<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE article PUBLIC "-//NLM//DTD Journal Publishing DTD v2.0 20040830//EN" "http://dtd.nlm.nih.gov/publishing/2.0/journalpublishing.dtd">
<article xmlns:xlink="http://www.w3.org/1999/xlink" article-type="letter" dtd-version="2.0">
  <front>
    <journal-meta>
      <journal-id journal-id-type="publisher-id">JMU</journal-id>
      <journal-id journal-id-type="nlm-ta">JMIR Mhealth Uhealth</journal-id>
      <journal-title>JMIR mHealth and uHealth</journal-title>
      <issn pub-type="epub">2291-5222</issn>
      <publisher>
        <publisher-name>JMIR Publications</publisher-name>
        <publisher-loc>Toronto, Canada</publisher-loc>
      </publisher>
    </journal-meta>
    <article-meta>
      <article-id pub-id-type="publisher-id">v11i1e50280</article-id>
      <article-id pub-id-type="pmid">37733387</article-id>
      <article-id pub-id-type="doi">10.2196/50280</article-id>
      <article-categories>
        <subj-group subj-group-type="heading">
          <subject>Letter to the Editor</subject>
        </subj-group>
        <subj-group subj-group-type="article-type">
          <subject>Letter to the Editor</subject>
        </subj-group>
      </article-categories>
      <title-group>
        <article-title>Concerns on Generalizability</article-title>
      </title-group>
      <contrib-group>
        <contrib contrib-type="editor">
          <name>
            <surname>Leung</surname>
            <given-names>Tiffany</given-names>
          </name>
        </contrib>
      </contrib-group>
      <contrib-group>
        <contrib id="contrib1" contrib-type="author" corresp="yes">
          <name name-style="western">
            <surname>Lin</surname>
            <given-names>Yongjian</given-names>
          </name>
          <degrees>MD</degrees>
          <xref rid="aff1" ref-type="aff">1</xref>
          <address>
            <institution>Department of Gastrointestinal and Gland Surgery</institution>
            <institution>First Affiliated Hospital of Guangxi Medical University</institution>
            <addr-line>No 6 Shuangyong Road</addr-line>
            <addr-line>Qingxiu District</addr-line>
            <addr-line>Nanning, 530021</addr-line>
            <country>China</country>
            <fax>86 1 387 887 0525</fax>
            <phone>86 1 387 887 0525</phone>
            <email>linyongjian163@163.com</email>
          </address>
          <ext-link ext-link-type="orcid">https://orcid.org/0000-0003-2774-5814</ext-link>
        </contrib>
      </contrib-group>
      <aff id="aff1">
        <label>1</label>
        <institution>Department of Gastrointestinal and Gland Surgery</institution>
        <institution>First Affiliated Hospital of Guangxi Medical University</institution>
        <addr-line>Nanning</addr-line>
        <country>China</country>
      </aff>
      <author-notes>
        <corresp>Corresponding Author: Yongjian Lin <email>linyongjian163@163.com</email></corresp>
      </author-notes>
      <pub-date pub-type="collection">
        <year>2023</year>
      </pub-date>
      <pub-date pub-type="epub">
        <day>21</day>
        <month>9</month>
        <year>2023</year>
      </pub-date>
      <volume>11</volume>
      <elocation-id>e50280</elocation-id>
      <history>
        <date date-type="received">
          <day>25</day>
          <month>6</month>
          <year>2023</year>
        </date>
        <date date-type="accepted">
          <day>28</day>
          <month>8</month>
          <year>2023</year>
        </date>
      </history>
      <copyright-statement>©Yongjian Lin. Originally published in JMIR mHealth and uHealth (https://mhealth.jmir.org), 21.09.2023.</copyright-statement>
      <copyright-year>2023</copyright-year>
      <license license-type="open-access" xlink:href="https://creativecommons.org/licenses/by/4.0/">
        <p>This is an open-access article distributed under the terms of the Creative Commons Attribution License (https://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work, first published in JMIR mHealth and uHealth, is properly cited. The complete bibliographic information, a link to the original publication on https://mhealth.jmir.org/, as well as this copyright and license information must be included.</p>
      </license>
      <self-uri xlink:href="https://mhealth.jmir.org/2023/1/e50280" xlink:type="simple"/>
      <related-article related-article-type="commentary-article" id="v11i1e41099" ext-link-type="doi" xlink:href="10.2196/41099" vol="11" page="e41099" xlink:type="simple">http://mhealth.jmir.org/2023/1/e41099/</related-article>
      <related-article related-article-type="commentary" id="v11i1e51852" ext-link-type="doi" xlink:href="10.2196/51852" vol="11" page="e51852" xlink:type="simple">http://mhealth.jmir.org/2023/1/e51852/</related-article>
      <kwd-group>
        <kwd>mHealth app</kwd>
        <kwd>mobile health</kwd>
        <kwd>mHealth</kwd>
        <kwd>app</kwd>
        <kwd>prediabetes</kwd>
        <kwd>traditional Chinese medicine</kwd>
        <kwd>TCM</kwd>
        <kwd>health-related quality of life</kwd>
        <kwd>body constitution</kwd>
        <kwd>meridian energy</kwd>
      </kwd-group>
    </article-meta>
  </front>
  <body>
    <sec>
      <title/>
