Observational studies of the association between glucose-lowering medications and cardiovascular outcomes: addressing methodological limitations

Treatment modification patterns of glucose-lowering agents in Saudi Arabia: A retrospective real-world data analysis

AIM

The growing number of antidiabetics has broadened therapeutic options, leading to heterogeneity in prescribing patterns. Studies identifying antidiabetics modification patterns are lacking in Saudi Arabia. Therefore, the aim of this study is to describe modification patterns in Saudi patients.

METHODS

Patients ≥ 18 years old with at least one antidiabetic between 2016 and 2022 were included. Follow-up started from the earliest to the last prescription.Two modification types were evaluated: "add-on," prescribing new antidiabetics within a treatment episode, and "switching", starting a new treatment episode after the preceding ends. Descriptive statistics were used to characterize patients and estimate events proportions.

RESULTS

Of 122,291 patients, 47.2 % had treatment interruption or modification, totaling 303,781 events. Interruptions accounted for 54 %, add-on for 11 %, and switching for 35 %. The median time to first event was 159 days. The most add-on included dipeptidyl peptidase-4 inhibitor (DPP-4) inhibitors to biguanide and sulfonylurea (8 %), and sulfonylurea to biguanide (8 %). Among 106,405 switching events, 23 % shifted from dual to monotherapy and 17 % from monotherapy to dual therapy.

CONCLUSION

Nearly half of patients experienced modifications or interruptions, with notable shifts between monotherapies and dual therapies. These findings highlight the evolving landscape of treatment patterns in Saudi Arabia and guide future research and decision-making.

Ibuprofen, other NSAIDs and COVID-19: a narrative review

At the start of the coronavirus disease 2019 (COVID-19) pandemic (March 2020), there was speculation that non-steroidal anti-inflammatory drugs (NSAIDs) such as ibuprofen, used to manage some of the symptoms of COVID-19, could increase the susceptibility to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection and negatively impact clinical outcomes. In the absence of any robust mechanistic and clinical evidence, this speculation led to confusion about the safety of ibuprofen, contributing to the so-called 'infodemic' surrounding COVID-19. A wealth of evidence has been generated in subsequent years, and this narrative review aims to consider the body of in vitro and in vivo research, observational studies, systematic reviews and meta-analyses on the use of NSAIDs, including ibuprofen, in COVID-19. Overall, the direction of evidence supports that NSAIDs do not increase susceptibility to infection, nor worsen disease outcomes in patients with COVID-19. Neither do they impact the immune response to COVID-19 vaccines. There is no basis to limit the use of NSAIDs, and doing so may deprive patients of effective self-care measures to control symptoms.

Active-comparator restricted disproportionality analysis for pharmacovigilance signal detection studies of chronic disease medications: An example using sodium/glucose cotransporter 2 inhibitors

AIMS

Disproportionality analysis is a common pharmacovigilance tool to detect safety signals of type 2 diabetes medications from spontaneous drug reporting databases. The aim was to demonstrate the impact of using active-comparator restricted disproportionality analysis (ACR-DA), wherein the reference group is restricted to reports with a clinically appropriate active comparator.

METHODS

Using reports from the Food and Drug Administration Adverse Event Reporting System, we assessed if sodium/glucose cotransporter 2 (SGLT2) inhibitors are associated with higher reporting of 5 potential adverse events: acute kidney injury, genitourinary tract infections, diabetic ketoacidosis, fractures, and amputations. For each adverse event, we calculated the proportional reporting ratio (PRR) and adjusted reporting odds ratio (aROR [95% confidence interval, CI]) using 3 types of reference groups: no SGLT2 inhibitor (background risk reference), other diabetes drugs (therapeutic class reference), and dipeptidyl peptidase 4 inhibitors (active comparator reference).

RESULTS

Based on ACR-DA, we did not detect a safety signal for acute kidney injury (PRR 0.92 [0.81-1.04]; aROR 0.78 [95% CI 0.72-0.85]) or fractures (PRR 0.44[95% CI 0.17-1.15]; aROR 0.74 [95% CI 0.61-0.91]) associated with SGLT2 inhibitors compared to dipeptidyl peptidase 4 inhibitors. However, we detected safety signals for genitourinary tract infections (PRR 2.75[2.02-3.76]; aROR 2.54[2.26-2.86], diabetic ketoacidosis (PRR 63.85[39.37-103.53; aROR 91.49[70.66-118.48]), and amputations (PRR 52.60 [19.66-140.75]; aROR 22.64 [15.32-33.42].

CONCLUSION

The use of the proposed ACR-DA to detect safety signals of type 2 diabetes medications may reduce false positive safety signals through careful selection of the comparator which is expected to reduce channelling bias.

Healthcare Resource Utilization and Costs for Empagliflozin Versus Glucagon-Like Peptide-1 Receptor Agonists in Routine Clinical Care in Denmark

INTRODUCTION

The sodium-glucose cotransporter 2 inhibitor (SGLT2i) empagliflozin has shown reductions in major adverse cardiac events similar to glucagon-like peptide-1 receptor agonists (GLP-1RAs). However, evidence is limited about how these therapies compare regarding overall healthcare resource utilization and costs in routine clinical care.

METHODS

We conducted a comparative cohort study based on linked prospective healthcare databases for the entire population of Denmark during 2015-2018. We included 13,747 new users of empagliflozin and 13,249 new users of GLP-1RAs. Propensity scores were applied to balance potential confounders across the two treatment groups through inverse probability treatment weighting (IPTW). We assessed directly referable costs per person-year associated with healthcare resource utilization (inpatient, emergency room, and outpatient clinic hospital care, primary care health services, and prescription medication costs at pharmacies) among drug initiators while on-treatment.

RESULTS

The two IPTW cohorts were well balanced at baseline (median age 61 years, 60% men, diabetes duration 6.7 years, 19% with pre-existing ischemic heart disease, 8% with pre-existing cerebrovascular disease), with similar healthcare costs in the previous year. During follow-up, average on-treatment costs per person-year were very similar among empagliflozin and GLP-1 RA initiators for the following services: inpatient hospitalizations (13,565 DKK versus 13,275 DKK), hospital outpatient clinic visits (12,007 DKK versus 12,152 DKK), emergency room visits (370 DKK versus 399 DKK), and primary care services (4108 DKK versus 4302 DKK). Total costs for any prescription drugs were clearly lower for empagliflozin initiators than for GLP-1 RA initiators (8946 DKK versus 14,029 DKK). In sum, overall healthcare costs on-treatment were lower for empagliflozin initiators (38,995 DKK per person-year) than for GLP-1RA initiators (44,157 DKK per person-year).

CONCLUSIONS

In this nationwide population-based cohort study, average healthcare costs after drug initiation and while on treatment were lower for empagliflozin initiators than for GLP-1RAs initiators, driven by lower drug costs.

REGISTRATION

The study protocol and analysis plan have been registered on the website of the European Network of Centres for Pharmacoepidemiology and Pharmacovigilance (ENCEPP) ( http://www.encepp.eu/encepp/viewResource.htm?id=37726 , first protocol registration 4 June 2019), and on clinicaltrials.gov ( https://clinicaltrials.gov/ct2/show/NCT03993132 , first posted 20 June 2019).

Reproducibility of real-world evidence studies using clinical practice data to inform regulatory and coverage decisions

Studies that generate real-world evidence on the effects of medical products through analysis of digital data collected in clinical practice provide key insights for regulators, payers, and other healthcare decision-makers. Ensuring reproducibility of such findings is fundamental to effective evidence-based decision-making. We reproduce results for 150 studies published in peer-reviewed journals using the same healthcare databases as original investigators and evaluate the completeness of reporting for 250. Original and reproduction effect sizes were positively correlated (Pearson's correlation = 0.85), a strong relationship with some room for improvement. The median and interquartile range for the relative magnitude of effect (e.g., hazard ratiooriginal/hazard ratioreproduction) is 1.0 [0.9, 1.1], range [0.3, 2.1]. While the majority of results are closely reproduced, a subset are not. The latter can be explained by incomplete reporting and updated data. Greater methodological transparency aligned with new guidance may further improve reproducibility and validity assessment, thus facilitating evidence-based decision-making. Study registration number: EUPAS19636.

Evolving channeling in prescribing SGLT-2 inhibitors as first-line treatment for type 2 diabetes

PURPOSE

Sodium-glucose cotransporter-2 inhibitors (SGLT-2i) are increasingly being considered as first-line treatment for type 2 diabetes (T2D). The benefits of SGLT-2i from cardiovascular outcome trials may lead to preferential prescribing of SGLT-2i to patients at high cardiovascular risk, possibly causing confounding in non-randomized studies of SGLT-2i as first-line treatment. We assessed evolving imbalances in characteristics of patients starting SGLT-2i versus metformin as first-line monotherapy.

