External validation of the PASO prediction score for primary aldosteronism

Graphical Abstract Abstract Background Clinical outcomes following adrenalectomy for primary aldosteronism (PA) can vary, particularly in patients with long-standing hypertension. The primary aldosteronism surgical outcome (PASO) score was developed to estimate the likelihood of clinical success following adrenalectomy. This study aimed to externally validate the PASO score in a surgical cohort. Methods This retrospective cohort study was conducted at a single tertiary endocrine surgery centre, including patients undergoing adrenalectomy for unilateral PA over a 10-year period with a follow-up of 60 months postoperatively. The PASO score, based on six preoperative variables, was calculated for each patient. PASO score-predicted outcomes were compared with observed postoperative clinical outcomes at short-term (6 months) and long-term (60 months) follow-ups, using PASO outcome classifications as the reference standard. Results Complete biochemical cure was achieved in 39/40 patients (97.5%), while complete clinical success occurred in 9/40 (22.5%) at 6 months increasing to 14/40 (35.0%) at 60 months. Agreement between predicted and observed clinical outcomes was fair at short-term follow-up (6 months; κ = 0.38) and improved to substantial agreement at long-term follow-up (60 months; κ = 0.65), indicating stronger alignment between preoperative predictions and clinical outcomes over time. Conclusion In this patient cohort, PASO score showed modest performance for short-term outcomes but stronger agreement with long-term clinical results after adrenalectomy for PA. It may therefore be more informative for longer-term outcomes and help guide preoperative discussions with patients.