Adaptability of High Dimensional Propensity Score Procedure in the Transition from ICD-9 to ICD-10 in the US Healthcare System.

Background: High-Dimensional Propensity Score procedure (HDPS) is a data-driven approach to assist control for confounding in pharmacoepidemiologic research. The transition to the International Classification of Disease (ICD-9/10) in the US health system may pose uncertainty in applying the HDPS procedure. Methods: We assembled a base cohort of patients in MarketScan® Commercial Claims Database who had newly initiated celecoxib or traditional NSAIDs to compare gastrointestinal bleeding risk. We then created bootstrapped hypothetical cohorts from the base cohort with predefined patient selection patterns from the ICD eras. Three strategies for HDPS deployment were tested: 1) split the cohort by ICD era, deploy HDPS twice, and pool the relative risks (pooled RR), 2) consider codes from each ICD era as a separate data dimension and deploy HDPS in the entire cohort (data dimensions) and 3) map ICD codes from both eras to Clinical Classifications Software (CCS) concepts before deploying HDPS in the entire cohort (CCS mapping). We calculated percent bias and root-mean-squared error to compare the strategies. Results: A similar bias reduction was observed in cohorts where patient selection pattern from each ICD era was comparable between the exposure groups. In the presence of considerable disparity in patient selection, we observed a bimodal distribution of propensity scores in the data dimensions strategy, indicating instrument-like covariates. Moreover, the CCS mapping strategy resulted in at least 30% less bias than pooled RR and data dimensions strategies (RMSE: 0.14, 0.19, 0.21, respectively) in this scenario. Conclusion: Mapping ICD codes to a stable terminology like CCS serves as a helpful strategy to reduce residual bias when deploying HDPS in pharmacoepidemiologic studies spanning both ICD eras.

Assessment of the Risk Evaluation and Mitigation Strategy (REMS) for Phentermine-Topiramate to Prevent Exposure During Pregnancy.

BACKGROUND: The U.S. Food and Drug Administration approved phentermine-topiramate for obesity in 2012 and required a Risk Evaluation and Mitigation Strategy (REMS) to prevent prenatal exposure. No such requirement was introduced for topiramate. OBJECTIVE: To evaluate the rate of prenatal exposure, contraceptive use, and pregnancy testing among patients with phentermine-topiramate compared with topiramate or other antiobesity medications (AOMs). DESIGN: Retrospective cohort study. SETTING: Nationwide health insurance claims database. PARTICIPANTS: Females aged 12 to 55 years with no infertility diagnosis or sterilization procedure. Patients with other indications for topiramate were excluded to identify a cohort that was likely treated for obesity. MEASUREMENTS: Patients initiated use of phentermine-topiramate, topiramate, or an AOM (liraglutide, lorcaserin, or bupropion-naltrexone). Pregnancy at treatment initiation, conception during treatment, contraceptive use, and pregnancy testing outcomes were ascertained. Measurable confounders were adjusted for, and extensive sensitivity analyses were done. RESULTS: A total of 156 280 treatment episodes were observed. Adjusted prevalence of pregnancy at treatment initiation was 0.9 versus 1.6 per 1000 episodes (prevalence ratio, 0.54 [95% CI, 0.31 to 0.95]) for phentermine-topiramate versus topiramate. The incidence rate of conception during treatment was 9.1 versus 15.0 per 1000 person-years (rate ratio, 0.61 [CI, 0.40 to 0.91]) for phentermine-topiramate versus topiramate. Both outcomes were similarly lower for phentermine-topiramate compared with AOM. Prenatal exposure was marginally lower in topiramate users compared with AOM users. Approximately 20% of patients in all cohorts had at least 50% of treatment days covered by contraceptives. Few patients had pregnancy tests before treatment (≤5%), but this was more common among phentermine-topiramate users. LIMITATIONS: Outcome misclassification; unmeasured confounding due to lack of prescriber data to account for possible clustering and spillover effects. CONCLUSION: Prenatal exposure seemed to be significantly lower among phentermine-topiramate users under the REMS. Pregnancy testing and contraceptive use appeared to be inadequate for all groups, which deserves attention to prevent the remaining potential exposures. PRIMARY FUNDING SOURCE: None.

