Joan L. Warren

Development of a comorbidity index using physician claims data

Important comorbidities recorded on outpatient claims in administrative datasets may be missed in analyses when only inpatient care is considered. Using the comorbid conditions identified by Charlson and colleagues, we developed a comorbidity index that incorporates the diagnostic and procedure data contained in Medicare physician (Part B) claims. In the national cohorts of elderly prostate (n = 28,868) and breast cancer (n = 14,943) patients assessed in this study, less than 10% of patients had comorbid conditions identified when only Medicare hospital (Part A) claims were examined. By incorporating physician claims, the proportion of patients with comorbid conditions increased to 25%. The new physician claims comorbidity index significantly contributes to models of 2-year noncancer mortality and treatment received in both patient cohorts. We demonstrate the utility of a disease-specific index using an alternative method of construction employing study-specific weights. The physician claims index can be used in conjunction with a comorbidity index derived from inpatient hospital claims, or employed as a stand-alone measure.

Overview of the SEER-Medicare data: content, research applications, and generalizability to the United States elderly population.

Background. The Surveillance, Epidemiology and End Results (SEER)-Medicare–linked database combines clinical information from population-based cancer registries with claims information from the Medicare program. The use of this database to study cancer screening, treatment, outcomes, and costs has grown in recent years. Research Design. This paper provides an overview of the SEER-Medicare files for investigators interested in using these data for epidemiologic and health services research. The overview includes a description of the linkage of SEER and Medicare data and the files included as part of SEER-Medicare. The paper also describes the types of research projects that have been undertaken using the SEER-Medicare data. The overview concludes with a comparison of selected characteristics of elderly persons residing in the SEER areas to the US total aged. Results. The paper identifies a number of potential uses of the SEER-Medicare data. The comparison of the elderly population in SEER areas to the US total shows that in the SEER areas there are a lower percentage of white persons and individuals living in poverty, and a higher percentage of urban-dwellers than the US total. Elderly persons in the SEER regions also have higher rates of HMO enrollment and lower rates of cancer mortality. Conclusions. The SEER-Medicare data are a unique resource that can be used for a variety of health services research projects. Although there are some differences between the elderly residing in the SEER areas and the US total, the SEER-Medicare data offer a large population-based cohort that can be used to longitudinally track care for persons over the course of cancer diagnosis, treatment, and follow-up.

Racial Differences in the Treatment of Early-Stage Lung Cancer

BACKGROUND If discovered at an early stage, non-small-cell lung cancer is potentially curable by surgical resection. However, two disparities have been noted between black patients and white patients with this disease. Blacks are less likely to receive surgical treatment than whites, and they are likely to die sooner than whites. We undertook a population-based study to estimate the disparity in the rates of surgical treatment and to evaluate the extent to which this disparity is associated with differences in overall survival. METHODS We studied all black patients and white patients 65 years of age or older who were given a diagnosis of resectable non-small-cell lung cancer (stage I or II) between 1985 and 1993 and who resided in 1 of the 10 study areas of the Surveillance, Epidemiology, and End Results (SEER) program (10,984 patients). Data on the diagnosis, stage of disease, treatment, and demographic characteristics of the patients were obtained from the SEER data base. Information on coexisting illnesses, type of Medicare coverage, and survival was obtained from linked Medicare inpatient-discharge records. RESULTS The rate of surgery was 12.7 percentage points lower for black patients than for white patients (64.0 percent vs. 76.7 percent, P<0.001), and the five-year survival rate was also lower for blacks (26.4 percent vs. 34.1 percent, P<0.001). However, among the patients undergoing surgery, survival was similar for the two racial groups, as it was among those who did not undergo surgery. Furthermore, analyses in which adjustments were made for factors that are predictive of either candidacy for surgery or survival did not alter the influence of race on these outcomes. CONCLUSIONS Our analyses suggest that the lower survival rate among black patients with early-stage, non-small-cell lung cancer, as compared with white patients, is largely explained by the lower rate of surgical treatment among blacks. Efforts to increase the rate of surgical treatment for black patients appear to be a promising way of improving survival in this group.

Cost of Care for Elderly Cancer Patients in the United States

BACKGROUND Timely estimates of the costs of care for cancer patients are an important element in the formulation of national cancer programs and policies. We estimated net costs of care for elderly cancer patients in the United States for the 18 most prevalent cancers and for all other tumor sites combined. METHODS We used Surveillance, Epidemiology, and End Results-Medicare files to identify 718,907 cancer patients and 1,623,651 noncancer control subjects. Within each tumor site, noncancer control subjects were matched to patients by sex, age group, geographic location, and phase of care (ie, initial, continuing, and last year of life). Costs of care were estimated for each phase by use of Medicare claims data from January 1, 1999, through December 31, 2003. Per-patient net costs of care were applied to the 5-year survival of cancer patients by phase of care to estimate 5-year costs of care and extrapolated to the elderly US Medicare population diagnosed with cancer in 2004. RESULTS Across tumor sites, mean net costs of care were highest in the initial and last year of life phases of care and lowest in the continuing phase. Mean 5-year net costs varied widely, from less than

Evaluation of Trends in the Cost of Initial Cancer Treatment

20,000 for patients with breast cancer or melanoma of the skin to more than

Association Between Colonoscopy and Colorectal Cancer Mortality in a US Cohort According to Site of Cancer and Colonoscopist Specialty

40,000 for patients with brain or other nervous system, esophageal, gastric, or ovarian cancers or lymphoma. For elderly cancer patients diagnosed in 2004, aggregate 5-year net costs of care to Medicare were estimated to be approximately

Population-based study of autoimmune conditions and the risk of specific lymphoid malignancies

21.1 billion. Costs to Medicare were highest for lung, colorectal, and prostate cancers, reflecting underlying incidence, stage distribution at diagnosis, survival, and phase-specific costs for these tumor sites. CONCLUSIONS The costs of cancer care to Medicare are substantial and vary by tumor site, phase of care, stage at diagnosis, and survival.

Data sources for measuring comorbidity: a comparison of hospital records and medicare claims for cancer patients.

BACKGROUND Despite reports of increases in the cost of cancer treatment, little is known about how costs of cancer treatment have changed over time and what services have contributed to the increases. METHODS We used data from the Surveillance, Epidemiology, and End Results (SEER)-Medicare linked database for 306,709 persons aged 65 and older and diagnosed with breast, lung, colorectal, or prostate cancer between 1991 and 2002 to assess the number of patients assigned to initial cancer care, from 2 months before diagnosis to 12 months after diagnosis, and mean annual Medicare payments for this care according to cancer type and type of treatment. Mutually exclusive treatment categories were cancer-related surgery, chemotherapy, radiation therapy, and other hospitalizations during the period of initial cancer care. Linear regression models were used to assess temporal trends in the percentage of patients receiving treatment and costs for those treated. We extrapolated our results based on the SEER data to the US Medicare population to estimate national Medicare payments by cancer site and treatment category. All statistical tests were two-sided. RESULTS For patients diagnosed in 2002, Medicare paid an average of

Adjuvant Therapy for Breast Cancer: Practice Patterns of Community Physicians

39,891 for initial care for each lung cancer patient,

Use of Medicare Hospital and Physician Data to Assess Breast Cancer Incidence

41 134 for each colorectal cancer patient, and