Costs and survival of patients with colorectal cancer in a health maintenance organization and a preferred provider organization.
BACKGROUND
Colorectal cancer is relatively frequent among adults of working age, yet few studies have examined treatment, outcomes, and costs for people under 65 years of age with this disease.


OBJECTIVE
The objective of this study was to compare the initial treatments, survival, cancer-related medical costs, and overall medical costs for working-aged persons with colorectal cancer in 2 large health insurance plans in Washington State, one a preferred provider organization (PPO) and the other a group model health maintenance organization (HMO).


METHODS
This study consisted of patients, aged 20-64 years, diagnosed with colorectal cancer in both health plans from 1996 to 1998. For each cancer case, up to 5 control subjects, matched on age and sex, were selected for the analysis.


METHODS
We calculated unadjusted, attributable, and overall medical costs using the Kaplan-Meier sample average estimator. We calculated relative mortality rates using Cox regression. We used propensity scores to adjust overall costs and survival for potential confounding factors.


RESULTS
Two hundred ten persons in the PPO and 136 persons in the HMO, aged 20-64 years, were diagnosed with cancer over the observation period and included in this study. Patients in the PPO were more likely to have local excision of their tumor (16% compared with 11%) and were less likely to receive chemotherapy (48% compared with 60%). The overall medical costs for the cancer cases were $46,000 in the HMO and $46,400 in the PPO (95% confidence interval for the difference: -$19,300 to 20,100). The cancer-attributable medical costs over 2 years were $40,400 in the HMO and $44,300 in the PPO (95% confidence interval for the difference: -$17,400 to 25,200). Survival was similar in the 2 health plans: the hazard ratio was 0.89 for those enrolled in the PPO (95% confidence interval: 0.50 to 1.59). Adjustment for potential confounding factors altered the results little.


CONCLUSIONS
There were differences in the initial treatment of the patients in each health plan, but costs and survival were not significantly different between the 2 plans.
Kerrigan
Matthew
M
Department of Pharmacy, University of Washington, Seattle, and the Fred Hutchinson Cancer Research Center, Public Health Sciences Division, Seattle, Washington 98109, USA.
Howlader
Nadia
N
Mandelson
Margaret T
MT
Harrison
Robert
R
Mansley
Edward C
EC
Ramsey
Scott D
SD
D000328:Adult; D015179:Colorectal Neoplasms / Q000191:economics* / Q000401:mortality* / Q000628:therapy; D005260:Female; D017048:Health Care Costs; D006279:Health Maintenance Organizations / Q000191:economics* / Q000706:statistics & numerical data; D006801:Humans; D008297:Male; D008498:Medical Record Linkage; D008875:Middle Aged; D009367:Neoplasm Staging; D011243:Preferred Provider Organizations / Q000191:economics* / Q000706:statistics & numerical data; D018426:SEER Program; D016019:Survival Analysis; D016896:Treatment Outcome; D014861:Washington / Q000453:epidemiology