Topiramate Utilization After Phentermine/Topiramate Approval for Obesity Management: Risk Minimization in the Era of Drug Repurposing.

INTRODUCTION: The US FDA required a Risk Evaluation and Mitigation Strategy (REMS) for phentermine/topiramate, an anti-obesity medication, to prevent congenital malformations. No REMS is required for single-ingredient topiramate, which may be used off-label for the same purpose. OBJECTIVE: The aim of this study was to evaluate the impact of phentermine/topiramate approval in 2012 on subsequent topiramate use among patients with obesity. METHODS: We used a national insurance claims database to conduct an interrupted time-series study (2009-2015). Enrollees aged 18-65 years in each examined calendar quarter had full insurance benefits during that quarter and the preceding 6 months. We required patients to have an obesity diagnosis and no other conditions warranting topiramate use. We calculated topiramate or comparator drug (atorvastatin, metformin) initiation rates and evaluated changes in trends before and after 2012 (transition period). RESULTS: Among topiramate users, 80% were female, and demographic characteristics remained consistent during the study period. Between 2009 and 2011, the topiramate initiation rate (95% confidence interval) among patients with obesity was 0.85 (0.73-0.98) per 1000 patients, with no significant upward or downward trend. In the first quarter of 2013, this rate had increased more than 2.5-fold (change: + 1.36 [1.19-1.52]). Metformin and atorvastatin initiation rates did not change. Topiramate initiation rates were threefold higher than phentermine/topiramate rates during the post-approval period. CONCLUSION: Phentermine/topiramate approval was associated with increased topiramate use among patients with obesity. Prescribers are encouraged to enhance patient education and monitoring in such clinical use since topiramate prescribing information, compared with REMS for phentermine/topiramate, has less emphasis on preventing prenatal exposure.

Utilization of chronic lung disease treatment before the respiratory syncytial virus season as palivizumab prophylaxis qualifier in the American Academy of Pediatrics Guidelines.

Guidelines from the American Academy of Pediatrics recommend palivizumab immunoprophylaxis for children with CLD in their second year of life if they continue to need treatment within 6 months before the RSV season. The utilization patterns of treatment (chronic corticosteroid therapy, diuretic therapy, or supplemental oxygen) are not well understood. We examined variations in CLD treatment for ten consecutive 20-day segments preceding RSV season onset. Among infants and children with CLD (n = 19,026), 35.2% received one or more medical treatments for CLD any time within 200 days before entering the second RSV season: 8.6%, 3.2%, and 29.7% received supplemental oxygen, diuretics, and corticosteroids, respectively. Utilization decreased as infants' age increased with corticosteroids surpassing oxygen and diuretics. To avoid the capture of intermittent use of corticosteroids for acute infections, we found requiring a minimum of 45 days cumulative exposure was reasonable to determine chronic use. What is Known: • Guidelines from the American Academy of Pediatrics recommend palivizumab immunoprophylaxis for children with CLD in their second year of life if they continue to need treatment within 6 months before the RSV season. • The utilization patterns of treatment (chronic corticosteroid therapy, diuretic therapy, or supplemental oxygen) are not well understood. A definition of chronic corticosteroid therapy in this setting is not available. What is New: • Among infants and children with CLD of prematurity, 35.2% received one or more medical treatments for CLD any time within 200 days before entering the second RSV season: 8.6%, 3.2%, and 29.7% received oxygen, diuretics, and corticosteroids, respectively. Utilization decreased as infants' age increased with corticosteroids surpassing oxygen and diuretics. • A minimum of 45 days cumulative corticosteroid use within the past 90 days would accurately capture chronic use to fulfill criteria for immunoprophylaxis while limiting the inclusion of intermittent use of corticosteroids for acute infections.

Calibration of Chronic Lung Disease Severity as a Risk Factor for Respiratory Syncytial Virus Hospitalization.

