Evidence map›Paper›PMID 42331583›Full record

Observational studyBMJ open2026

Skin tone and diagnostic equity in contactless blood pressure screening: a prospective observational field evaluation of remote photoplethysmography in Nigeria.

David Dasa, Philip Davies

Abstract readObservational StudyMulticenter Study
In one paragraph

Observational study in BMJ open, 2026. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Cited by 1 paper.

0numbers the graph read from it
0cells of the map it votes in
1citing papers in PubMed
–field-weighted citation impact
1 · What the graph read from it

What it found

Each row is one number read from the abstract, on the scale the paper reported it, with its interval. Left of the dashed line favours the treatment, right favours the comparator. Under each row is the sentence it came from. New to these charts? A ten-minute tutorial.

The abstract states no effect estimate the extractor could read, or names no intervention and outcome on the map, so this paper lights no cell and moves no belief. It is still indexed, cited and linked below.

2 · The registry

The trial behind it

Trials whose registry record cites this paper, or whose number appears in the abstract. A trial that started after this paper was published is citing it as background, not reporting it.

Neither the registry nor the abstract names a trial number. If this is a trial report, that itself is worth knowing.

3 · Its place in the literature

Who cites it

1 citing paper in PubMed.

  1. Disparities in Blood Pressure Measurement.Current hypertension reports · 2026
    Review
4 · The record

Corrections and comments

PubMed lists nothing against this paper. Absence here is not a guarantee, only a check that was made.

5 · Who and what money

Authors and funding

2 authors.

David DasaBournemouth University, Poole, UK ddasa@bournemouth.ac.uk.ORCID http://orcid.org/0009-0007-1535-5962
Philip DaviesBournemouth University, Poole, UK.

Funding

No grant is acknowledged in the PubMed record.

6 · The paper itself

Abstract

objectivesTo evaluate diagnostic equity, feasibility and acceptability of a remote photoplethysmography-based blood pressure screening application among adults with darker skin tones in Nigeria.

designProspective observational multisite field evaluation.

settingThree hospitals in Kebbi State, Nigeria.

participantsAdults 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.

resultsAmong 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).

conclusionsRemote 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.

Indexed as

Blood Pressure DeterminationHypertensionMass ScreeningPhotoplethysmographySkin PigmentationAdolescentAdultBlood PressureFeasibility StudiesFemaleHumansMaleMiddle AgedNigeriaProspective StudiesSensitivity and SpecificityDigital TechnologyHealth informaticsHypertensionMass ScreeningPUBLIC HEALTH

Identifiers

PMID42331583
PMCPMC13288978

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LicenceCC BY-NC
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Registered trials

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Read under generation 80e0d062 · epoch 390. Bibliography from PubMed, PubMed Central and OpenAlex; grants from NIH RePORTER; trial links from ClinicalTrials.gov; estimates, votes and beliefs from the OpenQuestion graph.