High prevalence of primary dyslipidaemia in black South African patients at a tertiary hospital in northern Gauteng, South Africa

Abstract

The American Heart Association predicted the rise in the prevalence of cardiovascular disease as 38.7% by 2020, where the coronary heart disease would rise for 8.6% and stroke for 3.6%. [1] In South Africa (SA), Liberty Life Insurance group has forecast the premature deaths due to heart and blood vessel diseases in people of working age (35-64 years) to increase by 41% between 2007 and 2030, with a warning of enormous negative economic impact. [2] Locally, an increased awareness of cardiovascular disease at the Dr George Mukhari referral hospital has led to more requests for plasma lipid profiles comprising fasting triglyceride (TG), total cholesterol (TC), high-density lipoprotein (HDL) cholesterol (HDLC) and low-density lipoprotein (LDL) cholesterol (LDLC). In 2013, 18 234 lipid profiles from 7 255 patients were analysed compared with 24 656 requests for 6 348 patients in 2014. The 35% increase occurred despite opening a new antiretroviral (ARV) clinic in the neighbourhood, which reduced patient flow at the tertiary hospital, and the introduction of electronic gatekeeping. Requests were in response to patients' history of early death among first-degree relatives due to heart disease and stroke, [3] and cardiovascular risk suggested by obesity, metabolic syndrome, smoking, sedentary lifestyle, lack of exercise and stressful living. Genetic disorders in lipoprotein metabolic pathways generally have a greater impact on risk and typically display more severe and/ or persistent lipid abnormalities after treating the secondary factors. [4,5] Cascade testing of the family is advised. [6] Admixture of primary and secondary causes is especially evident in Fredrickson hyperlipidaemia types III, IV and V, where predisposing variant genes are stressed by diet, obesity with insulin resistance, hormonal derangements and alcohol intake. In SA, at least three low-density lipoprotein receptor (LDLR) mutations are known in Afrikaans-speaking whites, one in Jewish people from Eastern Europe and one in Indians of Gujerati descent. [7,8] Familial hypercholesterolaemia (FH) is mostly due to a pathogenic mutation in one of three genes (LDLR, apolipoprotein B (apoB) or proprotein convertase subtilisin/kexin type 9). FH is relatively common (prevalence 1:200-1:500) and is therefore the most important monogenic disorder of lipoprotein metabolism. It exists as either heterozygous, where only one allele of the gene involved is mutated and the other allele is normal, or homozygous, where both alleles are abnormal. Persons with untreated

The burden of dyslipidaemia and factors associated with lipid levels among adults in rural northern Ghana: An AWI-Gen sub-study

“…The burden of dyslipidaemia in this population, as described by high LDL-C, TC or TG levels, was lower than that observed in Ghanaian urban settings [13,15] and lower than that noted in urban environments in other sub-Saharan African countries [12,37]. A previous study from Ghana comparing lipid profiles between urban and rural populations also demonstrated higher TC and LDL-C levels in the urban population, but higher TG levels in the rural cohort [15].…”

Familial Hypercholesterolemia Identification by Machine Learning Using Lipid Profile Data Performs as Well as Clinical Diagnostic Criteria

“…Dyslipidemia is, however, not an uncommon finding among Black South Africans, as a recent retrospective study done at another large South African academic hospital showed that 5.8% of Black patients with a lipid profile had a cholesterol-predominant profile (TC >5 mmol/L, LDL-C >3 mmol/L, and normal range triglyceride), although specific investigations to diagnose FH were not done. 43 These 2 studies, taken together, highlight the possibility that FH is severely underdiagnosed in the Black South African population. The application of ML could prove very valuable in identifying previously undiagnosed individuals with FH, especially those outside of the traditional screening approaches.…”

Dyslipidaemia in South Africa

“…A retrospective study performed on black SA patients treated at the Dr George Mukhari Hospital, Gauteng, found a significant burden and high prevalence of dyslipidaemia in black adults in whom a monogenic disorder should have been considered. [4] Severe hypercholesterolaemia (TG >7 mmol/L) was seen in 5% and extreme hypercholesterolaemia (TG >12 mmol/L) in 0.5% of patients. Elevated TG levels were noted in 9% of patients.…”

“…The authors concluded that the extent and severity of the dyslipidaemia justified a special clinic and laboratory to ensure accurate diagnosis, with effective intervention for patients and their families. [4] Indeed, there are very few dedicated, specialist lipid clinics in the public and private sectors in SA.…”