METHODS

Using claims data from two US commercial health insurance and Medicare, we identified patients with T2D aged ≥18 years (>65 years in Medicare) initiating first-line SGLT-2i or metformin from 2013 through 2019. Standardized differences (SDs) for patient characteristics were assessed during four consecutive calendar time blocks (T1:4/2013-12/2014; T2:1/2015-6/2016; T3:7/2016-12/2017; and T4:1/2018-12/2019). We also estimated the propensity score of receiving SGLT-2i versus metformin within each time block and evaluated time trends in model discrimination with c-statistics.

RESULTS

We identified 9113 initiators of first-line SGLT-2i and 810 348 initiators of first-line metformin. During T1, SGLT-2i initiators were younger (SD = -0.24) and less likely to have seen cardiologists (-0.07) with a similar prevalence of CVD (0.04) compared with metformin. During T4, patients were more balanced for age (-0.01). Cardiologist visits (0.08) and CVD (0.25) became more prevalent among SGLT-2i initiators.

CONCLUSIONS

When comparing initiators of first-line SGLT-2i versus metformin, imbalances in patient characteristics evolved from 2013 through 2019, particularly channeling SGLT-2i to individuals at high cardiovascular risk. Evolving channeling in prescribing first-line SGLT-2i should be expected and accounted for in non-randomized comparative effectiveness research.

Cardiovascular morbidity and mortality in patients with type 2 diabetes using novel antidiabetic medicines as add-on therapy: an observational real-world study

OBJECTIVE

To evaluate the effect of sodium-glucose co-transporter 2 inhibitors (SGLT2i) and glucagon-like peptide-1 receptor agonists (GLP-1RA), compared with dipeptidyl peptidase-4 inhibitors (DPP-4i) as add-on therapy on cardiovascular (CV) morbidity and mortality in patients with type 2 diabetes (T2D).

DESIGN AND SETTING

A nationwide cohort study using three linked healthcare databases from Slovenia (outpatient prescription claims data, hospitalisation claims data and death registry data).

PARTICIPANTS

Patients with T2D with newly introduced DPP-4i (n=3817), GLP-1RA (n=855) or SGLT2i (n=2851) add-on therapy between June 2014 and June 2018.

PRIMARY AND SECONDARY OUTCOME MEASURES

The primary outcome was a major adverse CV event (MACE), while the secondary outcomes were CV death and heart failure (HF). The effects of the antidiabetic medicine group on the risk of each outcome were estimated with Cox proportional hazards regression. Intention-to-treat and on-treatment approaches were used.

RESULTS

In the intention-to-treat analysis, SGLT2i as add-on therapy, when compared with DPP-4i, was associated with lower risk of MACE (HR=0.66; 95% CI 0.50 to 0.85; p=0.002) and CV death (HR=0.46; 95% CI 0.30 to 0.73; p=0.001). On-treatment analysis revealed lower HF risk in patients initiating SGLT2i (HR=0.54; 95% CI 0.30 to 0.99; p=0.047). In the intention-to-treat analysis, GLP-1RA add-on therapy was associated with a lower MACE risk when compared with DPP-4i (HR=0.64; 95% CI 0.43 to 0.97; p=0.034), but it had a non-significant effect on CV death (HR=0.62; 95% CI 0.34 to 1.14; p=0.128) and HF (HR=1.39; 95% CI 0.88 to 2.21; p=0.157). The results of on-treatment analyses were in agreement with the results of intention-to-treat analyses.

CONCLUSIONS

SGLT2i and GLP-1RA improved CV morbidity and mortality in patients with T2D when compared with DPP-4i as an add-on therapy. The results of this study may serve as a basis for the selection of an optimal add-on antidiabetic medicine to reduce CV morbidity and mortality in patients with T2D in clinical practice.

TRIAL REGISTRATION NUMBER

EUPAS32558.

Association Between Testosterone Treatment and Risk of Incident Cardiovascular Events Among US Male Veterans With Low Testosterone Levels and Multiple Medical Comorbidities

Background

Testosterone treatment is common in men, although risks for major cardiovascular events are unclear.

Methods and Results

A study was conducted in US male veterans, aged ≥40 years, with low serum testosterone and multiple medical comorbidities and without history of myocardial infarction, stroke, venous thromboembolism, prostate cancer, or testosterone treatment in the prior year. For the primary outcome, we examined if testosterone treatment was associated with a composite cardiovascular outcome (incident myocardial infarction, ischemic stroke, or venous thromboembolism). Testosterone use was modeled as intramuscular or transdermal and as current use, former use, and no use. Current testosterone users were compared with former users to reduce confounding by indication. The cohort consisted of 204 857 men with a mean (SD) age of 60.9 (9.9) years and 4.7 (3.5) chronic medical conditions. During follow‐up of 4.3 (2.8) years, 12 645 composite cardiovascular events occurred. In adjusted Cox regression analyses, current use of transdermal testosterone was not associated with risk for the composite cardiovascular outcome (hazard ratio [HR], 0.89; 95% CI, 0.76–1.05) in those without prevalent cardiovascular disease, and in those with prevalent cardiovascular disease was associated with lower risk (HR, 0.80; 95% CI, 0.70–0.91). In similar analyses, current use of intramuscular testosterone was not associated with risk for the composite cardiovascular outcome in men without or with prevalent cardiovascular disease (HR, 0.91; 95% CI, 0.80–1.04; HR, 0.98; 95% CI, 0.89–1.09, respectively).

Conclusions

In a large cohort of men without a history of myocardial infarction, stroke, or venous thromboembolism, testosterone treatment was not associated with increased risk for incident composite cardiovascular events.

Dipeptidyl peptidase-4 inhibitor cardiovascular safety in patients with type 2 diabetes, with cardiovascular and renal disease: a retrospective cohort study

Clinical trials investigating cardiovascular safety of dipeptidyl peptidase-IV inhibitors (DPP-4i) among patients with cardiovascular and renal disease rarely recruit patients with renal impairment, despite associations with increased risk for major adverse cardiovascular events (MACE). We investigated the risk of MACE associated with the use of DPP-4i among these high-risk patients. Using a new-user, retrospective, cohort design, we analyzed 2010–2015 IBM MarketScan Commercial Claims and Encounters for patients with diabetes, comorbid with cardiovascular disease and/or renal impairment. We compared time to first MACE for DPP-4i versus sulfonylurea and versus metformin. Of 113,296 individuals, 9146 (8.07%) were new DPP-4i users, 17,481 (15.43%) were new sulfonylurea users, and 88,596 (78.20%) were new metformin users. Exposure groups were not mutually exclusive. DPP-4i was associated with lower risk for MACE than sulfonylurea (aHR 0.84; 95% CI 0.74, 0.93) and similar risk for MACE to metformin (aHR 1.07; 95% CI [1.04, 1.16]). DPP-4i use was associated with lower risk for MACE compared to sulfonylureas and similar risk for MACE compared to metformin. This association was most evident in the first year of therapy, suggesting that DPP-4i is a safer choice than sulfonylurea for diabetes treatment initiation in high-risk patients.

Cardiovascular Events, Acute Hospitalizations, and Mortality in Patients With Type 2 Diabetes Mellitus Who Initiate Empagliflozin Versus Liraglutide: A Comparative Effectiveness Study

Background

In cardiovascular outcome trials, the sodium glucose cotransporter 2 inhibitor empagliflozin and glucagon‐like peptide‐1 (GLP‐1) receptor agonist liraglutide caused similar reductions in major adverse cardiac events (MACE). We compared clinical outcomes in routine clinical care.

Methods and Results

EMPLACE (Cardiovascular and Renal Outcomes, and Mortality in Danish Patients with Type 2 Diabetes Who Initiate Empagliflozin Versus GLP‐1RA: A Danish Nationwide Comparative Effectiveness Study) is an ongoing nationwide population‐based comparative effectiveness cohort study in Denmark. For the present study, we included 14 498 new users of empagliflozin and 12 706 new users of liraglutide, 2015 to 2018. Co‐primary outcomes were expanded major adverse cardiac events (stroke, myocardial infarction, unstable angina, coronary revascularization, hospitalization for heart failure [HHF], or all‐cause death); HHF or all‐cause death; and first HHF or first initiation of loop‐diuretic therapy. Secondary outcomes included all‐cause hospitalization or death. We applied propensity score balancing and Cox regression to compute adjusted hazard ratios (aHRs) in on‐treatment (OT) and intention‐to‐treat (ITT) analyses. Cohorts were well balanced at baseline (median age 61 years, 59% men, diabetes mellitus duration 6.6 years, 30% with preexisting cardiovascular disease). During mean follow‐up of 1.1 years in OT and 1.5 years in ITT analyses, empagliflozin versus liraglutide was associated with a similar rate of expanded major adverse cardiac events (OT aHR, 1.02; 95% CI, 0.91–1.14; ITT aHR, 1.06; 95% CI, 0.96–1.17), and HHF or all‐cause death (OT aHR, 0.97; 95% CI, 0.85–1.11; ITT aHR, 1.02; 95% CI, 0.91–1.14); and a decreased rate of a first incident HHF or loop‐diuretic initiation (OT aHR, 0.80; 95% CI, 0.68–0.94; ITT aHR, 0.87; 95% CI, 0.76–1.00), and of all‐cause hospitalization or death (OT aHR, 0.93; 95% CI, 0.89–0.98; ITT aHR, 0.93; 95% CI, 0.90–0.97).

