Defining predictors of response to intralesional verapamil injection therapy for Peyronie's disease

OBJECTIVE To assess factors that predict penile curvature responses to intralesional verapamil (ILV) injection therapy for men with Peyronie's disease (PD). PATIENTS AND METHODS Men with PD for <1 year were assessed at baseline and after 3 months of bi-monthly ILV-injection therapy. Curvature was assessed at the time of maximum penile rigidity. Univariate relationships were tested with correlation or chi-square analyses. Multivariate analyses included logistic and linear regression. We analysed curvature improvement, defined as a decrease of >= 10 degrees from baseline. Additionally, the relationship between curvature outcomes and patient age and degree of baseline penile curvature were assessed. RESULTS Data from 131 men were included and the rates of penile curvature change were: 26% improved, 12% worsened, and 62% stable. Age (r = -0.24, P < 0.01) and larger baseline penile curvature (r = 0.33, P < 0.01) were associated with improved curvature on univariate analysis. On multivariate analysis (logistic regression), both age [odds ratio (OR) 0.93, P < 0.01, 95% CI 0.89-0.97] and larger baseline penile curvature (OR 1.07, P < 0.01, 95% CI 1.04-1.11) were associated with improvements in curvature after ILV-injection therapy. Improvements in curvature were associated with age (<= 40 years vs >40 years; OR 0.27, P < 0.05, 95%CI 0.10-0.75) and degree of penile curvature at baseline (<= 30 degrees vs >30 degrees; OR 9.12, P < 0.01, 95%CI 1.94-42.84) when dichotomized as indicated. CONCLUSION Younger age and larger baseline penile curvature were predictive of favourable curvature outcomes. Analysis of dichotomized variables suggests that age and baseline curvature thresholds may be important to consider when deciding on ILV as a therapeutic strategy for PD.