# Cardiovascular disease and compliance with lipid-lowering therapy among young individuals with familial hypercholesterolemia in Norway – A register study

## TL;DR

This study examines cardiovascular disease and medication compliance in young Norwegians with familial hypercholesterolemia, finding low event rates and moderate adherence to lipid-lowering drugs.

## Contribution

The study provides new insights into cardiovascular risk and medication adherence in young FH patients using Norwegian national health registries.

## Key findings

- FH subjects had one CHD event and 6 deaths, with none of the deaths linked to CVD.
- Statin prescription coverage dropped from 85% to 70% after 8 years, indicating moderate compliance.
- Hazard ratios suggested increased CHD risk in FH subjects, but results were not statistically significant due to low event numbers.

## Abstract

Investigation of CV disease during 2008-2018, and use of lipid lowering drugs during 2004–2018 among 1351 young subjects with FH.•There was one cardiovascular event and 6 deaths among subjects with FH, and three CV events and 53 deaths among a general population control group.•None of the deaths among the FH subjects were due to CV disease.•Results may suggest increased risk of CV events among subjects with FH, but the number of events was too low to reliably determine this.•Statins were prescribed to 83 % and ezetimibe to 21 % of subjects, after one year 85 % were covered with statins, decreasing to 70 % after 8 years.

Investigation of CV disease during 2008-2018, and use of lipid lowering drugs during 2004–2018 among 1351 young subjects with FH.

There was one cardiovascular event and 6 deaths among subjects with FH, and three CV events and 53 deaths among a general population control group.

None of the deaths among the FH subjects were due to CV disease.

Results may suggest increased risk of CV events among subjects with FH, but the number of events was too low to reliably determine this.

Statins were prescribed to 83 % and ezetimibe to 21 % of subjects, after one year 85 % were covered with statins, decreasing to 70 % after 8 years.

Investigation of cardiovascular disease (CVD), all-cause death and use of statins and ezetimibe among young Norwegian individuals with heterozygous Familial hypercholesterolemia (FH).

We included subjects with genetically verified FH born 1988–2008 and twenty controls per FH subject, with linkage to prescription data, hospitalization data and cause of death from national Norwegian health registries. Data on CHD and death during 2008–2018, and for dispensed prescriptions during 2004–2018, were collected.

1351 subjects with FH and 27,015 controls were included. Mean age (SD) at start of follow-up was 12.3 (5.4) years. There was one Coronary Heart Disease (CHD) event and 6 deaths in the FH-group and 3 CHD events and 53 deaths in the control group. CHD and all-cause death were non-significantly increased in the FH-group, hazard ratios (95 % confidence intervals) 6.68 (0.69–64.20) and 2.26 (0.98–5.28), respectively. None of the deaths in the FH-group were related to cardiovascular disease. 83 % of subjects with FH had been prescribed a statin, and 21 % ezetimibe. During the first year after the first prescription, 18.5 % of subjects did not refill their prescription within 180 days after the end date of the previous prescription. 69 % and 60 % of subjects with a prescription had >80 % of days covered with statins and ezetimibe, respectively. After 8 years, around 70 % of subjects were covered with statins.

Results suggest increased risk of CHD in FH relative to controls, but measures are imprecise because of low absolute risks. Compliance with lipid lowering therapy was moderate.

Image, graphical abstract