Gender-based structural models of health care costs: alcohol use, physical health, mental health, and functioning.

BACKGROUND Most models of health services use or costs include gender as a covariate, combining data for men and women in analyses. This strategy may obscure differences in underlying processes producing differential health care use by men and women, particularly in examinations of factors that affect health care use and differ by gender (e.g. alcohol consumption and depression). AIMS To examine gender differences in the relationships between alcohol consumption, physical and mental health and functioning, and costs of health care. METHODS The setting was Kaiser Permanente Northwest, a large non-profit group practice model HMO serving northwest Oregon and southwest Washington in the northwest United States. Primary (survey) and secondary (health plan records of service use; diagnoses from medical chart review) data were collected for random samples of health plan members in the period 1989-1993 (n = 5,669). Health plan administrative records of service use were used to estimate health care costs. Gender-specific latent structure models predicting health care costs were created using self-reported mental health, physical health, functioning, alcohol consumption, and prior-year health plan record-based diagnoses of depression and alcohol problems. RESULTS Alcohol consumption and prior alcohol problems were directly related to health care costs, although in opposite directions, for both men and women. Alcohol consumption was negatively associated with costs, while prior alcohol problems predicted higher costs. Gender differences existed in the relationship between physical health and health care costs indirectly via drinking status. Prior depression had direct effects on increased health care costs, and this relationship was stronger for men than for women. The roles played by mental health symptoms were similar for men and women. Better mental health at the time of the survey was associated with reduced alcohol consumption or likelihood of consuming alcohol, but had no direct effects on later costs. Indirect effects of mental health were found via alcohol consumption. CONCLUSIONS Gender plays an important role in the factors underlying total costs of health care, and gender differences in these relationships appear more common among those who consume alcohol. For both genders, alcohol use predicts lower health care costs in this light-to-moderate drinking population, although prior diagnoses of alcohol problems predict higher costs. The direct relationship between depression diagnosis and higher health care costs is stronger among men.