Lung cancer outcome in the setting of chronic kidney disease: Does the glomerular filtration estimation formula matter?

Background The survival outcomes of lung cancer patients with coexisting chronic kidney disease (CKD) reported in the literature have been conflicting. We evaluate whether the survival of lung cancer patients with and without CKD differ significantly using two different formulas. Methods A retrospective, multicenter, propensity-matched study of lung cancer patients with and without CKD was conducted. CKD was defined as an estimated glomerular filtration rate (eGFR) < 60 mL/minute. Kaplan-Meier survival analysis was used to determine survival differences between CKD and non-CKD patients using the Cockcroft-Gault formula (CKD-CG) compared to the Chronic Kidney Disease Epidemiology Collaboration Formula (CKD-EPI). Results Baseline clinical characteristics did not differ statistically significantly between the groups. The CKD-CG formula demonstrated median survival of 10.61 months (95% confidence interval [CI] 9.33-11.89) for the non-CKD group compared to 10.58 months (95% CI 9.03-12.13) for the CKD group (P = 0.76). The CKD-EPI formula demonstrated median survival of 9.10 months (95% CI 8.01-10.20) for the non-CKD group compared to 7.59 months (95% CI 6.50-8.68) for the CKD group (P = 0.19). Cox regression analysis using both models revealed that CKD is not an independent risk factor for mortality in lung cancer patients. Although the CKD-EPI formula revealed an increased risk of mortality and the CKD-CG formula revealed decreased survival, these results were not statistically significant. Conclusion Lung cancer survival did not differ significantly between CKD and non-CKD patients using either formula.