Conclusions

Empagliflozin and liraglutide initiators had comparable rates of expanded major adverse cardiac events, and HHF or all‐cause death, whereas empagliflozin initiators had a lower rate of a first HHF or loop‐diuretic initiation.

Glucose-Lowering Drugs and Fracture Risk-a Systematic Review

PURPOSE OF REVIEW

Diabetes mellitus (DM) is associated with increased fracture risk. The aim of this systematic review was to examine the effects of different classes of glucose-lowering drugs on fracture risk in patients with type 2 DM. The heterogeneity of the included studies did not allow formal statistical analyses.

RECENT FINDINGS

Sixty studies were included in the review. Metformin, dipeptidylpeptidase-IV inhibitors, glucagon-like peptide-1 receptor agonists, and sodium-glucose cotransporter 2-inhibitors do not appear to increase fracture risk. Results for insulin and sulphonylureas were more disparate, although there may be an increased fracture risk related to hypoglycemia and falls with these treatments. Glitazones were consistently associated with increased fracture risk in women, although the evidence was sparser in men. New glucose-lowering drugs are continuously being developed and better understanding of these is leading to changes in prescription patterns. Our findings warrant continued research on the effects of glucose-lowering drugs on fracture risk, elucidating the class-specific effects of these drugs.

Dipeptidyl peptidase-4 inhibitors and cardiovascular events in patients with type 2 diabetes, without cardiovascular or renal disease

Background

Cardiovascular safety of dipeptidyl peptidase-IV inhibitors (DPP-4i) in patients without cardiovascular or renal disease, a majority of newly diagnosed patients with type 2 diabetes often excluded from clinical trials on this association, is poorly understood. Thus, we investigate the risk of major adverse cardiovascular events (MACE) associated with DPP-4i in low-risk patients with diabetes

Methods

Using a new-user retrospective cohort derived from IBM MarketScan Commercial Claims and Encounters (2010–2015), we identified patients aged 35–65 with type 2 diabetes, without cardiovascular or renal disease, initiating DPP-4i, sulfonylureas, or metformin. Primary composite outcome of time to first MACE was defined as the first of any of the following: myocardial infarction, cardiac arrest, coronary artery bypass graft, coronary angioplasty, heart failure, and stroke. Secondary outcomes were time to first heart failure, acute myocardial infarction, and stroke. We compared outcomes for DPP-4i versus sulfonylurea and DPP-4i versus metformin using propensity score weighted Cox proportional hazards, adjusting for demographics, baseline comorbidities, concomitant medications, and cumulative exposure.

Results

Of 445,701 individuals, 236,431 (53.0%) were male, median age was 51 (interquartile range: [44, 57]), 30,267 (6.79%) initiated DPP-4i, 52,138 (11.70%) initiated sulfonylureas, and 367,908 (82.55%) initiated metformin. After adjustment, DPP-4i was associated with lower risk of MACE than sulfonylurea (adjusted hazard ratio (aHR) = 0.87; 95% confidence interval (CI): 0.78–0.98), and similar risk to metformin (aHR = 1.07; 95% CI: 0.97–1.18). Risk for acute myocardial infarction (aHR = 0.70; 95% CI: 0.51–0.96), stroke (aHR = 0.57; 95% CI: 0.41–0.79), and heart failure (aHR = 0.57; 95% CI: 0.41–0.79) with DPP-4i was lower compared to sulfonylureas.

Conclusion

Our findings show that for this cohort of low-risk patients newly treated for type 2 diabetes, DPP-4i exhibited 13% lower risk for MACE compared to sulfonylureas and similar risk for MACE compared to metformin, suggesting DPP-4i is a low cardiovascular risk option for low-risk patients initiating antihyperglycemic treatment.

Cardiovascular outcomes, heart failure and mortality in type 2 diabetic patients treated with glucagon-like peptide 1 receptor agonists (GLP-1 RAs): A systematic review and meta-analysis of observational cohort studies

BACKGROUND

Cardiovascular outcomes trials (CVOTs) have assessed the effects of glucagon-like peptide-1 receptor agonists (GLP-1 RAs) on major adverse cardiovascular events (MACE) and mortality in high cardiovascular (CV) risk populations. Observational research can provide complementary evidence about these effects in unselected populations.

AIM

To systematically review retrospective observational cohort studies conducted in electronic healthcare databases (EHDs) assessing GLP-1 RAs´ effects on MACE and/or hospitalisation for heart failure (HHF) and/or all-cause mortality in Type 2 diabetes mellitus (T2DM) patients.

METHODS

We systematically searched studies meeting inclusion criteria, compared design, methods and population characteristics, assessed risk for bias and did a meta-analysis (MA) using a random-effects model to calculate overall hazard ratios (HRs) and 95% CI (confidence intervals).

RESULTS

Sixteen studies included 285,436 T2DM patients exposed to GLP-1 RAs (exenatide bid, liraglutide, lixisenatide, long-acting exenatide), n ranged from 219 to 160,803 patients. Comparators included: no exposure, other antidiabetic medications (OADs), combined OADs, canagliflozin or multiple comparators. Ten studies estimated all-cause mortality, hazard ratios (HRs) ranged from 0.17 (95% CI 0.02-1.22) to 1.29 (95% CI 0.54-3.13). Thirteen studies assessed cardiovascular events and/or MACE; HRs ranged from 0.27 (95% CI 0.14-0.53) to 1.11 (95% CI 0.99-1.24). Eight studies assessed HHF, HRs ranged from 0.12 (95% CI 0.02-0.66) to 1.64 (95% CI 1.28-2.13). Excluding two studies because of temporal bias, we obtained pooled estimates for all-cause mortality: HR 0.63 (0.44-0.89), CV outcomes HR 0.84 (0.75-0.94) and HHF; HR 0.94 (0.78-1.14), (high between-study variability: I²  = 83.35%; I²  = 70.3%; and I²  = 90.1%, respectively).

CONCLUSION

Pooled results of EHDs' studies assessing GLP-1 RAs effects favoured GLP-1 RAs for all-cause mortality and MACE while were neutral for HHF. Results should be interpreted cautiously because of studies' substantial heterogeneity and limitations of observational research.

Sulphonylureas monotherapy and risk of hospitalization for heart failure in patients with type 2 diabetes mellitus: A population-based cohort study in China

PURPOSE

The risk of heart failure associated with sulphonylureas is unclear. We evaluated the association between sulphonylureas and hospitalization of heart failure (HHF) in patients with type 2 diabetes mellitus (T2DM) in China.

METHODS

A retrospective cohort study was implemented using the Yinzhou Regional Health Care Database (YRHCD). We identified 15 752 adult patients with T2DM who were newly exposed to sulphonylurea monotherapy (N = 12 487) or acarbose monotherapy (N = 3265) from January 2010 to September 2016. Cox proportional hazards models weighted by inverse probability of treatment weights were used to compare the risk of HHF between initiators of sulphonylurea and acarbose.

RESULTS

During a median follow-up of 0.55 (0.49, 1.11) and 0.49 (0.35, 0.70) years for sulphonylureas and acarbose initiators separately, 320 patients developed HHF, with 279 events in sulphonylureas group, and 41 events in acarbose group. The incidence rates of HHF among sulphonylureas initiators and acarbose initiators were 22.2 (95% CI 19.6-24.9) and 18.3 (95% CI 13.2-24.9) per 1000 person-years, respectively. The adjusted hazard ratio (aHR) of HHF for sulphonylureas vs acarbose was 1.61 (95% CI 1.14-2.27). When stratified by history of heart failure, aHR was 1.55 (95% CI 0.79-3.06) in patients with a history of heart failure, and 1.64 (95% CI 1.10-2.45) in patients with no history of heart failure.

CONCLUSIONS

Our study suggested that use of sulphonylureas monotherapy compared with acarbose monotherapy for initial treatment of T2DM for approximately 0.5 years are significantly associated with a higher risk of HHF.

Predictive factors for category II pressure ulcers in older patients with hip fractures: a prospective study

OBJECTIVE

To identify the incidence of category II or higher hospital-acquired pressure ulcers (HAPU) and significantly associated factors in older patients with hip fractures. PUs are a frequent complication in hip fracture patients, negatively impacting patients' quality of life, the health-care system and society.

METHOD

A prospective cohort study was conducted. A consecutive sample of patients with pertrochanteric, femoral neck or subtrochanteric fractures requiring surgical treatment, were included. A stepwise, multiple regression was performed to identify factors associated with PU development.

RESULTS

A total of 761 patients aged ≥65 years were sampled. The incidence of category II or higher PUs was 12%. The study identified five factors that were significantly, independently associated with category II or higher PU development, including a higher preoperative Braden score (Hazard Ratio [HR]: 0.884; 95% confidence interval [CI]: 0.806-0.969), surgical procedure with osteosynthesis (HR 1.876; 95%CI: 1.183-2.975), a higher percentage of days with the presence of foam valve before surgery (HR: 1.010; 95%CI: 1.010-1.023) and a urinary catheter (HR: 1.013; 95%CI: 1.006-1.019) and diaper (HR: 1.007; 95% CI 1.001-1.013) in the postoperative period.

