Prevalence of Hypothyroidism and Thyroid Function Patterns Across Different Stages of Chronic Kidney Disease: A Hospital Based Cross Sectional Study

ABSTRACT Background: Thyroid disturbances are frequently encountered in chronic kidney disease (CKD), particularly when renal impairment is advanced. We assessed the frequency of hypothyroidism and the relationship of thyroid function with different stages of CKD. Objectives: To determine the prevalence of overt and subclinical hypothyroidism and examine stage-wise changes in the thyroid profile among adults with CKD. Materials and Methods: In this hospital-based cross-sectional study, 160 adults with CKD stages 3–5 were evaluated at Hassan Institute of Medical Sciences, Hassan, from March 2024 to February 2025. Serum total T3, total T4, free T3, free T4 and thyroid-stimulating hormone (TSH) were assessed. CKD stage was assigned using estimated creatinine clearance by the Cockcroft–Gault equation. The Kruskal Wallis and chi-square tests were used for stage-wise comparisons. Results: Of 160 participants (mean age 48.86 ± 12.44 years; 67.5% men), 119 (74.4%) had stage 5 CKD. Overt hypothyroidism occurred in 12 (7.5%) and subclinical hypothyroidism in 28 (17.5%); 68 (42.5%) were euthyroid and 52 (32.5%) had other thyroid abnormalities. Combined overt/subclinical hypothyroidism increased numerically across stages 3, 4 and 5 (14.3%, 20.0% and 27.7%), while mean TSH increased from 3.74 to 4.93 and 5.46 mIU/L, respectively (p = 0.039). The distribution of diagnostic thyroid categories did not differ significantly (p = 0.192). Conclusion: Our study demonstrates a positive stage-wise gradient in mean TSH and a parallel numerical rise in overt or subclinical hypothyroidism with increasing CKD severity. The TSH difference was statistically significant, although differences in thyroid diagnostic categories were not. These findings support considering renal disease stage when interpreting thyroid test results and prioritising careful thyroid evaluation in more advanced CKD. Keywords: Chronic kidney disease; hypothyroidism; subclinical hypothyroidism; thyroid-stimulating hormone; haemodialysis; cross-sectional study