How Many Patients? How Many Limbs? Analysis of Patients or Limbs in the Orthopaedic Literature: A Systematic Review

Bryant, Dianne; Havey, Thomas; Roberts, Robin S.; Guyatt, Gordon

doi:10.2106/jbjs.e.00272

Cited by 97 publications

(96 citation statements)

References 4 publications

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“…In a systematic review of orthopaedic literature, Bryant et al [2] found that 42% of clinical studies in high-impact-factor orthopaedic journals had inappropriately used multiple observations from single individuals. In clubfoot research, Duffy et al [7] combined multiple data from single individuals noting that an earlier study had observed no difference in findings when excluding data of one foot in bilateral clubfeet cases; however, this study had used statistical methods that assumed that each data point was independent [16].…”

Section: Discussionmentioning

confidence: 99%

“…It would not be assumed that the contralateral breast in someone with BRCA(+) breast cancer were independent data points, and it has been shown that they are not independent [5]. It has also been shown that multiple measurements taken from one patient (eg, two feet in bilateral cases) are more likely to be correlated than measurements taken from single limbs of multiple patients [2,13]. To determine the correct analysis for clubfoot trials, any correlation between the feet of bilateral cases first needs to be determined.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Bilateral Clubfeet Are Highly Correlated: A Cautionary Tale for Researchers

Gray

Gibbons

Little

et al. 2014

Clinical Orthopaedics &Amp; Related Research

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Background Congenital talipes equinovarus, or clubfoot, is a common pediatric orthopaedic condition of unknown origin. In many clubfoot clinical trials, interventions are assigned to a patient, but response to treatment is assessed separately in each foot. Trials commonly report x patients with y feet where y is greater than x (eg, 35 patients with 56 feet). However, common statistical tests assume that each data point is independent. Although data from unilateral cases of clubfoot are independent, it is unknown if each foot of patients with bilateral clubfeet are correlated. Questions/purposes The purpose of this study was to assess the correlation in the feet of patients with bilateral clubfeet by (1) evaluating the degree of severity between lower limbs of each patient with bilateral clubfeet at baseline; (2) determining if right and left feet of each patient responded to intervention in the same way; (3) determining the proportion of bilateral relapse; and (4) determining the proportion of right and left feet which required the same intervention to correct bilateral relapse. Methods We performed a chart review of the records of 33 patients with bilateral clubfeet (66 feet). Baseline severity was assessed using the Pirani score. The number of Ponseti serial casts to correct the deformity, the proportion of patients who underwent bilateral Achilles tenotomy, the proportion of bilateral relapse, and the treatment to correct bilateral relapse were examined. Results The degree of severity between right (Pirani score mean, 5.2; SD, 0.8) and left (Pirani score mean, 5.2; SD, 0.5) feet for each patient at baseline was highly correlated (r = 0.76, p \ 0.001). Response to intervention between lower limbs was highly correlated for the number of Ponseti casts required for initial correction (right mean, 5.2, SD, 1.1; left mean, 5.2, SD, 1.3) (r = 0.89, p \ 0.001) and the proportion of patients who underwent bilateral Achilles tenotomy (right, 17/18; left, 16/18) (r = 0.94, p \ 0.001). In the nine patients who experienced relapse, eight experienced bilateral involvement. In all cases of bilateral relapse, the right and left foot of each patient required the same intervention to correct the relapse. Conclusions In patients with bilateral clubfeet, baseline severity, response to initial Ponseti treatment, Achilles tenotomy, and relapse outcomes were highly correlated in

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Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Bilateral Clubfeet Are Highly Correlated: A Cautionary Tale for Researchers

Gray

Gibbons

Little

et al. 2014

Clinical Orthopaedics &Amp; Related Research

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“…After operative report and medical record screening, we included all 927 patients older than 18 years who had surgery for a pathologic or impending metastatic long bone fracture between January 1999 and December 2013. We included only the first surgery per patient if patients underwent multiple operations on different occasions so as to not violate the statistical assumption of independence [3]. We defined long bones as the femur, humerus, tibia, fibula, radius, and ulna; multiple long bones operated on during the same procedure were categorized separately.…”

Section: Methodsmentioning

confidence: 99%

2015 Marshall Urist Young Investigator Award: Prognostication in Patients With Long Bone Metastases: Does a Boosting Algorithm Improve Survival Estimates?

