Medical comorbidity and healthcare expenditures among people with severe mental illness

Background and Purpose: It is of concern to mental health policy makers that people with severe mental illness receive appropriate and equitable care for their comorbid health conditions. People with severe mental illness have higher rates of physical health conditions when compared to the general population. Previous studies also show that the mortality rate of people with severe mental illness is two or three times greater than that of the general population. About 60% of this excess mortality for people with severe mental illness has been reported to be the result of physical health conditions. Using a nationally representative sample, this study examined the extent to which comorbid medical conditions were associated with healthcare expenditures among people with severe mental illness.

Methods: Data were obtained from the 2007 Medical Expenditure Panel Survey (MEPS). The sample consisted of 13,185 adults (ages 18-64), which included 239 individuals with severe mental illness (ICD-9 codes: 295 or 296), 2,601 individuals with other mental illness, and 10,345 individuals without mental illness. Physical health conditions were identified through ICD-9 codes and then classified into diagnostic groups by using the Elixhauser index. Expenditures were compared among people with severe mental illness, people with other mental illness, and people without mental illness. Guided by the Andersen's behavioral model of health service use, a series of OLS regression models were conducted.

Results: Total healthcare expenditure for people with severe mental illness was about 2.9 times greater than that of people without mental illness ($10588 vs. $3633, respectively), and 1.6 times greater than that of people with mental illness ($10588 vs. $6733, respectively). About 39% of the individuals with severe mental illness had two or more health conditions, while about 59% of the individuals without mental illness had no health condition. With each additional physical health condition, the total healthcare expenditure for people with severe mental illness increased by 49.2%, which is approximately $5290. The additional cost burden per medical condition was $4255 for people with other mental illness, and $2921 for people without mental illness.

Conclusions: Further research considerations are an examination of the degree to which higher healthcare costs may be associated with the timeliness of seeking treatment. Persons with mental disorders may not receive preventive care or early intervention resulting in receiving more costly care later in their disease process. Also, the quality of the care received may differ resulting in higher crisis related costs.