The Obesity Paradox in Thyroid Surgery: Is Higher BMI Protective Against Hypoparathyroidism?

Abstract

With a demonstrated association between adiposity and parathyroid hormone (PTH) levels, we hypothesized that patients with a higher body mass index (BMI) would have lower rates of postoperative hypoparathyroidism following total thyroidectomy. retrospective review of patients undergoing total thyroidectomy from 2015 to 2021. Demographics, BMI, surgical indications, and laboratory data including pre- and postoperative PTH values were examined. Of the 352 patients with complete clinicopathologic data, most were female (n = 272, 77.3%) with an average age of 42.7 (SD+/-19.4). Obese (BMI 30-39.99) was most common BMI group (n = 108, 30.8%), with 11.7% (n = 41) morbidly obese (BMI > 40). Morbidly obese patients had significantly higher postoperative PTH levels than BMI < 18.5 (46.0 vs 19.3pg/mL, P = .004). Patient race was significantly associated with pre- and postoperative PTH (P = .03, P = .004.) On multivariable analysis, preoperative PTH, race, and BMI were independent predictors of higher postoperative PTH (P < .05 for all). Patients with higher BMI and non-white race have relative protection from postoperative hypoparathyroidism.