Pharmacoepidemiology, Volume 1, Issue 3 (December 2022) – 2 articles

Opioid use disorder (OUD) is a chronic disease requiring long-term treatment and is associated with opioid overdose and increased risk of mortality. However, existing randomized clinical trials focused on short-term treatment engagement and detoxification rather than overdose or mortality risk due to limited follow-up time and ethical considerations. We used a hypothetical trial framework to conduct a retrospective cohort study to assess the effectiveness of time-varying buprenorphine-naloxone on opioid overdose and death. We identified 58,835 insured adult patients with OUD diagnosis in the US, 2010–2017. We fit a marginal structural model using inverse probability weighting methods to account for measured baseline and time-varying confounders, as well as selection bias due to possibly differential loss-to-follow-up. We found that receipt of buprenorphine-naloxone was associated with reduced risk of opioid overdose (hazard ratio (HR) = 0.66, 95% confidence interval (CI): 0.49, 0.91), death (HR = 0.24, 95% CI: 0.08, 0.75), and overdose or death (HR = 0.58, 95% CI: 0.40, 0.84). The E-value for death was 7.8, which was larger than the upper 95% CI of the association between each measured baseline variable and all-cause death, which implies that the unmeasured confounding itself may not explain away the estimated effect of treatment on the endpoint of all-cause mortality. Full article

Background: Spironolactone is a mineralocorticoid receptor antagonist indicated for the management of heart failure with reduced ejection fraction (HFrEF). In a previous clinical trial, spironolactone significantly lowered the incidence of heart failure (HF) hospitalizations among HF patients with preserved ejection fraction (HFpEF). Real world utilization of spironolactone in HFrEF and HFpEF is unknown. Methods: We conducted a retrospective cohort study using data from FDA’s Sentinel System. We identified patients with HFrEF or HFpEF using diagnosis and procedure codes from a previously validated algorithm. We required patients to be continuously enrolled in the 183 days prior to HF diagnosis. Follow-up started on the day of HF diagnosis and ended at the earliest occurrence of a spironolactone dispensing, disenrollment, death, or end of data. We calculated the proportion of spironolactone utilization, and for those initiating treatment, we estimated the dose and duration of the first continuous treatment episode. Results: Among 2,009,529 HFrEF patients, 57.8% were male, and mean age was 73.8 ± 12.1 years. Among 9,257,514 HFpEF patients, 42.7% were male, and mean age was 73.0 ± 12.1 years. The proportion of spironolactone utilization following HFrEF diagnosis was 20.7% versus 7.6% after HFpEF. The median time (days) to initiation of spironolactone after HFrEF diagnosis was 90 (IQR: 19–385) versus 286 (IQR: 57–851) after HFpEF diagnosis. The median duration (days) of first treatment episode in HFrEF patients was 120 (IQR: 44–321) and 114 (IQR: 32–301) for HFpEF patients. The median dose was similar (25 mg/day) for both HF cohorts. Conclusion: Findings of low real-world utilization of spironolactone from our large, geographically, and demographically diverse multi-site study in the US are consistent with reports from smaller studies in the literature. Similar spironolactone dosing and duration were observed in both the HFpEF and HFrEF cohorts. Future research characterizing spironolactone treated and untreated HFpEF cohorts will be needed to identify treatment gaps. Full article