A Systematic Review on Power Estimation and Sample Size Calculation in Randomized Controlled Trials of Surgical...

Randomized controlled trials (RCTs) are considered the gold standard for evaluating surgical interventions for benign prostatic hyperplasia (BPH). However, the validity and reliability of their findings depend critically on adequate sample size determination and power estimations. Inadequate or absent reporting of these parameters can undermine the interpretability of trial outcomes. This systematic review aimed to evaluate the prevalence, methodological rigor, and temporal trends of sample size calculation (SSC) and power reporting in RCTs of surgical interventions for BPH. We conducted a comprehensive systematic search of PubMed and the Cochrane Central Register of Controlled Trials (CENTRAL). Eligible studies were RCTs that investigated surgical treatments for BPH and reported relevant clinical outcomes. Data extraction captured whether SSC and power estimation were reported, along with details of alpha levels, power values, year of publication, and intervention type. Subgroup analyses were performed according to intervention category, and associations were tested using Pearson's chi-square test with ORs and 95% CIs. Fifty-six RCTs were included. Of these, 30 trials (53.6%) reported performing SSC and power estimation, whereas 26 (46.4%) did not. Among those who reported SSC, most adopted a type I error threshold of 0.05 and a power value of at least 80%. Reporting practices demonstrated temporal improvement: SSC was documented in 33.3% of trials published between 1991 and 2000, 22.2% between 2001 and 2010, 64.0% between 2011 and 2020, and 57.9% between 2021 and 2025. Subgroup analysis revealed higher SSC reporting in novel minimally invasive surgical therapy (nMIST) trials than in non-MIST trials (62.5% vs. 31.3%, respectively). The association between intervention type and SSC reporting was statistically significant (χ²(1) = 4.49, p = 0.034), with the odds of SSC reporting being greater in nMIST-involved trials (OR 3.67, 95% CI 1.07-12.62). This review demonstrates gradual but meaningful improvements in SSC and power reporting in surgical RCTs for BPH over the past three decades, particularly in trials investigating minimally invasive techniques. Nonetheless, nearly half of the published trials continue to omit these critical methodological details, raising concerns about the robustness of their conclusions. Enhanced adherence to reporting standards, stricter editorial requirements, and improved researcher training are needed to ensure that future RCTs provide transparent and reproducible evidence to guide clinical practice.