      <p>We read the study by Chung et al [<xref ref-type="bibr" rid="ref1">1</xref>], which evaluated the effectiveness of a mobile health (mHealth) app based on traditional Chinese medicine (TCM) in patients with prediabetes. This randomized controlled trial showed that the TCM mHealth app improved physical energy, fitness, and quality of life in patients with prediabetes. However, the small sample sizes, short follow-up time, and multiple comparisons might limit the generalizability of the findings. After carefully reading this article, we present the suggestions below.</p>
      <p>First, as the authors described in the <italic>Methods</italic> section, participants were randomized by a computer-generated randomization list into 3 groups—the TCM mHealth app, the ordinary mHealth app, or the control group—rather than propensity score matching [<xref ref-type="bibr" rid="ref2">2</xref>]. In addition, most patients have individual polymorphisms in the real world, and although baseline patient characteristics are almost impossible to match in clinical studies (ie, clinical characteristics among patients in this study who received the TCM mobile), there were no significant differences between the general app and control groups. For baseline data, variable transformation, a nonparametric test using rank, or an approximate <italic>t</italic> test could be considered when performing a comparison between 2 small sample means if their overall variances are not equal. Therefore, the results of this study may not truly reflect patients in the real world.</p>
      <p>Second, the statistical analysis presents descriptive characteristics as percentages or as mean (SD), as appropriate. A paired <italic>t</italic> test was used to examine the changes in outcome variables within groups and a 1-way ANOVA was used for comparisons among groups. However, there was no description of these data. According to Bridge and Sawilowsky [<xref ref-type="bibr" rid="ref3">3</xref>], the Wilcoxon rank-sum test is recommended if the population characteristics are unknown, such as yang-deficiency, yin-deficiency, phlegm-stasis, body energy, and physical and mental component scores, and if the hypothesis being tested is a shift in means (or another location parameter).</p>
      <p>Third, an interaction is an action that occurs when 2 or more objects interact with each other [<xref ref-type="bibr" rid="ref4">4</xref>]. Since many variables are described in the first table of Chung et al’s [<xref ref-type="bibr" rid="ref1">1</xref>] paper, prespecified subgroup analyses based on these variables are necessary. Subgroup analyses based on age, gender, BMI, body composition, and blood pressure were not performed in this study. We suggest that prespecified subgroup analyses be conducted in the TCM mHealth app group, which might allow for more accurate conclusions.</p>
      <p>In conclusion, we thank the authors for this excellent work, which provides important evidence for the integration of TCM concepts into an mHealth app for patients with prediabetes. However, we believe that the conclusions of the study would have been stronger if the abovementioned issues had been addressed.</p>
    </sec>
  </body>
  <back>
    <app-group/>
    <glossary>
      <title>Abbreviations</title>
      <def-list>
        <def-item>
          <term id="abb1">mHealth</term>
          <def>
            <p>mobile health</p>
          </def>
        </def-item>
        <def-item>
          <term id="abb2">TCM</term>
          <def>
            <p>traditional Chinese medicine</p>
          </def>
        </def-item>
      </def-list>
    </glossary>
    <fn-group>
      <fn fn-type="conflict">
        <p>None declared.</p>
      </fn>
    </fn-group>
    <ref-list>
      <ref id="ref1">
        <label>1</label>
        <nlm-citation citation-type="journal">
          <person-group person-group-type="author">
            <name name-style="western">
              <surname>Chung</surname>
              <given-names>H</given-names>
            </name>
            <name name-style="western">
              <surname>Tai</surname>
              <given-names>C</given-names>
            </name>
            <name name-style="western">
              <surname>Chang</surname>
              <given-names>P</given-names>
            </name>
            <name name-style="western">
              <surname>Su</surname>
              <given-names>W</given-names>
            </name>
            <name name-style="western">
              <surname>Chien</surname>
              <given-names>L</given-names>
            </name>
          </person-group>
          <article-title>The effectiveness of a traditional Chinese medicine-based mobile health app for individuals with prediabetes: randomized controlled trial</article-title>
          <source>JMIR Mhealth Uhealth</source>
          <year>2023</year>
          <month>06</month>
          <day>20</day>
          <volume>11</volume>
          <fpage>e41099</fpage>
          <comment>
            <ext-link ext-link-type="uri" xlink:type="simple" xlink:href="https://mhealth.jmir.org/2023//e41099/"/>
          </comment>
          <pub-id pub-id-type="doi">10.2196/41099</pub-id>
          <pub-id pub-id-type="medline">37338977</pub-id>
          <pub-id pub-id-type="pii">v11i1e41099</pub-id>
          <pub-id pub-id-type="pmcid">PMC10337399</pub-id>
        </nlm-citation>
      </ref>
      <ref id="ref2">
        <label>2</label>
        <nlm-citation citation-type="journal">
          <person-group person-group-type="author">
            <name name-style="western">
