Evaluation of the US Food and Drug Administration sentinel analysis tools in confirming previously observed drug-outcome associations: The case of clindamycin and Clostridium difficile infection

Comparative Risk of Angioedema With Sacubitril-Valsartan vs Renin-Angiotensin-Aldosterone Inhibitors

BACKGROUND

Data on angioedema risk among sacubitril-valsartan (SV) users in real-world settings are limited.

OBJECTIVES

We sought to evaluate the risk of angioedema among SV new users compared with angiotensin-converting enzyme (ACE) inhibitor and angiotensin-receptor-blocker (ARB) new users separately.

METHODS

We conducted a propensity score-matched cohort study, comparing SV new users (no use of SV, ACE inhibitor, ARB 6 months before) and SV new users with prior use (within 183 or 14 days) of ACE inhibitor or ARB (ACE inhibitor-SV and ARB-SV users; recent ACE inhibitor-SV and recent ARB-SV users, respectively) vs ACE inhibitor and ARB new users separately.

RESULTS

Compared with ACE inhibitor, SV new (HR: 0.18; 95% CI: 0.11-0.29) and ACE inhibitor-SV users (HR: 0.31; 95% CI: 0.23-0.43) showed lower risk of angioedema. On the other hand, there was no difference in angioedema risk when SV new users (HR: 0.59; 95% CI: 0.35-1.01) or ARB-SV users (HR: 0.85; 95% CI: 0.58-1.26) were compared with ARB new users. Compared with SV new users, ACE inhibitor-SV users (HR: 1.62; 95% CI: 0.91-2.89) trended toward higher angioedema risk, which intensified when the ACE inhibitor to SV switch occurred within 14 days (recent ACE inhibitor-SV) (HR: 1.98; 95% CI: 1.11-3.53). Similarly, ARB-SV users (HR: 2.03; 95% CI: 1.16-3.54) experienced an increased risk compared with SV new users, which intensified for the more recent switchers (recent ARB-SV) (HR: 2.45; 95% CI: 1.36-4.43).

CONCLUSIONS

We did not observe an increased risk of angioedema among SV new users compared with ACE inhibitor or ARB users. However, there was an increased risk of angioedema among SV users who recently switched from ACE inhibitor or ARB compared with SV new users.

Risk of Nonmelanoma Skin Cancer in Association With Use of Hydrochlorothiazide-Containing Products in the United States

Background

European studies reported an increased risk of nonmelanoma skin cancer associated with hydrochlorothiazide (HCTZ)-containing products. We examined the risks of basal cell carcinoma (BCC) and squamous cell carcinoma (SCC) associated with HCTZ compared with angiotensin-converting enzyme inhibitors (ACEIs) in a US population.

Methods

We conducted a retrospective cohort study in the US Food and Drug Administration's Sentinel System. From the date of HCTZ or ACEI dispensing, patients were followed until a SCC or BCC diagnosis requiring excision or topical chemotherapy treatment on or within 30 days after the diagnosis date or a censoring event. Using Cox proportional hazards regression models, we estimated the hazard ratios (HRs), overall and separately by age, sex, and race. We also examined site- and age-adjusted incidence rate ratios (IRRs) by cumulative HCTZ dose within the matched cohort.

Results

Among 5.2 million propensity-score matched HCTZ and ACEI users, the incidence rate (per 1000 person-years) of BCC was 2.78 and 2.82, respectively, and 1.66 and 1.60 for SCC. Overall, there was no difference in risk between HCTZ and ACEIs for BCC (HR = 0.99, 95% confidence interval [CI] = 0.97 to 1.00), but there was an increased risk for SCC (HR = 1.04, 95% CI = 1.02 to 1.06). HCTZ use was associated with higher risks of BCC (HR = 1.09, 95% CI = 1.07 to 1.11) and SCC (HR = 1.15, 95% CI = 1.12 to 1.17) among Caucasians. Cumulative HCTZ dose of 50 000 mg or more was associated with an increased risk of SCC in the overall population (IRR = 1.19, 95% CI = 1.05 to 1.35) and among Caucasians (IRR = 1.27, 95% CI = 1.10 to 1.47).

Conclusions

Among Caucasians, we identified small increased risks of BCC and SCC with HCTZ compared with ACEI. Appropriate risk mitigation strategies should be taken while using HCTZ.

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.

Reproducing Protocol-Based Studies Using Parameterizable Tools-Comparison of Analytic Approaches Used by Two Medical Product Surveillance Networks

The US Sentinel System and the Canadian Network for Observational Drug Effect Studies (CNODES) are two medical product safety surveillance networks. Using Sentinel's preprogrammed, parameterizable analytic tools, we reproduced two protocol-based studies conducted by CNODES to assess the risks of acute pancreatitis and heart failure (HF) associated with the use of incretin-based drugs, compared with use of ≥ 2 oral hypoglycemic agents. Results from the replication new-user cohort analyses aligned with those from the CNODES nested case-control studies. The adjusted hazard ratios were 0.95 (0.81-1.12; vs. 1.03 (0.87-1.22) in CNODES) for acute pancreatitis and 0.91 (0.84-1.00; vs. 0.82 (0.67-1.00) in CNODES) for HF among patients without HF history. The CNODES's common protocol approach allows studies tailored to specific safety questions, whereas the Sentinel's common data model plus pretested program approach enables more rapid analysis. Despite these differences, it is possible to obtain comparable results using both approaches.

Treatments and limitations for methicillin-resistant Staphylococcus aureus: A review of current literature

Methicillin-resistant Staphylococcus aureus (MRSA) has remained a major threat to healthcare; in both hospital and community settings over the past five decades. With the current use of antibiotics for a variety of infections, including MRSA, emerging resistance is a major concern. Currently available treatments have restrictions limiting their use. These issues include, but are not limited to, side effects, cross-resistance, lack of understanding of pharmacokinetics and clinical pharmacodynamics, gradual increment in minimal inhibitory concentration over the period (MIC creep) and ineffectiveness in dealing with bacterial biofilms. Despite availability of various therapeutic options for MRSA, the clinical cure rates remain low with high morbidity and mortality. Given these challenges with existing treatments, there is a need for development of novel agents for MRSA. Along with prompt infection control strategies and strict implementation of antibiotic stewardship, cautious use of newer anti-MRSA agents will be of utmost importance. This article reviews the treatments and limitations of MRSA management and highlights the future path.

The Devil's in the details: Reports on reproducibility in pharmacoepidemiologic studies

PURPOSE

The U.S. Food and Drug Administration's Sentinel Initiative "modular programs" have been shown to replicate findings from conventional protocol-driven, custom-programmed studies. One such parallel assessment-dabigatran and warfarin and selected outcomes-produced concordant findings for three of four study outcomes. The effect estimates and confidence intervals for the fourth-acute myocardial infarction-had more variability as compared with other outcomes. This paper evaluates the potential sources of that variability that led to unexpected divergence in findings.

METHODS

We systematically compared the two studies and evaluated programming differences and their potential impact using a different dataset that allowed more granular data access for investigation. We reviewed the output at each of five main processing steps common in both study programs: cohort identification, propensity score estimation, propensity score matching, patient follow-up, and risk estimation.

RESULTS

Our findings point to several design features that warrant greater investigator attention when performing observational database studies: (a) treatment of recorded events (eg, diagnoses, procedures, and dispensings) co-occurring on the index date of study drug dispensing in cohort eligibility criteria and propensity score estimation and (b) construction of treatment episodes for study drugs of interest that have more complex dispensing patterns.

CONCLUSIONS

More precise and unambiguous operational definitions of all study parameters will increase transparency and reproducibility in observational database studies.