Patterns of health services use associated with Veterans Affairs outpatient substance-use treatment

This study examined service use and costs associated with receiving intensive outpatient (IOP) substance-use treatment.

Veterans Affairs national databases were used to identify all veterans receiving IOP substance-use treatment in fiscal year (FY) 1999. Changes in the use of health services (2 years pretreatment compared with 2 years posttreatment) were examined. Three IOP treatment groups were defined: (1) veterans attending 1-5 IOP visits (n=2,384), (2) 6-14 IOP visits (n=2,940), and (3) >or= 15 IOP visits (n=3,005). In addition, a demographically matched no-treatment group was defined as veterans in primary care with a substance-use diagnosis and no substance-use treatment in FY 1999 (n = 7,328). General medical, psychiatric, and substance-use encounters in inpatient and outpatient settings were retrieved for the 4 years. Generalized estimating equations analyses were used to compare changes in service use across the three IOP groups controlling for demographic characteristics and comorbidity.

Total outpatient visits increased in all three treatment groups after IOP, with the largest increase observed in the group with >or= 15 visits (mean visits = 5, 44, and 57, respectively). In comparison, total visits decreased in the no-treatment group (-7). This pattern was similar across settings (general medical, psychiatric, and substance use). Total inpatient days decreased among the four groups, with the no-treatment group having the least amount of decrease (mean change in days = .34, .32, .18, and .03, respectively). Analysis of cost data showed similar findings.

Results indicated that more intense IOP treatment is associated with increases in subsequent psychiatric, substance-use, medical, and total outpatient care and decreases in expensive inpatient care.