A modified Kidney Donor Risk Index for pediatric kidney transplant recipients.

BACKGROUND: The Kidney Donor Risk Index (KDRI) by Rao et al. was developed to measure the quality of kidney allografts. While Rao's KDRI has been found to be a robust measure of kidney allograft survival for adult kidney transplant recipients, many studies have indicated the need to create a distinct pediatric KDRI. METHODS: Our retrospective study utilized data from the United Network for Organ Sharing database. We examined 9295 deceased donor recipients' data for age < 18 years from 1990 to 2020. We performed a multivariate Cox regression to determine the significant recipient and transplant factors impacting pediatric kidney allograft survival. RESULTS: Multivariate analysis found 5 donor factors to be independently associated with graft failure or recipient death: age, female sex, anoxia as the cause of death, history of cigarette use, and cold ischemia time. Using receiver operator characteristic (ROC) curve analysis and analyzing the predictive value of each KDRI at 1, 5, and 10 years, the proposed pediatric KDRI had a statistically significant and higher predictive value for pediatric recipients at 5 (0.60 versus 0.57) and 10 years (0.61 versus 0.57) than the Rao KDRI. CONCLUSIONS: The proposed pediatric KDRI may provide a more accurate and simpler index to assess the quality of kidney allografts for pediatric recipients. However, due to the mild increase in predictive capabilities over the Rao index, the study serves as a proof of concept to develop a pediatric KDRI. Further studies should focus on increasing the index's predictive capabilities. A higher resolution version of the Graphical abstract is available as Supplementary information.

A simple method reveals minimum time required to quantify steady-rate metabolism and net cost of transport for human walking.

The U-shaped net cost of transport (COT) curve of walking has helped scientists understand the biomechanical basis that underlies energy minimization during walking. However, to produce an individual's net COT curve, data must be analyzed during periods of steady-rate metabolism. Traditionally, studies analyze the last few minutes of a 6-10 min trial, assuming that steady-rate metabolism has been achieved. Yet, it is possible that an individual achieves steady rates of metabolism much earlier. However, there is no consensus on how to objectively quantify steady-rate metabolism across a range of walking speeds. Therefore, we developed a simple slope method to determine the minimum time needed for humans to achieve steady rates of metabolism across slow to fast walking speeds. We hypothesized that a shorter time window could be used to produce a net COT curve that is comparable to the net COT curve created using traditional methods. We analyzed metabolic data from 21 subjects who completed several 7 min walking trials ranging from 0.50 to 2.00 m s-1. We partitioned the metabolic data for each trial into moving 1, 2 and 3 min intervals and calculated their slopes. We statistically compared these slope values with values derived from the last 3 min of the 7 min trial, our 'gold' standard comparison. We found that a minimum of 2 min is required to achieve steady-rate metabolism and that data from 2-4 min yields a net COT curve that is not statistically different from the one derived from experimental protocols that are generally accepted in the field.

Analysis of Research Productivity of Orthopedic Surgery Residency Applicants.

Background Orthopedic surgery has become an increasingly competitive specialty. With a pass-fail Step 1, an even greater emphasis on research has been placed to allow candidates to better distinguish themselves. This study analyzes the scholarly activity of accepted orthopedic residency applicants during medical school, assessing what factors, including the novel altmetric attention score, may be associated with greater research productivity. Methods A list of orthopedic residency programs was obtained from the Electronic Residency Application Service (ERAS). A total of 688 orthopedic residents from 180 programs who matriculated in 2020 from allopathic medical schools were identified. Resident demographic information and bibliometric data (total publications, orthopedic-related publications, h-index, and altmetric score) of publications published from July 1, 2016, to September 1, 2020, were collected. Descriptive statistics were calculated. Kruskal-Wallis tests analyzed the association between medical school characteristics and research productivity using Stata® 17.0 (StataCorp LLC, College Station, Texas). Results Postgraduate-Year-3 orthopedic residents (N=688) published 2,600 articles during medical school, averaging 3.8 articles per resident. The residents from a top 25 medical school for research had publication counts, altmetric scores, and h-indices, on average, that were higher than those from non-top 25 medical schools for research. Over 150 residents had no publications, and ~10 residents had more than 30 publications. Conclusions The results illustrate that medical school research status influences the research productivity of applicants. Also, given the average number of publications, most research listed on applications are abstracts and presentations. Utilization of the altmetric score may not yet be the best way of examining research experience because orthopedic applicants do not appear to use social networks for academic research.