CONCLUSION

Attention should be given by clinical staff to avoiding the use of foam valves, to limiting the use of diapers and to early removal of urinary catheters.

Using RWE research to extend clinical trials in diabetes: An example with implications for the future

BACKGROUND

Although randomized, controlled trials (RCTs) are seen as the gold standard for evidence in clinical medicine, a number of considerations are increasing the use of real-world data (RWD) to generate evidence. A series of methodological challenges must be overcome in order for such real-world evidence (RWE) to gain acceptance. In diabetes, RWE faces some particular issues that have limited its development. As the natural history of diabetes progresses, patients' disease changes over time and treatments will be modified as a result. This evolving disease and treatment pattern requires application of methods that account for such changes over time. Research developing RWE in diabetes and other conditions has sometimes been subject to important biases, and researchers should be aware of, and take steps to mitigate potential for bias in order to enhance the evidence produced.

RESULTS

We review a RWE study that replicated and extended evidence provided by a RCT regarding the effects of weekly exenatide relative to basal insulin (glargine or detemir) to illustrate a potential application of RWE. This study observed a 0.7% decrease in HbA1C for weekly exenatide relative to a 0.5% decrease in HbA1C for the comparator along with a 2 kg weight loss for weekly exenatide relative to a 0.25 kg weight gain, effects that were close to those from the RCT. Further, the RWE study was able to extend results to patient populations that were not well represented in the RCT.

CONCLUSION

Despite numerous challenges, RWE can be used to complement evidence from RCTs.

Transparency in real-world evidence (RWE) studies to build confidence for decision-making: Reporting RWE research in diabetes

Transparency of real-world evidence (RWE) studies is critical to understanding how findings of a specific study were derived and is a necessary foundation to assessing validity and determination of whether decisions should be informed by the findings. In the present paper, we lay out strategies to improve clarity in the reporting of comparative effectiveness studies using real-world data that were generated by the routine operation of a healthcare system. This may include claims data, electronic health records, wearable devices, patient-reported outcomes or patient registries. These recommendations were discussed with multiple stakeholders, including regulators, payers, academics and journal editors, and endorsed by two professional societies that focus on RWE. We remind readers interested in diabetes research of the utility of conceptualizing a target trial that is then emulated by a RWE study when planning and communicating about RWE study implementation. We recommend the use of a graphical representation showcasing temporality of key longitudinal study design choices. We highlight study elements that should be reported to provide the clarity necessary to make a study reproducible. Finally, we suggest registering study protocols to increase process transparency. With these tools the readership of diabetes RWE studies will be able to more efficiently understand each study and be more able to assess a study's validity with reasonably high confidence before making decisions based on its findings.

The present and future scope of real-world evidence research in diabetes: What questions can and cannot be answered and what might be possible in the future?

The last decade has witnessed an exponential growth in the opportunities to collect and link health-related data from multiple resources, including primary care, administrative, and device data. The availability of these "real-world," "big data" has fuelled also an intense methodological research into methods to handle them and extract actionable information. In medicine, the evidence generated from "real-world data" (RWD), which are not purposely collected to answer biomedical questions, is commonly termed "real-world evidence" (RWE). In this review, we focus on RWD and RWE in the area of diabetes research, highlighting their contributions in the last decade; and give some suggestions for future RWE diabetes research, by applying well-established and less-known tools to direct RWE diabetes research towards better personalized approaches to diabetes care. We underline the essential aspects to consider when using RWD and the key features limiting the translational potential of RWD in generating high-quality and applicable RWE. Only if viewed in the context of other study designs and statistical methods, with its pros and cons carefully considered, RWE will exploit its full potential as a complementary or even, in some cases, substitutive source of evidence compared to the expensive evidence obtained from randomized controlled trials.

The EMPagliflozin compaRative effectIveness and SafEty (EMPRISE) study programme: Design and exposure accrual for an evaluation of empagliflozin in routine clinical care

BACKGROUND

The EMPA-REG OUTCOME trial showed that empagliflozin reduced the risk of cardiovascular death and hospitalization for heart failure (HHF) in diabetic patients with cardiovascular disease. EMPRISE is a study programme on the effectiveness, safety and healthcare utilization of empagliflozin in routine care, leveraging real-world data from two commercial and one federal US data sources from 2014 to 2019.

OBJECTIVES

To describe rationale and design of EMPRISE, assess ability to minimize confounding and evaluate the time to reach sufficient statistical power for a key study outcome, HHF, using baseline information from the first year of EMPRISE.

METHODS

In 3 claims data sets, we identified a 1:1 propensity score (PS)-matched cohort of diabetic patients ≥18 years initiating empagliflozin or a dipeptidyl peptidase-4 inhibitor (DPP4i), resulting in 6643 total pairs. The PS model included >140 baseline covariates. We measured covariate balance via standardized differences (SD) and postmatching c-statistic. We computed the incidence rate (IR) of HHF, predicted exposure accrual over time and calculated expected power.

RESULTS

After PS matching, patient characteristics were balanced with SD <0.1 and c-statistic between 0.54 and 0.59. The population IR of HHF was 4.4 per 1000 person-years using a specific HHF definition and 14.8 using a broader HHF definition. In our projection, 80%-powered analyses would require a minimum of 169 HHF events, expected to accumulate by year 3 (specific definition) or year 2 (broader definition).

CONCLUSION

Baseline information from EMPRISE provided evidence of solid confounding control and adequate exposure accrual with expected powered analyses for the primary outcomes.

Long-Acting Injectable GLP-1 Receptor Agonists for the Treatment of Adults with Type 2 Diabetes: Perspectives from Clinical Practice

Randomized controlled trials (RCTs) have consistently shown glycemic and extra-glycemic benefits of long-acting injectable glucagon-like-peptide-1 receptor agonists (GLP-1RAs, liraglutide, albiglutide, exenatide once-weekly, dulaglutide, and semaglutide) in terms of reduction in the rates of cardiovascular events and mortality among patients with type 2 diabetes. Recently, the analyses of large datasets collecting routinely-accumulated data from clinical practice (ie, real-world studies, RWS) have provided new opportunities to complement the information obtained from RCTs. In this narrative review, we addressed clinically relevant questions that might be answered by well-conducted RWS: are subjects treated with GLP-1RAs in the "real-world" similar to those included in RCTs? Is the performance of GLP-1RA observed in the RWS (effectiveness) similar to that described in RCTs (efficacy)? Is the effectiveness similar in population of patients generally under-represented in RCTs? Are the cardiovascular benefits of GLP-1RAs confirmed in RWS? We also describe a few comparisons currently un-explored by specific RCTs, such as direct comparison between different administration strategies (eg, fixed- versus flexible-combination with basal-insulin) or between GLP-1RAs versus dipeptidyl-peptidase-4 inhibitor (DDP4i) or versus sodium/glucose cotransporter-2 inhibitors (SGLT-2i) on hard cardio-renal outcomes. Altogether, RWS provide highly informative information on treatment with GLP-1RAs. On the one side, RWS showed different clinical characteristics between subjects enrolled in RCTs versus those attending real-world clinics and receiving a GLP-1RA. On the other hand, RWS showed that GLP-1RA effectiveness is overall consistent in subgroups of patients less represented in RCTs. In addition, RWS allowed the identification of modifiable factors (eg, titration or adherence) that might guide physicians towards better GLP-1RAs use. Finally, multiple RWS reported better cardio-renal outcomes with GLP-1RAs than with DPP-4i, while initial findings from RWS described a weaker cardiovascular protection compared to SGLT-2i. Therefore, there is the need for further RWS and RCTs comparing these different classes of glucose lowering medications.

Long-term comparative safety analysis of the risks associated with adding or switching to a sulfonylurea as second-line Type 2 diabetes mellitus treatment in a US veteran population

AIM

To examine the risks of all-cause mortality and cardiovascular events associated with adding vs switching to second-line therapies in a comparative safety study of people with Type 2 diabetes mellitus.

METHODS

We conducted a retrospective cohort study using an as-treated analysis of people served by the Veterans Health Administration who were on metformin and subsequently augmented this treatment or switched to other oral glucose-lowering treatments between 1998 and 2012. This study included 145 250 people with long follow-up. Confounding was addressed through several strategies, involving weighted propensity score models with rich confounder adjustment and strict inclusion criteria, coupled with an incident-user design.

RESULTS

Second-line use of sulfonylureas was related to higher mortality (hazard ratio 1.39, 95% CI 1.14, 1.70) and cardiovascular risks (hazard ratio 1.19, 95% CI 1.09, 1.30) compared with thiazolidinedione therapy. Differential hazards were associated with discontinuing or not discontinuing metformin; switching to sulfonylurea therapy was associated with a higher risk of all-cause mortality and cardiovascular events compared with all other therapies. Furthermore, add-on sulfonylurea therapy was associated with an elevated risk for both outcomes when compared with thiazolidinedione add-on therapy.

