Skin tone and diagnostic equity in contactless blood pressure screening: a prospective observational field evaluation of remote photoplethysmography in Nigeria.
Authors: Dasa, D., Davies, P.
Journal: BMJ Open
Publication Date: 22/06/2026
Volume: 16
Issue: 6
Pages: e119311
eISSN: 2044-6055
DOI: 10.1136/bmjopen-2026-119311
Abstract:OBJECTIVES: To evaluate diagnostic equity, feasibility and acceptability of a remote photoplethysmography-based blood pressure screening application among adults with darker skin tones in Nigeria. DESIGN: Prospective observational multisite field evaluation. SETTING: Three hospitals in Kebbi State, Nigeria. PARTICIPANTS: Adults with Fitzpatrick skin types V-VI. OUTCOME MEASURES: Feasibility, agreement, diagnostic accuracy, acceptability, and equity relevant factors including facial tribal markings and internet bandwidth, using automated cuff measurements as the reference standard and a 140 over 90 mm Hg hypertension threshold. RESULTS: Among 306 enrolled participants, 249 (81.4%) produced usable readings. Agreement was poor (systolic mean absolute error (MAE) 15.4 mm Hg, root mean square error (RMSE) 19.9; diastolic MAE 10.9 mm Hg, RMSE 13.6). Sensitivity for threshold-based systolic and diastolic blood pressure classification was very low (systolic 0.04; diastolic 0.10), with systolic sensitivity 0.00 in Fitzpatrick type VI. Specificity was high (systolic 0.99; diastolic 0.89). Lower internet bandwidth correlated with reading failure (r = -0.69 to -0.51). While 70% of patients and over 90% of staff rated the tool favourably, technical limitations created a clear perception-performance gap. In an exploratory interaction analysis, Fitzpatrick type VI was associated with higher odds of measurement failure (OR 5.08, 95% CI 2.41 to 10.72), but there was no clear evidence that facial tribal markings modified this association (interaction OR 0.66, 95% CI 0.16 to 2.73; p=0.564). CONCLUSIONS: Remote photoplethysmography (rPPG)-based blood pressure screening was feasible but showed inadequate performance in this darker-skinned field cohort, with critically low sensitivity. Without algorithmic recalibration for skin tone diversity and improved offline functionality, cloud-dependent rPPG systems deployed without spectrum-balanced validation may risk exacerbating diagnostic inequities in similar settings.
Source: PubMed
Skin tone and diagnostic equity in contactless blood pressure screening: a prospective observational field evaluation of remote photoplethysmography in Nigeria
Authors: Dasa, D., Davies, P.
Journal: BMJ OPEN
Publication Date: 22/06/2026
Volume: 16
Issue: 6
ISSN: 2044-6055
DOI: 10.1136/bmjopen-2026-119311
Source: Web of Science
Skin Tone and Diagnostic Equity in Contactless Blood Pressure Screening: A Prospective observational Field Evaluation of Remote Photoplethysmography in Nigeria
Authors: Dasa, D., Davies, P.
Journal: BMJ Open
Publication Date: 10/06/2026
Publisher: BMJ Publishing Group
eISSN: 2044-6055
ISSN: 2044-6055
DOI: 10.1136/bmjopen-2026-119311
Abstract:Objectives To evaluate diagnostic equity, feasibility, and acceptability of a remote photoplethysmography based blood pressure screening application among adults with darker skin tones in Nigeria.
Design Prospective observational multi-site field evaluation.
Setting Three hospitals in Kebbi State, Nigeria.
Participants Adults with Fitzpatrick skin types V to VI.
Outcome measures Feasibility, agreement, diagnostic accuracy, acceptability, and equity relevant factors including facial tribal markings and internet bandwidth, using automated cuff measurements as the reference standard and a 140 over 90 mm Hg hypertension threshold.
Results Among 306 enrolled participants, 249 (81.4%) produced usable readings. Agreement was poor (systolic MAE 15.4 mm Hg, RMSE 19.9; diastolic MAE 10.9 mm Hg, RMSE 13.6). Sensitivity for threshold-based SBP and DBP classification was verylow (systolic 0.04; diastolic 0.10), with systolic sensitivity 0.00 in Fitzpatrick type VI.
Specificity was high (systolic 0.99; diastolic 0.89). Lower internet bandwidth correlated with reading failure (r = −0.69 to −0.51). While 70% of patients and over 90% of staff rated the tool favourably, technical limitations created a clear perception–performance gap. In an exploratory interaction analysis, Fitzpatrick type VI was associated with higher odds of measurement failure (OR 5.08, 95% CI 2.41–10.72), but there was no clear evidence that facial tribal markings modified this association (interaction OR 0.66, 95% CI 0.16–2.73; p=0.564).
Conclusions rPPG-based blood pressure screening was feasible but showed inadequate performance in this darker-skinned field cohort, with critically low sensitivity.
Without algorithmic recalibration for skin tone diversity and improved offline functionality, cloud-dependent rPPG systems deployed without spectrum-balanced validation may risk exacerbating diagnostic inequities in similar settings.
Source: Manual
Skin tone and diagnostic equity in contactless blood pressure screening: a prospective observational field evaluation of remote photoplethysmography in Nigeria.
Authors: Dasa, D., Davies, P.
Journal: BMJ open
Publication Date: 06/2026
Volume: 16
Issue: 6
Pages: e119311
eISSN: 2044-6055
ISSN: 2044-6055
DOI: 10.1136/bmjopen-2026-119311
Abstract:Objectives
To evaluate diagnostic equity, feasibility and acceptability of a remote photoplethysmography-based blood pressure screening application among adults with darker skin tones in Nigeria.Design
Prospective observational multisite field evaluation.Setting
Three hospitals in Kebbi State, Nigeria.Participants
Adults with Fitzpatrick skin types V-VI.Outcome measures
Feasibility, agreement, diagnostic accuracy, acceptability, and equity relevant factors including facial tribal markings and internet bandwidth, using automated cuff measurements as the reference standard and a 140 over 90 mm Hg hypertension threshold.Results
Among 306 enrolled participants, 249 (81.4%) produced usable readings. Agreement was poor (systolic mean absolute error (MAE) 15.4 mm Hg, root mean square error (RMSE) 19.9; diastolic MAE 10.9 mm Hg, RMSE 13.6). Sensitivity for threshold-based systolic and diastolic blood pressure classification was very low (systolic 0.04; diastolic 0.10), with systolic sensitivity 0.00 in Fitzpatrick type VI. Specificity was high (systolic 0.99; diastolic 0.89). Lower internet bandwidth correlated with reading failure (r = -0.69 to -0.51). While 70% of patients and over 90% of staff rated the tool favourably, technical limitations created a clear perception-performance gap. In an exploratory interaction analysis, Fitzpatrick type VI was associated with higher odds of measurement failure (OR 5.08, 95% CI 2.41 to 10.72), but there was no clear evidence that facial tribal markings modified this association (interaction OR 0.66, 95% CI 0.16 to 2.73; p=0.564).Conclusions
Remote photoplethysmography (rPPG)-based blood pressure screening was feasible but showed inadequate performance in this darker-skinned field cohort, with critically low sensitivity. Without algorithmic recalibration for skin tone diversity and improved offline functionality, cloud-dependent rPPG systems deployed without spectrum-balanced validation may risk exacerbating diagnostic inequities in similar settings.Source: Europe PubMed Central