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

BACKGROUND The prevalence of cardiovascular disease is projected to be 38.7% for the USA in 2020, including coronary heart disease at 8.6% and stroke at 3.6%. In South Africa (SA), premature deaths due to heart and blood vessel diseases in people of working age (35 - 64 years) have been predicted to increase by 41% between 2007 and 2030, with enormous negative economic impact. Atherosclerosis underlies much of the pathogenesis, which involves risk factors including dyslipidaemia. Secondary dyslipidaemia associated with diabetes mellitus, hypothyroidism, chronic renal disease, cholestasis, nephrotic syndrome, alcohol excess, drugs such as thiazide diuretics and antiretroviral agents may respond to treatment of underlying causes, but residual dyslipidaemia may in such cases be due to primary disorders of metabolism. Primary dyslipidaemias are uncommon and to a large extent underdiagnosed, especially in the black population of SA, reflecting a lack of clinical and laboratory awareness or expertise. Specific diagnoses enable effective intervention in the patients as well as the families. OBJECTIVE To assess the burden and prevalence of dyslipidaemia in the SA black population at Dr George Mukhari Hospital in the north region of Gauteng. METHOD A retrospective data analysis of 12-month lipid profiles comprising triglyceride (TG), total cholesterol (TC), high-density lipoprotein cholesterol and directly measured low-density lipoprotein (LDL) cholesterol (LDLC). RESULTS There were 24 656 requests for 6 348 patients. The lipid cut-off levels were somewhat arbitrary but were based on the commonly used decision-making levels in the treatment guidelines. Severe hypercholesterolaemia (>7 mmol/L) was seen in 299 (4.7%) patients and extreme hypercholesterolaemia (>12 mmol/L) was seen in 30 (0.5%) patients. LDLC (>5 mmol/L) occurred in 80 (1.3%) patients and >10 mmol/L in 19 (0.3%) patients. A predominant triglyceride problem was seen in 578 (9.1%) patients with TG (>2 mmol/L) and TC (<5 mmol/L), whereas moderate hypertriglyceridaemia (>5 mmol/L) was present in 113 (1.8%) patients, and more severe hypertriglyceridaemia (>10 mmol/L) in 10 (0.2%). TC (>5 mmol/L) with LDL (>3 mmol/L) but TG in the normal range was seen in 369 (5.8%) patients, indicating a cholesterol-predominant problem. In contrast, LDLC (>3 mmol/L) and TG (>1.7 mmol/L) was seen in 249 (3.87%) representing mixed hyperlipidaemia. Paediatric patients with severe dyslipidaemia mostly suffered from nephrotic syndrome. CONCLUSION A significant burden and a high prevalence of dyslipidaemias were present in adults in whom a monogenic disorder should be considered. The extent and severity of dyslipidaemia justify a special clinic and laboratory to ensure accurate diagnosis with effective intervention for patients and their families.