Comparison of Effects in Randomized Controlled Trials With Observational Studies in Digestive Surgery

Nakayama, Takeo; Noguchi, Yoshinori; Taji, Yoshinori; Yamagishi, Hisakazu

doi:10.1097/01.sla.0000225356.04304.bc

Cited by 76 publications

(49 citation statements)

References 35 publications

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“…Our study extends and expands on the work of Concato and colleagues, 3 Benson and Hartz, 4 Ioannidis and colleagues 5 and Shikata and colleagues 6 as, to our knowledge, it is the first to explicitly examine comparisons of 2 surgical procedures rather than medical versus surgical treatment and to compare RCT versus nRCT studies not previously included in a meta-analysis of breast cancer surgery. Interestingly, our results are similar to previous published results.…”

Section: Discussionmentioning

confidence: 71%

“…[3][4][5][6] The present study demonstrates that the effect estimates comparing 2 surgical procedures for breast cancer in RCTs and corresponding nRCTs showed clinically important differences in 20%-40% of cases. The proportion of clinically important differences varied depending on which of our metrics was used.…”

Section: Discussionmentioning

confidence: 92%

“…This result is comparable to our finding of disagreement for 2 of 10 (20%) comparisons in breast cancer surgery. Shikata and colleagues, 6 who reported on digestive surgery topics previously studied in meta-analyses, found a greater than 2-fold difference in effect estimates for 7 of 16 (44%) of topics.…”

Section: Discussionmentioning

confidence: 99%

“…We selected this as the most clinically rel evant comparison measure using the precedent found in the studies of Ioannidis and colleagues 5 and Shikata and colleagues. 6 Third, we evaluated whether there was a failure to demonstrate consistency of the statistical differences shown by the summary RRs. Agreement using this method implies that either both study types reflected no statistical difference in treatment effect or that there was a statistical difference shown and in the same direction for both study types.…”

Section: Discussionmentioning

confidence: 99%

“…Surgical studies made up a small proportion of the topics compared. Shikata and colleagues, 6 using a similar methodology to Ioannidis and colleagues, reported on a comparison of effects in RCTs versus nRCTs of digestive surgery. The authors reported that one-quarter of nRCTs gave different results than RCTs.…”

mentioning

confidence: 99%

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Meta-analytic comparison of randomized and nonrandomized studies of breast cancer surgery

Edwards¹,

Kelly²,

Lin³

et al. 2012

Can J Surg

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Meta-analytic comparison of randomized and nonrandomized studies of breast cancer surgeryBackground: Randomized controlled trials (RCTs) are thought to provide the most accurate estimation of "true" treatment effect. The relative quality of effect estimates derived from nonrandomized studies (nRCTs) remains unclear, particularly in surgery, where the obstacles to performing high-quality RCTs are compounded. We performed a meta-analysis of effect estimates of RCTs comparing surgical procedures for breast cancer relative to those of corresponding nRCTs.Methods: English-language RCTs of breast cancer treatment in human patients published from 2003 to 2008 were identified in MEDLINE, EMBASE and Cochrane databases. We identified nRCTs using the National Library of Medicine's "related articles" function and reference lists. Two reviewers conducted all steps of study selection. We included studies comparing 2 surgical arms for the treatment of breast cancer. Information on treatment efficacy estimates, expressed as relative risk (RR) for outcomes of interest in both the RCTs and nRCTs was extracted. Results:We identified 12 RCTs representing 10 topic/outcome combinations with comparable nRCTs. On visual inspection, 4 of 10 outcomes showed substantial differences in summary RR. The pooled RR estimates for RCTs versus nRCTs differed more than 2-fold in 2 of 10 outcomes and failed to demonstrate consistency of statistical differences in 3 of 10 cases. A statistically significant difference, as assessed by the z score, was not detected for any of the outcomes. Conclusion:Randomized controlled trials comparing surgical procedures for breast cancer may demonstrate clinically relevant differences in effect estimates in 20%-40% of cases relative to those generated by nRCTs, depending on which metric is used. Contexte :On estime que les essais randomisés et contrôlés (ERC) offrent l'estimation la plus juste de l'effet « réel » des traitements. La qualité relative de l'estimation de l'effet dérivée des études non randomisées (EnRC) reste indéterminée, particulièrement en ce qui concerne la chirurgie, où les obstacles à la réalisation d'ERC optimaux sont nombreux. Nous avons procédé à une méta-analyse des estimations de l'effet dérivées d'ERC qui comparaient des interventions chirurgicales pour le cancer du sein, aux estimations dérivées d'EnRC assortis. Méthodes :Nous avons relevé les ERC sur le traitement du cancer du sein chez l'humain publiés en langue anglaise entre 2003 et 2008 à partir des bases de données MEDLINE, EMBASE et Cochrane. Nous avons relevé les EnRC à l'aide des listes bibliographiques et de la fonction « articles connexes » de la National Library of Medicine. Deux examinateurs se sont chargés de toutes les étapes de la sélection des études. Nous avons inclus les études qui comparaient 2 groupes soumis à une chirurgie pour le traitement du cancer du sein. Nous avons extrait l'information sur les estimations de l'efficacité des traitements, exprimées sous forme de risque relatif (RR) de survenue des paramètres r...

