Prevalence of multimorbidity of cardiometabolic conditions and associated risk factors in a population-based sample of South Africans: A cross-sectional study

Abstract

Objectives: Ageing populations have led to a growing prevalence of multimorbidity. Cardiometabolic multimorbidity (CM), the co-existence of two or more cardiometabolic disorders in the same person, is rapidly increasing. We examined the prevalence and risk factors associated with CM in a population-based sample of South African adults.

Study design: Data were analysed on individuals aged ≥15 years from the South African National Health and Nutrition Examination Survey (SANHANES), a cross sectional population-based survey conducted in 2011-2012.

Methods: CM was defined as having ≥2 of hypertension, diabetes, stroke and angina. Hypertension was defined as blood pressure ≥140/90 mmHg or self-reported antihypertensive medication use. Diabetes was defined by HbA1c ≥ 6.5% or self-reported medication use. Stroke and angina were assessed by self-report. Multivariable logistic regression was used to investigate the sociodemographic and modifiable risk factors associated with CM. The association of CM with the functional status of individuals was examined using logistic regression, where functional status was measured by the WHO DAS 2.0 12-item instrument.

Results: Of the 3832 individuals analysed, the mean age was 40.8 years (S.D. 18.3), 64.5% were female and 18% were ≥60 years. The prevalence of CM was 10.5%. The most prevalent CM cluster was hypertension and diabetes (7.3%), followed by hypertension and angina (2.6%) and hypertension and stroke (1.9%). Of the individuals with diabetes, nearly three quarters had multimorbidity from co-occurring hypertension, angina and/or stroke and of those with hypertension, 30% had co-occurring diabetes, angina and/or stroke. Age (30-44 years Adjusted Odds Ratio (AOR) = 2.68, 95% CI: 1.15-6.26), 45-59 years AOR = 16.32 (7.38-36.06), 60-74 years AOR = 40.14 (17.86-90.19), and ≥75 years AOR = 49.54 (19.25-127.50) compared with 15-29 years); Indian ethnicity (AOR = 2.58 (1.1-6.04) compared with black African ethnicity), overweight (AOR = 2.73 (1.84-4.07)) and obesity (AOR = 4.20 (2.75-6.40)) compared with normal or underweight) were associated with increased odds of CM. When controlling for age, sex and ethnicity, having ≥2 conditions was associated with significantly higher WHO DAS percentage scores (β = 5.4, S.E. = 1.1, p < 0.001).

Conclusions: A tenth of South Africans have two or more cardiometabolic conditions. The findings call for immediate prioritisation of prevention, screening and management of cardiometabolic conditions and their risk factors to avert large scale health care costs and adverse health outcomes associated with multimorbidity.

Keywords: Cardiometabolic multimorbidity; Diabetes; Hypertension; Non-communicable diseases; South Africa.

Fig. 1

Prevalence of number of cardiometabolic conditions by age group.