To the Editor:

We thank Dr Ja-Ho Leigh et al. [1] for their interest in our study [2] and the opportunity to address some of the posted questions. First, per your comment, a sizable number of traumatic spinal cord injury (SCI) could be excluded from this study sample because we only analyzed the national health insurance which excludes the national worker’s compensation and automobile insurance. It’s not easy to identify the exact incidences and prevalence of specific diseases showing a small frequency of occurrence such as acute SCI with a national database. And the accessibility of related data of the national worker’s compensation is impossible currently due to their closed-access policy. However, from July 2013, the database of the Health Insurance Review and Assessment Service (HIRA) includes that of automobile insurance because HIRA conducts the appropriateness of treatment for patients with automobile insurance after signing the contract of entrustment for the examination of medical expenses [3]. Therefore, we can analyze the incidence of acute SCI more precisely by using both the database of national health insurance and automobile insurance, and we compared the number of cases of acute SCI and age-adjusted rate per 100,000 persons from 2007 to 2012 and from 2014 to 2017.

In this study, from 2007 to 2012 and from 2014 to 2017, the number of cases of acute SCI were 1032.3 and 1209.8, respectively, and 25.7 and 27.4 were age-adjusted rate per 100,000 persons during the same period. We compared the differences in the number of cases of acute SCI and age-adjusted rate per 100,000 persons using the Mann-Whitney nonparametric analysis, and they showed statistically significant differences (p < 0.05). Therefore, your opinions might be appropriate, and a more careful research design is warranted to analyze the effect of including those with automobile insurance by setting a sufficient period through HIRA data since July 2013.

Second, the peak incidence occurred among adults in their 50 s for the entire observational period in our study and this tendency continued after the year 2014, which incorporate the database of the automobile insurance. Also, the proportion of national worker’s compensation in the total acute SCI would be not considered to be high because it is mandatory to demonstrate the cause-and-effect relationship for reimbursement to the national worker’s compensation. Therefore, it is deemed necessary for a high level of evidence-based study to refute the high ratio of middle and old ages in acute SCI, which is the result of this study.

Lastly, we also agree with your comment that the medical system and the database of South Korea are appropriate for developed countries, which merits consideration when discussing international comparisons. However, some specific medical issues such as pulmonary tuberculosis show a typical feature of developing countries. Therefore, aside from discussing whether South Korea is a developed country or not, we believe that national population-based studies could help to elucidate the current status and treatment trends of specific medical issues.