BACKGROUND: Guidelines assume children with chronic lung disease (CLD) who require medical support within 6 months before the second respiratory syncytial virus (RSV) season remains at high risk of severe RSV disease. We determined the number of days since the last treatment (DSL) when the risk of RSV hospitalization among children with CLD becomes equivalent to the risk for those not qualified for immunoprophylaxis. METHODS: The study cohort was assembled using Medicaid billing records from 1999 to 2010 linked to Florida and Texas birth certificate records. We developed DSL-trend discrete time logistic regression models within a survival analysis framework, adjusting for use of immunoprophylaxis, to compare the hospitalization risk of CLD infants at 4 age points to that of term infants at 1 month of age with siblings. RESULTS: The study cohort included 858 830 healthy term and 5562 preterm infants with CLD. Among 1-month-old term infants, the RSV hospitalization risk averaged across all covariate strata was 14.8 (95% confidence interval [CI], 13.5-16.1) per 1000 patient season-months. Risk for preterm CLD children reached the threshold derived from term infants when DSL was 76 (95% CI, 22-198.5), 52 (95% CI, 6.5-123), 35 (95% CI, 0-93.5), and 12 (95% CI, 0-61.5) at the respective ages of 12, 15, 17.2, and 21 months. CONCLUSIONS: The 180-day threshold used to define CLD severity at season start can be shortened to 120 days, 90 days, and 60 days for children with CLD at age 15, 17.2, and 21 months, respectively.

Validation of algorithms to estimate gestational age at birth in the Medicaid Analytic eXtract-Quantifying the misclassification of maternal drug exposure during pregnancy.

PURPOSE: Accurate ascertainment of gestational age (GA) has been a challenge in perinatal epidemiologic research. To date, no study has validated GA algorithms in Medicaid Analytic eXtract (MAX). METHODS: We linked livebirths of mothers enrolled in Medicaid ≥30 days after delivery in 1999-2010 MAX to state birth certificates. We used clinical/obstetric estimate of gestation on the birth certificates as gold standard to validate claims-based GA algorithms. We calculated the proportions of deliveries with algorithm-estimated GA within 1-/2-weeks of the gold standard, the sensitivity, specificity, and positive/negative predictive value (PPV/NPV) of exposure to select medications during specific gestation windows, and quantified the impact of exposure misclassification on hypothetical relative risk (RR) estimates. RESULTS: We linked 1 336 495 eligible deliveries. Within 1-week agreement was 77%-80% overall and 47%-56% for preterm deliveries. The trimester-specific drug exposure status had high sensitivities and PPVs (88.5%-98.5%), and specificities and NPVs (>99.0%). Assuming a hypothetical RR of 2.0, bias associated with exposure misclassification during first trimester ranged from 10% to 40% under non-differential/differential misclassification assumptions. CONCLUSIONS: Claims-based GA algorithms had good agreement with the gold standard overall, but lower agreement among preterm deliveries, potentially resulting in biased risk estimated for pregnancy exposure evaluations.

Use of Sodium-Glucose Cotransporter 2 Inhibitors in Patients With Type 1 Diabetes and Rates of Diabetic Ketoacidosis.

OBJECTIVE: To estimate real-world off-label use of sodium-glucose cotransporter 2 (SGLT2) inhibitors in patients with type 1 diabetes, estimate rates of diabetic ketoacidosis (DKA), and compare them with DKA rates observed in sotagliflozin clinical trials. RESEARCH DESIGN AND METHODS: We identified initiators of SGLT2 inhibitors in the Sentinel System from March 2013 to June 2018, determined the prevalence of type 1 diabetes using a narrow and a broad definition, and measured rates of DKA using administrative claims data. Standardized incidence ratios (SIRs) were calculated using age- and sex-specific follow-up time in Sentinel and age- and sex-specific DKA rates from sotagliflozin trials 309, 310, and 312. RESULTS: Among 475,527 initiators of SGLT2 inhibitors, 0.50% and 0.92% met narrow and broad criteria for type 1 diabetes, respectively. Rates of DKA in the narrow and broad groups were 7.3/100 person-years and 4.5/100 person-years, respectively. Among patients who met narrow criteria for type 1 diabetes, rates of DKA were highest for patients aged 25-44 years, especially females aged 25-44 years (19.7/100 person-years). More DKA events were observed during off-label use of SGLT2 inhibitors in Sentinel than would be expected based on sotagliflozin clinical trials (SIR = 1.83; 95% CI 1.45-2.28). CONCLUSIONS: Real-world off-label use of SGLT2 inhibitors among patients with type 1 diabetes accounted for a small proportion of overall SGLT2 inhibitor use. However, the risk for DKA during off-label use was notable, especially among young, female patients. Although real-word rates of DKA exceeded the expectation based on clinical trials, results should be interpreted with caution due to differences in study methods, patient samples, and study drugs.

