1. Pitfalls of Single Measurement Screening for Diabetes and Hypertension in Community-Based Settings
- Author
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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, and Vukuzazi Study team
- Subjects
hypertension ,diabetes ,screening ,Diseases of the circulatory (Cardiovascular) system ,RC666-701 ,Public aspects of medicine ,RA1-1270 - 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.
- Published
- 2021
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