Are Observational Studies on Distal Radius Fracture Treatment Robust? An E-value Approach to Analysis

Abstract

BackgroundReported complication frequencies after distal radius fracture (DRF) treatment vary widely in the literature and are based mostly on observational evidence. Whether that evidence is sufficiently robust to use in practice is controversial. The E-value is an innovative sensitivity analysis that quantitates the robustness of observational evidence against unmeasured confounders, whereby a greater E-value usually implies more robust evidence and vice versa; with DRF complications, this approach can help guide readers to a more confident interpretation of the available evidence.Questions/purposesIn this study, we sought (1) to compare the complication frequencies among different DRF treatment modalities, and (2) to evaluate the robustness of these observational studies using the E-value as an index for unmeasured confounding.MethodsWe searched PubMed, Embase, and SCOPUS for observational studies on the management of DRFs that were published from January 2001 to July 2021 with the last database search performed on July 31, 2021. All articles that compared different DRF treatment modalities with reported complication frequencies were included to accurately capture the quality of the observational studies in research about DRF. Risk ratios (RRs) of the overall complication and major complication risks were calculated for each subgroup comparison: volar plating versus dorsal plating, casting, external fixation, and percutaneous K-wire fixation. The RRs and their corresponding lower limits of the 95% confidence intervals (CIs) were used to derive the E-values. E-values can have a minimum possible value of 1, which signifies that the treatment-outcome association is not strong and can readily be overturned by unmeasured confounders. By contrast, a large E-value means that the observed treatment-outcome association is robust against unmeasured confounders. We averaged RRs and E-values for the effect estimates and lower limits of CIs across studies in each treatment comparison group. We identified 36 comparative observational studies that met the inclusion criteria. Seven studies compared volar with dorsal plating techniques. Volar plating was also compared with casting (eight studies), external fixation (15 studies), and percutaneous K-wire fixation (six studies).ResultsTotal and major complication risks did not differ among different DRF treatments. The mean RRs for total and major complications were 1.2 (95% CI 0.4 to 3.9; p = 0.74) and 1.8 (95% CI 0.4 to 11.4; p = 0.52) for the volar versus dorsal plating group; 1.2 (95% CI 0.3 to 11.2; p = 0.87) and 1.5 (95% CI 0.3 to 14.9; p = 0.74) for the volar plating versus casting group; 0.6 (95% CI 0.2 to 2.2; p = 0.33) and 0.8 (95% CI 0.2 to 6.7; p = 0.86) for the volar plating versus external fixation group; and 0.6 (95% CI 0.2 to 2.6; p = 0.47) and 0.7 (95% CI 0.2 to 4.0; p = 0.67) for the volar plating versus K-wire fixation group. The mean E-values for total and major complication frequencies for the between-group comparison ranged from 3.1 to 5.8; these were...

CORR Insights®: Are Observational Studies on Distal Radius Fracture Treatment Robust? An E-value Approach to Analysis

“…In my opinion, it is probably more important for readers to be aware of the problems with E-values that Ioannidis et al [2] have pointed out than the E-value itself, because their critiques get to the heart of the limits of analyzing observational data. For instance, in the context of the current study [5] of rates of adverse events after various types of operative distal radius fracture treatment, we can observe several important areas of debate and variation. Let's focus on the definition and measurement of adverse events or complications to make the point.…”

“…In a paper in this month’s Clinical Orthopaedics and Related Research ® , Wang et al [5] applied E-values to observational comparative data on adverse events after surgical treatment of a fracture of the distal radius. The considered treatments included dorsal plates, volar plates, external fixation, and percutaneous pinning.…”

“…Fourth, structure research questions based on the principle that counts of various events are less important than the impact of those events on comfort and capability. Complication counts, as used in the study under consideration [5], can be particularly misleading. Fifth, we are not looking for a winner.…”

“…The study of Wang et al [5] highlights the shortcomings of observational data and the need to carefully consider alternative interpretations. In my opinion, it is probably more important for readers to be aware of the problems with E-values that Ioannidis et al [2] have pointed out than the E-value itself, because their critiques get to the heart of the limits of analyzing observational data.…”