Data linkage in pharmacoepidemiology: A call for rigorous evaluation and reporting.

PURPOSE: The purpose of this paper is to provide guidance on the evaluation of data linkage quality through the development of a checklist for reporting key elements of the linkage process. METHODS: Responding to a call for manuscripts from the International Society for Pharmacoepidemiology (ISPE), a working group including international representation from the academic, industry, and contract research, and regulatory sectors was formed to develop a checklist for evaluation of data linkage performance and reporting data linkage specifically for pharmacoepidemiologic research. This checklist expands on the reporting of studies conducted using observational routinely collected health data specific to pharmacoepidemiology (RECORD-PE) guidelines. RESULTS: A key aspect of data linkage evaluation for pharmacoepidemiology is to articulate how a linkage process was performed and its accuracy in terms of validation and verification of the resulting linked data. This study generates a checklist, which covers domains including data sources, linkage variables, linkage methods, linkage results, and linkage evaluation. For each domain, specific recommendations provide a clear and transparent assessment of the linkage process. CONCLUSIONS: Linking data sources can help to enrich analytic databases to more accurately define study populations, enable adjustment for confounding, and improve the capture of health outcomes. Clear and transparent reporting of data linkage processes will help to increase confidence in the evidence generated from these data by allowing researchers and end users to critically assess the potential for bias owing to the data linkage process.

Usability of encounter data for Medicaid comprehensive managed care vs traditional Medicaid fee-for-service claims among pregnant women.

BACKGROUND: The completeness of medical encounters capture among Medicaid enrollees in comprehensive managed care (CMC) has been shown to vary across states and years. CMC penetration has grown, and CMC encounter capture specific to pregnancy care is understudied. OBJECTIVES: To compare the completeness of encounter data for pregnant beneficiaries in CMC versus traditional fee-for-service (FFS) in Texas and Florida between 2007 and 2010. METHODS: Using Medicaid Analytic eXtract (MAX) data linked to Florida and Texas birth certificate records, for each state and study year, we compared proportions using seven themes: (a) delivery; (b) prenatal visits; (c) dispensed prescriptions during pregnancy; (d) gestational diabetes and blood glucose testing; (e) antidiabetics and diagnosis of diabetes mellitus; (f) antibiotics for urinary tract infection and outpatient encounter; and (g) bacterial vaginosis and dispensing for metronidazole or clindamycin. We considered CMC data to be acceptable if proportions were no less than 10% below the corresponding (2007 to 2010) FFS control values. RESULTS: Pregnancy-related characteristics of FFS vs CMC denominators were comparable. Proportions for the seven measures among FFS controls ranged from 26% to 98%. In Texas, CMC encounter data met the thresholds for all measures between 2007 and 2010. Florida had usable CMC encounter data starting from 2009 with incomplete medical and pharmacy records in 2007 and 2008. CONCLUSIONS: The quality of CMC encounter data in MAX files for pregnant women varied in Florida and Texas and improved over time. Use of pregnancy-specific measures can aid researchers in selecting states and years with acceptable encounter data quality.

Validation of mother-infant linkage using Medicaid Case ID variable within the Medicaid Analytic eXtract (MAX) database.

