The effect of alcoholism treatment on medical care use

The objective of this study was to assess changes in outpatient and inpatient medical care utilization associated with outpatient and inpatient treatment of alcohol abuse by comparing alcoholics who engaged in treatment to alcoholics who presented for, but did not engage in, treatment.

Claims and encounter data of 29,122 adults receiving benefits from both a behavioral managed care company and its parent medical care insurance company who had a diagnosis of alcoholism were analyzed. The nontreated alcoholics in this sample (n = 13,133) were used for comparison and to control for historical time trend in medical utilization across the study years 1993-1999. A longitudinal over-dispersed Poisson regression model was fit by the generalized estimating equation method to compare differences in medical utilization before and after outpatient and inpatient alcoholism treatment.

The pattern of medical utilization before and after alcoholism treatment appears basically symmetric. There is a gradual increase, which accelerates in the year before treatment and then falls off rapidly for the first year after treatment and then falls more gradually. Such a pattern does not suggest any net savings over time. The area under the curve before treatment is basically equivalent to that after treatment. Slopes of medical utilization for both treatment groups before 1 year before treatment were statistically similar to the control groups, but during 1 year before treatment, both treatment groups' outpatient utilization increased 1.25% and inpatient utilization increased 1.8% relative to the nontreated group. The slopes posttreatment showed differential effects over time of inpatient versus outpatient alcoholism treatment on inpatient and outpatient medical utilization.

Although a clear increase in medical utilization before treatment and a decrease in utilization after treatment was found, it is not clear if the change is linked to changes in the status of the individuals as they prepare to enter alcoholism treatment or if there is a real causal effect of the alcoholism treatment.