Abstract
BACKGROUND: Almost half of Medicare beneficiaries diagnosed with cancer from 1992 to 2005 had at least one comorbid condition. Conditions affect a range of domains from clinical decision-making to quality of life, which are important to consider when conducting cancer research. We introduce a new Surveillance, Epidemiology, and End Results (SEER)-Medicare resource to facilitate using claims data for patients with cancer. METHODS: We use the SEER-Medicare resource to estimate prevalence of comorbidities, 5-year survival rate by cancer site, stage, age and comorbidity severity, and prevalence of surgery by comorbidity for breast, prostate, colorectal and lung cancers. RESULTS: Overall, the most prevalent comorbidities in the year prior to cancer diagnosis were diabetes (27%), chronic obstructive pulmonary disease (22%), peripheral vascular disease (14%), and congestive heart failure (12%). Comorbidity severity had a greater impact on the probability of dying from noncancer causes than dying from cancer. Severity of comorbidity and age consistently increased the probability of noncancer death. The percentage of persons receiving surgery tended to be lower among those with severe comorbidity. CONCLUSIONS: This study demonstrates the utility of new SEER*Stat databases that contain Medicare beneficiaries and claims-based measures of comorbidity. Our results demonstrate that comorbidity is common among older persons diagnosed with cancer and the impact of comorbidity on the probability of dying from cancer varies by cancer site, stage at diagnosis, and age. IMPACT: Comorbidity is common among persons with cancer and affects survival. Future research on the impact of comorbidity among cancer survivors is facilitated by new databases.