PURPOSE: The state-assigned Case ID number in the Medicaid Analytic eXtract (MAX) allows for potential linkage of mothers to infants. No validation of respective linkage algorithms is available. We established and validated an algorithm within MAX that links mothers to infants and to identify factors influencing successful mother-infant linkage. METHODS: We identified all mother-infant pairs in FL and TX birth certificates records (BCR) that could be linked individually to MAX records (1999-2005 for FL and 1999-2010 for TX) based on Social Security Number (gold standard pairs). Case ID linkage performance was evaluated as the proportion of gold standard mother-infant pairs that were identified by the algorithm (sensitivity) and the proportion of algorithm defined mother-infant pairs that were correctly linked. Generalized estimating equations were used to calculate the probability for successful Case ID algorithm linkage versus non-linkage using maternal and infant characteristics. RESULTS: We identified 323,160 gold standard pairs in FL BCR and MAX and 1,025,350 in TX BCR and MAX. Depending on Medicaid enrollment the algorithm sensitivity ranged from 85.51% to 87.96% in FL and 19.60% to 35.75% in TX. In both states, positive predictive value exceeded 99%, regardless of enrollment periods. Determinants for successful linkage varied across states, but suggested better results for younger mothers, minority women, and those with lower educational achievement. CONCLUSIONS: Our algorithm can correctly link liveborn infants to their mothers. The algorithm's sensitivity in identifying pairs varied across states, but PPV was consistently high. Linkage performance was associated with certain characteristics that may affect representativeness of successfully linked pairs.

Misclassification in Assessment of First Trimester In-utero Exposure to Drugs Used Proximally to Conception: the Example of Letrozole Utilization for Infertility Treatment.

Letrozole is an aromatase inhibitor that has an unapproved use for ovulation induction with infertility. Because of the proximity of this use to conception, we selected letrozole to study the effect of 3 different methods for identifying the pregnancy start date and their impact on exposure misclassification. Using electronic health data from the US Sentinel database (2001-2015), we identified live-birth pregnancies conceived through in-vitro fertilization or intrauterine insemination. The pregnancy start was calculated using 1) a validated algorithm to estimate the last menstrual period (LMP), 2) LMP + 14 days (i.e., conception estimate), and 3) the fertility-procedure date. We identified 47,628 live-births after intrauterine insemination (n = 24,962) and in-vitro fertilization (n = 22,666), in which 2,458 (5.3%) mothers received letrozole. The algorithm-based conception estimate occurred within 14 days of the fertility procedure for 78.3% of pregnancies. Defining pregnancy start as LMP (45.7/1,000 pregnancies) or LMP + 14 days (12.7/1,000 pregnancies) overestimated letrozole exposure during pregnancy by 8.4-fold and 2.3-fold, respectively, compared with defining it at the date of the fertility procedure (5.5/1,000 pregnancies). While most studies of drug utilization in pregnancy use LMP as the conventional pregnancy start, this introduced substantial exposure misclassification in the example of letrozole. LMP + 14 days was less biased. Researchers should carefully consider the impact of the method for identifying the pregnancy start date on the potential for exposure misclassification.

Evaluation of the US Food and Drug Administration Sentinel Analysis Tools Using a Comparator with a Different Indication: Comparing the Rates of Gastrointestinal Bleeding in Warfarin and Statin Users.

BACKGROUND: The US Food and Drug Administration's Sentinel System was established to monitor safety of regulated medical products. Sentinel investigators identified known associations between drugs and adverse events to test reusable analytic tools developed for Sentinel. This test case used a comparator with a different indication. OBJECTIVE: We tested the ability of Sentinel's reusable analytic tools to identify the known association between warfarin and gastrointestinal bleeding (GIB). Statins, expected to have no effect on GIB, were the comparator. We further explored the impact of analytic features, including matching ratio and stratifying Cox regression analyses, on matched pairs. METHODS: This evaluation included data from 14 Sentinel Data Partners. New users of warfarin and statins, aged 18 years and older, who had not received other anticoagulants or had recent GIB were matched on propensity score using 1:1 and 1:n variable ratio matching, matching statin users with warfarin users to estimate the average treatment effect in warfarin-treated patients. We compared the risk of GIB using Cox proportional hazards regression, following patients for the duration of their observed continuous treatment or until a GIB. For the 1:1 matched cohort, we conducted analyses with and without stratification on matched pair. The variable ratio matched cohort analysis was stratified on the matched set. RESULTS: We identified 141,398 new users of warfarin and 2,275,694 new users of statins. In analyses stratified on matched pair/set, the hazard ratios (HR) for GIB in warfarin users compared with statin users were 2.78 (95% confidence interval [CI] 2.36-3.28) in the 1:1 matched cohort and 3.10 (95% CI 2.76-3.49) in the variable ratio matched cohort. The HR was lower in the analysis of the 1:1 matched cohort not stratified by matched pair (2.22, 95% CI 1.97-2.49), and highest early in treatment. Follow-up for warfarin users tended to be shorter than for statin users. CONCLUSIONS: This study identified the expected GIB risk with warfarin compared with statins using an analytic tool developed for Sentinel. Our findings suggest that comparators with different indications may be useful in surveillance in select circumstances. Finally, in the presence of differential censoring, stratification by matched pair may reduce the potential for bias in Cox regression analyses.

