug Administration states that the effect of PPIs on the efficacy of dabrafenib use by patients with metastatic melanoma is unknown. As a precautionary measure, the European Society for Medical Oncology recommends avoiding PPIs for patients receiving dabrafenib.

OBJECTIVES

To determine the effect of the concomitant use of PPIs and BRAF/MEK inhibitors in patients with metastatic melanoma.

METHODS

Patients with advanced melanoma receiving BRAF/MEK inhibitors as first-line treatments between 2015 and 2017 in France were selected using the French National Health Insurance database. We compared time-to-treatment discontinuation (TTD) and overall survival (OS) according to concomitant PPI exposure. We balanced the baseline characteristics of patients exposed and nonexposed to PPIs using an overlap weighting method based on a propensity score.

RESULTS

The metastatic melanoma cohort comprised 1028 patients receiving BRAF/MEK inhibitors, including 361 (35.1%) patients using PPIs. PPI users had more comorbidities and a more severe metastatic disease. After having equally distributed metastatic sites and comorbidities across patients exposed and nonexposed to PPIs, concomitant PPI use was not associated with shorter TTD [weighted hazard ratio (wHR) 1.03, 95% confidence interval (CI) 0.86-1.24] or OS (wHR 1.11, 95% CI 0.88-1.39). Consistent results were observed when restricting the population to patients receiving dabrafenib, or when narrowing exposure to PPIs with stronger inhibition of cytochromes.

CONCLUSIONS

In a population-based cohort of patients with advanced melanoma, the concomitant use of PPIs and BRAF/MEK inhibitors was not associated with worse outcome.

Empagliflozin is associated with lower risk of cardiovascular events and all-cause mortality in routine care in East Asia: Results from the EMPRISE study

AIMS/INTRODUCTION

The EMPA-REG OUTCOME® trial demonstrated benefits of empagliflozin, a sodium-glucose cotransporter-2 inhibitor (SGLT2i), on cardiovascular, renal outcomes and all-cause mortality in patients with type 2 diabetes and established cardiovascular disease. The EMPRISE study program evaluates how these effects translate in a broad population of patients with type 2 diabetes in routine clinical care across countries.

MATERIALS AND METHODS

The study included patients ≥18 years with type 2 diabetes initiating empagliflozin or any dipeptidyl peptidase-4 inhibitors (DPP-4i) from large administrative databases in Japan, South Korea, and Taiwan. Propensity score-matched (1:1) 'as-treated' analyses comparing the risk of cardiovascular outcomes and all-cause mortality between empagliflozin and DPP-4i use were performed in each country. Pooled hazard ratios (pHR) with 95% confidence intervals (CI) were computed using random effects meta-analysis models comparing both empagliflozin and SGLT2i with DPP-4i use, respectively. Intention-to-treat and subgroup analyses in patients with/without cardiovascular disease and in patients receiving 10 mg empagliflozin were performed.

RESULTS

The study included 28,712 and 70,233 matched patient pairs for empagliflozin/DPP-4i and SGLT2i/DPP-4i analyses, respectively. The risk of composite outcomes including (i) hospitalization for heart failure (HHF) and all-cause mortality was lower with empagliflozin (pHR 0.76, 95% CI 0.67-0.86) and SGLT2i (0.71, 0.65-0.77); (ii) combined myocardial infarction, stroke, and all-cause mortality was also lower with empagliflozin (0.74, 0.61-0.88) and SGLT2i (0.69, 0.60-0.78) compared to DPP-4i. The intention-to-treat and three subgroup analyses were consistent with results of the main analyses.

CONCLUSIONS

The results suggest that both empagliflozin and SGLT2i compared with DPP-4i are associated with a lower risk of cardiovascular events and all-cause mortality in routine clinical care in East Asia.

Healthcare Resource Utilization and Associated Costs in New Users of Empagliflozin versus DPP-4 Inhibitors and GLP-1 Agonists: A Comparative Analysis Based on Retrospective Real-World Data from German Sickness Funds

Purpose

Achieving good glycemic control in type 2 diabetes (T2DM) may require individualized pharmacological approaches. We aimed to compare direct healthcare costs in patients treated with empagliflozin (EMPA) compared to dipeptidyl peptidase-4 inhibitors (DPP-4i) or glucagon-like peptide-1 receptor agonists (GLP-1-RA).

