The relationship between estimated glomerular filtration rate and thyroid function: an observational study

Background: Estimated glomerular filtration rate (eGFR) is now routinely reported by most National Health Service laboratories. There are many limitations when interpreting eGFR: thyroid dysfunction is not widely recognized as being one of these. Methods: We extracted from the pathology computer system results of all patients with hypothyroidism and hyperthyroidism who also had serum creatinine measured. We also extracted creatinine data on euthyroid patients. eGFR was calculated using the simplified Modification of Diet in Renal Disease Study equation. Results: The median eGFRs of the hypothyroid, euthyroid and hyperthyroid patients were 64, 77 and 107 mL/min/1.73 m(2), respectively; all groups were significantly different from each other (P < 0.001). Conclusion: Thyroid dysfunction is associated with significant alterations in eGFR and actual GFR.