Chronic kidney disease and risk of kidney or urothelial malignancy: systematic review and meta-analysis

Background Chronic kidney disease (CKD) is highly prevalent, affecting approximately 11% of US adults. Multiple studies have evaluated a potential association between CKD and urinary tract malignancies. Summary estimates of urinary tract malignancy risk in CKD patients with and without common co-existing conditions may guide clinical practice recommendations.Methods Four electronic databases were searched for original cohort studies evaluating the association between CKD and urinary tract cancers (kidney cancer and urothelial carcinoma) through 25 May 2023, in persons with at least moderate CKD and no dialysis or kidney transplantation. Quality assessment was performed for studies meeting inclusion criteria using the Newcastle-Ottawa Scale. Meta-analysis with a random-effects model was performed for unadjusted incidence rate ratios (IRR) as well as adjusted hazard ratios (aHR) for confounding conditions (diabetes, hypertension and/or tobacco use), shown to have association with kidney cancer and urothelial carcinoma. Sub-analysis was conducted for estimates associated with CKD stages separately.Results Six cohort studies with 8 617 563 persons were included. Overall, the methodological quality of the studies was good. CKD was associated with both higher unadjusted incidence and adjusted hazard of kidney cancer (IRR 3.36, 95% confidence interval (CI) 2.32-4.88; aHR 2.04, 95% CI 1.77-2.36) and urothelial cancer (IRR 3.96, 95% CI 2.44-6.40; aHR 1.35, 95% CI 1.22-1.50) compared with persons without CKD. Examining incident urinary tract cancers by CKD severity, risks were elevated in stage 3 CKD (kidney aHR 1.89, 95% CI 1.56-2.30; urothelial carcinoma aHR 1.35, 95% CI 1.20-1.52) as well as in stages 4/5 CKD (kidney cancer aHR 2.30, 95% CI 2.00-2.66; urothelial carcinoma aHR 1.24, 95% CI 1.04-1.49).Conclusions Even moderate CKD is associated with elevated risk of kidney cancer and urothelial carcinoma. Providers should consider these elevated risks when managing individuals with CKD, particularly when considering evaluation for the presence and etiology of hematuria. Graphical Abstract