SECTION 3 Preventive medicine and public health for benefits than for evidence of harm For benefits, USPSTF helical computed tomography(CT). The number of patient ill only accept evidence from randomized controlled trial ives potentially saved must be weighed against the risk of (RCTs), community trials, meta-analyses, or systematic subjecting healthy patients to potentially harmful screening reviews However, it will take into account evidence of cohort tests. with this tension and when in doubt the Task force studies and case-control studies in calculations of harm seems to prefer being late to being wrong Prevention studies describe the upper bounds of efficacy In other words, controlled trials describe a best-case scenario with well-trained and highly motivated providers and C. Evidence Review and Recommendations tients. The Task force assumes that in the real world, with Developing a recommendation is a two-part process: review- unselected providers and in the general population, the ing the evidence and formulating recommendations effectiveness of a screening program will be lower Although the Task Force itself makes the recommendations, Delivery of a screening service is not an outcome. Diag independent centers review the evidence. USPSTF has estab nosis of a disease also is not an outcome. Therefore the lished 12 such evidence-based practice centers(EPCs). The benefit of a screening program lies not in the number of literature review and recommendation process is highly atients screened or the number of patients diagnosed with structured and includes various steps to safeguard the Task disease, but only in the health outcomes. Health outcomes Force's integrity and to help it pursue its goals of transpar are changes in a patient's health or health perception, such ency, accountability, consistency, and independence(Table outcomes, intermediate outcomes are measurements of members, stringent policies regarding conflict of interest, pathology or physiology that can lead to health outcomes dual review of each abstract, and a comment period for com (e.g, high blood pressure). USPSTF will give no weight to munity partners and the public evidence of number of screening events or cases found, and it gives greater weight to studies of health outcomes than to CRITICAL APPRAISAL QUESTIONS those of intermediate outcom Do the studies have the appropriate research design to Because the standard for evidence is so high, USPSTF may answer the key question wait longer than other organizations before endorsing What is the internal validity? screening modalities, as with lung cancer screening using What is the external validity? Table 18-1 Procedures for Developing a Recommendation Statement Activity Responsible Parties Timeline Topic selection Topic Prioritization Workgroup, a subset of Task The Workgroup meets periodically Force members and AhRQ and EPC stafl Work plan developme The EPC writes work plans with guidance from a From start to finish, these activities development, peer review, and approval-take 3-6 months plan peer review work plans are reviewed by experts in the field reviewed work plant All members of USPSTE Evidence reports are written by EPC or by AHRQ Peer review of by lest for review, and Task force leaders are Draft recommendation statement Task force members draft recommendatio Completed within 2-4 weeks, with AHRQ med USPSTF review of cvidence and vote All members of USPSTF on draft recommendation statement Final evidence report EPC and AhrQ medical officer incorporate itted to aHRQ within 3-6 mont eviewer comments and finalize evidence report. fter USPSTF vote Peer review of draft recommendation 22 partners of USPSTF Partners typically have 2-3 weeks to Approval of final recommendation Task Force members USPSTF members typically approve atement recommendation statement as final Release of recommendation statement HRO staff Time from vote to release ( journal and posting on website)of recommendation varies odified from Guirguis-Blake 1: Ann Intern Med 147: 117-121, 2007. rs at a Task Force meeting, alt in the case of topic updates, work plan peer review and Task Force approval are exceptional rather than usuaL. edicare and Medicaid Services, Food and Drug Administration, Indian Health Service, National Institutes of Health, AHRQ, Agency for Healthcare Research and Quality; EPC, evidence-based practice center; USPSTF U.S. Preventive Services Task Force