Influence of study characteristics, methodological rigour and publication bias on efficacy of pharmacotherapy in obsessive-compulsive disorder: a systematic review and meta-analysis of randomised, placebo-controlled trials.

QUESTION: We examined the effect of study characteristics, risk of bias and publication bias on the efficacy of pharmacotherapy in randomised controlled trials (RCTs) for obsessive-compulsive disorder (OCD). STUDY SELECTION AND ANALYSIS: We conducted a systematic search of double-blinded, placebo-controlled, short-term RCTs with selective serotonergic reuptake inhibitors (SSRIs) or clomipramine. We performed a random-effect meta-analysis using change in the Yale-Brown Obsessive-Compulsive Scale (YBOCS) as the primary outcome. We performed meta-regression for risk of bias, intervention, sponsor status, number of trial arms, use of placebo run-in, dosing, publication year, age, severity, illness duration and gender distribution. Furthermore, we analysed publication bias using a Bayesian selection model. FINDINGS: We screened 3729 articles and included 21 studies, with 4102 participants. Meta-analysis showed an effect size of -0.59 (Hedges' G, 95% CI -0.73 to -0.46), equalling a 4.2-point reduction in the YBOCS compared with placebo. The most recent trial was performed in 2007 and most trials were at risk of bias. We found an indication for publication bias, and subsequent correction for this bias resulted in a depleted effect size. In our meta-regression, we found that high risk of bias was associated with a larger effect size. Clomipramine was more effective than SSRIs, even after correcting for risk of bias. After correction for multiple testing, other selected predictors were non-significant. CONCLUSIONS: Our findings reveal superiority of clomipramine over SSRIs, even after adjusting for risk of bias. Effect sizes may be attenuated when considering publication bias and methodological rigour, emphasising the importance of robust studies to guide clinical utility of OCD pharmacotherapy. PROSPERO REGISTRATION NUMBER: CRD42023394924.

Ethnic differences in response to atypical antipsychotics in patients with schizophrenia: individual patient data meta-analysis of randomised placebo-controlled registration trials submitted to the Dutch Medicines Evaluation Board.

BACKGROUND: Little is known about the effect of ethnicity on the response to antipsychotic medication in patients with schizophrenia. AIMS: To determine whether ethnicity moderates the response to antipsychotic medication in patients with schizophrenia, and whether this moderation is independent of confounders. METHOD: We analysed 18 short-term, placebo-controlled registration trials of atypical antipsychotic medications in patients with schizophrenia (N = 3880). A two-step, random-effects, individual patient data meta-analysis was applied to establish the moderating effect of ethnicity (White versus Black) on symptom improvement according to the Brief Psychiatric Rating Scale (BPRS) and on response, defined as >30% BPRS reduction. These analyses were corrected for baseline severity, baseline negative symptoms, age and gender. A conventional meta-analysis was performed to determine the effect size of antipsychotic treatment for each ethnic group separately. RESULTS: In the complete data-set, 61% of patients were White, 25.6% of patients were Black and 13.4% of patients were of other ethnicities. Ethnicity did not moderate the efficacy of antipsychotic treatment: pooled ß-coefficient for the interaction between treatment and ethnic group was -0.582 (95% CI -2.567 to 1.412) for mean BPRS change, with an odds ratio of 0.875 (95% CI 0.510-1.499) for response. These results were not modified by confounders. CONCLUSIONS: Atypical antipsychotic medication is equally effective in both Black and White patients with schizophrenia. In registration trials, White and Black patients were overrepresented relative to other ethnic groups, limiting the generalisability of our findings.

Gender differences in the response to antipsychotic medication in patients with schizophrenia: An individual patient data meta-analysis of placebo-controlled studies.

OBJECTIVE: To determine whether gender and menopausal status moderate the response to antipsychotic medication in patients with schizophrenia. METHODS: We analyzed data of 22 short-term placebo-controlled registration trials of antipsychotic medications, which included 5,231 patients with schizophrenia. We applied two-step individual patient data meta-regression analyses to establish the influence of gender and menopausal status on treatment response in mean difference in symptom severity and difference in response (>30% symptom reduction). Analyses were performed both with and without correction for baseline (negative) symptom severity. RESULTS: Antipsychotic treatment is associated with larger mean symptom reduction in women than in men with schizophrenia. The number needed to treat (NNT) for a response in women was 6.9, in men 9.4. Although, we found an age by gender effect, the gender by treatment effect was independent of premenopausal status and baseline (negative) symptom severity. CONCLUSION: In the treatment of schizophrenia we found evidence of a higher response to antipsychotic medication in women relative to men. We found no evidence that this effect was driven by menopausal status, or baseline (negative) symptom severity. Despite the impact of gender and age on effect size in acute antipsychotic treatment, efficacy was clinically relevant in all subgroups.