![]() ![]() However, some elements should be adapted specifically to the inclusion of non-randomized studies because their study designs inherently differ from RCTs. Similar to systematic reviews of RCTs, reviews including non-randomized studies are expected to follow the general recommendations for good conduct, such as retrieving all relevant studies and assessing their risk of bias. Therefore, an increasing number of systematic reviews and meta-analyses are including data from non-randomized studies to assess therapeutic interventions. ![]() A comprehensive assessment in 2009 indicated that 54 % of CER studies had an observational study design. With the aim of generating evidence that will guide healthcare decisions, the field of comparative effectiveness research (CER) emphasizes the need to incorporate data from observational studies to complement RCTs. In contrast, observational studies, the overarching term for all non-experimental non-randomized studies (including cohort, case–control, and cross-sectional studies), generally are more likely to reflect clinical practice in real life because of their broader range of participants, longer follow-up time, and lower costs than RCTs. Also, conducting an RCT is sometimes impossible or inappropriate (eg, when studying rare or long-term events), which results in critical information gaps. However, the applicability of their results has been criticized because of restrictive selection criteria, with, commonly, exclusion of older adults and people with co-morbidities or severe disease. Randomized controlled trials (RCTs) are considered the gold standard for evidence-based medicine because they are designed to minimize the risk of bias. Some key methodological components of the systematic review process-search for grey literature, description of the type of NRSI included, assessment of risk of confounding bias and reporting of whether crude or adjusted estimates were combined-are not adequately carried out or reported in meta-analyses including NRSI. Reporting bias was assessed in 127 (68 %). Heterogeneity across studies was assessed in 182 meta-analyses (97 %) and further explored in 157 (84 %). In 131 (70 %), whether crude or adjusted estimates of treatment effect for NRSI were combined was unclear or not reported. In 130 meta-analyses (69 %), the design of each NRSI was not clearly specified. An assessment of methodological quality or risk of bias was reported in 135 meta-analyses (72 %) but this assessment considered the risk of confounding bias in only 33 meta-analyses (18 %). “Grey literature” was searched for 72 meta-analyses (38 %). Half of the meta-analyses ( n = 92, 49 %) evaluated non-pharmacological interventions. One hundred eighty eight meta-analyses were selected: 119 included both randomized controlled trials (RCTs) and non-randomized studies of interventions (NRSI) and 69 only NRSI. Two reviewers independently assessed the general characteristics and key methodological components of the systematic review process and meta-analysis methods. Etiological assessments and meta-analyses with no comparison group were excluded. Methodsįor this methodological review, we searched MEDLINE via PubMed, from Januto Decemfor meta-analyses including at least one non-randomized study evaluating therapeutic interventions. We aimed to systematically assess the methods used in meta-analyses including non-randomized studies evaluating therapeutic interventions. There is an increasing number of meta-analyses including data from non-randomized studies for therapeutic evaluation. ![]()
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |