Albuminuria and the risk of cancer: the Stockholm CREAtinine Measurements (SCREAM) project

BACKGROUND: Studies investigating the association of chronic kidney disease and cancer have focused on estimated glomerular filtration (eGFR) rather than on albuminuria. This study aimed to examine whether albuminuria is associated with cancer incidence, and whether this association is independent of eGFR. METHODS: We included subjects of the Stockholm Creatinine Measurements (SCREAM) project without a history of cancer—250 768 subjects with at least one urine albumin–creatinine ratio (ACR) test (primary cohort) and 433 850 subjects with at least one dipstick albuminuria test (secondary cohort). Albuminuria was quantified as KDIGO albuminuria stages. The primary outcome was overall cancer incidence. Secondary outcomes were site-specific cancer incidence rates. Multivariable Cox proportional hazards regression models adjusted for confounders including eGFR to calculate hazard ratios and 95% confidence intervals (HRs, 95% CIs). RESULTS: During a median follow-up of 4.3 (interquartile range 2.0–8.2) years, 21 901 subjects of the ACR cohort developed de novo cancer. In multivariable analyses, adjusting among others for eGFR, subjects with an ACR of 30–299 mg/g or ≥300 mg/g had a 23% (HR 1.23; 95% CI 1.19–1.28) and 40% (HR 1.40; 95% CI 1.31–1.50) higher risk of developing cancer, respectively, when compared with subjects with an ACR <30 mg/g. This graded, independent association was also observed for urinary tract, gastrointestinal tract, lung and hematological cancer incidence (all P < .05). Results were similar in the dipstick albuminuria cohort. CONCLUSIONS: Albuminuria was associated with the risk of cancer independent of eGFR. This association was primarily driven by a higher risk of urinary tract, gastrointestinal tract, lung and hematological cancers.