How long do patients with erectile dysfunction continue to use sildenafil citrate? Dropout rate from treatment course as outcome in real life

OBJECTIVES: To study the dropout rate for use of sildenafil after initial prescription and during successful treatment to clarify their risk factors. METHODS: A total of 1036 patients with erectile dysfunction who were treated with sildenafil were analyzed. The dropout rate during successful treatment and its risk factors were assessed using the Kaplan-Meier method and Cox proportional hazards model, respectively. RESULTS: Thirty-one percent (n = 322) of the patients dropped out after the initial prescription. The cumulative dropout rate during successful treatment at 3 years after starting usage was 48%. A lower International Index of Erectile Function (IIEF-5) score before treatment was a significant risk factor for dropout during a successful treatment course (P < 0.029 by the Cox proportional hazards model). CONCLUSIONS: Approximately 30% and 50% of the patients dropped out of treatment after the first prescription and at 3-year follow-up, respectively. Adequate initial instruction and long-term follow-up are required even for patients with successful treatment.