              <surname>Gillespie</surname>
              <given-names>IA</given-names>
            </name>
            <name name-style="western">
              <surname>Floege</surname>
              <given-names>J</given-names>
            </name>
            <name name-style="western">
              <surname>Gioni</surname>
              <given-names>I</given-names>
            </name>
            <name name-style="western">
              <surname>Drüeke</surname>
              <given-names>Tilman B</given-names>
            </name>
            <name name-style="western">
              <surname>de Francisco</surname>
              <given-names>Angel L</given-names>
            </name>
            <name name-style="western">
              <surname>Anker</surname>
              <given-names>SD</given-names>
            </name>
            <name name-style="western">
              <surname>Kubo</surname>
              <given-names>Y</given-names>
            </name>
            <name name-style="western">
              <surname>Wheeler</surname>
              <given-names>DC</given-names>
            </name>
            <name name-style="western">
              <surname>Froissart</surname>
              <given-names>M</given-names>
            </name>
            <collab>on behalf the ARO Steering Committee collaborators</collab>
          </person-group>
          <article-title>Propensity score matching and persistence correction to reduce bias in comparative effectiveness: the effect of cinacalcet use on all-cause mortality</article-title>
          <source>Pharmacoepidemiol Drug Saf</source>
          <year>2015</year>
          <month>07</month>
          <volume>24</volume>
          <issue>7</issue>
          <fpage>738</fpage>
          <lpage>47</lpage>
          <comment>
            <ext-link ext-link-type="uri" xlink:type="simple" xlink:href="https://europepmc.org/abstract/MED/26011775"/>
          </comment>
          <pub-id pub-id-type="doi">10.1002/pds.3789</pub-id>
          <pub-id pub-id-type="medline">26011775</pub-id>
          <pub-id pub-id-type="pmcid">PMC5033013</pub-id>
        </nlm-citation>
      </ref>
      <ref id="ref3">
        <label>3</label>
        <nlm-citation citation-type="journal">
          <person-group person-group-type="author">
            <name name-style="western">
              <surname>Bridge</surname>
              <given-names>PD</given-names>
            </name>
            <name name-style="western">
              <surname>Sawilowsky</surname>
              <given-names>SS</given-names>
            </name>
          </person-group>
          <article-title>Increasing physicians' awareness of the impact of statistics on research outcomes: comparative power of the t-test and and Wilcoxon rank-sum test in small samples applied research</article-title>
          <source>J Clin Epidemiol</source>
          <year>1999</year>
          <month>03</month>
          <volume>52</volume>
          <issue>3</issue>
          <fpage>229</fpage>
          <lpage>35</lpage>
          <pub-id pub-id-type="doi">10.1016/s0895-4356(98)00168-1</pub-id>
          <pub-id pub-id-type="medline">10210240</pub-id>
          <pub-id pub-id-type="pii">S0895435698001681</pub-id>
        </nlm-citation>
      </ref>
      <ref id="ref4">
        <label>4</label>
        <nlm-citation citation-type="journal">
          <person-group person-group-type="author">
            <name name-style="western">
              <surname>Drees</surname>
              <given-names>Becky L</given-names>
            </name>
            <name name-style="western">
              <surname>Thorsson</surname>
              <given-names>Vesteinn</given-names>
            </name>
            <name name-style="western">
              <surname>Carter</surname>
              <given-names>Gregory W</given-names>
            </name>
            <name name-style="western">
              <surname>Rives</surname>
              <given-names>Alexander W</given-names>
            </name>
            <name name-style="western">
              <surname>Raymond</surname>
              <given-names>Marisa Z</given-names>
            </name>
            <name name-style="western">
              <surname>Avila-Campillo</surname>
              <given-names>Iliana</given-names>
            </name>
            <name name-style="western">
              <surname>Shannon</surname>
              <given-names>Paul</given-names>
            </name>
            <name name-style="western">
              <surname>Galitski</surname>
              <given-names>Timothy</given-names>
            </name>
          </person-group>
          <article-title>Derivation of genetic interaction networks from quantitative phenotype data</article-title>
          <source>Genome Biol</source>
          <year>2005</year>
          <volume>6</volume>
          <issue>4</issue>
          <fpage>R38</fpage>
          <comment>
            <ext-link ext-link-type="uri" xlink:type="simple" xlink:href="https://genomebiology.biomedcentral.com/articles/10.1186/gb-2005-6-4-r38"/>
          </comment>
          <pub-id pub-id-type="doi">10.1186/gb-2005-6-4-r38</pub-id>
          <pub-id pub-id-type="medline">15833125</pub-id>
          <pub-id pub-id-type="pii">gb-2005-6-4-r38</pub-id>
          <pub-id pub-id-type="pmcid">PMC1088966</pub-id>
        </nlm-citation>
      </ref>
    </ref-list>
  </back>
</article>
