National estimates of the inpatient burden of pediatric bipolar disorder in the United States.

BACKGROUND Pediatric bipolar disorder (BPD) is a debilitating recurrent chronic mental illness, characterized by cycling states of depression, mania, hypomania, and mixed episodes. Similarly to adults, children and adolescents with BPD are typically treated with pharmacotherapy and adjunctive psychotherapy. Nevertheless, emergency-room visits and hospitalizations are common for those suffering from pediatric BPD. Previous studies have shown declining trends in mean inpatient costs and length of stay (LOS) in the hospital for children with BPD. AIMS The objectives of this study were to calculate national estimates of the annual burden of inpatient hospitalizations of children and adolescents with BPD in the United States; to describe and compare the mean burden across various patient characteristics, hospital characteristics, and key comorbidities associated with BPD; and to determine the independent effects of these factors on hospitalization costs. METHODS Hospitalizations for children and adolescents whose primary diagnosis was BPD were selected from the Kids' Inpatient Database (KID) in 2003 and 2006. The burden for each year was estimated as total number of days in the hospital and total costs. Mean costs were calculated overall and for subpopulations identified by patient and hospital characteristics and by the top six comorbidities found for BPD. Ordinary-least-squares regression models explaining cost were estimated for both 2003 and 2006, and the models were compared by way of a Chow statistical test. RESULTS There were 39,136 (40,679) BPD in hospitalizations in 2003 (2006), with total associated costs of USD 176 (USD 233) million in 2003 (2006). The mean cost was USD 4,490 (USD 5,725), while the mean LOS was 8.12 (8.99) days in 2003 (2006). Factors associated with higher cost included youth (younger than 13), being black, being from a high-income family, having many diagnoses, being insured by Medicaid, living in the North East or West regions of the country, and having a long hospital stay. Post-traumatic stress disorder and oppositional defiant disorder were associated with higher costs in 2006. DISCUSSION Declining trends in mean cost and LOS, documented in previous studies for children with BPD, persisted into 2003 but showed a slight reversal by 2006. Over the three years, mean LOS rose by a little less than one day, while mean cost (not adjusted for inflation) rose by USD 1,235. Children and adolescents insured through Medicaid tended to stay in the hospital longer and have higher costs than those children who were privately insured. IMPLICATIONS FOR HEALTH POLICIES Due to relatively few expensive inpatient procedures for BPD patients, pediatric BPD hospitalizations, relative to hospitalizations overall, were significantly more burdensome on average in terms of days spent in the hospital than in terms of cost. To the extent that early detection of the disease along with appropriate outpatient treatment can be achieved, there could be significant reductions in the risk of hospitalizations for children with BPD. IMPLICATIONS FOR FURTHER RESEARCH Further studies should be conducted to determine if average LOS and mean hospitalization cost remain consistent with declining trends or whether the increase between 2003 and 2006 represents a trend reversal.