The Post-Stroke Depression Risk Scale (PoStDeRiS): Development of an Acute-Phase Prediction Model for Depression 6 Months After Stroke.

Background: Depression after stroke is common but often undertreated as increasing depression prevalence and decreasing health care contacts diverge after the event.

Objective: To develop an acute-phase prediction scale for prognosis of depression 6 months after stroke.

Methods: Participants (N = 226) were consecutively recruited and assessed within the first week after ischemic stroke for history of depression, stroke severity (National Institutes of Health Stroke Scale), and functional independence (Barthel Index). Early depressive symptoms were self-reported via the Patient Health Questionnaire-2 and external-rated by nurses via the Signs of Depression Scale. Six months later, 183 participants were assessed for Diagnostic and Statistical Manual of Mental Disorders, 5th edition diagnosis of depression. Significant predictors of depression were identified in multivariate logistic regression analysis and their coefficients transformed into a risk scale. Measurement precision was identified using receiver operating characteristic curve analysis.

Results: Depression was diagnosed in 32 (17.5%) participants 6 months after stroke. History of depression, the Barthel Index, and the Patient Health Questionnaire-2 were significant predictors of depression. Transformation of the coefficients yielded the Post-Stroke Depression Risk Scale that demonstrated good discrimination (area under the receiver operating characteristic curve = 0.84; 95% confidence interval = 0.78/0.90). The optimum cutoff showed a sensitivity of 0.81, a specificity of 0.72, a positive predictive value of 0.38, and a negative predictive value of 0.95.

Conclusions: The Post-Stroke Depression Risk Scale accurately identifies people in the acute phase with low risk of depression 6 months later. While the sensitivity indicates that recognition of people with later depression is adequate, positive results in the acute phase show low predictivity. Clinical and methodological reasons for these results as well as implications for future research to increase case-finding ability are discussed.