Presence of hypertension might pose a potential pitfall in detection of diabetes mellitus non-invasively using the second derivative of photoplethysmography

ABSTRACTIndices derived from photoplethysmography (PPG) have shown promising results as non-invasive digital biomarkers for the detection of diabetes mellitus (DM). Considering the mutual endothelial insult leading to similar undesirable peripheral hemodynamic perturbations, hypertension (HT) may blunt this classification performance. Second derivative PPG (SD-PPG) indices were derived from the second derivative of the PPG signal. The variables of interest were the previously described peaks of the initial positive (a), early negative (b), re-increasing (c), late re-decreasing (d), diastolic positive (e) and negative (f) waves and the ratios between them. Patients were classified according to their type 2 DM and hypertension phenotypes. SD-PPG indices were compared between diseased subgroups, healthy controls and also dichotomous classification performance was evaluated. Two SDPPG indices, b/a ratio and the vascular ageing index (VAI = (b-c-d-e)/a) responded to isolated DM type 2 (n = 29) amongst healthy subjects (n = 106) (area under the curve (AUC) = 0.629 p = 0.034 and 0.631 p = 0.031 20 respectively). However, the classification performance became insignificant with the inclusion of HT patients (n=30). (p = 0.839 vs. p = 0.656). These results suggest that the coexistence of HT and DM may hinder the use of SD-PPG for noninvasive DM detection.KEYWORDS: Second-derivative photoplethysmographydiabetesnon-invasive cardiovascular screeningfingertip waveformshypertension Abbreviations Body Mass Index=BMIDiabetes Mellitus=DMDiabetes Mellitus Type-2=DM2Diastolic Blood Pressure=DBPHypertension=HTPhotoplethysmography=PPGSecond derivative of Photoplethysmography=SD-PPGVascular Ageing Index=VAISystolic Blood Pressure=SBPDisclosure statementNo potential conflict of interest was reported by the authors.Author contributionsStudy conception and design was made by Ahmet Tas. All authors (Ahmet Tas, Yaren Alan, Ilke Kara, Abdullah Savas, Muhammed Ikbal Bayhan, Diren Ekici, Zeynep Atay, Fatih Sezer, Cagla Kitapli, Sabahattin Umman, Murat Sezer) have contributed to material preparation, data collection and analysis (signal and/or statistical and/or intellectual) and interpretation of results. The first draft of the manuscript was written by Ahmet Tas, and all authors (Ahmet Tas, Yaren Alan, Ilke Kara, Abdullah Savas, Muhammed Ikbal Bayhan, Diren Ekici, Zeynep Atay, Fatih Sezer, Cagla Kitapli, Sabahattin Umman, Murat Sezer) commented on previous versions of the manuscript. All authors (Ahmet Tas, Yaren Alan, Ilke Kara, Abdullah Savas, Muhammed Ikbal Bayhan, Diren Ekici, Zeynep Atay, Fatih Sezer, Cagla Kitapli, Sabahattin Umman, Murat Sezer) read and approved the final manuscript.Ethics approvalThe data is retrieved from open-dataset published in Nature Scientific Data (https://www.nature.com/articles/sdata201820#). The data collection had ethical approval denoted in data descripting article and all participants have given written consent per open-data descripting article. All authors meet authorship criteria of ICMJE.Additional informationFundingThe authors reported there is no funding associated with the work featured in this article.