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The subjects were subsequently categorized based on the presence or absence of CVD. The proportions of abnormal stiffness index (SI), the sine-waveform ratio (SIN ratio), a morphological index of PPG waveform regularity used as a marker for cardiovascular pathological aging, and total power (TP), derived from heart rate variability (HRV) frequency-domain analysis to reflect autonomic nervous system activity, were compared.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Results<\/jats:title>\n                    <jats:p>\n                      A total of 144 participants were enrolled in this study (CVD group,\n                      <jats:italic>n<\/jats:italic>\n                      \u2009=\u200954; healthy control group,\n                      <jats:italic>n<\/jats:italic>\n                      \u2009=\u200990). CVD group had higher SIN ratio (37.4\u2009\u00b1\u200927.8% vs. 21\u2009\u00b1\u200923.9%) and lower TP (1587.0\u2009\u00b1\u2009262.9 vs. 1804.7\u2009\u00b1\u2009261.7ms\u00b2) compared to healthy controls (\n                      <jats:italic>p<\/jats:italic>\n                      \u2009&lt;\u20090.001). CVD group had higher rates of abnormal SI (46% vs. 24%) and SIN ratio\u2009&gt;\u200940% (42.6% vs. 23.5%), all\n                      <jats:italic>p<\/jats:italic>\n                      \u2009&lt;\u20090.01. The combination of abnormal SI values, SIN ratio\u2009&gt;\u200940%, and TP\u2009&lt;\u20091500 ms\u00b2 indicated a high likelihood of CVD (\n                      <jats:italic>p<\/jats:italic>\n                      \u2009&lt;\u20090.001).\n                    <\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Conclusion<\/jats:title>\n                    <jats:p>PPG-derived SI, SIN ratio, and TP are valuable indicators that are potentially associated with cardiovascular health. Our results provided a convenient, inexpensive, and automated approach for preliminary assessment of the presence of CVD. Further large-scale studies are needed to validate these findings.<\/jats:p>\n                  <\/jats:sec>","DOI":"10.1186\/s12872-026-05914-6","type":"journal-article","created":{"date-parts":[[2026,5,9]],"date-time":"2026-05-09T07:12:25Z","timestamp":1778310745000},"update-policy":"https:\/\/doi.org\/10.1007\/springer_crossmark_policy","source":"Crossref","is-referenced-by-count":0,"title":["Evaluating the efficacy of photoplethysmography-derived stiffness index, sine-waveform ratio, and heart rate variability total power for cardiovascular health assessment"],"prefix":"10.1186","volume":"26","author":[{"given":"Lei","family":"Wang","sequence":"first","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Meng-Yu","family":"Hsiao","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Zi-Jun","family":"Chen","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Ruo-Jhen","family":"Wu","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-4655-6907","authenticated-orcid":false,"given":"Meng-Ting","family":"Wu","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"297","published-online":{"date-parts":[[2026,5,9]]},"reference":[{"key":"5914_CR1","doi-asserted-by":"publisher","first-page":"2529","DOI":"10.1016\/j.jacc.2019.10.009","volume":"74","author":"GA Mensah","year":"2019","unstructured":"Mensah GA, Roth GA, Fuster V. 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