Utilization of drugs with pregnancy exposure registries during pregnancy.

PURPOSE: To describe the utilization of drugs with pregnancy exposure registries by trimester during pregnancy, in comparison with matched nonpregnant episodes and a pre-pregnancy period. METHODS: We identified live-born deliveries from women aged 10 to 54 years and matched the pregnancies 1:1 with nonpregnant episodes from a comparator cohort not delivering live-born infants, using data from 2001 to 2013 in the Sentinel Distributed Database. We evaluated the utilization of 34 drugs with pregnancy exposure registries, comparing utilization during pregnancy to the matched nonpregnant episodes, and to the 90 days before pregnancy. RESULTS: We identified 1 895 597 pregnancies ending in live births in 1 598 697 women and 1 895 597 matched nonpregnant episodes in 1 582 581 women. We observed a lower prevalence of use for most drugs during pregnancy compared with the matched nonpregnant episodes, and the 90-day pre-pregnancy period. The median (interquartile range) prevalence ratio of use, at any time during pregnancy, for all products was 0.2 (0.1-0.3) comparing pregnant to nonpregnant episodes. Overall, there was a decrease in drug utilization by trimester; from 2.6% in the 90 days preceding pregnancy to 2.1% in the first trimester, 1.1% in the second trimester, and 0.9% in the third trimester. CONCLUSIONS: Among drugs with pregnancy exposure registries, use was less during pregnancy compared with before pregnancy and to the matched nonpregnant episodes. The lower utilization during pregnancy suggests that women may be avoiding these drugs to minimize potentially harmful exposure during pregnancy. This lower utilization may increase the challenges of further studying the safety of these drugs using pregnancy exposure registries.

Enrollment and Retention in 34 United States Pregnancy Registries Contrasted with the Manufacturer's Capture of Spontaneous Reports for Exposed Pregnancies.

INTRODUCTION: Pregnancy registries and spontaneous reports are essential pharmacovigilance tools to evaluate drug safety during pregnancy. OBJECTIVES: The aim of this study was to evaluate postmarket capture of exposed pregnancies. METHODS: Pregnancy registries for drugs and biologics were identified in a systematic review. Through a standardized questionnaire, manufacturers provided information on (1) pregnancy registry enrollment and retention, and (2) worldwide receipt of spontaneous reports for exposed pregnancies. A validated algorithm for live-birth pregnancies allowed calculation of exposure rates per 100,000 live births using claims data. RESULTS: Among 34 products with a pregnancy registry, median (interquartile range) registry enrollment was 36 pregnancies (5-258) and median spontaneous report capture was 450 pregnancies (89-1192). Products used in >20/100,000 live births had a median registry enrollment of 490 pregnancies and median capture of 1061 spontaneously reported exposed pregnancies. Lower median registry enrollment and spontaneous report capture was observed for products used in 0.5-20/100,000 live births (36 from registries, 541 spontaneous reports) and <0.5/100,000 live births (3 from registries, 41 spontaneous reports). Among 24 registries enrolling ≥10 pregnancies, median capture of pregnancy outcomes (e.g. live birth, spontaneous abortion) was 83.9%. For 19 registries enrolling ≥10 infants, the median proportion of infants achieving protocol-specified follow-up was 89.9% for up to 4 weeks post-birth, 75.0% for 1-5 months, and 57.1% for ≥6 months. CONCLUSIONS: Relatively higher product utilization among pregnant women predicted greater pregnancy registry enrollment. For products rarely used during pregnancy, registry enrollment was low and differences in registry enrollment compared with worldwide spontaneous report receipt were most pronounced. Products with very low utilization levels during pregnancy may require a combination of worldwide pharmacovigilance, pregnancy registries, and additional study methods to achieve adequate surveillance.