CONCLUSIONS

The results of the present study may inform decisions on whether to augment or discontinue metformin; when considering the long-term risks, switching to a sulfonylurea appears unfavourable compared with other therapies. Instead, adding a thiazolidinedione to existing metformin therapy appears to be superior to adding or switching to a sulfonylurea.

Glucose-lowering medications and the risk of cancer: A methodological review of studies based on real-world data

AIM

To review the methodology of observational studies examining the association between glucose-lowering medications and cancer to identify the most common methodological challenges and sources of bias.

METHODS

We searched PubMed systematically to identify observational studies on glucose-lowering medications and cancer published between January 2000 and January 2016. We assessed the design and analytical methods used in each study, with a focus on their ability to achieve study validity, and further evaluated the prevalence of major methodological choices over time.

RESULTS

Of 155 studies evaluated, only 26% implemented a new-user design, 41% used an active comparator, 33% implemented a lag or latency period, and 51% adjusted for diabetes duration. Potential for immortal person-time bias was identified in 63% of the studies; 55% of the studies adjusted for variables measured during the follow-up without appropriate statistical methods. Aside from a decreasing trend in adjusting for variables measured during the follow-up, we observed no trends in methodological choices over time.

CONCLUSIONS

The prevalence of well-known design and analysis flaws that may lead to biased results remains high among observational studies on glucose-lowering medications and cancer, limiting the conclusions that can be drawn from these studies. Avoiding known pitfalls could substantially improve the quality and validity of real-world evidence in this field.

Cardiovascular safety of linagliptin compared with other oral glucose-lowering agents in patients with type 2 diabetes: A sequential monitoring programme in routine care

AIM

To evaluate the safety of linagliptin versus other glucose-lowering medications in a multi-year monitoring programme using insurance claims data.

METHODS

In two commercial US claims databases, we identified three pairwise 1:1 propensity-score (PS)-matched cohorts of patients with type 2 diabetes (T2D) aged ≥18 years initiating linagliptin or a comparator (other dipeptidyl peptidase-4 [DPP-4] inhibitors [n = 31 492 pairs], pioglitazone [n = 23 316 pairs], or second-generation sulphonylureas [n = 19 731 pairs]) between May 2011 and December 2015. The primary endpoint was the risk of a composite cardiovascular (CV) outcome (hospitalization for myocardial infarction, stroke, unstable angina, or coronary revascularization). We estimated pooled hazard ratios (HRs) and 95% confidence intervals (CIs), controlling for >100 baseline characteristics.

RESULTS

Patient characteristics were well balanced after PS-matching. The mean age was 55 years and mean follow-up was 0.8 years. Linagliptin conferred a similar risk of the composite CV outcome compared to other DPP-4 inhibitors (HR 0.91, 95% CI 0.79-1.05) and pioglitazone (HR 0.98, 95% CI 0.84-1.15), and showed a reduced risk of CV outcomes compared to second-generation sulphonylureas (HR 0.76, 95% CI 0.64--0.92). Key findings were signalled at the first interim analysis in June 2013 and solidified during ongoing monitoring until 2015.

CONCLUSION

Analyses from a large monitoring programme in routine care of patients with T2D, showed that linagliptin had similar CV safety compared to other DPP-4 inhibitors and pioglitazone, and a reduced CV risk compared to sulphonylureas.

Empagliflozin and the Risk of Heart Failure Hospitalization in Routine Clinical Care

BACKGROUND

The EMPA-REG OUTCOME trial (Empagliflozin Cardiovascular Outcome Event Trial in Type 2 diabetes Mellitus Patients) showed that empagliflozin, a sodium-glucose cotransporter-2 inhibitor, reduces the risk of hospitalization for heart failure (HHF) by 35%, on top of standard of care in patients with type 2 diabetes mellitus (T2D) and established cardiovascular disease. The EMPRISE (Empagliflozin Comparative Effectiveness and Safety) study aims to assess empagliflozin's effectiveness, safety, and healthcare utilization in routine care from August 2014 through September 2019. In this first interim analysis, we investigated the risk of HHF among T2D patients initiating empagliflozin versus sitagliptin, a dipeptidyl peptidase-4 inhibitor.

METHODS

Within 2 commercial and 1 federal (Medicare) claims data sources in the United States, we identified a 1:1 propensity score-matched cohort of T2D patients ≥18 years old initiating empagliflozin or sitagliptin from August 2014 through September 2016. The HHF outcome was defined as a HF discharge diagnosis in the primary position (HHF-specific); a broader definition was based on a HF discharge diagnosis in any position (HHF-broad). Hazard ratios (HRs) and 95% CIs were estimated controlling for over 140 baseline characteristics in each data source and pooled by fixed-effects meta-analysis.

RESULTS

After propensity-score matching, we identified 16,443 patient pairs who initiated empagliflozin or sitagliptin. Average age was approximately 59 years, almost 54% of the participants were males, and approximately 25% had records of existing cardiovascular disease. Compared with sitagliptin, the initiation of empagliflozin decreased the risk of HHF-specific by 50% (HR, 0.50; 95% CI, 0.28-0.91), and the risk of HHF-broad by 49% (HR, 0.51;95% CI, 0.39-0.68), over a mean follow-up of 5.3 months. The results were consistent in patients with and without baseline cardiovascular disease, and for empagliflozin at both the 10- and 25-mg daily doses; analyses comparing empagliflozin versus the dipeptidyl peptidase-4 inhibitor class, and comparing sodium-glucose cotransporter-2 inhibitor versus dipeptidyl peptidase-4 inhibitor classes also produced consistent findings.

CONCLUSIONS

The first interim analysis from EMPRISE showed that compared with sitagliptin, the initiation of empagliflozin was associated with a decreased risk of HHF among patients with T2D as treated in routine care, with and without a history of cardiovascular disease.

CLINICAL TRIAL REGISTRATION

URL: https://www.clinicaltrials.gov . Unique identifier: NCT03363464.

Bias in pharmacoepidemiologic studies using secondary health care databases: a scoping review

BACKGROUND

The availability of clinical and therapeutic data drawn from medical records and administrative databases has entailed new opportunities for clinical and epidemiologic research. However, these databases present inherent limitations which may render them prone to new biases. We aimed to conduct a structured review of biases specific to observational clinical studies based on secondary databases, and to propose strategies for the mitigation of those biases.

METHODS

Scoping review of the scientific literature published during the period 2000-2018 through an automated search of MEDLINE, EMBASE and Web of Science, supplemented with manually cross-checking of reference lists. We included opinion essays, methodological reviews, analyses or simulation studies, as well as letters to the editor or retractions, the principal objective of which was to highlight the existence of some type of bias in pharmacoepidemiologic studies using secondary databases.

RESULTS

A total of 117 articles were included. An increasing trend in the number of publications concerning the potential limitations of secondary databases was observed over time and across medical research disciplines. Confounding was the most reported category of bias (63.2% of articles), followed by selection and measurement biases (47.0% and 46.2% respectively). Confounding by indication (32.5%), unmeasured/residual confounding (28.2%), outcome misclassification (28.2%) and "immortal time" bias (25.6%) were the subcategories most frequently mentioned.

CONCLUSIONS

Suboptimal use of secondary databases in pharmacoepidemiologic studies has introduced biases in the studies, which may have led to erroneous conclusions. Methods to mitigate biases are available and must be considered in the design, analysis and interpretation phases of studies using these data sources.

Associations between statins and coronary artery disease and stroke risks in patients with asthma-chronic obstructive pulmonary disease overlap syndrome: A time-dependent regression study

BACKGOUND AND AIMS

We aimed at determining the effects of statin use on coronary artery disease (CAD) and stroke risks in patients with asthma-chronic obstructive pulmonary disease overlap syndrome (ACOS).

METHODS

We retrospectively enrolled patients with ACOS treated with (N = 916) and without (N = 6338) statins. The cumulative incidence of CAD and stroke (ischemic and hemorrhagic) was analyzed through time-dependent Cox proportional regression. After adjustment for sex, age, comorbidities, inhaled corticosteroid steroid (ICS) use, and oral steroid (OS) use, we calculated the adjusted hazard ratios (aHRs) and their 95% confidence intervals (CIs) for CAD or stroke in the statin users (long-term [>600 days] and short-term [≤600 days]) compared with the non-users.

RESULTS

Among the statin users, aHRs (95% CIs) for CAD and stroke were 0.50 (0.41-0.62) and 0.83 (0.63-1.09), respectively; moreover, aHRs were 0.30 (0.09-0.99) and 0.90 (0.68-1.20) for ischemic and hemorrhagic stroke, respectively. aHRs (95% CIs) for CAD and stroke were 0.58 (0.47-0.71) and 0.93 (0.70-1.23), respectively, in the short-term users and 0.23 (0.13-0.41) and 0.42 (0.19-0.89), respectively, in the long-term users.

CONCLUSIONS

CAD risk was lower in all statin users, regardless of the duration of use, whereas ischemic stroke risk was lower only in the long-term statin users. No association was observed between hemorrhagic stroke risk and statin use.

