Likelihood of Tadalafil-associated Adverse Events in Integrated Multiclinical Trial Database: Classification Tree Analysis in Men With Erectile Dysfunction

OBJECTIVES To identify the patient demographic factors, comorbidities, and concomitant medications associated with a change in the likelihood of tadalafil-associated adverse events (AEs) in men with erectile dysfunction. METHODS Pooled safety data were analyzed from 3488 tadalafil-treated men who participated in 21 placebo-controlled clinical trials of tadalafil taken as needed or once daily. Three categories of tadalafil-associated AEs were defined: vasodilatory (headache, flushing, nasal congestion, nasopharyngitis, and dizziness); musculoskeletal (back pain and myalgia); and gastrointestinal (dyspepsia). A classification and regression tree analysis was used to determine the patient characteristics most likely to be associated with a change in the likelihood of these types of AEs. RESULTS Of the 3488 tadalafil-treated patients, 973 (27.9%) had any vasodilatory, musculoskeletal, and/or gastrointestinal tadalafil-associated AE. The patient characteristics associated with a change in the likelihood of any tadalafil-associated AE were diabetes, geographic region, and age. The patient characteristics associated with a change in the likelihood of a vasodilatory tadalafil-associated AE included antihypertensive medication use, geographic region, and height, with several additional splits occurring along these primary and secondary nodes. No patient characteristics associated with a change in the likelihood of musculoskeletal or gastrointestinal AEs were identified owing to the limitation of a relatively low incidence of these types of AEs. CONCLUSIONS The findings from classification and regression tree analyses could help physicians to better understand some of the associations between patient characteristics and the tolerability of phosphodiesterase type 5 inhibitors and could contribute to improved patient outcomes, satisfaction, treatment seeking, and treatment persistence. UROLOGY 73: 756-761, 2009. (C) 2009 Elsevier Inc.