Background: Although poststroke depression has a significant impact on a patient's ability to recover after stroke, it is generally not recognized. Structured screening can help nurses identify symptoms of depression in stroke patients. In clinical practice, the utility of an instrument is as importantas its validity and reliability.
Objective: To investigate the reliability, validity, and clinical utility of the nine-item and two-item patient health questionnaires (PHQ-9 and PHQ-2, respectively) in stroke patients in a clinical nursing setting. The results of these questionnaires will be compared against those from the Geriatric Depression Scale.
Methods: The PHQ-9 was administered by 43 ward nurses in 55 patients with an intracerebral hemorrhage or ischemic infarction who were able to communicate adequately. The interrater reliability, test-retest reliability and internal consistency, concurrent validity, diagnostic accuracy, and clinical utility were evaluated.
Results: The interrater reliability (intraclass correlation [ICC] = 0.98, 95% CI [0.96, 0.99]), test-retest reliability (ρ(Sp) = 0.75, p < .001), and internal consistency (Cronbach's α = 0.79) of the PHQ-9 were good. The concurrent validity was moderate for the PHQ-9, with a Pearson's correlation of .7 (p < .001) and acceptable for the PHQ-2 with a Pearson's correlation of .8 (p < .01). The optimum cutoff point of the PHQ-9 for major depression was 10 (sensitivity, 100%; specificity,86%; positive predicted value, 50%; and negative predicted value, 100%). For the PHQ-2, the optimum cutoff point was 2 (sensitivity, 100%; specificity, 77%; positive predicted value, 38%; and negative predicted value, 100%).
Discussion: The PHQ is a brief and easy-to-use instrument for nursing practice. It shows good reliability, validity, and clinical utility when used in stroke patients who are able to communicate adequately.