Observational research on sodium glucose co-transporter-2 inhibitors: A real breakthrough?

Sodium glucose co-transporter-2 inhibitors have attracted the interest of the scientific community following the results from dedicated cardiovascular outcome trials, which demonstrated remarkable reduction in all-cause mortality and other cardiovascular (CV) endpoints with empagliflozin and canagliflozin. These impressive results raised further expectations on real world data from large observational cohort studies. They were designed to address the possible existence of a class effect, and the uncertainty on whether this benefit can be extended from secondary to primary CV prevention of patients with type 2 diabetes. In this review, we collated data from existing observational studies (including the celebrated CVD-REAL cohorts) and critically appraised results and methodological issues with the aim of providing clinical insight, including unsettled aspects, and proposing a research agenda for future investigations.

Prospective Prognostic Cohort Study of Pressure Injuries in Older Adult Patients with Hip Fractures

OBJECTIVE

The aim of this study was to assess the rate of pressure injury and real predictors thereof in the older adult population with hip fractures in an orthopedic hospital.

METHODS

In this prospective prognostic cohort study, all patients admitted with fragility hip fractures were monitored over a 12-month period. On a daily basis, ward nurses and physiotherapists assessed the condition of the patients' skin and collected data about all the predictors connected to their healthcare and hospital organization until the patients were discharged from hospital or until the onset of pressure injury.

RESULTS

From October 1, 2013, to September 30, 2014, 467 older adult patients with fragility fractures were enrolled in the study. Of these, 27% (n = 127) developed a pressure injury. Multivariate analysis identified the following predictive factors: age older than 81 years, type of surgery, and placing the limb in a foam rubber splint. No other factor connected to the patient or medical, nursing, or rehabilitation treatment was significantly correlated to the onset of pressure injury, even when the univariate analysis showed some of them were possible predictors.

CONCLUSIONS

Pressure injury in older adults with hip fractures is a relatively common complication, especially in high-risk patients or following certain treatments. These potential indicators could help provide safe and targeted care by preemptively identifying patients at highest risk of pressure injury.

Promises and pitfalls of electronic health record analysis

Routinely collected electronic health records (EHRs) are increasingly used for research. With their use comes the opportunity for large-scale, high-quality studies that can address questions not easily answered by randomised clinical trials or classical cohort studies involving bespoke data collection. However, the use of EHRs generates challenges in terms of ensuring methodological rigour, a potential problem when studying complex chronic diseases such as diabetes. This review describes the promises and potential of EHRs in the context of diabetes research and outlines key areas for caution with examples. We consider the difficulties in identifying and classifying diabetes patients, in distinguishing between prevalent and incident cases and in dealing with the complexities of diabetes progression and treatment. We also discuss the dangers of introducing time-related biases and describe the problems of inconsistent data recording, missing data and confounding. Throughout, we provide practical recommendations for good practice in conducting EHR studies and interpreting their results.

Claims-based studies of oral glucose-lowering medications can achieve balance in critical clinical variables only observed in electronic health records

AIM

To evaluate the extent to which balance in unmeasured characteristics of patients with type 2 diabetes (T2DM) was achieved in claims data, by comparing against more detailed information from linked electronic health records (EHR) data.

METHODS

Within a large US commercial insurance database and using a cohort design, we identified patients with T2DM initiating linagliptin or a comparator agent within class (ie, another dipeptidyl peptidase-4 inhibitor) or outside class (ie, pioglitazone or a sulphonylurea) between May 2011 and December 2012. We focused on comparators used at a similar stage of diabetes to linagliptin. For each comparison, 1:1 propensity score (PS) matching was used to balance >100 baseline claims-based characteristics, including proxies of diabetes severity and duration. Additional clinical data from EHR were available for a subset of patients. We assessed representativeness of the claims-EHR-linked subset, evaluated the balance of claims- and EHR-based covariates before and after PS-matching via standardized differences (SDs), and quantified the potential bias associated with observed imbalances.

RESULTS

From a claims-based study population of 166 613 patients with T2DM, 7219 (4.3%) patients were linked to their EHR data. Claims-based characteristics in the EHR-linked and EHR-unlinked patients were similar (SD < 0.1), confirming the representativeness of the EHR-linked subset. The balance of claims-based and EHR-based patient characteristics appeared to be reasonable before PS-matching and generally improved in the PS-matched population, to be SD < 0.1 for most patient characteristics and SD < 0.2 for select laboratory results and body mass index categories, which was not large enough to cause meaningful confounding.

CONCLUSION

In the context of pharmacoepidemiological research on diabetes therapy, choosing appropriate comparison groups paired with a new-user design and 1:1 PS matching on many proxies of diabetes severity and duration improves balance in covariates typically unmeasured in administrative claims datasets, to the extent that residual confounding is unlikely.

When and How Can Real World Data Analyses Substitute for Randomized Controlled Trials?

Regulators consider randomized controlled trials (RCTs) as the gold standard for evaluating the safety and effectiveness of medications, but their costs, duration, and limited generalizability have caused some to look for alternatives. Real world evidence based on data collected outside of RCTs, such as registries and longitudinal healthcare databases, can sometimes substitute for RCTs, but concerns about validity have limited their impact. Greater reliance on such real world data (RWD) in regulatory decision making requires understanding why some studies fail while others succeed in producing results similar to RCTs. Key questions when considering whether RWD analyses can substitute for RCTs for regulatory decision making are WHEN one can study drug effects without randomization and HOW to implement a valid RWD analysis if one has decided to pursue that option. The WHEN is primarily driven by externalities not controlled by investigators, whereas the HOW is focused on avoiding known mistakes in RWD analyses.

The Association Between the Use of Zolpidem and the Risk of Alzheimer's Disease Among Older People

OBJECTIVES

To evaluate the association between zolpidem use and the risk of Alzheimer's disease among older people.

DESIGN

A retrospective cohort study using data from 2001 to 2011 from the National Health Insurance Research Database.

SETTING

Taiwan.

PARTICIPANTS

A total of 6,922 patients aged 65 years or older enrolled from January 2002 to December 2004 (the enrollment period).

INTERVENTION (EXPOSURE)

Zolpidem users were identified as patients who used zolpidem during the enrollment period. The index date was the date of the first zolpidem prescription. Dosage of zolpidem use was defined using cumulative defined daily dose (cDDD) based on the cumulative dosage that patients took within one year after the index date (grouped as: less than 28, 28-90, 91-180, and more than 180 cDDD).

MEASUREMENTS

The occurrence of Alzheimer's disease was defined as the time period from the end of one year after the index date to the date of the Alzheimer's disease diagnosis. The propensity score was used to adjust the measured confounders of Alzheimer's disease. Cox proportional hazards models were used to evaluate the association between zolpidem use and the incidence of Alzheimer's disease.

RESULTS

Zolpidem users with a high cumulative dose (>180 cDDD) in the first year after initiation had a significantly greater risk of Alzheimer's disease than non-zolpidem users (HR = 2.97, 95% CI = 1.61-5.49) and low cumulative dose (<28 cDDD) users (HR = 4.18, 95% CI = 1.77-9.86).

CONCLUSION

We found the use of a high cumulative dose of zolpidem was associated with an increased risk of Alzheimer's disease among older people living in Taiwan. It is advised to use caution when considering long-term use of zolpidem in older patients.

Risk of Breast Cancer With Long-Term Use of Calcium Channel Blockers or Angiotensin-Converting Enzyme Inhibitors Among Older Women

Controversy exists about breast cancer risk associated with long-term use of calcium channel blockers (CCBs) or angiotensin-converting enzyme inhibitors (ACEis), respectively. Our objective in this study was to separately evaluate associations between duration of CCB or ACEi use and breast cancer in hypertensive women aged ≥55 years at 3 sites in the Kaiser Permanente health-care system (1997–2012). Exposures included CCB or ACEi use of 1–12 years’ duration, determined from pharmacy dispensings. Outcomes included invasive lobular or ductal carcinoma. Statistical methods included discrete-time survival analyses. The cohort included 19,674 (17.9%) CCB users and 90,078 (82.1%) ACEi users. Two percent (n = 397) of CCB users and 1.9% (n = 1,733) of ACEi users developed breast cancer. Compared with 1–<2 years of use, in adjusted analysis, there was no association between CCB use for 2–<12 years and breast cancer: All 95% confidence intervals included 1. Increasing duration of ACEi use was associated with reduced breast cancer risk: Compared with 1–<2 years of use, the adjusted hazard ratio was 0.76 (95% confidence interval: 0.63, 0.92) for 5–<6 years of use and 0.63 (95% confidence interval: 0.43, 0.93) for 9–<10 years of use. We conclude that among older women with hypertension, long-term CCB use does not increase breast cancer risk and long-term treatment with ACEis may confer protection against breast cancer.

Predictive Factors for Pressure Ulcers in an Older Adult Population Hospitalized for Hip Fractures: A Prognostic Cohort Study

Background

Older adult patients with fragility hip fractures constitute a population at high risk for complications, in particular pressure ulcers. The aim was to evaluate the incidence of pressure ulcers and potential predictive factors.

