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 was assessed at time of diagnosis and after at least two and five years follow-up.

Results — Among 922,464 individuals, 2,440 (0.26%) met criteria for definite/probable FH, and 72,893 (7.90%) for severe hypercholesterolemia. At diagnosis, mean LDL-C was 9.52 mmol/L for definite FH, 5.83 mmol/L for probable FH, 5.73 mmol/L for severe hypercholesterolemia, and 3.33 mmol/L for all other individuals. After >5 years, LDL-C remained elevated at 3.58 mmol/L for definite FH, 2.72 mmol/L for probable FH, and 2.93 mmol/L for severe hypercholesteremia. Use of statin therapy was initially high (83% definite FH, 78% probable FH, 62% severe hypercholesterolemia); however, fewer patients remained on statins at >5 years follow-up (62% definite FH, 67% probable FH, 58% severe hypercholesterolemia).

Conclusions — Among older Ontarians, we estimated 1 in 378 individuals had FH and 1 in 13 had severe hypercholesterolemia. Despite being at substantially increased cardiovascular risk, LDL-C control was suboptimal and treatment declined at follow-up.