Risk Adjusting Survival Outcomes in Hospitals That Treat Patients With Cancer Without Information on Cancer Stage

Abstract

Importance: Instituting widespread measurement of outcomes for cancer hospitals using administrative data is difficult owing to lack of cancer-specific information such as disease stage.

Objective: To evaluate the performance of hospitals that treat patients with cancer using Medicare data for outcome ascertainment and risk adjustment and to assess whether hospital rankings based on these measures are altered by the addition of cancer-specific information.

Design, setting, and participants: Risk-adjusted cumulative mortality rates of patients with cancer were captured in Medicare claims data from 2005 through 2009 nationally and assessed at the hospital level. Similar analyses were conducted using Surveillance, Epidemiology, and End Results (SEER)-Medicare data for the subset of the United States covered by the SEER program to determine whether the inclusion of cancer-specific information (only available in cancer registries) in risk adjustment altered measured hospital performance. Data were from 729 279 fee-for-service Medicare beneficiaries treated for cancer in 2006 at hospitals treating 10 or more patients with each of the following cancers, according to Medicare claims: lung, prostate, breast, colon, and other. An additional sample of 18 677 similar patients were included from the SEER-Medicare administrative data.

Main outcomes and measures: Risk-adjusted mortality overall and by cancer category, stratified by type of hospital; measures of correlation and agreement between hospital-level outcomes risk adjusted using Medicare data alone and Medicare data with SEER data.

Results: There were large survival differences between different types of hospitals that treat Medicare patients with cancer. At 1 year, mortality for patients treated by hospitals exempt from the Medicare prospective payment system was 10% lower than at community hospitals (18% vs 28%) across all cancers, and the pattern persisted through 5 years of follow-up and within specific cancer categories. Performance ranking of hospitals was consistent with or without SEER-Medicare disease stage information (weighted κ ≥ 0.81).

Conclusions and relevance: Potentially important outcome differences exist between different types of hospitals that treat patients with cancer after risk adjustment using information in Medicare administrative data. This type of risk adjustment may be adequate for evaluating hospital performance, since the additional adjustment for data available only in cancer registries does not seem to appreciably alter measures of performance.

Figure 1

Risk of death each year (bars) and over time (curve) under the care of different categories of hospitals that treat patients with cancer after Medicare risk adjustment.* Note y-axes are scaled to improve visibility. (PPS = prospective payment system exempt; NCI = hospitals designated by the National Cancer Institute that are not PPS; AMC = Academic hospitals that are not PPS or NCI; Comm = other types of hospitals, *Adjusted for age, sex, median income in the ZIP code of residence and for comorbidity using the 3M CRG software as explained in Methods.)

Figure 2

Comparison of ranks of hospitals with Medicare risk adjustment and SEER risk adjustment. The vertical bars delineate rank changes of more than 20% and more than 40%.