We report the case of a 58-year-old woman who was referred to the Endocrine clinic in November 2017 with longstanding dyslipidaemia. Past lipid panel since 2006 (table) had revealed intermittent hypertriglyceridaemia, a mild elevation in her total cholesterol and low-density lipoprotein (LDL) levels and notably, extremely low high-density lipoprotein cholesterol (HDL-C) levels, with a nadir of 0.21mmol/L. Cardiovascular risk factors included overweight (body mass index 26.3kg/m2) and a 10-pack-year smoking history. She had no diabetes, hypertension or symptoms of cardiovascular disease (CVD). There was no known family history of dyslipidaemia or premature CVD. She took no regular medications. Her Australian Absolute CVD risk score indicated moderate to high risk.1 Advice on lifestyle modification was provided. Treatment with low dose Pravastatin was started in August 2017. Repeat lipid analysis whilst on Pravastatin revealed improved lipid levels however with persistently low HDL-C levels of 0.20-0.34mmol/L. Pravastatin dose was gradually uptitrated with a goal to reduce her LDL-C level to improve her LDL-C/HDL-C ratio.
Low HDL-C correlates with an increased risk of CVD 2,3 and extremely low HDL-C is defined as level <0.52mmol/L.3,4 Causes of low HDL-C, either familial or acquired, must be ascertained. Management of acquired low HDL-C involves correction of secondary factors including insulin resistance, hypertriglyceridaemia, overweight and obesity, very high carbohydrate intake, dysglobulinaemia, cigarette smoking and use of progestational agents and anabolic steroids.2,4 Reduction of the risk of atherosclerosis is the primary goal in the management of low HDL-C, with lifestyle intervention as the first line management.2,4 Currently available drugs do not robustly raise HDL-C. Statins generally increase HDL-C by 5-10%, however most risk reduction is achieved by lowering LDL-C.5 No clear recommendations are available thus far for targeting HDL-C due to lack of convincing outcomes data for HDL-C specific therapies. Several HDL-C-raising novel therapies are currently undergoing trials.4,5