Testosterone levels increase following bariatric surgery - validation of preceding literature in a large-scale population analysis.

Abstract

The effects of bariatric surgery on testosterone levels in men with obesity and hypogonadism have not been thoroughly explored yet. To investigate the possible effects of bariatric surgery on T levels in obese hypogonadal men by comparing T levels before and after surgery using a comprehensive claims database. The TriNetX US Collaborative Network database was used to identify men ages 18-80 who underwent a bariatric procedure and had a serum T value of<350ng/dL prior to surgery. Men who received testosterone therapy before/or after surgery were excluded. We conducted a retrospective self-matched cohort analysis to examine the difference in serum T levels before and after bariatric surgery. A sub-analysis was carried out to explore differences between men who reached eugonadal status or maintained low T levels following surgery. Descriptive statistics detailed sociodemographic and clinical characteristics, with continuous and categorical data compared using unpaired t-tests and chi-square analysis, respectively. Changes in T levels and body mass index (BMI) before and after surgery were compared using an unpaired t-test with a<0.05 set for significance. All analyses were conducted using the TriNetX platform which utilizes both Python and R software. The study analyzed 69 hypogonadal men who underwent bariatric surgery and had T levels assessed before and after the procedure. The mean (standard deviation) pre-surgery serum T level was 208±79ng/dL, which post-surgery increased to 371±164ng/dL, marking an average increase of 163±164ng/dL. Likewise, the mean (standard deviation) body mass index decreased from 42.9±9.0 to 38.8±5.7kg/m2. Post-surgery, 45% (31 men) achieved eugonadal status, while 55% (38 men) continued to have low T levels. A comparison between the post-surgery eugonadal cohort and the persistent low T cohort revealed that the former had higher pre-surgery serum T levels (235±71ng/dL vs. 184±80.4ng/dL, p=0.007), a higher pre-surgery body mass index (45.5±4.5kg/m2 vs. 41.1±11.5kg/m2, p=0.041), and a significantly greater reduction in body mass index post-surgery (7.3±7.2kg/m2 vs. 2.0±12.8kg/m2, p=0.04). Notably, the increase in T was significantly higher in the eugonadal cohort compared to the persistent low testosterone cohort (257±143ng/dL vs. 95±178ng/dL, p<0.0001). This study provides evidence of bariatric surgery's positive effect on serum T levels in obese men with baseline low T. Almost one out of two men with low T reached normal T levels after bariatric surgery. As the most comprehensive study to date, it validates and substantiates previous work suggesting that weight loss can improve T levels physiologically.