Methods and Findings

A prospective multicentric prognostic cohort study in orthopedic wards in three Italian public hospitals. Participants were all consecutive patients 65 years of age or older diagnosed with a fragility hip fracture. Outcomes were incidence of pressure ulcers. The exposure variables were grouped into three macro areas in order to facilitate reading: “intrinsic” variables, “extrinsic” variables and variables linked to the organization of patient care. One thousand eighty-three older adult patients with fragility hip fractures were enrolled from October 1^st, 2013 to January 31^st, 2015, and pressure ulcers developed in 22.7%. At multivariate analysis, the following were found to be risk factors: age> 80 years (odds ratio (OR) 1.03; p = 0.015), the length of time a urinary catheter was used (OR 1.013; p<0.001), the length of time pain was present (OR 1.008; p = 0.008), the absence of side rails on the bed (OR 1.668; p = 0.026) and the use of a foam position valve (OR 1.025; p<0.001). Instead, the protective factors were the presence of a caregiver for at least half a day daily (OR 0.994; p = 0.012) and the number of positionings during the postoperative period (OR 0.897; p = 0.008).

Conclusions

The study allowed the identification of the patients most at risk for developing pressure ulcers, and the construction of a pragmatic predictive model using significant risk or protective factors in order to reduce the number of pressure ulcers.

Association of insulin dosage with mortality or major adverse cardiovascular events: a retrospective cohort study

BACKGROUND

Existing studies have shown conflicting evidence regarding the safety of exogenous insulin therapy in patients with type 2 diabetes. In particular, observational studies have reported an increased risk of death and cardiovascular disease among users of higher versus lower doses of insulin. We aimed to quantify the association between increasing dosage of insulin exposure and death and cardiovascular events, while taking into account time-dependent confounding and mediation that might have biased previous studies.

METHODS

We did a cohort study using primary care records from the UK-based Clinical Practice Research Datalink (CPRD). New users of metformin monotherapy were identified in the period between Jan 1, 2001, and Dec 31, 2012. We then identified those in this group with a new prescription for insulin. Insulin exposure was categorised into groups according to the mean dose (units) per day within 180-day time segments throughout each patient's follow-up. Relative differences in mortality and major adverse cardiovascular events (non-fatal myocardial infarction, non-fatal stroke, cardiovascular-related mortality) were assessed using conventional multivariable Cox proportional hazards models. Marginal structural models were then applied to reduce bias introduced by the time-dependent confounders affected by previous treatment.

FINDINGS

We identified 165 308 adults with type 2 diabetes in the CPRD database. After applying our exclusion criteria, 6072 (mean age 60 years [SD 12·5], 3281 [54%] men, mean HbA_1c 8·5% [SD 1·75], and median follow-up 3·1 years [IQR 1·7-5·3) were new add-on insulin users and were included in the study cohort; 3599 were new add-on insulin users and were included in the subcohort linked to hospital records and death certificate information. Crude mortality rates were comparable between insulin dose groups; <25 units per day (46 per 1000 person-years), 25 to <50 units per day (39 per 1000 person-years), 50 to <75 units per day (27 per 1000 person-years), 75 to <100 units per day (34 per 1000 person-years), and at least 100 units per day (32 per 1000 person-years; p>0·05 for all; mean rate of 31 deaths per 1000 person-years [95% CI 29-33]). With adjustment for baseline covariates, mortality rates were higher for increasing insulin doses: less than 25 units per day [reference group]; 25 to <50 units per day, hazard ratio (HR) 1·41 [95% CI 1·12-1·78]; 50 to <75 units per day, 1·37 [1·04-1·80]; 75 to <100 units per day, 1·85 [1·35-2·53]; and at least 100 units per day, 2·16 [1·58-2·93]. After applying marginal structural models, insulin dose was not associated with mortality in any group (p>0·1 for all).

INTERPRETATION

In conventional multivariable regression analysis, higher insulin doses are associated with increased mortality after adjustment for baseline covariates. However, this effect seems to be confounded by time-dependent factors such as insulin exposure, glycaemic control, bodyweight gain, and the occurrence of cardiovascular and hypoglycaemic events. This study provides reassurance of the overall safety of insulin use in the treatment of type 2 diabetes and contributes to our understanding of the contrasting conclusions from non-randomised and randomised studies regarding dose-dependent effects of insulin on cardiovascular events and mortality.

FUNDING

Canadian Institutes of Health Research, Heart and Stroke Foundation of Canada, and the Newfoundland and Labrador Research and Development Corporation.

The association between comorbid anxiety disorders and the risk of stroke among patients with diabetes: An 11-year population-based retrospective cohort study

BACKGROUND

Diabetes and anxiety disorders are independent risk factors for stroke. However, it remains unclear whether the risk of stroke is higher among diabetic patients with comorbid anxiety than without comorbid anxiety. Therefore, the purpose of this study was to investigate the association between comorbid anxiety and the risk of stroke among patients with diabetes.

METHODS

This is a retrospective cohort study. We used the National Health Insurance Research Database in Taiwan to identify a diabetes cohort with a new diagnosis of an anxiety disorder but without a history of stroke. The enrollment period was 2001-2006 with up to 11 years of follow-up data. Comorbid anxiety was defined by both a clinical diagnosis of the DSM-IV (ICD-9-CM) and prescriptions for anxiolytic medications. Propensity score matching was performed to balance the selected confounders between the anxiety-exposed group and anxiety non-exposed group. Cox-propositional hazard regression models were used to evaluate the association between comorbid anxiety and the risk of stroke.

RESULTS

Among patients with diabetes (N=40,846), an estimated 5.8% (N=2374) of patients had comorbid anxiety disorders. Diabetic patients with comorbid anxiety were significantly associated with a higher risk of stroke compared to patients without comorbid anxiety (hazard ratio: 1.33, 95% confidence interval: 1.02-1.72).

LIMITATIONS

The severity of anxiety or diabetes could not be measured from the claims data. Residual confounding may still exist.

CONCLUSION

A significantly elevated risk of stroke was observed in association with comorbid anxiety among patients with diabetes. Psychiatrists should consider routine screening for anxiety disorders to prevent a stroke event among patients with diabetes.

Metformin and other glucose-lowering drug initiation and rates of community-based antibiotic use and hospital-treated infections in patients with type 2 diabetes: a Danish nationwide population-based cohort study

OBJECTIVE

Data on early risk of infection in patients receiving their first treatment for type 2 diabetes are limited. We examined rates of community-based antibiotic use and hospital-treated infection in initiators of metformin and other glucose-lowering drugs (GLDs).

DESIGN

Population-based cohort study using medical databases.

SETTING

General practice and hospitals in Denmark.

PARTICIPANTS

131 949 patients with type 2 diabetes who initiated pharmacotherapy with a GLD between 2005 and 2012.

EXPOSURE

Initial GLD used for pharmacotherapy.

MAIN OUTCOME MEASURES

We computed rates and adjusted HRs of community-based antibiotic use and hospital-treated infection associated with choice of initial GLD with reference to metformin initiation, using an intention-to-treat approach.

RESULTS

The rate of community-based antibiotic use was 362 per 1000 patient-years at risk (PYAR) and that for hospital-treated infection was 51 per 1000 PYAR. Compared with metformin, the risk of hospital-treated infection was slightly higher in sulfonylurea initiators (HR 1.12, 95% CI 1.08 to 1.16) and substantially higher in insulin initiators (HR 1.63, 95% CI 1.54 to 1.72) initiators after adjustment for comorbid conditions, comedications and other confounding factors. In contrast, virtually no difference was observed for overall community-based antibiotic use (HR 1.02, 95% CI 1.01 to 1.04, for sulfonylurea initiators; and 1.04, 95% CI 1.01 to 1.07, for insulin initiators).

CONCLUSIONS

Rates of community-based antibiotic treatment and hospitalisation for infection were high in patients receiving their first treatment for type 2 diabetes and differed with the choice of initial GLD used for pharmacotherapy.

Comparative cardiovascular safety of glucagon-like peptide-1 receptor agonists versus other antidiabetic drugs in routine care: a cohort study

AIMS

To evaluate the comparative cardiovascular disease (CVD) safety of glucagon-like peptide-1 receptor agonists (GLP-1 RAs) in head-to-head comparisons with dipeptidyl peptidase-4 (DPP-4) inhibitors, sulphonylureas or insulin, when added to metformin, as used in 'real-world' patients with type 2 diabetes mellitus (T2DM).

METHODS

Within a large US commercial health plan database linked to laboratory test results, we identified three pairwise 1 : 1 propensity-score-matched cohorts of patients with T2DM aged ≥18 years treated with metformin who initiated a GLP-1 RA or a comparator, i.e. DPP-4 inhibitor (n = 35 534), second-generation sulphonylureas (n = 28 138) or insulin (n = 47 068), between 2005 and 2013. We examined the association between drug initiation and a composite CVD endpoint, comprising hospitalizations for acute myocardial infarction, unstable angina, stroke or coronary revascularization.

