Little direct assessment has been made of the quality of medication prescribing to elderly nursing home residents. Medicaid is a means of delivering medical care to eligible needy individuals. The study of elderly nursing home Medicaid beneficiaries is relevant to optimal use of Medicaid funds since expenditures for pharmaceutical and health care services for these nursing home residents are proportionately much higher than for any other group. The purpose of this project was to study the prescribing of inappropriate medications to the elderly Medicaid beneficiaries residing in Louisiana's Intermediate Care Facilities I (ICFs I) and its influence on relevant economic and clinical outcomes.

Relevant data for geriatric Medicaid beneficiaries in Louisiana's ICFs I for 1994 were extracted from three Medicaid files (Claim History file, Provider Master file and Drug file) containing a total of 1,430,629 records for 19,932 beneficiaries in the study population. Explicit criteria were used to identify inappropriate drugs. Hypertensive and diabetic beneficiaries in the study population were identified using the drug therapeutic classes.

The extracted data were analyzed using multiple linear and binomial logit regression models. Results of the study showed that the number of different drugs prescribed to a beneficiary was influenced by a beneficiary's geographic region and race and was likely to be higher for a beneficiary who used a larger number of physicians and pharmacies. The number of different inappropriate drugs prescribed to a beneficiary was influenced by a beneficiary's geographic region and age and was likely to be higher for a beneficiary who used a larger number of physicians and pharmacies and was prescribed a larger number of different drugs. The outcome measures, costs of pharmaceutical and health care services, number of inpatient hospital days and probability of beneficiary mortality, were influenced by sex, age, race and geographic region of a beneficiary. They were likely to be higher for a beneficiary who used a larger number of physicians and/or pharmacies and was prescribed a larger number of different inappropriate drugs.

It was concluded that the demographic and health care provider-related factors influenced the number of different drugs prescribed, the number of different inappropriate drugs prescribed and the economic and clinical outcomes for an elderly Medicaid beneficiary residing in a Louisiana ICF I. Avoiding prescribing of the inappropriate drugs or prescribing them in smallest possible numbers to a beneficiary may be cost-effective.