Prospective Postmarketing Surveillance of Acute Myocardial Infarction in New Users of Saxagliptin: A Population-Based Study.

OBJECTIVE: The cardiovascular safety of saxagliptin, a dipeptidyl-peptidase 4 inhibitor, compared with other antihyperglycemic treatments is not well understood. We prospectively examined the association between saxagliptin use and acute myocardial infarction (AMI). RESEARCH DESIGN AND METHODS: We identified patients aged ≥18 years, starting from the approval date of saxagliptin in 2009 and continuing through August 2014, using data from 18 Mini-Sentinel data partners. We conducted seven sequential assessments comparing saxagliptin separately with sitagliptin, pioglitazone, second-generation sulfonylureas, and long-acting insulin, using disease risk score (DRS) stratification and propensity score (PS) matching to adjust for potential confounders. Sequential testing kept the overall chance of a false-positive signal below 0.05 (one-sided) for each pairwise comparison. RESULTS: We identified 82,264 saxagliptin users and more than 1.5 times as many users of each comparator. At the end of surveillance, the DRS-stratified hazard ratios (HRs) (95% CI) were 1.08 (0.90-1.28) in the comparison with sitagliptin, 1.11 (0.87-1.42) with pioglitazone, 0.79 (0.64-0.98) with sulfonylureas, and 0.57 (0.46-0.70) with long-acting insulin. The corresponding PS-matched HRs were similar. Only one interim analysis of 168 analyses met criteria for a safety signal: the PS-matched saxagliptin-pioglitazone comparison from the fifth sequential analysis, which yielded an HR of 1.63 (1.12-2.37). This association diminished in subsequent analyses. CONCLUSIONS: We did not find a higher AMI risk in saxagliptin users compared with users of other selected antihyperglycemic agents during the first 5 years after U.S. Food and Drug Administration approval of the drug.

Safety assessment of niacin in the US Food and Drug Administration's mini-sentinel system.

PURPOSE: The Heart Protection Study 2-Treatment of HDL to Reduce the Incidence of Vascular Events (HPS2-THRIVE) trial found higher incidence rates of adverse reactions, including bleeding, in patients receiving the combination of extended-release niacin and laropiprant versus placebo. It is not known whether these adverse events are attributable to laropiprant, not approved in the USA, or to extended-release niacin. We compared rates of major gastrointestinal bleeding and intracranial hemorrhage among initiators of extended-release niacin and initiators of fenofibrate. METHODS: We used Mini-Sentinel (now Sentinel) to conduct an observational, new user cohort analysis. We included data from 5 Data Partners covering the period from January 1, 2007 to August 31, 2013. Individuals who initiated extended-release niacin were propensity score-matched to individuals who initiated fenofibrate. Within the matched cohorts, we used Cox proportional hazards models to compare rates of hospitalization for major gastrointestinal bleeding events and intracranial hemorrhage assessed using validated claims-based algorithms. RESULTS: A total of 234 242 eligible extended-release niacin initiators were identified, of whom 210 389 (90%) were 1:1 propensity score-matched to eligible fenofibrate initiators. In propensity score-matched analyses, no differences were observed between exposure groups in rates of major gastrointestinal bleeding (hazard ratio [HR], 0.98; 95% confidence interval [CI], 0.82 to 1.18) or intracranial hemorrhage (HR, 1.21; 95% CI, 0.66 to 2.22). Results were similar in pre-specified sensitivity and subgroup analyses. CONCLUSIONS: We did not observe evidence for an association between extended-release niacin versus fenofibrate and rates of major gastrointestinal bleeding or intracranial hemorrhage.