The present study reports upon contemporary, nationwide lung cancer resection outcomes as they relate to differences in gender, race and socioeconomic status. These results suggest that after accounting for the potential confounding influence of over 50 different variables, female gender was a significant, independent correlate of postoperative morbidity and mortality and was associated with reduced odds of death and postoperative complications compared to males. Race was also a significant predictor of postoperative complications. Moreover, risk-adjusted mortality was significantly influenced by socioeconomic status, and the odds of death increased with declining mean income. Importantly, among these factors, gender proved to be the strongest predictor of postoperative death and morbidity. To our knowledge, these findings represent the most comprehensive report of current nationwide outcomes following lung cancer resections to address the contribution of important demographic factors that have been implicated in health disparities within the United States. Thus, these data provide an analysis of valuable patient related factors to be considered by thoracic surgeons and patients in the preoperative setting.
In this report, the effect of gender was a significant correlate of postoperative mortality and morbidity and is in agreement with other reported series [3
]. In one recent series reporting on outcomes from the national Society of Thoracic Surgeons (STS) General Thoracic Surgery Database, male gender was associated with elevated odds of mortality (OR=1.37, p=0.013) as well as the composite outcome of mortality and major morbidity (OR=1.12, p=0.031) following lung cancer resections [3
]. Furthermore, the beneficial effects of female gender on 5-year survival rates for women with stage I–III tumors were noted in another prospective series of 1,085 patients with non-small cell lung carcinoma [8
]. Important to consider in the results of the present study is the relative disproportion of females to males within this NIS dataset as well as the relative strength of female gender as an independent risk factor for the primary outcomes of interest. Considering the estimated associations between female gender and outcomes, we would expect that the effect of female gender on risk-adjusted outcomes may be even more dramatic in datasets with more equal distribution of gender. Moreover, although not directly assessed in the present study, the influences of tumor type and disease stage must be considered as contributing to the improved perioperative outcomes for females undergoing lung cancer resections.
The present results provide a valuable extension to accumulated data regarding the influence of race and socioeconomic status on lung cancer treatment and outcomes [5
]. In a recent population-based study of 76,086 lung cancer resection patients (1998–2002) within a Florida cancer registry, African American patients were diagnosed with lung cancer at an earlier age, with more advanced disease, comprised the largest proportion of low income patients, and were less likely to undergo surgical resection, which resulted in reduced median survival times compared to Caucasians (7.5 years vs. 8.8 years, p
]. However, after risk-factor adjustment, race failed to be a multivariate correlate of survival in this series, while severe poverty was an independent predictor of worse survival (HR=1.05, p
=0.001). Importantly, in this series no significant differences were observed for patient undergoing surgical resections, and the study is limited by the fact that only 22% of their cohort underwent surgical resection, their analysis failed to address postoperative morbidity, and the results reflect trends that may not be current. Other series, however, corroborate these findings among single institutional experiences and various cancer registries and are complementary to those of the present analysis [5
The potential explanations for disparities in outcomes related to gender, race and socioeconomic status in this study are complex and multifactorial. Substantial evidence exists describing the interaction of various factors on patient outcomes, including ethnicity, education level, language barriers, socioeconomic status, cultural values, poor physician-patient communication, provider bias, disparities in hospital resource utilization, and access to specialized care [16
]. In this large observational analysis, we also demonstrate the independent influence of several of these factors. Specifically, these results indicate that many of the racial and socioeconomic influences that have been documented as potential culprits for disparities in patient outcomes appear related. When individually accounted for through regression analysis, various modifiable social, health system and economic factors largely account for the observed differences. In fact, these data, as well as those presented elsewhere [5
], demonstrate that many ethnic disparities in lung cancer outcomes could be reduced, and even improved, with appropriate utilization of operative intervention and adjuvant therapy.
The presented results are subject to select limitations. Due to the retrospective study design, selection bias must be considered. In addition, we are unable to account for certain data, including tumor type, pathologic or clinical stage, preoperative performance status or predicted pulmonary function. Use of community-level income status, such as mean income by ZIP code, is admittedly imperfect, and this definition of socioeconomic status may differ compared to other studies. However, previous research has supported the use of such definitions as a valid proxy for socioeconomic status [18
]. The use of de-identified data and the lack of long-term follow-up within the NIS limits the ability to scrutinize the data further, and this study also did not directly examine the effects of insurance or primary payer status on risk-adjusted outcomes. The impact of varying insurance types on risk-adjusted outcomes, however, has been documented in other recent surgical series [16
]. Despite these limitations, use of the NIS provides important benefits as the data represented herein is broadly applicable to patients nationwide and allows for the effective adjustment for certain social and economic influences that are often poorly captured or unavailable in other institutional or registry datasets,.
The results reported herein demonstrate important differences in lung cancer resection outcomes as they relate to disparate differences in gender, race and socioeconomic status. Based upon these analyses, female gender is associated with decreased risk-adjusted mortality and morbidity following lung cancer resections, while the odds of postoperative complications are lower for Black, Hispanic and Asian patients. Low socioeconomic status increases the risk of in-hospital death. These factors should be considered during individual patient risk stratification for lung cancer resection, and optimization of modifiable patient-, provider-, and system-related factors may help to reduce health disparities and outcomes for this patient population.