Tapping into the dataset, Valuck described the Distributed Ambulatory Research in Therapeutics Network (DARTNet). DARTNet is a federally supported network of electronic health data created to promote comparative effectiveness research. The database already covers 500,000 individuals (without identifiers). Because of the nature of data acquisition, and lack of possibility of random allocation, it has limitations. But the dataset is highly useful because its patients represent the “real world” of treatment, rather than the exacting standards of treatment necessary for randomized controlled trials. It includes primary care, where, Valuck noted, 50 percent of depression care is rendered.

The database has not yet been used to study suicidality, but it does offer potential for such study, especially for conduct of prospective cohort studies. It also facilitates the conduct of retrospective and case-control studies. Within each of its more than 500 sites of clinical practice, it captures a broad mix of patient-level information (e.g., vital signs, social history, family history) from electronic health records, laboratory tests, imaging results, pharmacy use databases, and billing systems (e.g., Medicaid and Department of Veterans Affairs). The data can be used to determine if patients actually fill prescriptions, for example. The system does have drawbacks: lack of severity data, unmeasured covariates, and unvalidated outcomes, among others.

Valuck and colleagues, drawing from another dataset, conducted a large nested case-control study of suicide attempts using claims data from managed care organizations (Valuck et al., 2009). Although claims data are not ideal, the study examined 10,500 suicide attempters over the period 1999 to 2006 against nearly 42,000 controls. After controlling for confounders related to depression severity, antidepressants were shown to protect against a suicide attempt, while antidepressant discontinuation was a significant risk factor for having a suicide attempt. Nevertheless, the study did show that the highest risk of a suicide attempt was indeed associated with the initiation of treatment, which is a finding consistent with other studies.

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