Rationale & objective: Reduced kidney function is associated with an increased risk of cancer however it is unclear if cancer increases the risk of kidney failure treated with replacement therapy (KFRT). We assessed the risk of KFRT among patients with various types of cancer collectively and with specific types of cancer.
Study design: Retrospective population-based cohort study.
Setting & participants: A total of 2,473,095 participants with (n=824,365) or without (n=1,648,730) cancer registered in the Korean National Health Insurance Service database.
Predictors: Cancer and cancer subtypes defined using the International Classification of Diseases, 10th Revision, Clinical Modification (ICD-10-CM) codes.
Outcomes: Primary outcome was KFRT defined as the initiation of hemodialysis or peritoneal dialysis, or kidney transplantation.
Analytical approach: For each cancer patient, two controls that were age-, sex-, estimated glomerular filtration rate-, diabetes- and hypertension-matched were included. To address the competing risk of death, a competing risk survival analysis was conducted using Fine and Gray’s method.
Results: Occurrence of KFRT was higher in cancer patients than in non-cancer controls (incidence rates of 1.07 versus 0.51 cases per 1,000 person-years). Competing risk analysis showed that cancer was significantly associated with an increased risk of KFRT after adjusting for other potential predictors (adjusted hazard ratio, 2.29 [95% CI, 2.20-2.39]). Multiple myeloma, leukemia, lymphoma, and kidney, ovarian, and liver cancer were most significantly associated with an elevated KFRT risk, with multiple myeloma conferring the highest risk across age and sex groups. All cancer patient subgroups (age, sex, smoking, alcohol, exercise, obesity, and comorbid conditions) exhibited a higher risk of KFRT.
Limitations: Causal association between cancer and kidney outcomes could not be confirmed.
Conclusions: Patients with cancer, particularly those with multiple myeloma, exhibited an increased risk of KFRT after accounting for the competing risk of death.