Among those receiving HAART, our study found that relative to those with no mental illness, the adjusted hazard probability for discontinuation of HAART was significantly lower during the first and second years following initiation of HAART among those with SMI and significantly lower during the first year among those with depressive disorders. The probabilities did not significantly differ in years 3 and 4 among any of the diagnostic groups. These findings suggest that among those receiving HAART, those with mental illness are significantly more likely to stay in clinic care in the early years of HAART treatment, a critical time when adherence to HAART may have the most clinical impact.
In order to further evaluate why those with mental illness may be more likely to remain on HAART, we evaluated whether the number of mental health visits impacted the rates of discontinuation of HAART. We found that among those with a mental illness, patients with six to 11 mental health visits in a year were 22% less likely to discontinue HAART, whereas those with 12 or more mental health visits in a year were 40% less likely to discontinue HAART compared with patients with no mental health visits. The frequency of visits compares well with other studies that have found the median number of treatment visits for mental health problems in general to be 7.4 visits per year [22
] and for depression in particular the mean number of treatment visits to be 8.7 visits per year [23
]. Our findings suggest that a dose-response relationship may exist, such that patients with ongoing mental health treatment with consistent and frequent follow-up benefited the most. In contrast, those patients who were seen less consistently, those receiving five or fewer mental health visits in a year were no more likely to discontinue HAART compared with those without a mental illness. Those receiving only one mental health visit in a year in fact were significantly more likely to discontinue HAART compared with those with no mental health visits. This latter group may represent patients who had the most difficulty engaging in mental healthcare and may require more careful follow-up from their HIV providers. Finally, our results raise the interesting possibility that the increased contact and support associated with reduced HAART discontinuation that we found in our study may be found among patients without significant psychiatric conditions as well.
Our findings build on previous findings from other studies. For example, results from the Women’s Interagency HIV Study (WIHS) cohort found that after controlling for depression those who used mental health services had 20% increase in the adjusted odds of utilizing HAART as compared with those who did not use mental health services [12
]. Data from HIV Cost and Services Utilization Study (HCSUS) found that among HIV-infected individuals with a psychiatric disorder, the presence of care from a psychiatric health provider was significantly associated with a 50% increase in the odds of receiving HAART [24
]. It also builds on evidence that suggests that receipt of mental health treatment may increase the probability that individuals with psychiatric disorders receive and adhere to HAART [18
Our study is also among the first to demonstrate that those with SMI were less likely to discontinue HAART compared with those without mental illness. This finding builds on earlier cross-sectional evidence that suggests that those with SMI are as likely to initiate or access HAART compared with those without SMI [17
]. It is also consistent with evidence that providers are willing to consider prescribing HAART to individuals with schizophrenia who are receiving psychiatric care [28
]. It is possible that those with SMI may benefit from receiving colocated HIV and mental healthcare (as was the case in this study) that may result in improved treatment coordination and adherence to HAART [29
]. This association may be supported by the mental health visit data presented above as well as some [30
] but not all [32
] previous studies evaluating use of non-HIV somatic healthcare by those with SMI.
Our finding that those with depressive disorders who receive mental health treatment are less likely to discontinue HAART is consistent with other studies. One retrospective study in an urban clinic with integrated mental healthcare found that compared with HAART-naïve individuals with AIDS without a mental disorder, those HAART-naïve individuals with AIDS with a mental disorder who were receiving mental health treatment were 50% more likely to receive HAART, had over twice the odds of remaining on HAART for at least 6 months, and were 40% more likely to survive through the study period [11
]. Another study [33
] found among a sample of HIV-infected patients receiving HIV medical care in one of eight clinics in five American southern states that having depressive symptoms was not associated with time to discontinuation of antiretroviral therapy. Finally, a study [18
] of patients in the University of Washington HIV Cohort found that there was no delay in HAART initiation among those patients who received treatment for depression/anxiety compared with those with no mental disorders. However, it is important to note that in the absence of mental health treatment, symptoms of depression have been reported to be associated with poor adherence to HAART [8
Our study has several important limitations. First, the sample is not nationally representative and does not generalize to all HIV care sites. The sites in the sample do encompass a geographic distribution that is in keeping with the HIV epidemic, and multisite studies afford greater generalizeability than single-site studies. Moreover, the sites in the HIVRN were all highly experienced in the treatment of HIV with high rates of HAART [34
] and opportunistic infection prophylaxis rates [35
]; results may differ at sites with less provider experience with HIV or a smaller caseload of patients with HIV. Also, not all of the sites in the HIVRN collect comprehensive mental health and utilization data; therefore, we were only able to include five of the 17 adult sites in the Network. However, these five sites represent nearly 40% of the total patients captured by the HIVRN. As these sites have the capacity to provide mental health data, they may be more likely to provide a higher level of care for individuals with cooccurring mental health and substance abuse disorders. Third, as our definition of SMA was based on ICD-9 codes and not based on patient clinical interviews, we were unable to confirm the validity of the diagnoses. Furthermore, the ICD-9 codes reflect use of psychiatric services provided within the clinic and does not capture use of mental health services provided outside of the clinic. As all the clinics have onsite psychiatric services, it is unlikely that many patients seek mental healthcare outside the clinic. Fourth, in this analysis, we assumed that the majority of patients who dropped out of care at the HIVRN clinic also discontinued HAART. Although this assumption has considerable face validity, we are not aware of any published data that fully support this assumption.
Among those who initiate HAART, individuals with mental illness were significantly less likely to discontinue HAART or clinical care in the first and second years relative to those without mental illness. Mental health visits were associated with decreased risk of discontinuing HAART, suggesting the importance of ongoing and consistent mental health treatment among HIV-positive people with cooccurring mental health conditions.