Suboptimal Thyroid Hormone Replacement Is Associated With Wo
A retrospective cohort study, using the propensity score-based fine stratification method to balance covariates, was conducted using a large, US-based, commercial claims database from January 1, 2008 to December 31, 2015. Participants included patients aged 64 years and younger who had a thyrotropin (TSH) level collected before a hospital admission. Covariates included age, sex, US region, type of admission, year of admission, and comorbidities. Exposure included clinical hypothyroidism, which was divided into 4 subgroups based on prehospitalization TSH level: low (TSH<0.40 mIU/L), normal (TSH 0.40-4.50 mIU/L), intermediate (TSH 4.51-10.00 mIU/L), and high (TSH>10.00 mIU/L).

A total of 43478 patients were included in the final study population, of whom 8873 had a diagnosis of hypothyroidism. Those with a high prehospitalization TSH level had an LOS that was 1.2 days longer (95% CI, 1.1-1.3; P=.003), a 49% higher risk of 30-day readmission (relative risk [RR] 1.49; 95% CI, 1.20-1.85; P<.001), and a 43% higher rate of 90-day readmission (RR 1.43; 95% CI, 1.21-1.67; P<.001) compared to balanced controls. Patients with normal TSH levels exhibited decreased risk of in-hospital mortality (RR 0.46; 95% CI, 0.27-0.79; P=.004) and 90-day readmission (RR 0.92; 95% CI, 0.85-0.99; P=.02). The results suggest suboptimal treatment of hypothyroidism is associated with worse hospital outcomes, including longer LOS and higher rate of readmission.