Study Set Content:
Accuracy and reliability of a diagnostic test
Cross-over study of index test (newtest) vs. referencemethod (“gold standard”) in cohort of patientsatriskof having diseas
Prognosis
Patient cohort studies with follow-up at uniformpoints in clinical course of disease
Accuracy and reliability of a screening test
Cross-over study of index test vs. referencemethod(“gold standard”) in representative cross-sectionofasymptomatic population at-risk for disease
Efficacy (for health outcomes) of screening or diagnostic tests
RCT if time and resources allow; observational studiesand RCTs rigorously linked for analytic validity, clinicalvalidity, and clinical utility
Efficacy (for health outcomes) of most therapies and preventive interventions
RCT
Efficacy of interventions for otherwise fatal conditions
Non-randomized trials, case series
Safety, effectiveness of incrementally modified technologies posing no known additional risk
Registries, especially to complement findingsofavailable RCTs and PCTs
Rates of recall or procedures precipitated by false positive screening results
Cohort studies
Complication rates from surgery, other procedures
Registries, case series
Identification of a cause of a suspected iatrogenic (caused by a physician or therapy) disorder
Case-control studies
Incidence of common adverse events potentially due to an intervention
RCTs, nested case-control studies, n-of-1trial forparticular patients, surveillance, registries
Incidence of rare or delayed adverse events potentially due to an intervention
Surveillance; registries; n-of-1 trial for particularpatients; large, long-termRCT if feasible
are not the best study design for answering all evidence questions of potential relevance to an HTA
RCT's
Researchers often use () or other frameworks to portray the relative qualityof variousstudy designs for the purposes of evaluating single studies as well as a body of evidence comprisingmultiple studies.
evidence hierarchies
An example of a basic evidence hierarchy is:
Systematic reviews and meta-analyses of RCTs Randomized controlled trials (RCTs) Non-randomized controlled trials Prospective observational studies Retrospective observational studies Expert opinion
) reflects the demand for real-world evidence to support practicaldecisions. It emphasizes evidence from direct comparisons, effectiveness in real-world health caresettings,health care outcomes, and ability to identify different treatment effects in patient subgroups.
Comparative effectiveness research (CER)
retain the methodological strengths of prospective, randomized design, butuse large numbers of patients, more flexible patient entry criteria and multiple study sites to generateeffectiveness data and improve external validity.
Large simple trials (LSTs)
are a related group of trial designs whose mainattributesinclude: comparison of clinically relevant alternative interventions, a diverse population of study participants,participants recruited from heterogeneous practice settings, and data collection on a broad rangeof healthoutcomes.
Pragmatic (or practical) clinical trials (PCTs
involve randomized assignment of interventions at the level of natural groupsororganizations rather than at the level of patients or other individuals. That is, sets of clinics, hospitals, nursinghomes, schools, communities, or geographic regions are randomized to receive interventions or comparators.Such designs are used when it is not feasible to randomize individuals or when an interventionis designedtobe delivered at a group or social level. These are also known as “group,” “place,” or “community” randomizedtrials.
Cluster randomized trials
use accumulating data to determine how to modify the design of ongoingtrialsaccording to a pre-specified plan.
Adaptive clinical trials
