Long-term Cost Effects of Collaborative Care for Late-life Depression
Published Online: February 15, 2008
Jurgen Unutzer, MD, MPH; Wayne J. Katon, MD; Ming-Yu Fan, PhD; Michael C. Schoenbaum, PhD; Elizabeth H. B. Lin, MD, MPH; Richard D. Della Penna, MD; and Diane Powers, MA
Major depression and dysthymic disorder (chronic depression) are common in older adults. In addition to causing impairment of functioning and quality of life, depression in late life has been associated with substantial increases in total healthcare costs.1,2 The Improving Mood: Promoting Access to Collaborative Treatment (IMPACT) trial3 enrolled 1801 depressed older primary care patients from 8 healthcare systems in a randomized controlled trial of a collaborative care management program for depression compared with care as usual. Participants from each organization were randomly assigned to collaborative care or to care as usual.
Earlier findings from the IMPACT study3 reported that the collaborative care program was substantially more effective than care as usual in reducing depression and in improving physical and social function. Intervention patients continued to have significantly less depression than patients in usual care even at the 24-month follow-up, 12 months after the end of the intervention program.4 Analyses from the IMPACT trial5 found the collaborative care program to be substantially more cost-effective than care as usual. IMPACT participants experienced 107 more depression-free days during a 24-month period than patients assigned to care as usual. During the initial study year, total healthcare costs (including the costs of the IMPACT intervention) were slightly higher among the intervention group than among control subjects, but a slight decrease in costs among the intervention group compared with usual care patients was observed in the second year, suggesting that an initial investment in better depression care may result in long-term cost savings.5
In this article, we report long-term (4-year) effects of collaborative care for late-life depression on total healthcare costs from a payer’s perspective. Our findings are based on cost data available from 2 participating group-model health maintenance organizations.
Detailed information about the methodology, clinical results, and 2- year cost-effectiveness outcomes from the IMPACT trial are reported elsewhere.3,5-7 The institutional review boards of all participating organizations and the study coordinating center approved all study procedures, and all patients provided written informed consent. A waiver of written informed consent for thce use of an additional 2 years of cost data was obtained from the institutional review boards of the 2 participating healthcare organizations (group-model health maintenance organizations in California and Washington) and the study coordinating center.
Enrollment and Dropout
Participants were identified by systematic depression screening or were referred by primary care physicians. Inclusion criteria included being aged 60 years or older, meeting criteria for current major depression or dysthymia on the Structured Clinical Interview for the Diagnostic and Statistical Manual of Mental Disorders (Fourth Edition),8 and planning to continue using 1 of the participating primary care medical offices during the next year. Exclusion criteria included current alcohol abuse, severe cognitive dysfunction, acute risk of suicide, and a history of bipolar disorder or psychosis. Patients were recruited into the study between July 1999 and August 2001. During this time, 2% to 3% of the older population served by the participating medical offices were enrolled in the IMPACT trial.3,6 Eligible patients who agreed to participate in the study were randomly assigned to the IMPACT intervention or to usual care.
The number of dropouts because of death or disenrollment by the end of each year in the 2 centers participating in the present study were 17, 13, 57, and 27, for years 1 through 4, respectively, without significant differences in the number of dropouts between intervention and usual care patients. The resulting sample sizes were 534, 521, 464, and 437 in years 1 through 4, respectively. All available cost information was included in the analyses. For example, if a patient died between year 2 and year 3, this patient’s year 1 and year 2 costs were included in the analyses.
The IMPACT intervention was a 1-year stepped collaborative care program provided by a nurse or a psychologist care manager working in the participant’s primary care clinic to support the patient’s regular primary care clinician. The depression care manager completed an initial biopsychosocial history and provided education about antidepressant medication and psychotherapy treatment options. Care managers used behavioral activation with all patients; in addition, they offered a choice of treatment with an antidepressant medication or with problem-solving treatment in primary care.9-11 Problem-solving treatment in primary care is a 6- to 8-session psychotherapy program designed for primary care patients9-11 that has been found to be as effective as antidepressant medication for treating major depression.10 Depression care managers received training on pharmacotherapy and problem- solving treatment in primary care during a 2-day workshop, including didactic training using a treatment manual11 and role plays, and completed at least 5 videotaped training cases of problem-solving treatment in primary care supervised by a psychologist. The depression care manager participated in weekly supervision under a primary care physician with geriatric expertise and under a psychiatrist to monitor the progress of cases and to adjust treatment plans according to a steppedcare treatment algorithm.6 This algorithm guided acute and continuation therapy, as well as relapse prevention recommendations, during the 12-month treatment period. The depression care manager followed up patients in person or by telephone approximately every 2 weeks during the acutephase treatment and approximately monthly during the continuation phase. At the end of the 12-month intervention period, care managers completed a relapse prevention plan with intervention participants, after which all patients continued in care as usual.
Patients randomly assigned to receive usual care were told that they met the criteria for major depression or dysthymia and were encouraged to follow up with their primary care provider for treatment. The primary care provider was also notified of the diagnosis. Patients with this condition were eligible to receive all treatments routinely provided for depression (antidepressant medication, supportive counseling by their physician, and self- or physician-referral to specialty mental healthcare).
All cost outcome data used for these analyses were obtained from cost-accounting systems of the 2 participating healthcare organizations. These systems track costs of all healthcare delivered directly by the organizations (including overhead costs) and costs of all paid claims for services delivered outside of the organization. They cover costs for all outpatient and inpatient health services, as well as costs for prescription medications provided by or purchased under contract by the participating health maintenance organizations. Cost data cover the period from 1999, the initial year of enrollment, through 2006 (4 years after the last patient was enrolled in the trial). Data for each participant cover a 4-year period beginning with their enrollment in the trial.
For purposes of our analyses, healthcare costs were summarized into the following categories: IMPACT intervention costs (only relevant for the intervention group in year 1), outpatient specialty mental health costs, pharmacy costs (all medications provided by health plan pharmacies), other outpatient costs (outpatient primary care and specialty medical and surgical visits, physical therapy, occupational therapy, urgent care, emergency department care, and other outpatient services), inpatient mental health and substance abuse treatment costs, and inpatient medical costs. Using the same methods as described in the original cost-effectiveness article from the IMPACT trial,5 we estimated the costs of providing the IMPACT intervention based on the following factors: detailed study records of all patient contacts (in person and by telephone), mean salary and benefit costs of depression care managers plus 30% overhead costs to account for such costs as space and administrative support (the same approach used in a similar study12 and to account for the fact that such clinicians cannot be 100% efficient13), the cost of supervision and consultation from team psychiatrists and primary care experts at each site plus 30% overhead costs, and the cost of intervention materials.5
For each cost category, we provide the mean cost during the 4-year period for the intervention and usual care groups. The difference in mean costs between these 2 groups and its 95% confidence interval are provided. We also generated 1000 bootstrap samples to estimate the probability that total healthcare costs were lower in the intervention group than in the usual care group during the 4-year time frame. The probability was estimated by dividing the number of bootstrap samples in which the intervention group had higher total healthcare costs than the usual care group by 1000. The analyses were performed using SAS 9.1 (SAS Institute Inc, Cary, NC).
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