Falls and Fractures in Patients with Parkinson's Disease-Related Psychosis Treated with Pimavanserin vs Atypical Antipsychotics: A Cohort Study.

BACKGROUND: Parkinson's disease-related psychosis increases patients' risk of falls. Pimavanserin is an atypical antipsychotic approved in the USA in 2016 for the treatment of hallucinations and delusions associated with Parkinson's disease-related psychosis. OBJECTIVE: We aimed to compare the risk of falls/fractures among patients with Parkinson's disease-related psychosis treated with pimavanserin vs other atypical antipsychotics. PATIENTS AND METHODS: We identified a cohort of patients with Parkinson's disease-related psychosis aged ≥ 40 years initiating either pimavanserin or a comparator antipsychotic (clozapine, quetiapine, risperidone, olanzapine, aripiprazole, brexpiprazole) in US commercial insurance and supplementary Medicare claims (2015-2019). Comparators were propensity score matched 2:1 with pimavanserin initiators; incidence rates of falls/fractures were compared using incidence rate ratios (IRRs) and 95% confidence intervals (CIs). RESULTS: We identified 112 eligible pimavanserin initiators and 982 comparators. Pimavanserin initiators were younger and had fewer severe comorbidities, indicators of impairment, and healthcare encounters, though they had higher Parkinson's disease medication use. The crude incidence rates [cases/100 person-years] (95% CI) for composite falls/fractures were 17.8 (7.7-35.0) for pimavanserin and 40.8 (35.0-47.4) for comparators. Matching retained 108 pimavanserin initiators and 216 comparators-all characteristics were well balanced after matching-with a matched IRR (pimavanserin vs comparator) of 0.71 (95% CI 0.27-1.67). Sensitivity analysis IRR estimates were consistently below 1.00, with a sensitivity analysis not requiring a diagnosis of psychosis resulting in an IRR estimate of 0.55 (95% CI 0.34-0.86). CONCLUSIONS: The results of this study do not suggest an increase in the risk of falls or fractures associated with pimavanserin compared with other antipsychotics in patients with Parkinson's disease-related psychosis. Sensitivity analyses suggest a decreased risk.

Variation in Cardiovascular Risk Related to Individual Antimuscarinic Drugs Used to Treat Overactive Bladder: A UK Cohort Study.

BACKGROUND: Blocking muscarinic receptors could have an effect on cardiac function, especially among elderly patients with overactive bladder (OAB). STUDY OBJECTIVE: To investigate the risk of cardiovascular (CV) events in users of antimuscarinic drugs to treat OAB. DESIGN, SETTING, AND PARTICIPANTS: Cohort study of new users of darifenacin, fesoterodine, oxybutynin, solifenacin, tolterodine, or trospium, 18 years or older, in the United Kingdom's Clinical Practice Research Datalink (CPRD), 2004-2012. OUTCOME MEASUREMENTS AND MAIN RESULTS: Using tolterodine as the reference, we estimated propensity-score-stratified incidence rate ratios (IRRs) for acute myocardial infarction, stroke, CV mortality, major adverse cardiac events (MACE, a combined end point of the previous three), and all-cause death for individual antimuscarinic drugs. The study cohort included 119,912 new users of OAB drugs. The mean age at cohort entry was 62 years, 70% were female, and the mean follow-up was 3.3 years. The adjusted IRR for MACE and current use of oxybutynin compared with current use of tolterodine was 1.14 (95% confidence interval [CI] 1.01-1.30). In contrast, the IRR was 0.65 (CI 0.56-0.76) for current use of solifenacin compared with tolterodine. In this study, performed with health care data, the distribution of risk factors was relatively similar across users of different OAB drugs and, although our analyses controlled for a range of measured potential confounders, residual confounding cannot be ruled out. CONCLUSIONS: In an observational comparative study of users of medications to treat OAB conducted in routine clinical practice, the risk for CV side effects was increased in users of oxybutynin and decreased in users of solifenacin compared with users of tolterodine.

Cancer Incidence after Initiation of Antimuscarinic Medications for Overactive Bladder in the United Kingdom: Evidence for Protopathic Bias.

STUDY OBJECTIVE: To estimate the incidence of 10 common cancers among patients treated with antimuscarinic medications for overactive bladder (AMOABs). DESIGN: Retrospective cohort study. DATA SOURCE: United Kingdom's Clinical Practice Research Datalink. PATIENTS: A total of 119,912 adults with no previous cancer diagnosis who were new users of AMOABs-darifenacin, fesoterodine, oxybutynin, solifenacin, tolterodine, or trospium-between January 2004 and December 2012. MEASUREMENTS AND MAIN RESULTS: Sex-specific incidence rates per 1000 person-years and 95% confidence intervals (CIs) were estimated for each study cancer (bladder, breast, colorectal, lung, melanoma, non-Hodgkin lymphoma, pancreatic, prostate, renal, and uterine cancer) overall and stratified by time since cohort entry and by cumulative AMOAB dose. Among the 119,912 patients followed for 399,365 person-years, 4117 incident study cancers occurred. The incidence rate of prostate cancer was 14.2 (95% CI 12.9-15.5) in the year after cohort entry and decreased markedly thereafter. The incidence rate of bladder cancer was also higher in the year after cohort entry than subsequently (men: 5.5, 95% CI 4.8-6.4; women: 1.2, 95% CI 1.0-1.5). The incidence rates of both prostate and bladder cancer decreased with increasing cumulative dose of AMOAB. We observed no similar relations between incidence rates of other study cancers and time since cohort entry. CONCLUSION: High incidence rates of bladder and prostate cancer soon after AMOAB initiation and a negative correlation between incidence and cumulative AMOAB dose suggest that protopathic bias is a more likely explanation for these findings than causality. (Protopathic bias in this context means patients' urinary symptoms prompted treatment with an AMOAB, but the symptoms were actually due to a cancer that was already present, although not yet diagnosed or not yet recorded.) To avoid unnecessary delays in the diagnosis of prostate and bladder cancer, physicians should consider these diseases in patients for whom treatment with AMOABs is indicated.