An exploratory study of the association between thyroid hormone and survival of amyotrophic lateral sclerosis

The objective of the study was to determine the correlation of thyroid hormones (THs) and survival in patients with amyotrophic lateral sclerosis (ALS). A total of 278 patients with ALS were enrolled and followed up prospectively every 3 months by face-to-face interviews or phone calls. Level of fasting serum TH was determined at the time of enrollment. Clinical data including age, onset age, onset body region, ALS Functional Rating Scale- Revised (ALS-FRS-R), and survival were collected. Patients were separated into four subgroups according to the quartile distribution of TH, and survival was compared among them. There was no significant difference in baseline characteristics, including onset age, gender, onset form as well as treatment with riluzole among different levels of TH subgroups. Chi-square test indicated that the lowest quartile of FT3 (<4.26 mg/L) might correlate with higher incidences of death (OR 0.374, 95 % CI 0.173-0.813), while second and third quartiles of FT4 (range 14.25-18.0 mg/L) with lower incidences of death in ALS. However, after correction for onset age and onset form using logistic regression analysis, no statistical difference was revealed in survival among patients with different TH levels. TH does not correlate with survival and is not a prognostic factor for ALS.