Prevalence and Treatment of Familial Hypercholesterolemia and Severe Hypercholesterolemia in Older Adults in Ontario, Canada

BACKGROUND: A simplified Canadian definition was recently developed to enable identification of individuals with familial hypercholesterolemia (FH) and severe hypercholesterolemia in the general population. Our objective was to use a modified version of this new definition to assess contemporary disease prevalence, treatment patterns, and low-density lipoprotein cholesterol (LDL-C) control in Ontario, Canada. METHODS: We identified individuals aged 66 to 105 years who were alive as of January 1, 2011, using the Cardiovascular Health in Ambulatory Care Research Team (CANHEART) database, which was created by linking 19 population-based health databases in Ontario. Hypercholesterolemia was identified using LDL-C values. Cholesterol reduction and lipid-lowering treatment were assessed at time of diagnosis and after at least 2 and 5 years’ follow-up. RESULTS: Among 922,464 individuals, 2440 (0.26%) met criteria for definite or probable FH, and 72,893 (7.90%) for severe hypercholesterolemia. At diagnosis, mean LDL-C concentration was 9.52 mmol/L for those with definite FH, 5.83 mmol/L for those with probable FH, 5.73 mmol/L for those with severe hypercholesterolemia, and 3.33 mmol/L for all other individuals. After > 5 years, LDL-C concentration remained elevated at 3.58 mmol/L for those with definite FH, 2.72 mmol/L for those with probable FH, and 2.93 mmol/L for those with severe hypercholesteremia. Use of statin therapy was initially high (83% of those with definite FH, 78% of those with probable FH, 62% of those with severe hypercholesterolemia); however, fewer patients remained on statins at follow-up at > 5 years (62% of those with definite FH, 67% of those with probable FH, 58% of those with severe hypercholesterolemia). CONCLUSIONS: Among older Ontarians, we estimated that 1 in 378 individuals had FH, and 1 in 13 had severe hypercholesterolemia. Despite being at substantially increased cardiovascular risk, these patients acheived suboptimal LDL-C level control and fewer were on medical therapy at follow-up.