Abstract
Objective: To summarize the evidence regarding the association between subclinical thyroid dysfunctions and chronic kidney disease (CKD) in adults. Methods: The literature was searched for English-published studies from inception till the 16th of December 2022. The search included MEDLINE/PubMed, Academic Search Complete (EBSCOhost) and Web of Science using the terms ('subclinical hypothyroidism and thyroid dysfunction') AND ("chronic kidney disease or chronic renal failure or ckd or esrd'). Results: Eleven studies were included. Subclinical hypothyroidism was significantly associated with a higher risk of CKD compared to euthyroid individuals (Odds ratio (OR): 1.43, (95% CI: 1.23-1.65), P<0.001, n=11). Subgroup analyses by adjusting for confounders or diabetes mellitus did not alter the results significantly. However, the ORs were significantly lower with longitudinal studies compared to cross-sectional studies (OR: 1.17 vs. 1.68, respectively, p<0.001). Subclinical hyperthyroidism was associated with a higher risk of CKD than euthyroid individuals, but the association was not significant (OR: 1.19, (95% CI: 0.92-1.53), P=0.18, n=3). Conclusions: Subclinical hypothyroidism is significantly associated with an increased risk of CKD. However, more longitudinal studies are required to confirm the effect of subclinical hypothyroidism as an exposure on the outcome of newly diagnosed CKD. The association between subclinical hyperthyroidism and CKD is understudied and warrants more research to ascertain its effect on the risk of CKD.