Prevalence of Subclinical Hypothyroidism in Patients with End-Stage Renal Disease and the Role of Serum Albumin: A Cross-Sectional Study from South India

BACKGROUND/AIM: Subclinical hypothyroidism (SCH) and end-stage renal disease (ESRD) are independent risk factors for cardiovascular mortality. We aimed to study the prevalence of SCH in ESRD patients and assessed its associated risk factors. METHODS: This cross-sectional study was conducted at 2 tertiary-care centers in Chennai, India, over a 3-year period. The study group comprised 137 patients with ESRD on thrice weekly regular maintenance hemodialysis. Free thyroxine (FT(4)) and thyroid-stimulating hormone (TSH) were measured using an electrochemiluminescence immunoassay. SCH was defined as TSH ranging between 4.5 and 10 mIU/l with normal FT(4) (0.93-1.7 ng/dl). Patients with overt hypothyroidism, SCH and overt hyperthyroidism, those on medications affecting thyroid function and pregnant women were excluded from the study. RESULTS: Of 137 ESRD patients (mean age: 43 ± 13.38 years), 107 were males (78.1%), 45 diabetics (32.8%), 127 hypertensives (92.7%), and 38 smokers (27.7%). Prevalence of SCH was 24.8%. In unadjusted (OR: 3.37, 95% CI: 1.91-5.21) and adjusted (for age, gender, HbA(1C), and albumin/creatinine ratio; OR: 3.11, 95% CI: 2.15-4.98) logistic regression analysis, serum albumin was significantly associated with SCH. Further, multiple linear regression identified that for every 1 g/dl drop in serum albumin TSH increased by 4.61 mIU/l (95% CI: 2.75-5.92). CONCLUSION: We observed a high prevalence of SCH in our ESRD patients. Also, serum albumin was significantly associated with SCH in our study.