RESULTS

During the course of 1 year, there were 13.9 and 13.7 CVD events per 1000 person-years among propensity-score-matched initiators of GLP-1 RAs versus DPP-4 inhibitors [hazard ratio (HR) 1.02; 95% confidence interval (CI) 0.84-1.24]; and 12.1 versus 14.0 events among initiators of GLP-1 RAs versus sulphonylureas (HR 0.86; 95% CI 0.69-1.08). The effect estimates for GLP-1 RAs versus insulin were sensitive to the adjustment for glycated haemoglobin, after which the HR was 1.01 (95% CI 0.73-1.41). Results were robust across several sensitivity analyses, including an as-treated analysis considering up to 8.7 years of follow-up.

CONCLUSIONS

This large study, performing head-to-head comparisons of GLP-1 RAs with other antidiabetic agents in real-world patients, provides estimates of relative safety precise enough to exclude large differences in CVD risk and adds further understanding to results from recent clinical trials.

Cardiovascular risk associated with the use of glitazones, metformin and sufonylureas: meta-analysis of published observational studies

BACKGROUND

The results of observational studies evaluating and comparing the cardiovascular safety of glitazones, metformin and sufonylureas are inconsistent.To conduct and evaluate heterogeneity in a meta-analysis of observational studies on the risk of acute myocardial infarction (AMI) or stroke in patients with type 2 diabetes using non-insulin blood glucose-lowering drugs (NIBGLD).

METHODS

We systematically identified and reviewed studies evaluating NIBGLD in patients with type 2 diabetes indexed in Medline, Embase, or the Cochrane Library that met prespecified criteria. The quality of included studies was assessed with the RTI item bank. Results were combined using fixed- and random-effects models, and the Higgins I(2) statistic was used to evaluate heterogeneity. Sensitivity analyses by study quality were conducted.

RESULTS

The summary relative risk (sRR) (95% CI) of AMI for rosiglitazone versus pioglitazone was 1.13 (1.04-1.24) [I(2) = 55%]. In the sensitivity analysis, heterogeneity was reduced [I(2) = 16%]. The sRR (95% CI) of stroke for rosiglitazone versus pioglitazone was 1.18 (1.02-1.36) [I(2)  = 42%]. There was strong evidence of heterogeneity related to study quality in the comparisons of rosiglitazone versus metformin and rosiglitazone versus sulfonylureas (I (2) ≥ 70%). The sRR (95% CI) of AMI for sulfonylurea versus metformin was 1.24 (1.14-1.34) [I(2) = 41%] and for pioglitazone versus metformin was 1.02 (0.75-1.38) [I(2) = 17%]. Sensitivity analyses decreased heterogeneity in most comparisons.

CONCLUSION/INTERPRETATION

Sulfonylureas increased the risk of AMI by 24% compared with metformin; an imprecise point estimate indicated no difference in risk of AMI when comparing pioglitazone with metformin. The presence of heterogeneity precluded any conclusions on the other comparisons. The quality assessment was valuable in identifying methodological problems in the individual studies and for analysing potential sources of heterogeneity.

Does Metformin Reduce Cancer Risks? Methodologic Considerations

The substantial burden of cancer and diabetes and the association between the two conditions has been a motivation for researchers to look for targeted strategies that can simultaneously affect both diseases and reduce their overlapping burden. In the absence of randomized clinical trials, researchers have taken advantage of the availability and richness of administrative databases and electronic medical records to investigate the effects of drugs on cancer risk among diabetic individuals. The majority of these studies suggest that metformin could potentially reduce cancer risk. However, the validity of this purported reduction in cancer risk is limited by several methodological flaws either in the study design or in the analysis. Whether metformin use decreases cancer risk relies heavily on the availability of valid data sources with complete information on confounders, accurate assessment of drug use, appropriate study design, and robust analytical techniques. The majority of the observational studies assessing the association between metformin and cancer risk suffer from methodological shortcomings and efforts to address these issues have been incomplete. Future investigations on the association between metformin and cancer risk should clearly address the methodological issues due to confounding by indication, prevalent user bias, and time-related biases. Although the proposed strategies do not guarantee a bias-free estimate for the association between metformin and cancer, they will reduce synthesis of and reporting of erroneous results.

Case-control study of oral glucose-lowering drugs in combination with long-acting insulin and the risks of incident myocardial infarction and incident stroke

BACKGROUND

The use of oral glucose-lowering therapies with insulin is common, but the cardiovascular effects are largely unknown. Among users of long-acting insulin, we conducted a population-based case-control study to evaluate the incident myocardial infarction (MI) and incident stroke risks associated with the use of sulfonylureas and the use of metformin.

METHODS

Cases were Group Health Cooperative enrollees with type 2 diabetes who used long-acting insulin at the time of diagnosis with a first MI (n = 413) or first stroke (n = 247) from 1995 to 2010. Controls (n = 443) with type 2 diabetes who used long-acting insulin were matched to cases on age, sex, and calendar year. Sulfonylurea and metformin use was classified as current, past, or never using electronic pharmacy records. MI and stroke diagnoses were validated by medical record review. Analyses were adjusted for potential confounders.

RESULTS

Current use of sulfonylureas compared with never use was associated with a higher risk of MI (odds ratio [OR] 1.67; 95% confidence interval [CI], 1.10-2.55) but not stroke (OR 1.22; 95%CI, 0.74-2.00). Current use of metformin compared with never use was associated with a lower risk of stroke (OR 0.54; 95%CI, 0.31-0.95) but not MI (OR 0.77; 95%CI, 0.44-1.33). Past use of sulfonylureas and past use of metformin were not associated with either outcome.

CONCLUSIONS

Sulfonylureas in combination with long-acting insulin may increase the risk of MI compared with the use of insulin alone. Metformin may be an important cardiovascular disease prevention therapy for patients on insulin therapy. Copyright © 2015 John Wiley & Sons, Ltd.

Association between Withholding Angiotensin Receptor Blockers in the Early Postoperative Period and 30-day Mortality

Background:

Despite widespread use, there is limited information to guide perioperative management of angiotensin receptor blockers (ARBs).

Methods:

In this retrospective cohort study, the authors evaluated the patterns of postoperative ARB use in veterans regularly prescribed ARBs admitted for noncardiac surgery at the Veterans Affairs Healthcare system between 1999 and 2011. Multivariable and propensity score–matched Cox proportional hazards models were used to determine the independent effect of failure to resume ARB by postoperative day 2 on the primary outcome of all-cause 30-day mortality.

Results:

Out of 1,167,482 surgical admissions, 30,173 inpatient surgical admissions met inclusion criteria. Approximately 10,205 patients (33.8%) in the cohort did not resume ARB by day 2. Those that resumed ARB had a 30-day mortality rate of 1.3% (260 of 19,968), whereas 3.2% (323 of 10,205) died in the group that withheld ARB. The unadjusted hazard ratio (HR) for 30-day mortality was 2.45 (95% CI, 2.08 to 2.89; P &lt; 0.001) for those that withheld ARB compared with those that resumed, whereas the multivariable adjusted HR was 1.74 (95% CI, 1.47 to 2.06; P &lt; 0.001). When restricted to a propensity score–matched subset of 19,490, the HR was similar (1.47; 95% CI, 1.22 to 1.78; P &lt; 0.001). Withholding ARB in younger patients increased mortality risk (HR = 2.52; 95% CI, 1.69 to 3.76; P &lt; 0.001 for age &lt;60 yr) compared with older patients (HR = 1.42; 95% CI, 1.09 to 1.85; P = 0.01 for age &gt;75 yr).

Conclusions:

Postoperative delay in resuming ARB is common, particularly in patients who are frail after surgery. Withholding ARB is strongly associated with increased 30-day mortality, especially in younger patients, although residual confounding may be present.

Cardiovascular safety of sulphonylureas: over 40 years of continuous controversy without an answer

More than 40 years after publication of the University Group Diabetes Program trial, the cardiovascular safety of sulphonylureas is still contentious. Although several hypotheses linking sulphonylureas to adverse cardiovascular effects exist, none provide conclusive evidence. Adding to the controversy, current clinical trials and observational studies provide inconsistent, and sometimes conflicting, evidence for the cardiovascular effects of sulphonylureas. Overall, observational evidence suggests that an increased risk of adverse cardiovascular outcomes is associated with sulphonylureas; however, these data may be subject to residual confounding and bias. Although evidence from randomized controlled trials has suggested a neutral effect, the majority of these studies were not specifically designed to assess the effect of sulphonylureas on adverse cardiovascular event risk. Current ongoing large clinical trials may provide some clarity on the cardiovascular safety of sulphonylureas, but the results are not expected for several years. With the continued uncertainties concerning the cardiovascular safety of all antidiabetic drugs, a clear answer with regard to sulphonylureas is warranted. The objectives of the present article were to provide an overview of the controversy surrounding sulphonylurea-related cardiovascular effects, to discuss the limitations of the current literature, and to provide recommendations for future studies aiming to elucidate the true relationship between sulphonylureas and adverse cardiovascular effects in people with type 2 diabetes.