The Effect of Payer Status on Survival of Patients with Stage I/II Non-small Cell Lung Cancer: NCDB 1998-2011.

Background: One of the challenges to improving access to care is identifying disparities in health care. To determine the influence of insurance status on outcome for patients with non-small cell lung cancer (NSCLC), we analyzed data from the National Cancer Data Base (NCDB) from 1998-2011.

Materials And Methods: Data from 299,914 patients diagnosed with NSCLC registered in the NCDB were analyzed. Overall survival (OS) was the outcome variable, and payer status was the primary predictor variable. Other variables included stage, grade, lymph node status, age, race, Charlson Comorbidity Index, income, education, distance travelled, cancer program, diagnosing/treating facility, treatment delay, surgery, chemotherapy and radiation therapy. Multivariate Cox regression was used to investigate the effect of payer status on OS while adjusting for secondary predictive factors.

Results: The majority of patients diagnosed at stage I-II had Medicare (61.72%), while less than one third were privately insured (29.57%). In univariate analysis, the median OS was 2.90, 3.42, 3.86, 4.19, and 6.23 years for Medicare, Medicaid, uninsured, unknown, and privately insured patients, respectively. Multivariate analysis revealed a statistically significant relationship between insurance status and OS. Interaction effects of treatment between radiation and surgery were statistically significant: patients receiving radiation in addition to surgery had a 37% increased mortality compared to patients undergoing surgery alone. Compared to receiving no treatment (radiation, surgery, chemotherapy), the 5-year direct adjusted survival probability increased by 44.70%, 40%, 3.91%, 9.42%, 31.56% and 33.20% for patients treated with surgery and chemotherapy, surgery alone, chemotherapy alone, radiation alone, radiation plus surgery, and radiation plus surgery and chemotherapy, respectively.

Conclusion: Insurance status proved to be a statistically significant predictor of OS, which remained true after adjusting for all other factors. Uninsured and Medicaid patients had the highest mortality. Multivariate analysis revealed that chemotherapy in addition to surgery provided the best 5-year direct adjusted survival probability.