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Section: Discussionmentioning

confidence: 71%

Section: Discussionmentioning

confidence: 92%

Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

mentioning

confidence: 99%

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Meta-analytic comparison of randomized and nonrandomized studies of breast cancer surgery

Edwards¹,

Kelly²,

Lin³

et al. 2012

Can J Surg

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Associations of Bariatric Interventions With Micronutrient and Endocrine Disturbances

et al. 2020

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IMPORTANCE Few studies have described the longitudinal trajectories of serum levels of micronutrients whose deficiencies are associated with serious sequelae following bariatric procedures, such as anemia, osteoporotic fractures, and neuropathies. Furthermore, previous studies comparing laparoscopic sleeve gastrectomy (LSG) vs Roux-en-Y gastric bypass (LRYGB) or one-anastomosis gastric bypass (OAGB) procedures may have been limited by selection and confounding biases.OBJECTIVE To appraise the spectrum and temporal course of micronutrient deficiencies associated with bone metabolism and erythropoiesis after LSG vs OAGB or LRYGB procedures, using the propensity score as a balancing score.

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Healthcare outcomes assessed with observational study designs compared with those assessed in randomized trials

Anglemyer

Horváth

Bero

2014

Cochrane Database of Systematic Reviews

408

361

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Our results across all reviews (pooled ROR 1.08) are very similar to results reported by similarly conducted reviews. As such, we have reached similar conclusions; on average, there is little evidence for significant effect estimate differences between observational studies and RCTs, regardless of specific observational study design, heterogeneity, or inclusion of studies of pharmacological interventions. Factors other than study design per se need to be considered when exploring reasons for a lack of agreement between results of RCTs and observational studies. Our results underscore that it is important for review authors to consider not only study design, but the level of heterogeneity in meta-analyses of RCTs or observational studies. A better understanding of how these factors influence study effects might yield estimates reflective of true effectiveness.

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Comparison of Effects in Randomized Controlled Trials With Observational Studies in Digestive Surgery

Abstract: One fourth of observational studies gave different results than randomized trials, and between-study heterogeneity was more common in observational studies in the field of digestive surgery.

Cited by 76 publications

References 35 publications

Meta-analytic comparison of randomized and nonrandomized studies of breast cancer surgery

Meta-analytic comparison of randomized and nonrandomized studies of breast cancer surgery

Associations of Bariatric Interventions With Micronutrient and Endocrine Disturbances

Healthcare outcomes assessed with observational study designs compared with those assessed in randomized trials

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