Vol. 1, Issue 2, Part A (2017)

Background: Thyroid hormones play a crucial role in regulating renal physiology, including glomerular filtration rate (GFR), electrolyte handling, and tubular function. Both hypothyroidism and hyperthyroidism can cause significant alterations in renal parameters, which are often reversible upon restoration of normal thyroid function. This study aimed to evaluate the impact of thyroid dysfunction on renal function markers and explore the associations between thyroid hormones and renal indices in patients attending tertiary care centers in India.

Materials and Methods: This observational study was conducted over one year at ICARE Institute of Medical Sciences, Haldia. A total of 124 individuals aged 25-55 years were divided into three groups: euthyroid controls (n = 40), newly diagnosed drug-naïve primary hypothyroid patients (n = 42), and primary hypothyroid patients under treatment for more than two months (n = 42). Serum TSH, free T4, creatinine, urea, estimated GFR (by MDRD and CKD-EPI equations), and urinary albumin-to-creatinine ratio (ACR) were measured and analyzed using ANOVA, Bonferroni post hoc, and Pearson’s correlation tests.

Results: Compared to controls, drug-naïve hypothyroid patients showed significantly elevated TSH (19.10±9.75 µIU/mL), reduced free T4 (0.75±0.22 ng/dL), increased serum creatinine (1.16±0.13 mg/dL), elevated urea (25.30±6.45 mg/dL), reduced eGFR (CKD-EPI: 68.40±9.40 mL/min/1.73 m²), and marked microalbuminuria (ACR: 116.10±30.80 mg/gm) (p<0.001). Patients under treatment showed partial normalization of these parameters. TSH correlated positively with creatinine, urea, and ACR, and negatively with eGFR (p<0.001).

Conclusion: Primary hypothyroidism significantly impairs renal function, as reflected by reduced eGFR and increased creatinine and ACR. These alterations are largely reversible with levothyroxine therapy. Early detection and treatment of thyroid dysfunction may prevent progression to chronic kidney complications.