Case finding of lifestyle and mental health disorders in primary care: validation of the 'CHAT' tool.

BACKGROUND Primary care is accessible and ideally placed for case finding of patients with lifestyle and mental health risk factors and subsequent intervention. The short self-administered Case-finding and Help Assessment Tool (CHAT) was developed for lifestyle and mental health assessment of adult patients in primary health care. This tool checks for tobacco use, alcohol and other drug misuse, problem gambling, depression, anxiety and stress, abuse, anger problems, inactivity, and eating disorders. It is well accepted by patients, GPs and nurses. AIM To assess criterion-based validity of CHAT against a composite gold standard. DESIGN OF STUDY Conducted according to the Standards for Reporting of Diagnostic Accuracy statement for diagnostic tests. SETTING Primary care practices in Auckland, New Zealand. METHOD One thousand consecutive adult patients completed CHAT and a composite gold standard. Sensitivities, specificities, positive and negative predictive values, and likelihood ratios were calculated. RESULTS Response rates for each item ranged from 79.6 to 99.8%. CHAT was sensitive and specific for almost all issues screened, except exercise and eating disorders. Sensitivity ranged from 96% (95% confidence interval [CI] = 87 to 99%) for major depression to 26% (95% CI = 22 to 30%) for exercise. Specificity ranged from 97% (95% CI = 96 to 98%) for problem gambling and problem drug use to 40% (95% CI = 36 to 45%) for exercise. All had high likelihood ratios (3-30), except exercise and eating disorders. CONCLUSION CHAT is a valid and acceptable case-finding tool for most common lifestyle and mental health conditions.