Analysis of clinical features and 7-year all-cause mortality in older male patients with non-thyroidal illness syndrome on general wards.

Abstract

Older patients with non-thyroidal illness syndrome (NTIS) have a poor prognosis. However, there are few studies on the association of NTIS and mortality among older inpatients on general wards. In a 7-year retrospective observational study, we aimed to investigate the clinical features of NTIS and the association of NTIS and all-cause mortality in older inpatients. A total of 959 older male inpatients whose average age was 86.3 ± 8.1years were enrolled and divided into the NTIS group and non-NTIS group. Cox models were performed to explore the association of thyroid hormone level and mortality. Patients had more respiratory disease and chronic kidney disease in the NTIS than in the non-NTIS group, especially in primary nursing care, respiratory failure and haemodialysis patients; serum total protein, albumin, prealbumin, haemoglobin, uric acid and high-density lipoprotein cholesterol levels were lower, and urea nitrogen and fasting blood glucose levels were higher, in the NTIS than in the non-NTIS group. Patients in the NTIS group had a lower survival rate over 7years follow-up (P < 0.01). A lower free T3 level was associated with all-cause mortality with a HR of 1.50 (1.36, 1.66). Lower free T4 level was associated with reduced all-cause mortality with a HR of 0.91 (0.88, 0.94) even after adjusting for confounding factors (P < 0.01). Among older male inpatients, the survival rate was lower in the NTIS group. A reduced free T3 level with low albumin and Hb levels was associated with all-cause mortality; moreover, a higher free T4 in the normal range may be a strong predictor for long-term mortality risk in hospitalised older male patients.