Background: Pediatric bipolar disorder (PBD) is a severe, chronic illness and it is a significant cause of suffering and disability. Atypical antipsychotics are commonly used to treat PBD, but the economic and health outcomes of atypical antipsychotic treatment have been extraordinarily understudied. Major objectives for this dissertation are to evaluate the evolving pattern of drug utilization in children and adolescents with bipolar disorder (BD) and to assess the difference in health care utilization and costs between children and adolescents treated with and without atypical antipsychotics.
Methods: The study design was a retrospective cohort data analysis of the PharMetrics, a large longitudinal national managed care claims database from 1998 to 2002. The study population included 19,325 youths (7≤age≤18) with a bipolar diagnosis indicated by ICD9 codes. Of those, a total of 488 patients who received atypical antipsychotic (ATYP) monotherapy treatment, 1784 patients who received mood stabilizer (MS) monotherapy treatment, and 1182 patients who received atypical antipsychotic-mood stabilizer (ATYP-MS) combination therapy were identified. Propensity scores were used to control for the selection bias inherent in drug treatment selection. Six months of follow-up health care utilization and costs data were compared between propensity-score matched groups using paired t-tests.
Results: The prevalence of atypical antipsychotic use increased from 13.23 prescriptions per 100 recipients per quarter to 63.12 prescriptions per 100 recipients per quarter during the study period. Compare to MS monotherapy subjects, ATYP monotherapy subjects had fewer bipolar-related physician office visits (p=0.0093) and bipolar-related outpatient hospitalization visits (p=0.034) but similar bipolar-related days of hospitalization (p=0.24), and bipolar-related emergency department visits (p=0.23). ATYP-MS combination therapy subjects had more health utilization like bipolar-related physician office visits (p<0.0001), bipolar-related outpatient hospitalization visits (p<0.0001), bipolar-related days of hospitalization (p<0.0001), and bipolar-related emergency department visits (p=0.049), and higher health care costs like bipolar-related physician office visits (p=0.00020), bipolar-related outpatient hospitalization visits (p=0.0026), bipolar-related inpatient hospitalizations (p<0.0001), as well as total health care costs (p<0.0001).
Conclusions: Over the five years 1998-2002, off-label use of atypical antipsychotics had established itself as one of the treatments for PBD. The results showed that ATYP monotherapy has comparable economic and health outcomes versus standard MS monotherapy, while ATYP-MS combination therapy may be reserved for severe PBD patients. The future study is warranted to focus on clinical consequences of treating BD and other mental health conditions using atypical antipsychotics.