As they described in the background, this study aimed to (1) evaluate the relationship between generalized joint laxity (GJL) and lumbar disc herniation (LDH), and (2) compare clinical outcomes after conservative treatment in LDH patients with and without GJL. We understood that they used both the study group (patients with LDH) and the control group (without LDH) to explain (1), and presented the results in Table 2 and Table 3 by Han et al.1) To prove (2), they only used the study group and results were in Table 4 by Han et al.1)

These expressions seemed to describe the analytical methods for Table 2 by Han et al.1) If so, the expression 'To compare the differences between the LDH patients with and without GJL' appeared in the first sentence should be 'To compare the differences between the patients with and without LDH.'

In this study, they measured the LDH as a binary scale (study or control group), and it is more appropriate to use the Wilcoxon rank sum (Mann-Whitney) test to show the differences of other variables between two groups, like Table 1 by Park.2) Furthermore, we could not understand the result that body mass index (BMI), one of the matched variables, was significantly correlated with the primary LDH occurrence, because this is contrary to the result shown in Table 1 by Park.2)

Although age and BMI could be considered as confounding factors which may affect the outcome variable, if the control group was matched for age and BMI with the study group described in Methods section, they do not play roles as confounding factors anymore. So there was no need to include the matched variables in multivariate analysis.

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