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OBJECTIVE: To characterize the prevalence and predictors of diagnosed depression among persons with HIV on Medicaid and antidepressant treatment among those diagnosed, and to compare utilization and costs between depressed HIV-infected individuals treated with and without antidepressant medications.
DESIGN: Merged Medicaid and surveillance data were used to compare health services utilized by depressed individuals who were or were not treated with antidepressant medications, controlling for other characteristics.
SETTING AND PARTICIPANTS: The study population comprised Medicaid recipients in New Jersey who were diagnosed with HIV or AIDS by March 1996 and received Medicaid services between 1991 and 1996.
MEASUREMENTS AND MAIN RESULTS: Logistic regression and ordinary least squares regressions were employed. Women were more likely and African Americans were less likely to be diagnosed with depression. Women and drug users in treatment were more likely to receive antidepressant treatment. Depressed patients treated with antidepressants were more likely to receive antiretroviral treatment than those not treated with antidepressants. Monthly total expenditures were significantly lower for individuals diagnosed with depression and receiving antidepressant therapy than for those not treated with antidepressants. After controlling for socioeconomic and clinical characteristics, treatment with antidepressant medications was associated with a 24% reduction in monthly total health care costs.
CONCLUSIONS: Depressed HIV-infected patients treated with antidepressants were more likely than untreated subjects to receive appropriate care for their HIV disease. Antidepressant therapy for treatment of depression is associated with a significantly lower monthly cost of medical care services.
Depression is a major health risk for the HIV-infected 1,2 and is associated with declines in immune function, 3,4 acceleration of the course of disease progression, 5 increased disability and lower quality of life, 6 shorter survival, 7 and greater probability of dying. 8 However, data on treatment of depression among HIV-infected patients paint a distinctly hopeful picture. Many efficacy studies have concluded that the symptoms of carefully selected depressed HIV-infected patients are reduced by a variety of antidepressants. 9–14 Though it has been suggested that depressive symptoms and depressive disorders accompanying medical illness often lead to higher rates of health care utilization, 15–18 recent studies have found reductions in the costs of health care due to treatment of depression. 19,20 Prior research also suggests that antidepressant treatment failure is associated with an increase in health service expenditures, 21 and discontinuation of use of antidepressants is associated with increased overall costs of medical care. 22 However, findings of medical cost being offset by mental health care are far from universal. 23 For example, providing mental health consultation to psychologically distressed patients who are high users of medical services does not reduce utilization. 24
Previous studies of HIV-infected individuals, however, have not elucidated the effectiveness of antidepressant treatment in broader community practice. Findings from controlled trials may not be readily generalizable to hard-to-treat sectors of the HIV-infected population, particularly those on Medicaid who are poor, socially marginal, and have multiple medical or substance abuse comorbidities. Medicaid recipients represent a vulnerable population with restricted access to quality mental health care. 25 Furthermore, to date, no study has investigated the relation between antidepressant treatment and health service utilization among depressed HIV-infected patients. Such knowledge is vital to program and policy development in the era of managed care, particularly since several states are developing specialized capitated managed care programs to provide comprehensive care for special needs populations such as those with HIV. 26
This article builds on prior research by investigating the incidence of depression and the impact of antidepressant treatment on use of medical services among persons with HIV diagnosed with depression. We examine depression and treatment of depression among Medicaid beneficiaries with HIV/AIDS and explore the relation between antidepressant treatment and use of medical care services among those diagnosed with depression.
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The prevalence of diagnosed depression we found was in the range found by others studying depression and HIV. 1 As in virtually all studies of depression, women predominated. 30 Nor is it surprising that non-IDUs and IDUs with no indication of current drug abuse were less likely to be diagnosed with depression, since depression is a common complication of drug abuse. 31 We also found that minorities were underrepresented among those diagnosed with depression, consistent with accumulating evidence that the incidence of depression is greater in whites than African Americans. This pattern has also been found in substance-dependent treatment-seeking groups, in which whites have been found to have higher rates of lifetime major depression. 32 Because we relied on diagnoses associated with care episodes, a difference in diagnosed depression between whites and African Americans could also be influenced by differences in care seeking, access, or quality of care; studies report that African Americans are referred for evaluation of depression and diagnosed with depression less often 33 and are less likely than whites to receive mental health care. 34–36
In this community sample of poor patients with HIV, we found that nearly 40% of patients diagnosed with “depression” did not receive antidepressant prescriptions. Our finding is consistent with studies of primary care in which 40% of primary care visits with a diagnosis of depression did not include prescription of an antidepressant. 37 It is difficult to know from the inspection of claims data what is impeding the prescription of antidepressant medications. When treating HIV-infected patients, some clinicians may view pathologically depressed mood in these patients as “normal” or “reactive.” In some cases, they may fail to target the diagnosed depression because they too quickly attribute fatigue, sleep problems, or difficulty concentrating to HIV or medication side effects, thus failing to appreciate the full impact of depression on functioning. Some clinicians may be disposed to prescribe, but find that patients with HIV/AIDS are reluctant to add antidepressants to what is often a complex medication regimen, or tolerate side effects that may further diminish functioning.
