Objectives: To present the results of a pooled analysis of three double-blind, placebo-controlled studies of doxazosin in benign prostatic hyperplasia (BPH). Heterogeneous symptom and bother score data collected using different symptom indices were transformed to enable a comparison of the data and to conduct a pooled, in-depth analysis.
Methods: Urinary flow rates, and symptom and bother score data were shown by analysis of covariance methods to give consistent estimates of the efficacy of doxazosin across different studies, thus confirming the validity of pooling the results. Prior to analysis, symptom and bother score data were transformed so that all scales started from zero (least symptoms or bother) and were expressed as a percentage of the maximum score.
Results: Doxazosin produced a significantly greater improvement than placebo in peak urinary flow rate (P = 0.0017), symptom severity (P < 0.0001), and bother caused by symptoms (P < 0.0001). Stratification showed that a greater improvement was obtained during doxazosin treatment by those with more severe symptoms at baseline (P = 0.0001). Stratification by age showed that age did not affect the capacity to benefit from treatment. Analysis of the pooled peak flow-rate data showed that doxazosin produced a consistently greater increase in flow compared with placebo. Doxazosin was well tolerated, with 10% of patients having withdrawn due to adverse events versus 4% with placebo (P < 0.05).
Conclusions: Doxazosin is well tolerated and effective in the treatment of BPH. Pooling of data has enabled more extensive and robust conclusions to be drawn than was possible for each one of the individual three studies.