HEALTHCARE COST-BENEFITS ASSOCIATED WITH ANTIDEPRESSANT PHARMACOTHERAPY, OR PHARMACOTHERAPY PLUS PSYCHOTHERAPY, IN PATIENTS WITH TYPE II DIABETES MELLITUS AND COMORBID DEPRESSION IN THE U.S., 2002-2003

Depression and type II diabetes mellitus (T2DM) are costly and chronic conditions. This study investigated depression treatment, i.e., antidepressant pharmacotherapy (AP) or pharmacotherapy plus psychotherapy (AP+P), and associated healthcare costs and utilization in a real-world setting for patients with comorbid T2DM. We hypothesized that patients who initiate depression treatment should have a reduction in healthcare costs compared to a 12-month pre-period with no depression treatment. Further, the specific costs for emergency department (ED) visits should decrease with depression treatment. We also hypothesized that patients in the AP and AP+P groups would show a cost-benefit once receiving treatment for depression. This was a retrospective study using claims data from the ThomsonReuters MarketScan® Research Database for privately insured patients during the calendar year 2002-2003. The study cohorts, n = 927 per group, were created using propensity score matching and analyzed with multivariate statistical methodologies. We calculated benefit-cost ratios (BCR) for healthcare costs during the 12-month post-period. The mean number of outpatient visits for T2DM-related healthcare increased for the AP+P from 10.1 per patient in the pre-period to 16.1 in the post-period. Medication adherence was higher for the AP group with odds ratio for nonadherence 1.88, 99% CIs [1.26, 2.69] for the AP+P group. Total depression-related treatment cost for the AP group, was $1,101 (SD = $885) and for the AP+P group it was $905 (SD = $3,108) per patient. We found a statistically significant decrease in T2DM-realted inpatient costs for the AP+P group with $675 (SD = $807) per patient in the post-period. However, the outpatient costs increased by $688 (SD = $510). The results of the BCR indicated that the total amount of dollars invested for depression treatment was greater than the total cost difference, i.e. savings, for all other healthcare services and for services for T2DM for both the AP and the AP+P group. Following treatment selection of AP or AP+P, patients with depression and T2DM had very few statistically significant differences. However, patient selection of AP+P may enhance health-related benefits by increasing T2DM outpatient visits that incorporate preventative care and consequently resulted in the reduction of amputation and renal disease compared to the AP group. Conversely, the AP group had a significantly higher rate of medication adherence compared with the AP+P group. Higher medication adherence may have resulted in the AP group's reduction of hypertensive disease, a medical comorbidity typically treated with medication. Limitations in our study included the general issues with claims data research including interpretation of coding, and generalizability of our sample to the population. Despite the limitations, this study provided a broad view of the year following initiation into depression treatment. The results indicated that treatment for depression influences not just depression, but comorbid chronic conditions such as T2DM. The present study highlights the continued need for research in the integration of healthcare services in order to reduce costs, improve health and potentially augment quality of life.