Our findings on the relation of ARV with depression treatment and the cost-effectiveness of treating depression underscore the need for clinicians to devise ways to promote treatment for depression in this group. Although concern exists about older tricyclic antidepressants, 14 several effective options are available that are better tolerated, including selective serotonin reuptake inhibitors, “alternative” antidepressant therapies (e.g., dextroamphetamine or testosterone replacement therapy), 38,39 and interpersonal psychotherapy. 40,41 Care should be taken in selection of a treatment that is easily tolerated and produces rapid clinical response, because one study has found that, compared with a matched seronegative group with depression, the seropositive group was slower to improve with antidepressant improvement. 42 The medical comorbidities associated with the late stages of HIV illness need not rule out treatment, since there are data suggesting that, even for these patients, comorbid depression may be influencing somatic symptoms thought to result from HIV, so that a 6-week trial of antidepressants produced improvement in somatic symptoms. 43
We found that in this population treatments tend to cluster (with one type associated with higher probability of receiving another). For example, among patients diagnosed with depression, patients receiving treatment for depression were more likely than patients not treated for depression to receive a prescription for ARV drugs. Similarly, patients in drug treatment were more likely than patients with current drug abuse and no treatment claims to receive an antidepressant. This pattern could reflect either a patient group's level of involvement with the service delivery system, or the treated group's elevated capacity to seek out health care resources (possibly as a result of treatment), or both. Regular drug treatment may provide more opportunities for mental health care, or patients in drug treatment may take better care of their health. A more nuanced understanding of these processes may reveal opportunities for clinicians to engage socially marginal patients in a network of care.
Our finding that 59% of patients with AIDS received ARV therapy during a 1-year follow-up should be viewed in the context of prevailing clinical practices during the period covered by the study. This figure is lower than with the rate (74%) reported by Smith and Kirking using data from the AIDS Cost and Service Utilization Study. 44 However, lack of precise information on the illness severity of the patients in our population (e.g., CD4 counts) makes it difficult to compare treatment rates in our HIV group with those found in other studies. The absence of an ethnicity effect in the treatment of depression and ARV therapy is notable, since whites have been reported to have some access advantages in general 45 and in among AIDS populations. 46 This absence may reflect special characteristics of the depression subgroup, or it may reflect the documented reduction in ethnicity differences that has occurred in the course of the epidemic. 27
Our study found that antidepressant treatment is associated with lower total health care costs, consistent with earlier research mentioned in the introduction. Given the high levels of disability generally found with depression, an estimation of indirect costs associated with untreated depression (e.g., the hours of labor required of friends and loved ones who provide instrumental support) might further strengthen the economic warrant for treatment.
There are limitations to the inferences that can be drawn from studies such as ours that rely on health care claims data to model outcomes. In studies that compare administrative data files on utilization with information from clinical charts on diagnoses and procedures, 47 good agreement is usually reported, including excellent agreement for major psychiatric disorders 29,48 and associated secondary diagnoses. 49 Reliability of clinical diagnoses has been a problem, however, for more transient or less well-specified conditions, such as depressive disorder, not otherwise classified. 29 Diagnoses (or misdiagnoses) of depression might occur for several reasons such as reimbursement issues, mistaking the symptoms of one disorder for another, or concern regarding stigma. 50 Although we had some measures of disease stage and physical health status such as primary diagnosis and vital status, this study lacked good independent measures of illness severity such as CD4 counts that would have been helpful in interpreting some of our findings.
Our study is based on a single payer (Medicaid) and excludes patients seeking health care outside the Medicaid system, and episodes of care that might occur in a setting not reimbursed by Medicaid (e.g., privately financed or uncompensated care, or services provided in a Veterans Administration hospital). The pattern of depression diagnoses and treatment we report may not be generalizable to the full population with HIV/AIDS, and our cost calculations do not capture expenses incurred outside the Medicaid system. However, HIV-infected individuals tend to be high-cost patients, most have their care financed by Medicaid, and these costs can be expected to grow as improved treatment increases survival rates. Thus, despite the limitations of these naturalistic data, our findings suggest that substantial cost savings may be associated with treatment of depression and point to the need for well-designed intervention studies that control for selection effects and capture medical expenditures, regardless of payment source.
Finally, although our study precedes the era of HAART therapy in treating HIV infection, the results are important because the antiviral drugs included in our study continue to be important components of current HAART regimens. A key policy concern is how to encourage and enable persons to comply with the complex and costly regimens involving protease inhibitors. Given the evidence that patients with a history of depression have significant delays in protease inhibitor initiation, 51 the association between antidepressant treatment and ARV therapy identified in our study supports the value of recognition and treatment of depression for this population.