Statistical fragility of randomized clinical trials in shoulder arthroplasty

Abstract

Background:The P value is a statistical tool used to assess the statistical significance of clinical trial outcomes in orthopedic surgery. However, the P value does not evaluate research quality or clinical significance. The Fragility Index (FI) is an alternative statistical method that can be used to assess the quality and significance of clinical research and is defined as the number of patients in a study intervention group necessary to convert an outcome from statistically significant to statistically insignificant or vice versa. The primary purpose of this study was to evaluate the statistical robustness of clinical trials regarding shoulder arthroplasty using the FI. The secondary goal was to identify trial characteristics associated greater statistical fragility. Methods: A systematic review of randomized clinical trials in shoulder arthroplasty was performed. The FI was calculated for all dichotomous, categorical study outcomes discussed in the identified studies. Descriptive statistics and the Pearson correlation coefficient were used to evaluate all studies and characterize associations between study variables. Results: A total of 13 randomized controlled trials were identified and evaluated; these trials had a median sample size of 47 patients (mean, 54 patients; range, 26-102 patients) and a median of 7 patients (mean, 5.8 patients; range, 0-14 patients) lost to follow-up. The median FI was 6 (mean, 5; range, 1-11), a higher FI than what has been observed in other orthopedic subspecialties. However, the majority of outcomes (74.4%) had an FI that was less than the number of patients lost to follow-up, and most outcomes (89.7%) were statistically insignificant. Conclusion: Randomized controlled trials in shoulder arthroplasty have comparable statistical robustness to the literature in other orthopedic surgical subspecialties. We believe that the inclusion of the FI in future comparative studies in the shoulder arthroplasty literature will allow surgeons to better assess the statistical robustness of future research.

The Statistical Fragility of Operative vs Nonoperative Management for Achilles Tendon Rupture: A Systematic Review of Comparative Studies

“…For the outcomes included in this analysis, the median FI was 2.5 (IQR 2-4), the mean FI was 2.9 (±1.58), the median FQ was 0.032 (IQR 0.012-0.069), and the mean FQ was 0.049 (±0.062). These values are consistent with the current orthopaedic literature reporting an average median FI of 3.81 10 – 14 , 17 , 18 , 21 , 23 , 29 – 31 , 36 , 38 , 42 , 47 – 53 , 55 …”

“…These values are consistent with the current orthopaedic literature reporting an average median FI of 3.81 10–14,17,18,21,23,29 –31,36,38,42,47 –53,55 –57 and FQ of 0.048. 10–12,18,21,…”

“…For the outcomes included in this analysis, the median FI was 2.5 (IQR 2-4), the mean FI was 2.9 (±1.58), the median FQ was 0.032 (IQR 0.012-0.069), and the mean FQ was 0.049 (±0.062). These values are consistent with the current orthopaedic literature reporting an average median FI of 3.81 [10][11][12][13][14]17,18,21,23,[29][30][31]36,38,42,[47][48][49][50][51][52][53][55][56][57] and FQ of 0.048. [10][11][12]18,21,23,31,[47][48][49][50][51]53 The hypothesis of this study was confirmed, with more than half (78%) of outcomes analyzed having a loss to follow-up greater than the fragility index for that outcome.…”

Fragility Index as a Measure of Randomized Clinical Trial Quality in Adult Reconstruction: A Systematic Review

“…and McCormick et al. recently described the “reverse fragility index,” which determines FI in nonstatistically significant outcomes in general and orthopedic research, respectively [ 12 , 13 ]. This allows the FI to be applied to a much larger body of research.…”

Innovative technologies for reverse total shoulder arthroplasty in Australia: Market access challenges and implications for patients, decision-makers, and manufacturers

“…The absence of standardisation limits data synthesis in systematic reviews, as results are restricted to studies that have used the same tools to report selected outcomes [ 18 ]. Similarly, issues in methodological quality are prevalent in shoulder replacement studies [ 19 ], exacerbate the difficulties in evaluating data from various studies to aid decision-making [ 20 ].…”