The Inaugural Pre-Treatment Nomogram to Assess the Eight-Week Efficacy of Dapoxetine: A Prospective Multi-Center Study

Background: Although a nomogram for predicting the efficacy of dapoxetine (DapE-Nomo) has already been developed, its reliability is limited due to only 4 weeks of follow-up and a lack of external validation. Several patients with premature ejaculation (PE) achieve satisfactory therapeutic effects after longer periods of treatment clinically, we therefore aimed to develop and validate an 8-week DapE-Nomo. Methods: The training cohort included 243 patients with lifelong PE from Xijing Hospital and Northwest Women's and Children's Hospital (Jan 2019-Jul 2020), while the validation cohort comprised 397 patients from Xijing Hospital and Xi'an Daxing Hospital (Aug 2020-Jan 2022). Efficacy was measured using the Clinical Global Impression of Change (CGIC) scale, with a CGIC score >= 1 indicating an improvement (iCGI). LASSO regression was utilized to identify the most valuable predictors (MVPs) of iCGI. The DapE-Nomo was developed utilizing logistic regression coefficients of MVPs and validated across both cohorts. Results: After 8 weeks of medication, 47.7% of patients in the training cohort and 47.6% in the validation cohort achieved iCGI. MVPs of iCGI included intravaginal ejaculation latency time, difficulty delaying ejaculation, and education level. The DapE-Nomo showed discriminatory abilities of 0.722 and 0.709 in internal and external validations, respectively, with satisfactory calibration and clinical utility in both. The optimal cutoff value of the DapE-Nomo was identified as 153.4 in both cohorts. Individuals with scores >= 153.4 exhibited a 3.833-fold and 4.137-fold chance of achieving iCGI, respectively, compared with those with scores < 153.4. Conclusion: We constructed and validated the inaugural 8-week DapE-Nomo. In outpatient settings, it will enable andrologists to more accurately evaluate the efficacy and promptly adjust treatment plans for patients with scores below 153.4. Moreover, It will help patients who've taken dapoxetine for 4 weeks with poor results decide whether to stop.