Impact of Chronic Kidney Disease Stages 3-5 on Mortality and Morbidity Outcomes in Patients with Esophageal Cancer: A Propensity-Score-Matched Cohort Study.

Chronic kidney disease (CKD) may reduce physiologic reserve among patients with esophageal cancer, but evidence beyond postoperative cohorts is limited. Using the TriNetX Global Collaborative Network, we studied adults with esophageal cancer diagnosed during 2010-2023. CKD stages 3-5 were defined by diagnostic codes plus estimated glomerular filtration rate < 60 mL/min/1.73 m2 within 6 months before or on the index date; dialysis-dependent patients were excluded. Non-CKD patients served as comparators. Prespecified outcomes from day 1 to up to 3 years included all-cause mortality, subsequent recorded metastatic diagnosis, pneumonia, sepsis, blood transfusion, and major adverse cardiovascular events. Propensity score matching produced 832 pairs. All-cause mortality was not significantly higher in the overall cohort with CKD stages 3-5 than in the non-CKD cohort (HR, 1.13; 95% CI, 0.98-1.31; p = 0.099), whereas CKD stages 4-5 were associated with higher mortality in the stage-specific analysis (HR, 1.46; 95% CI, 1.03-2.06; p = 0.031). CKD stages 3-5 were also associated with higher risks of blood transfusion (HR, 1.45; 95% CI, 1.04-2.01; p = 0.025) and MACEs (HR, 1.22; 95% CI, 1.02-1.47; p = 0.027), and with a lower risk of subsequent recorded metastatic diagnosis (HR, 0.80; 95% CI, 0.65-0.99; p = 0.036). These findings suggest that the associations of CKD with post-diagnostic outcomes varied by outcome type, with higher mortality observed in the separate CKD stages 4-5 analysis.