Pitfalls of Single Measurement Screening for Diabetes and Hypertension in Community-Based Settings

Stephen Olivier; Thomas Murray; Philippa Matthews; Ngcebo Mhlongo; Resign Gunda; Kathy Baisley; Dickman Gareta; Tshwaraganang Modise; Theresa Smit; Kobus Herbst; Xolile Mpofana; Thumbi Ndung'u; Olivier Koole; Deenan Pillay; Willem Hanekom; Emily Wong; Mark J Siedner; Vukuzazi Study team

doi:10.5334/gh.1083

Pitfalls of Single Measurement Screening for Diabetes and Hypertension in Community-Based Settings

Glob Heart. 2021 Dec 3;16(1):79. doi: 10.5334/gh.1083. eCollection 2021.

Authors

Stephen Olivier¹, Thomas Murray¹, Philippa Matthews^{1

2}, Ngcebo Mhlongo¹, Resign Gunda¹, Kathy Baisley^{1

3}, Dickman Gareta¹, Tshwaraganang Modise¹, Theresa Smit¹, Kobus Herbst^{1

4}, Xolile Mpofana¹, Thumbi Ndung'u^{1

5

6

7}, Olivier Koole^{1

3}, Deenan Pillay^{1

7}, Willem Hanekom^{1

7}, Emily Wong^{1

8}, Mark J Siedner^{1

9}; Vukuzazi Study team

Affiliations

¹ Africa Health Research Institute, KwaZulu-Natal, ZA.
² Islington GP Federation, London, UK.
³ London School of Hygiene and Tropical Medicine, London, UK.
⁴ DSI-MRC South African Population Research Infrastructure Network (SAPRIN), Durban, ZA.
⁵ HIV Pathogenesis Programme, The Doris Duke Medical Research Institute, Nelson R. Mandela School of Medicine, University of KwaZulu-Natal, ZA.
⁶ Max Planck Institute for Infection Biology, Berlin, DE.
⁷ Division of Infection and Immunity, University College London, London, UK.
⁸ Division of Infectious Diseases, University of Alabama Birmingham, Birmingham, AL, US.
⁹ Harvard Medical School, Boston, MA, US.

PMID: 34900570
PMCID: PMC8641532
DOI: 10.5334/gh.1083

Abstract

Background: Cross-sectional screening programs are used to detect and refer individuals with non-communicable diseases to healthcare services. We evaluated the positive predictive value of cross-sectional measurements for Diabetes Mellitus (DM) and hypertension (HTN) as part of a community-based disease screening study, 'Vukuzazi' in rural South Africa.

Methods: We conducted community-based screening for HTN and DM using the World Health Organization STEPS protocol and glycated haemoglobin A1c (HbA1c) testing, respectively. Nurses conducted follow-up home visits for confirmatory diagnostic testing among individuals with a screening BP above 140/90 mmHg and/or HbA1c above 6.5% at the initial screen, and without a prior diagnosis. We assessed the positive predictive value of the initial screening, compared to the follow up measure. We also sought to identify a screening threshold for HTN and DM with greater than 90% positive predictive value.

Results: Of 18,027 participants enrolled, 10.2% (1,831) had a screening BP over 140/90 mmHg. Of those without a prior diagnosis, 871 (47.6%) received follow-up measurements. Only 51.2% (451) of those with completed follow-up measurements had a repeat BP>140/90 mmHg at the home visit and were referred to care. To achieve a 90% correct referral rate, a systolic BP threshold of 192 was needed at first screening. For DM screening, 1,615 (9.0%) individuals had an HbA1c > 6.5%, and of those without a prior diagnosis, 1,151 (71.2%) received a follow-up blood glucose. Of these, only 34.1% (395) met criteria for referral for DM. To ensure a 90% positive predictive value i.e. a screening HbA1c of >16.6% was needed.

Conclusions: A second home-based screening visit to confirm a diagnosis of DM and HTN reduced health system referrals by 48% and 66%, respectively. Two-day screening programmes for DM and HTN screening might save individual and healthcare resources and should be evaluated carefully in future cost effectiveness evaluations.

Keywords: Diabetes; Screening; hypertension.

Publication types

Research Support, Non-U.S. Gov't

MeSH terms

Blood Pressure
Cross-Sectional Studies
Diabetes Mellitus* / diagnosis
Diabetes Mellitus* / epidemiology
Humans
Hypertension* / diagnosis
Hypertension* / epidemiology
Mass Screening

Grants and funding

201433/Z/16/A/WT_/Wellcome Trust/United Kingdom