Predictors of success and risk factors for attrition in the use of intracavernous injection

Purpose: We identified potential predictors, a high risk period and reasons for attrition, as well as the therapeutic alternatives chosen by men who discontinued intracavernous injection. Materials and Methods: After patients had followed the protocol of evaluation and a home trial, they were given prostaglandin El; a triple mixture of papaverine, phentolamine and prostaglandin El; papaverine and phentolamine, or papaverine and prostaglandin E1. Data on the 1,089 patients enrolled in the pharmacological erection program from 1988 to 1996 were retrospectively reviewed to compare characteristics of active patients and those who discontinued therapy. Results: Our attrition rate was 37.6% overall and 27.5% among prostaglandin El users. Patients who continued active therapy remained in the program for a mean of 26 months. We could identify no risk factor for erectile dysfunction or associated condition as a risk factor for attrition. More than 50% of men who discontinued therapy did so within the first 2 months of the program but the attrition rate for the 2 years following this time was less than 10%. Among those who dropped out of therapy 52% received a penile prosthesis. Conclusions: Failure of prostaglandin Fl and triple drug therapy is the best predictor of failure of intracavernous injection. We suggest that clinicians carefully follow and counsel patients at high risk for failure about alternative treatment within the first 3 months. Remaining on intracavernous injection beyond the first 2 months is a likely predictor of long-term success, confirming intracavernous injections to be an effective long-term therapeutic option.