Patients and Methods

This German claims data study included continuously insured persons with at least two outpatient diagnoses and/or one inpatient diagnosis of T2DM if they started EMPA, DPP-4i, or GLP-1-RA in 2015-2018. Healthcare costs were assessed from therapy initiation until the end of data availability, death, or therapy discontinuation and compared among propensity score-matched cohorts.

Results

Of 24,465 patients included, 3285 received EMPA, 19,443 DPP-4i, and 1747 GLP-1-RA. Matched cohorts were balanced on baseline characteristics (EMPA versus DPP-4i: n1/n2 = 3100/3100 and EMPA versus GLP-1-RA: n3/n4 = 1346/1346). Mean total costs after start of DPP-4i were €7009 (95%-CI: 6573-7444) versus €4274 (3982-4566) for EMPA. Costs associated with GLP-1-RA treatment were also significantly higher compared with EMPA (€6851 [6183-7518] versus €4895 [4345-5445]).

Conclusion

Although the individual clinical patient profile and physician assessment are paramount in treatment decisions, substantial differences in the economic impact of different antidiabetic therapies should be considered.

Describing long-term opioid use utilizing Nordic Prescription Registers - A Norwegian example

Previous studies have defined long-term opioid use in varying ways, decreasing comparability, reproducibility, and clinical applicability of the research. Based on recommendations from recent systematic reviews, we aimed to develop a methodology to estimate the prevalence of use persisting more than three months utilizing one of the Nordic prescription registers. We used the Norwegian Prescription Register (NorPD) to extract data on all opioid dispensations between 1 January 2004 and 31 October 2019. New users of opioids (washout 365 days) were defined as long-term users if they fulfilled two criteria: 1) they had ≥2 dispensations of opioids, 91-180 days apart; 2) days 0-90 included ≥90 dispensed administration units (e.g., tablets) of opioids. Overall, there were 2,543,224 new users of opioids during the study period. Of these, 354,666 (13.9%) fulfilled the criteria for long-term opioid use at least once. Compared with those who did not fulfill the criteria (short-term users), long-term users were older, more likely women, and used tramadol, oxycodone, and buprenorphine more frequently as their first opioid. In conclusion, we found that 1/7 of opioid users continued use longer than 3 months. Future outcome research should identify the clinically most important dose requirements for long-term opioid use criteria.

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.

Metformin Use and Risk of Asthma Exacerbation Among Asthma Patients with Glycemic Dysfunction

BACKGROUND

Diabetes is associated with worse asthma morbidity. Metformin, which treats diabetes, may have a role among patients with asthma and glycemic dysfunction.

OBJECTIVE

To determine the association between metformin use and asthma exacerbations among patients with diabetes.

METHODS

We queried the Johns Hopkins electronic health record from April 1, 2013, to May 31, 2018. Adults with asthma and diabetes were followed from first hemoglobin A1c (HbA1c) test to an asthma-related systemic corticosteroid prescription, emergency department (ED) visit, or hospitalization. Multivariable Cox models estimated time to each outcome associated with metformin use, modeled as either time-invariant (status at HbA1c testing) or time-dependent (based on fill data). Mediation of results by HbA1c was assessed. Sensitivity analysis was performed by propensity score matching.

RESULTS

The cohort comprised 1749 adults with asthma and diabetes. Metformin use at entry was associated with a lower hazard of asthma-related ED visits (adjusted hazard ratio [aHR], 0.40; 95% CI, 0.22-0.75) but not steroid prescription (aHR, 0.89; 95% CI, 0.70-1.13) or hospitalization (aHR, 0.38; 95% CI, 0.13-1.12). HbA1c did not mediate the association with ED visits. With metformin exposure modeled as time-dependent, metformin use was additionally associated with lower hazard of asthma-related hospitalization (aHR, 0.30; 95% CI, 0.09-0.93). Results were consistent within a subcohort of 698 metformin users matched 1:1 to nonusers by propensity score.

CONCLUSIONS

Metformin use, independent of glycemic control and obesity, was associated with lower hazard of asthma-related ED visits and hospitalizations. Metformin may have benefit in patients with asthma and glycemic dysfunction.