Janssen

Heijden

Dijke

et al. 2015

Clin Orthop Relat Res

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Background Survival estimation guides surgical decisionmaking in metastatic bone disease. Traditionally, classic scoring systems, such as the Bauer score, provide survival estimates based on a summary score of prognostic factors. Identification of new factors might improve the accuracy of these models. Additionally, the use of different algorithms-nomograms or boosting algorithms-could further improve accuracy of prognostication relative to classic scoring systems. A nomogram is an extension of a classic scoring system and generates a more-individualized survival probability based on a patient's set of characteristics using a figure. Boosting is a method that automatically trains to classify outcomes by applying classifiers (variables) in a sequential way and subsequently combines them. A boosting algorithm provides survival probabilities based on every possible combination of variables. Questions/purposes We wished to (1) assess factors independently associated with decreased survival in patients with metastatic long bone fractures and (2) compare the accuracy of a classic scoring system, nomogram, and boosting algorithms in predicting 30-, 90-, and 365-day survival. Methods We included all 927 patients in our retrospective study who underwent surgery for a metastatic long bone fracture at two institutions between January 1999 and December 2013. We included only the first procedure if patients underwent multiple surgical procedures or had more than one fracture. Median followup was 8 months (interquartile range, 3-25 months); 369 of 412 (90%) patients who where alive at 1 year were still in followup. Multivariable Cox regression analysis was used to identify One author (SJ) certifies that he has received, an amount less than USD 10,000, from the Anna Foundation (Oegstgeest, The Netherlands), an amount less than USD 10,000 from the De Drie Lichten Foundation (Hilversum, The Netherlands), an amount less than USD 10,000 from the KWF Kankerbestrijding (Amsterdam, The Netherlands), and an amount less than USD 10,000, from the Michael van Vloten Foundation (Rotterdam, The Netherlands). One author (JS) certifies that he or a member of his family has or may receive payments or benefits, an amount less than USD 10,000, from Stryker (Kalamazoo, MI, USA), and an amount less than USD 10,000, from Biom'up (Saint-Priest, Lyon, France). All ICMJE Conflict of Interest Forms for authors and Clinical Orthopaedics and Related Research 1 editors and board members are on file with the publication and can be viewed on request. Each author certifies that his or her institution approved the human protocol for this investigation, that all investigations were conducted in conformity with ethical principles of research. This work was performed at Massachusetts General Hospital, Boston, MA, USA. clinical and laboratory factors independently associated with decreased survival. We created a classic scoring system, nomogram, and boosting algorithms based on identified variables. Accuracy of the algorithms was assessed using area unde...

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“…Numerous articles and reviews explore the basics of research methodology to provide a sound understanding of proper design and conduct of studies [1,2,5,7,8,11,15]. Associations found in trials, however, may derive from four sources: chance, bias, confounding, or a true effect.…”

Section: Introductionmentioning

confidence: 99%

Management of Confounding in Controlled Orthopaedic Trials

Vavken

Culen

Dorotka

2008

Clinical Orthopaedics &Amp; Related Research

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Confounding occurs when the effect of an exposure on an outcome is distorted by a confounding factor and will lead to spurious effect estimates in clinical studies. Although confounding can be minimized at the design stage, residual confounding may remain. An argument therefore can be made for controlling for confounding during data analysis in all studies. We asked whether confounding is considered in controlled trials in orthopaedic research and hypothesized the likelihood of doing so is affected by participation of a scientifically trained individual and associated with the magnitude of the impact factor. We performed a cross-sectional study of all controlled trials published in 2006 in eight orthopaedic journals with a high impact factor. In 126 controlled studies, 20 (15.9%; 95% confidence interval, 9.5%-22.3%) studies discussed confounding without adjusting in the analysis. Thirty-eight (30.2%; 95% confidence interval, 22.2%-38.2%) controlled for confounding, although we suspect the true proportion might be somewhat higher. Participation of a methodologically trained researcher was associated with (odds ratio, 3.85) controlling for confounding, although there was no association between impact factor and controlling for confounding. The question remains to what extent the validity of published findings is affected by failure to control for confounding.

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How Many Patients? How Many Limbs? Analysis of Patients or Limbs in the Orthopaedic Literature: A Systematic Review

Cited by 97 publications

References 4 publications

Bilateral Clubfeet Are Highly Correlated: A Cautionary Tale for Researchers

Bilateral Clubfeet Are Highly Correlated: A Cautionary Tale for Researchers

2015 Marshall Urist Young Investigator Award: Prognostication in Patients With Long Bone Metastases: Does a Boosting Algorithm Improve Survival Estimates?

Management of Confounding in Controlled Orthopaedic Trials

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