Association of chronic kidney disease with mortality risk in patients with lung cancer: a nationwide Taiwan population-based cohort study

OBJECTIVE Our population-based research aimed to clarify the association between chronic kidney disease (CKD) and mortality risk in patients with lung cancer. DESIGN Retrospective cohort study SETTING: National health insurance research database in Taiwan PARTICIPANTS: All (n=1 37 077) Taiwanese residents who were diagnosed with lung cancer between 1997 and 2012 were identified. Eligible patients with baseline CKD (n=2269) were matched with controls (1:4, n=9076) without renal disease according to age, sex and the index day of lung cancer diagnosis. METHODS The cumulative incidence of death was calculated by the Kaplan-Meier method, and the risk determinants were explored by the Cox proportional hazards model. RESULTS Mortality occurred in 1866 (82.24%) and 7135 (78.61%) patients with and without CKD, respectively (P=0.0001). The cumulative incidences of mortality in patients with and without chronic renal disease were 72.8% vs 61.6% at 1 year, 82.0% vs 76.6% at 2 years and 88.9% vs 87.2% at 5 years, respectively. After adjusting for multiple confounding factors including age and comorbidities, Cox regression analysis revealed that CKD was associated with an increased risk of mortality (adjusted HR 1.38; 95% CI 1.29 to 1.47). Stratified analysis further showed that the association was consistent across patient subgroups. CONCLUSION Comorbidity associated with CKD is a risk factor for mortality in patients with lung cancer.