Association of CKD and Cancer Risk in Older People

People with ESRD are at increased risk for cancer, but it is uncertain when this increased risk begins in the spectrum of chronic kidney disease (CKD). The aim of our study was to determine whether moderate CKD increases the risk for cancer among older people. We linked the Blue Mountains Eye Study, a prospective population-based cohort study of 3654 residents aged 49 to 97 yr, and the New South Wales Cancer Registry. During a mean follow-up of 10.1 yr, 711 (19.5%) cancers occurred in 3654 participants. Men but not women with at least stage 3 CKD had a significantly increased risk for cancer (test of interaction for gender P = 0.004). For men, the excess risk began at an estimated GFR (eGFR) of 55 ml/min per 1.73 m² (adjusted hazard ratio [HR] 1.39; 95% confidence interval [CI] 1.00 to 1.92) and increased linearly as GFR declined. For every 10-ml/min decrement in eGFR, the risk for cancer increased by 29% (adjusted HR 1.29; 95% CI 1.10 to 1.53), with the greatest risk at an eGFR <40 ml/min per 1.73 m² (adjusted HR 3.01; 95% CI 1.72 to 5.27). The risk for lung and urinary tract cancers but not prostate was higher among men with CKD. In conclusion, moderate CKD (stage 3) may be an independent risk factor for the development of cancer among older men but not women, and the effect of CKD on risk may vary for different types of cancer.Chronic kidney disease (CKD) is common in older people. Among those aged ≥50 yr, the prevalence of moderate (stage 3) CKD or worse, defined as estimated GFR (eGFR) <60 ml/min per 1.73 m², is >20% in the United States and Australia.^1,2 CKD is associated with significant morbidity and premature death. Cardiovascular complications and deaths are increased in the CKD population independent of traditional risk factors such as diabetes, hypertension, and dyslipidemia.^3–5 Increased cancer risk is also well defined in the end-stage kidney disease (ESKD) and kidney transplant populations.^6–8 The overall cancer incidence after transplantation is approximately three-fold greater than in the general population.Observational studies have suggested an increased cancer risk in people with early-stage CKD, before requiring dialysis or transplantation.^9,10 An excess risk of 1.2 times for all cancers was reported during the 5 yr before renal replacement therapy in a population-based cohort study of dialysis and transplant patients, but inclusion was limited to those who progressed to ESKD, and comorbidity data were limited.⁶ Recently, an association between elevated albumin-to-creatinine ratio and cancer incidence was reported in a longitudinal population-based study of older individuals.¹¹ Previous studies have not evaluated the threshold of CKD that is associated with an increased risk for cancer, adjusted for measurement error in estimating the severity of CKD, or determined the independent effect of CKD after accounting for known risk factors for cancer. The aim of our study was to estimate the independent effect of mild to moderately reduced kidney function on the risk for incident cancers among older people and to identify the threshold at which any excess risk begins.