Methods: A retrospective longitudinal cohort study examined the Medicaid enrollment patterns for a cohort of people with SMI over a four-year time period (2007-2010). This cohort included 9,676 adults with SMI, ages 18-61, living in a large metropolitan area in the Midwest. The mean age of participants was 40.3 (SD = 11.3). Six-three percent of participants were women, 48% were black, and 69% were single. Thirty-nine percent of participants had a primary diagnosis of schizophrenia, 33% major depression, 19% bipolar disorder, and 10% anxiety disorder. Descriptive statistics, logistic regression, and negative binomial models were used to examine the association between gaps in Medicaid enrollment and service use patterns. Interaction effects between mental health diagnosis and behavioral health service use were explored.
Results: Logistic models found that individuals with 1 gap were 76% (B=.57, p<.000) more likely to receive any acute care and that individuals with 2 or more gaps were 183% (B=1.04, p<.000) more likely to receive any acute care than those continuously enrolled during the study period. The number of outpatient days used and case management days used were statistically significant, but relatively weak predictors of acute care use (B =.002, p<.003; B =.002, p<.000). Individuals with 1 enrollment gap received 22% (B =-0.25, p<.000) fewer outpatient service days and individuals with 2 or more gaps received 32% (B=-0.39, p<.000) fewer outpatient days than did those continuously enrolled. Mental health diagnosis did not moderate the relationship between enrollment gap category and receipt of any acute care or outpatient services, nor did it moderate the relationship between gap category and number of outpatient days received.
Conclusion/Implications: Previous research has shown that gaps in Medicaid coverage are associated with increased acute care use for people with SMI. The current analysis established this correlation across a wider range of mental health diagnoses and additionally examined outpatient and case management service use patterns in a cohort of individuals with SMI. Individuals who received more outpatient and case management services did not have lower odds of receiving acute care services. These findings suggest that efforts to effectively reduce acute care use may need to address factors beyond outpatient service engagement and Medicaid enrollment stability. Rather, the factors that predict lapses in Medicaid coverage may also contribute to increased acute care utilization and decreased outpatient service engagement. Possible explanations for acute care use may include symptom severity, inability to meet care needs through existing outpatient services (e.g. limited access to afterhours care), or other confounding factors. Future research is needed to explore the complexities of these relationships.