Dear Editor,
We read with great interest a recent article by Eraydin and Avsar1 titled "The Effect of Foot Exercise on Wound Healing in Type 2 Diabetes Patients With a Foot Ulcer." In this article, the authors aimed to investigate the effect foot exercise on distribution of diabetic food ulcer (DFU) area averages and distribution of DFU total depth. The authors started study with 65 participants and completed with 60 participants. They divided subjects into 2 groups and each group was evaluated at baseline and weeks 4,8, and 12. Indeed, they investigated their variables in same participants (with one difference in number of them) in different time-points. As stated in the data analysis section of the article, the authors used analysis of variance and Kruskal-Wallis test to compare differences in means of numerical variables of different time-points of measurement. Since they investigated the same sample of participants in each group during different time-points (ie, beginning, 4th week, 8th week, and 12th week), their measurements are dependent.2-4 Analysis of variance and Kruskal-Wallis test are used for comparison of the means of more than 2 independent groups.5-7 Two groups of the study are independent but the measurement of variables in each groups during different time-points is dependent. Indeed, they measured their variables in 2 groups of participants every 4 weeks. After assessment of the normal distribution of studied quantitative variables including distribution of DFU area averages and distribution of DFU total depth, the authors must use repeated measures analysis of variance or Friedman test for comparison of the means of each variable at baseline and weeks 4, 8, and 12.8-10 Moreover, they should have used a Wilcoxon test and paired t test for comparison of distribution of DFU area averages and distribution of DFU total depth between 2 time-points of measurement.
Abolfazl Zahedi
Student Research Committee, Kashan University of
Medical Sciences, Kashan, Iran
Milad Ebrahimi, MS
Department of Immunology, School of Medicine,
Shahed University, Tehran, Iran
REFERENCES