Our study provides information about the association of hospital-level characteristics with the use of surgical procedures for Medicare beneficiaries with NSCLC. We found that receiving care at a teaching hospital or at hospitals with relatively larger percentages of white patients were associated with higher odds of patients undergoing surgical procedures. First, black and white patients seem to receive their lung cancer care at different hospitals. Most white patients were treated in hospitals that were predominantly white, whereas the majority of black patients were treated in hospitals that had a high number of black patients. Second, we found that the higher the percentage of black patients treated at a hospital, the less likely patients of either race were to undergo surgery for lung cancer. Lastly, in all hospitals, regardless of the racial mix, white patients were more likely to obtain surgery versus black patients, even when controlling for common confounders.
Our model attempted to account for the major confounders, including patient volume, income, stage of disease, and SEER registry. The role of patient factors such as insurance was difficult to ascertain, as all patients were Medicare recipients, although those patients who were listed as low income had state buy-in for insurance and were also less likely to obtain surgery. This effect is independent of the patient race and hospital effect.
Access to care has always been an important issue in discerning the cause of racial disparities in cancer treatment.26
Our work looks at the effects of race in an equal access system, and recent published work has indicated that where patients obtain care can be an important factor contributing to racial disparities.14,16,27-29
The distribution of care demonstrated in is consistent with recent studies in the literature.30
Our analysis, using a multivariable regression model, demonstrated that the likelihood of obtaining surgery for early-stage lung cancer decreased with increasing percentage of black patients in a hospital. The model contained the traditional patient level covariates for stage, patient race, comorbid disease, socioeconomic status, SEER registry, and sex. It is of interest to note that black race remained a significant negative predictor of surgery for lung cancer, even with the hospital-level factors, racial composition, and patient volume in the model. This indicates that hospital racial composition affects care in addition to (not because of) individual patient race.
The effect of volume of the hospital did seem to indicate that patients seen at smaller-volume hospitals also obtained surgery less than in patients seen in larger-volume hospitals. In all analyses, black race seemed to be a negative predictive factor in undergoing surgery for early-stage lung cancer, and this effect was similar in strength but was independent of the racial composition of the hospital. The effect of SEER registry is likely multifactorial, combining some elements of regional treatment patterns and proximity to major treatment centers.
There are some limitations to our study. Our analytic database combines data from the SEER registries and Medicare claims. Medicare claims were not created for research and can suffer from coding error. In addition, comorbidity adjustment using administrative data might miss some relevant factors that physicians use in choosing which patients are likely to tolerate surgery24,31
and is not a proxy for performance status. Because our analysis was limited to Medicare-enrolled patients, we were unable to examine patients younger than 65 years of age. Patients in health maintenance organizations were excluded and may have different patterns of care. It is possible that the hospitals with higher numbers of black patients are safety net or county hospitals, but we were unable to discern hospital type in the SEER-Medicare database. Identifying patients based on hospital admission is imperfect but necessary, given the constraints of administrative databases like SEER-Medicare. Likewise, income estimates can also be imprecise, given the intimation of income via census tract data.
We have shown that, regardless of race, patients are less likely to have surgery for nonmetastatic NSCLC if they are treated at hospitals with larger black populations. Furthermore, black patients seem to be treated for lung cancer more often at predominantly black hospitals. It is well known that black patients have surgery less often for NSCLC compared with white patients. Hospital-level characteristics, such as racial composition of the hospital, are often determined by regional resources. The reasons for the hospital-level effect of racial composition we observed are unknown but could be the result of historical treatment and referral patterns. Indeed, many safety net or county hospitals are large-volume teaching hospitals that traditionally provide care to the underserved. If the hospitals that treat the majority of black patients are overburdened and/or underfunded, then an exacerbation of the already present treatment disparities is bound to occur. Future research should focus on the specific characteristics of the hospitals that correspond to improved access to lung cancer care for all patients, regardless of race or ethnicity.