Study On Renal Function Status in Patients with Hypothyroidism Attending a Tertiary Care Hospital at Kishanganj, Bihar

Background: Thyroid hormones profoundly influence renal hemodynamics, glomerular filtration, tubular function, and electrolyte homeostasis. Hypothyroidism is associated with reduced renal blood flow and glomerular filtration rate (GFR), leading to mild renal dysfunction that may reverse after hormone replacement. Objectives: To assess renal function status in hypothyroid patients and evaluate the relationship between thyroid hormone levels and renal function impairment. Materials & Methods: This hospital-based cross-sectional study was conducted in the Department of Biochemistry, MGM Medical College & LSK Hospital, Kishanganj, Bihar, over 18 months. One hundred hypothyroid patients aged 18–70 years were enrolled after applying inclusion and exclusion criteria. Serum free triiodothyronine (fT3), free thyroxine (fT4), thyroid-stimulating hormone (TSH), urea, and creatinine were analyzed using chemiluminescent immunoassay and standard biochemical methods. Estimated GFR was calculated using the CKD-EPI (2021) equation. Statistical analysis was performed using SPSS v26; p<0.05 was considered significant. Results: Among 100 subjects, the mean age was 57.3 ± 11.9 years with a male-to-female ratio of 1.63:1. Thyroid dysfunction was observed in 38% of CKD patients, predominantly subclinical hypothyroidism (27%), followed by overt hypothyroidism (8%) and subclinical hyperthyroidism (3%). Mean serum TSH levels increased significantly with CKD progression (Stage 3: 3.67 ± 3.6; Stage 4: 4.73 ± 3.7; Stage 5: 7.40 ± 3.8; p = 0.003). Serum urea and creatinine rose significantly with declining eGFR (p< 0.0001). Conclusion: Renal dysfunction is common among hypothyroid patients, and the severity of hypothyroidism correlates with worsening renal function. Routine monitoring of thyroid function in CKD and renal profile in hypothyroid individuals is recommended for early intervention