Direct costs of bipolar disorder versus other chronic conditions: an employer-based health plan analysis.

OBJECTIVE: This study was a retrospective data-based analysis of health care utilization and costs for patients diagnosed as having bipolar disorder compared with patients with diagnoses of depression, diabetes, coronary artery disease, or asthma.
METHODS: Data were from an employer-based health plan. Consistent diagnosis and continuous enrollment from 2004 to 2007 were used to identify the study population (total N = 7,511), including those with bipolar disorder (N = 122), depression (N = 1,290), asthma (N = 2,770), coronary artery disease (N = 1,759), diabetes (N = 1,418), and diabetes with coronary artery disease (N = 455). Resource utilization quantified as cost (total, specialty care, psychiatric outpatient) and number of visits (specialty care and outpatient psychiatric care) was compared across groups.
RESULTS: Patients with bipolar disorder had higher adjusted mean per member per month (PMPM) costs than any other comparison group except for those with both diabetes and coronary artery disease. The cost was predominantly related to pharmacy costs and both inpatient and outpatient psychiatric care. A subset of 20% of patients with bipolar disorder accounted for 64% of the total costs. This subgroup of patients was more likely to be female, to have frequent hospital stays, and to have a higher number of comorbidities. Depressed patients, in contrast to bipolar disorder patients, had higher adjusted mean PMPM costs in primary care and nonpsychiatric inpatient costs.
CONCLUSIONS: Health care costs for bipolar disorder exceeded those for several common chronic illnesses. These data provide further evidence for employers, insurers, and providers to seek innovative models to deliver effective and efficient care to individuals with bipolar illness.