UTILIZATION OF SPECIALTY AND PRIMARY-CARE - THE IMPACT OF HMO INSURANCE AND PATIENT-RELATED FACTORS

BACKGROUND. Appropriate utilization of primary and specialty care has stimulated substantial debate, but the portion of the discussion focus ed on policies that restrict or discourage direct access to specialist s has been largely uninformed by empirical analysis. Using data from t he National Ambulatory Care Survey (1985 to 1992 surveys), we examined the associations of patient and physician demographics and health mai ntenance organization (HMO) insurance status with the utilization of p rimary compared with specialty care. METHODS. Office visits for adult patients seen by primary care physicians and specialists were analyzed for: (1) patient-initiated utilization of specialists (patient self-r eferral) compared with that of primary care physicians; and (2) utiliz ation of specialists compared with that of primary care physicians, st ratified by HMO insurance status. RESULTS. After multivariate adjustme nt, patient self-referral was less likely among black patients (adjust ed odds ratio [AOR] = 0.67; 95% confidence interval [CI] = 0.59 to 0.7 6), self-pay (AOR = 0.81; 95% CI = 0.74 to 0.88), or patients with Med icaid (AOR = 0.51; 95% CI = 0.43 to 0.61), The proportion of non-HMO p atients seeing specialists remained stable (44.9%). For HMO patients, the proportion of total visits made to specialists increased from 27.6 % in 1985 to 41.3% in 1991, then dropped to 33.2% in 1992. Disparities in utilization of specialists by women, blacks, and patients with Med icaid observed among non-HMO patients were not found in the HMO popula tion. Specialists were more likely to see HMO patients for follow-up o f a known problem, whereas non-HMO patients were more likely to have s pecialist follow-up visits for new problems, CONCLUSIONS. The results suggest greater utilization of specialists by male, white, and private ly insured patients. The findings may partially account for disparitie s in specialty procedure use, and suggest that HMO insurance may reduc e some of these disparities, The less frequent and more selective use of specialists among HMO patients suggests an evolving role for specia lists in managed care.