Estimating benefits and harms of screening across subgroups: the Canadian Task Force on Preventive Health Care integrates the GRADE approach and overcomes minor challenges

Abstract Objective This paper describes the integration of the GRADE (Grading of Recommendations Assessment, Development and Evaluation) approach into their clinical preventive guideline development process by the new Canadian Task Force on Preventive Health Care. Study Design The GRADE approach focused the analytic framework and key questions on patient-important benefits and harms related to screening that incorporated detection, treatment, and follow-up. It also led to an explicit consideration of values and preferences and resource implications on the basis of the recommendations. Results There are challenges, however, in incorporating the GRADE approach to clinical prevention, as the randomized controlled trials in this field have needed to be very large and of long duration, given the rare occurrence of primary outcome events in asymptomatic individuals. We provide examples of how we met these challenges in relation to developing clinical guidelines for screening for breast cancer, cervical cancer, diabetes, hypertension, and depression in primary care settings. Conclusion The focus on the patient-important outcomes was helpful in estimating effectiveness of screening approaches and providing explicit detailing of the basis of our recommendations across subgroups.