OBJECTIVE: To determine whether children on fee-for-service Medicaid who switch primary care doctors use less health care and are less up to date with preventive care visits than children who do not switch primary care doctors.

DESIGN: Retrospective cohort study using Medicaid claims data.

SETTING: 51,027 children enrolled on Medicaid in Monroe County, New York.

PATIENTS: 14,187 children enrolled continuously on fee-for-service Medicaid between January 1992 and December 1994.

MAIN OUTCOME MEASURES: Utilization of primary care, emergency department (ED) services, and specialty care and proportion up to date with preventive care visits according to American Academy of Pediatrics guidelines.

RESULTS: During the 2-year study period, 22% of children switched primary care doctors. Compared with children who did not switch primary care doctors, those who switched had more primary care visits (4.7 vs. 3.2 visits/year, P < .01), age-adjusted preventive care visits (1.2 vs. 1.0 visits/year), ED visits (0.72 vs. 0.47 visits/year, P < .01), and specialist visits (0.99 vs. 0.31, P < .01). On multivariate analysis, doctor switching was associated with increased odds of being up to date with preventive care visits (odds ratio [OR] = 1.7; 95% confidence interval [CI] 1.3 to 2.1). However, on multivariate analysis stratified by age, the association was significant only for older children (ages 11 to 14). Altogether, 68% of all children and 44% of infants less than 1 year old made the recommended number of preventive care visits during the study period.

CONCLUSIONS: All groups of children received less preventive care than recommended by the American Academy of Pediatrics. Children who switched primary care doctors had higher utilization of health care, including primary care, ED, and specialty care. Contrary to expectations, they were more likely to be up to date with preventive care visits. The heavy utilization of health services by doctor switchers indicates that this subgroup of children on Medicaid may not be at risk for poor access to health care, but additional research is needed to determine whether the quality of care is related to doctor switching.