Evaluation of New York State's Child Health Plus: methods.

BACKGROUND: The State Children's Health Insurance Program (SCHIP) is the largest public investment in child health care in 30 years, targeting 11 million uninsured children, yet little is known about the impact of health insurance on uninsured children. In 1991 New York State implemented Child Health Plus (CHPlus), a health insurance program that was a prototype for SCHIP. A study was designed to measure the association between CHPlus and access to care, utilization of services, and quality of care.

METHODS: The setting was a 6-county region in upstate New York (population 1 million) around and including the city of Rochester. A before-and-during design was used to compare children's health care for the year before they enrolled in CHPlus versus the first year during CHPlus, for 1828 children (ages 0-6.99 years at enrollment) who enrolled between November 1, 1991 and August 1, 1993. An additional study involved 187 children 2 to 12.99 years old who had asthma. Parents were interviewed to assess demographic characteristics, sources of health care, experience with CHPlus, and impact of CHPlus on their children's quality of care and health status. Medical charts were reviewed to measure utilization and quality of care, for 1730 children 0 to 6.99 years and 169 children who had asthma. Charts were reviewed at all primary care offices and at the 12 emergency departments and 6 public health department clinics in the region. CHPlus claims files were analyzed to determine costs during CHPlus and to impute costs before CHPlus from utilization data.

ANALYSES: Logistic regression and Poisson regression were used to compare the means of dependent measures with and without CHPlus coverage, while controlling for age, prior insurance type, and gap in insurance coverage before CHPlus.

CONCLUSIONS: This study developed and implemented methods to evaluate the association between enrollment in a health insurance program and children's health care. These methods may also be useful for evaluations of SCHIP.