Weight Loss Threshold and Inflection Points for Biochemical Remission of Male Obesity-Associated Secondary Hypogonadism After Sleeve Gastrectomy.

INTRODUCTION: Male obesity-associated secondary hypogonadism (MOSH) is common in men with obesity and can improve following metabolic bariatric surgery (MBS). However, the quantitative relationship between postoperative weight loss and biochemical remission of MOSH remains unclear. This study aimed to characterize the nonlinear association between percentage total weight loss (TWL%) and MOSH remission after laparoscopic sleeve gastrectomy (LSG), and to identify clinically relevant weight-loss thresholds. METHODS: This retrospective study included MOSH patients undergoing LSG with one-year follow-up. Restricted cubic spline (RCS) modeling evaluated the nonlinear relationship between TWL% and remission. Patients were grouped by RCS-derived thresholds, and logistic regression with interaction analyses examined the association and effect modification. RESULTS: Among 230 patients, mean TWL% was 31.60% and remission rate was 82.17% at one year after LSG. RCS revealed a nonlinear association (P = 0.041) with an exploratory effect-initiation threshold at 21.8% TWL% and a suggested plateau period at 36.0% TWL%. Corresponding remission rates were 47.1% (< 21.8% TWL%), 88.9% (21.8-36.0% TWL%), and 87.1% (≥ 36.0% TWL%). Both higher TWL% groups had significantly greater odds of remission compared with the lowest group (adjusted odds ratio [aOR]: 10.61 and 10.64, respectively). Age, preoperative body mass index (BMI), and type 2 diabetes mellitus (T2DM) did not modify the relationship. CONCLUSION: Achieving 21.8% TWL% may represent an exploratory lower threshold for high remission probability, while 36.0% TWL% may indicate the onset of a plateau period. These findings provide preliminary reference points that require prospective validation before being considered for clinical guidance. KEY POINTS: • 21.8% TWL% may represent an exploratory minimum threshold for high MOSH remission probability after LSG. • 36.0% TWL% may indicate a plateau; further weight loss appears to yield no additional remission benefit. • These exploratory thresholds showed consistency across age, preoperative BMI, and T2DM subgroups in this cohort.