Familial hypercholesterolaemia leads to lifelong elevated low-density lipoprotein cholesterol with increased risk of coronary heart disease and pre-mature death. It is unknown whether the prognosis for individuals with familial hypercholesterolaemia has improved over the past four decades as registration of this condition has been limited worldwide. However, in Danish nationwide registries, modified ICD coding has allowed such registration since 1978. This study tested the hypothesis that age at death and coronary heart disease has improved from 1978 to 2021 in individuals with vs. those without familial hypercholesterolaemia.

From nationwide registries, all Danish residents were included in a retrospective cohort study. Inclusion and follow-up were from 1978 to 2021. Individuals diagnosed with familial hypercholesterolaemia were identified, and trends over time were examined for age at death and age at coronary heart disease.

During follow-up for those with (n = 10 199) and without (n = 9 174 926) familial hypercholesterolaemia, 27% and 27% died and 34% and 9% experienced coronary heart disease. Age at death was 22 years younger in 1978 (P < .001) but similar in 2021 (P = .16) in individuals with vs. without familial hypercholesterolaemia. Although the corresponding age at coronary heart disease was 20 years younger in 1978 (P < .001), it was still 7 years younger in 2021 (P < .001) in individuals with vs. without familial hypercholesterolaemia. These results were similar in women and men and in a 1:100 matched analysis by sex, ethnicity, and time of birth.

Nationwide from 1978 to 2021 in Denmark, normalization of age at death but not age at coronary heart disease was observed for individuals diagnosed with familial hypercholesterolaemia.