Prevalence of genetically verified familial hypercholesterolemia among young (<45 years) Norwegian patients hospitalized with acute myocardial infarction.

Background: Patients with familial hypercholesterolemia (FH) have an increased risk of premature myocardial infarction (MI).

Objectives: The objective of the study is to investigate the prevalence of FH among young patients hospitalized with acute MI.

Methods: Data were collected from medical charts of all patients aged <45 years admitted with acute MI to the Department of Cardiology, Oslo University Hospital Ullevål, in the period 2012 to 2016. Patients who had not already been genetically tested for FH were contacted and offered genetic testing if the pretreatment or the statin-adjusted low-density lipoprotein cholesterol level was >4.0 mmol/L (155 mg/dL).

Results: Of 9332 patients admitted with acute MI, 357 were aged <45 years. Sixteen patients were deceased, and 13 patients did not have MI on an atherosclerotic basis. Of the remaining 328 patients eligible for investigation, 130 had the pretreatment or statin-adjusted low-density lipoprotein cholesterol level >4.0 mmol/L (155 mg/dL). Of these, data from 52 patients genetically tested for FH were available. Eleven patients had genetically verified FH constituting 3.4% of the total eligible population (n = 328), 8.5% of those with indications for genetic testing (n = 130), and 21.2% of those actually tested (n = 52). A Dutch Lipid Clinic Network score for clinical FH diagnosis of "definite FH" identified only 5 of the 11 patients with positive genetic test (45%). Including a score of "probable FH" identified all patients with FH but also 17 of the 41 patients (41%) with a negative genetic test.

Conclusion: The prevalence of FH in young patients with acute MI was higher than in the general population. Routine evaluation of FH diagnosis among these patients could identify more patients with FH, thereby increasing the possibility of initiating early and adequate treatment also among affected relatives.