Costs of physical and mental comorbidities among employees: a comparison of those with and without bipolar disorder.

OBJECTIVE

To compare the cost and utilization of health care services for various comorbid conditions among employees with bipolar disorder (BPD) and two other population cohorts: employees without BPD and employees with other mental disorders (OMD).

METHODS

Retrospective database analysis on a 2-year study period, from January 1, 2001, through December 31, 2002 using adjudicated health insurance medical claims on more than 230 000 employees plus their eligible dependents. Study comparisons were performed among employees with BPD (cohort BPD), employees without BPD (cohort NBD), and employees with OMD (cohort OMD). Outcome measures included the cost and utilization of health services for various comorbid conditions as defined by the Agency for Healthcare Research and Quality (AHRQ); using 261 specific categories (SCs) and the 17 Major Diagnostic Categories (MDCs).

RESULTS

Employees in cohort BPD (n = 761) had greater average annual medical and prescription drug costs than the two other employee cohorts. Costs for cohort BPD were significantly greater (p <or= 0.05) than for cohort NBD (n = 229 145) for six of the 17 MDCs, including the categories of mental disorders (2036 dollars vs. 65 dollars), injury and poisoning (544 dollars vs. 162 dollars), musculoskeletal/connective tissue (607 dollars vs. 315 dollars), other conditions (274 dollars vs. 134 dollars), respiratory system (217 dollars vs. 104 dollars), and nervous system/sensory organs (225 dollars vs. 119 dollars). Similarly, comparisons across AHRQ's 261 SCs found the annual medical costs associated with BPD were greater in 137 (52%) of the 261 categories. Differences between cohort BPD and cohort OMD (n = 26 776) were significant (p <or= 0.05) in three MDCs, with BPD 3.4 times greater than OMD in the mental disorders category: 2036 dollars vs. 596 dollars, respectively.

CONCLUSION

Employees with BPD have greater cost and utilization of services due to various mental and physical comorbidities than either employees without BPD or employees with OMD. The findings are consistent with current literature concerning the comorbidities associated with BPD, and suggest that further longitudinal and observational investigation is necessary to attempt to improve diagnosis and treatment of not only BPD, but also associated targeted diseases commonly found in employees with BPD.