Disenrollment from an HMO and its relationship with the characteristics of Medicare beneficiaries.

To examine the relationship between Medicare beneficiaries' characteristics and disenrollment, a longitudinal study was conducted in an HMO in California. Approximately 10 percent of the Medicare beneficiaries disenrolled within the first year of enrollment. There was no difference between those who continuously enrolled and those who disenrolled in terms of age, gender, mental and physical health status, previous utilization, and anticipated utilization in the coming year. However, people with limited social activities and people not living in a single-family house were more likely to disenroll. The authors also examined the disenrollment rates among physicians groups. The rates were significantly different.