Time to review policy on screening for, and managing, hypertension in South Africa: Evidence from primary care

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

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.

Rising prevalence, and improved but suboptimal management, of hypertension in South Africa: A comparison of two national surveys

Aim

To examine the changes in prevalence, awareness, treatment and control of hypertension between 1998 and 2016 in ≥15-year-old South African men and women and the sociodemographic characteristics associated with those changes.

Methods

In nationally representative surveys in 1998 and 2016, multi-stage sampling was used to select, interview and collect blood pressure and anthropometric measurements in ≥15-year-old adults. Logistic regression analyses evaluated the independent effects of selected sociodemographic characteristics on hypertension management.

Results

Among 13,217 participants in 1998 and 7830 in 2016 (59-60% women in both surveys), hypertension prevalence increased from 27% to 45% in men and 31% to 48% in women. Hypertension increased equally in participants with and without obesity and in daily cigarette smokers vs. their counterparts. Prevalence of awareness among participants with hypertension increased from 7% to 18% (men) and from 17% to 29% (women). Among those aware, hypertension treatment improved markedly from 8% to 85% (men) and from 12% to 82% (women). Hypertension control among those on treatment increased from 17% to 26% (men) and from 21% to 30% (women). Increasing age and survey year were consistently associated with higher prevalence, awareness, treatment and control of hypertension. The richest vs. poorer women, and lower vs. higher educated women were more likely to be treated for hypertension.

Conclusions

The high and rising hypertension burden together with suboptimal awareness and control levels warrant greater attention to curb hypertension-related morbidity and mortality in South Africans. Novel strategies involving community-based or workplace hypertension programmes may overcome some barriers to optimal care.

Undiagnosed Hypertension in a Workplace: The Case of a Logistics Company in Gauteng, South Africa

A large proportion of the population with hypertension remains undiagnosed, untreated, or inadequately treated, contributing to the rising burden of cardiovascular diseases in South Africa. A workplace may either mitigate or accentuate the risk factors for hypertension. A cross sectional study was conducted to determine the prevalence of undiagnosed hypertension and associated factors among 312 employees in a Logistics Company, South Africa. A modified, validated, self-administered WHO STEPwise questionnaire was used to collect data on demography, lifestyle factors, anthropometry and blood pressure (BP). Hypertension was defined at BP ≥ 140/90 mmHg. Data was analysed using STATA 14. Mean age of employees was 40 ± 10 years, with a 50% prevalence of undiagnosed hypertension. No significant association was observed between occupation and undiagnosed hypertension, except for high prevalence of undiagnosed hypertension among truck drivers and van assistants (43%), and general workers (27%), having higher odds of increased waist-to-height ratio. Hypertension was associated with age (OR = 2.3, 95%CI; 1.21–4.27), alcohol use (AOR = 1.8, 95%CI; 1.05–2.93), waist circumference (AOR = 2.3, 95%CI; 1.29–4.07) and waist-to-height-ratio (AOR = 3.7, 95%CI; 1.85–7.30). Improved and effective workplace health programs and policies are necessary for management of undiagnosed hypertension among employees. Longitudinal studies on mediation of occupation in association of demographic and lifestyle factors with hypertension in workplaces are needed.

Noncommunicable Diseases Burden and Risk Factors in a Cohort of HIV+ Elderly Patients in Malawi

HIV-infected patients have increased risk of noncommunicable diseases (NCDs). HIV+ patients in Africa are experiencing growing comorbidities due to increase in life expectancy and long-time antiretroviral therapy (ART). HIV prevalence in Malawi is one of highest in the world (10.8% in women and 6.4% in men); few data are available about NCDs epidemiology in HIV+ elderly patients in Malawi. A retrospective analysis of routine medical records in 14 health centers run by Disease Relief through Excellent and Advanced Means (DREAM) program in Malawi was carried out. All HIV+ patients aged >40 years in care in the period January 01, 2017-December 31, 2018 were included. Clinical and laboratory features were collected in the last visit of the study period. Files from 7,071 patients (62.1% women) in ART were analyzed, 362 (5.1%) were aged >65 years. Median time on ART was 98.9 (64.8-118.0) months; median body mass index, haemoglobin (HB), and CD4 count were, respectively, 21.63 kg/m² (19.5-24.5), 13 mg/dL (12-14), and 457 cell/mm³ (328-613). Elderly patients >65 years were more likely to be malnourished (odds ratio [OR] = 2.0, confidence interval [CI]: 1.54-2.59), diagnosed with arterial hypertension (OR = 2.5, CI: 1.94-3.43), affected with diabetes (OR = 2.7, CI: 1.25-6.22), have macrocytic anemia (OR = 2.5, CI: 2.00-3.35), and increased serum creatinine (OR = 1.5, CI: 1.03-2.43]). Other factors were associated with NCD burden, but age remained always independently related. Two concomitant chronic conditions in addition to HIV were present in 19.2% (66/343) of elderly people and 5.2% (338/6.454) of patients aged <65 years (OR = 4.3, CI: 3.22-5.76). Some associations were observed: nevirapine (NVP) was associated with kidney disease (OR = 1.5, CI: 1.22-2.06), NVP and protease inhibitor (PI) with hypertension (OR = 2.79, CI: 2.16-3.35 and OR = 2.15, CI: 1.52-3.02), azidothymidine (AZT) with macrocytic anemia (OR = 15.6, CI: 13.18-18.68). NVP, AZT, and duration of any ART >3 years were associated with the presence of two or more comorbidities (OR = 2.1 1.54-2.96, OR = 2.6 1.87-3.71, and OR = 1.7 1.12-2.84). Our data show the burden of NCDs in aging HIV+ patients in Malawi. The expansion of HIV treatment programs will require special attention to such comorbidities in elderly patients.