HMO membership and patient age and the use of specialty care for hospitalized patients with acute stroke: The Minnesota Stroke Survey

BACKGROUND. The number of older patients enrolling in health maintenance organizations (HMOs) is increasing. Concerns have been raised that older patients may be targeted by HMOs for more stringent cost-containment mechanisms, including reduced access to expensive specialty care. OBJECTIVES. We investigated the relationship between membership in an HMO and the decision to consult with a neurologist or admit to a neurology ward for patients hospitalized with acute stroke. We then compared 1-year mortality of patients who received neurology care to the 1-year mortality of those who did not receive neurology care. DESIGN. Retrospective medical record review. SUBJECTS. A sample of hospitalized acute stroke patients (age range, 30-79 years) who were discharged from Minneapolis-St. Paul metropolitan hospitals with a diagnosis code of acute cerebrovascular disease from 1991 to 1993. MEASURES. Trained nurses abstracted the medical records. Stroke events (n = 2,320) were validated using clinical criteria and neuroimaging reports. Mortality data were obtained from the Minnesota Death Index. RESULTS. Among patients enrolled in HMOs, 30% of validated stroke patients did not receive neurology care in comparison with 19% of patients not enrolled in HMOs. After adjusting for patient mix and hospital characteristics, the odds of receiving neurology care were half as great for patients enrolled in HMOs as compared with patients not enrolled in HMOs (odds ratio [OR] = 0.52, 95% confidence interval [CI] 0.36-0.74). The association of membership in HMOs with lower use of neurology care was concentrated in older patients. Within each age group, the odds ratios and 95% CI of receiving neurology care for patients enrolled in HMOs versus patients not enrolled in HMOs were: < 55 years (1.06, 0.42-2.67), 55 to 64 years (0.54, 0.34-0.87), 65 to 74 years (0.51, 0.36-0.71), and >75 years (0.40, 0.24-0.68). Using Cox regression, 30-day mortality did not differ between patients who received neurology care and those who did not. Among 30-day survivors, the mortality hazards ratio (HR) during the next 11 months for patients who received neurology care was 71% of the hazard for patients who did not receive neurology care (HR = 0.71, 95% CI = 0.55-0.91).