Background: To evaluate the ability of therapeutic intensity score (TIS) in predicting the clinical outcomes of partial (PA) and total adrenalectomy (TA) for UPA. Methods: Between 2011 and 2022, a four-center adrenalectomy dataset was queried for “unilateral adrenal mass” and “UPA” (n = 90). Preoperative TIS of each antihypertensive medication were individually calculated and merged to create a single, cumulative variable. Probability of complete clinical, partial, and absent pooled success rates according to TIS were assessed for the overall cohort by Kaplan–Meier. Cox analyses were used to identify predictors of complete clinical and partial/absent success, respectively. For all analyses, a two-sided p < 0.05 was considered significant. Results: At a median follow-up of 42 months (IQR 27–54) complete partial, and absent clinical success were observed in 60%, 17.7%, and 22.3%, respectively. On Kaplan–Meier analysis, TIS < 1 predicted higher complete success rates (p < 0.001), while TIS ≥ 1 was predictor of either partial and absent clinical success (p = 0.008). On multivariable analysis, TIS < 1 (HR 0.25; 95% CI 0.11–0.57; p = 0.001) and adenoma size (HR 1.11; 95% CI 1–1.23; p = 0.0049) were independent predictors of complete clinical success, while TIS ≥ 1 (HR 2.84; 95% CI 1.32–6.1; p = 0.007) was the only independent predictor of absent clinical success. Conclusions: TIS score and adenoma size may help to identify patients who are likely to be at risk of persistent hypertension after surgery.