Survival associated with chronic obstructive pulmonary disease among SEER-medicare beneficiaries with non-small-cell lung cancer

Abstract

Objective: We investigated the impact of preexisting COPD and its subtypes, chronic bronchitis and emphysema, on overall survival among Medicare enrollees diagnosed with non-small-cell lung cancer (NSCLC). Methods: Using SEER-Medicare data, we included patients ≥66 years of age diagnosed with NSCLC at any disease stage between 2006 and 2010 and continuously enrolled in Medicare Parts A and B in the 12 months prior to diagnosis. Preexisting COPD in patients with NSCLC were identified using ICD-9 codes. Kaplan–Meier method and log-rank tests were used to examine overall survival by COPD status and COPD subtype. Multivariable Cox proportional hazards models were fit toassessthe risk of death after cancer diagnosis. Results: We identified 66,963 lung cancer patients. Of these, 22,497 (33.60%) had documented COPD before NSCLC diagnosis. For each stage of NSCLC, median survival was shorter in the COPD compared to the non-COPD group (Stage I: 692 days vs 1,130 days, P<0.0001; Stage II: 473 days vs 627 days, P<0.0001; Stage III: 224 days vs 229 days; P<0.0001; Stage IV: 106 days vs 112 days, P<0.0001). For COPD subtype, median survival for patients with preexisting chronic bronchitis was shorter compared to emphysema across all stages of NSCLC (Stage I: 672 days vs 811 days, P<0.0001; Stage II 582 days vs 445 days, P<0.0001; Stage III: 255 days vs 229 days, P<0.0001; Stage IV: 105 days vs 112 days, P<0.0001). In Cox proportional hazard model, COPD patients exhibited 11% increase in risk of death than non-COPD patients (HR: 1.11, 95%CI: 1.09–1.13). Conclusion: NSCLC patients with preexisting COPD had shorter survival with marked differences in early stages of lung cancer. Chronic bronchitis demonstrated a greater association with time to death than emphysema.