The clinical history and costs associated with delayed diagnosis of bipolar disorder.

The purpose of this reported study was to determine healthcare utilization and costs associated with delayed diagnosis of bipolar disorder. With use of automated data from a large integrated health system in the Midwest, all patients with newly diagnosed bipolar disorder recorded in any inpatient or outpatient encounter from January 1, 2000 to August 31, 2002 were identified. The date of initial diagnosis was the index date. For each patient in the bipolar cohort, 5 comparison patients were randomly selected from the general population of health system members and matched with the bipolar patients by sex, race, and age (-/+ 5 years). Data on healthcare utilization (inpatient, outpatient, emergency department, pharmacy) were collected with a focus on mental health, from January 1, 1990, through 1 year after the index date. The cohort is 62% female and 64% White. Median time between initial mental health diagnosis and bipolar diagnosis was 21 months, with 33% of subjects receiving a bipolar diagnosis within 6 months of their initial mental health diagnosis; however, for 31% of the remaining bipolar subjects, the time of their initial mental health presentation to bipolar diagnosis was 4 years or more. The number and duration of treatment with antidepressants increased as time to bipolar diagnosis increased. Patients with bipolar disorder had at least twice the number of interactions with the healthcare system before the index date than the non-bipolar comparison group. Mean monthly costs before and after bipolar diagnosis were not strikingly different for patients with bipolar disorder, but costs after bipolar diagnosis increased with increasing time to bipolar diagnosis. Bipolar disorder is a costly illness for which the impact on the healthcare system may vary depending on how quickly it is diagnosed. Delays in diagnosis appear related to additional costs after diagnosis.