Diagnostic value of diverse formulas of basal metabolic rate for chronic hyperthyroid myopathy

Objective:To investigate the diagnostic value of diverse formulas of basal metabolic rate (BMR) in patients with chronic hyperthyroid myopathy (CTM).Methods:A total of 46 untreated CTM patients (CTM group) who were initially diagnosed in the First Affiliated Hospital of Guangxi Medical University from January 2022 to August 2022 were selected, along with 49 age-and gender-matched patients with hyperthyroidism without CTM (hyperthyroidism without CTM group) and 46 healthy subjects as healthy control group during the same period.Nine BMR formulas, including Gale, Reed, Read, Takeda, Kosa, Jenkins, RPP, Harris-Benedict and Cunningham, were selected for description.Clinical data(including age, sex, body weight and upper arm circumference, etc.), free triiodothyronine (FT₃), free thyroxine (FT₄), thyrotropin receptor antibody (TRAb) and BMR calculated by different formulas were compared in each group.The receiver operating characteristic(ROC)curve was used to evaluate the diagnostic value of nine BMR formulas for CTM.Results:BMR(including Gale, Reed, Read, Takeda, Kosa, Jenkins and rate pressure product), FT₃, FT₄ and TRAb in CTM group were higher than those in hyperthyroidism without CTM group and healthy control group (P< 0.05).The area under ROC curve(AUC) for CTM diagnosis using the Gale formula was 0.83 (95% CI: 0.74-0.91) (P< 0.05) with a sensitivity 73.91% and specificity 81.63%.The cut-off value for CTM was more than 46.00, which had better specificity than the Read formula(P< 0.05).Conclusion:BMR evaluated by Gale formula has a certain reference value for the diagnosis of CTM.