Lipoprotein (a) plasma levels and association to cardiovascular disease in a Stockholm County cohort – a retrospective observational cohort registry study  

Karin Littmann (1), MD, Jonas Brinck (2), MD, PhD, Mats Eriksson (2) MD, PhD, Paolo Parini (1,2), MD, PhD 
(1) Div. of Clinical Chemistry, Dept. of Laboratory Medicine, Karolinska Institutet and Function Area Clinical Chemistry, Karolinska University Laboratory, Karolinska University Hospital, Stockholm, Sweden
(2) Metabolism Unit, Dept. of Medicine, Karolinska Institutet and Patient Area Endocrinology and Nephrology, Inflammation and Infection Theme, Karolinska University Hospital, Stockholm Sweden

Aim: 
Lipoprotein(a) (Lp(a)) is a strong independent genetic risk factor for cardiovascular disease (CVD). At Lp(a) levels above 50 mg/dL, increased relative risk (1.46) for myocardial infarction (MI) and (1.95) for aortic stenosis (AS) has been reported (Afshar et.al. 2016). Whether reduction of Lp(a) leads to decreased risk is debated. Afshar et.al. estimated that 1 in 14 MI and 1 in 7 AS could be prevented by lowering Lp(a) to < 50 mg/dL. 
This study aims to define distribution of Lp(a) in a Stockholm County cohort, investigate its association to CVD, other diagnosis and risk factors. 
Methods: 
From the database at Karolinska University Laboratory (KUL), all Lp(a) results were retrieved. Laboratory data from each subject are combined with data from Swedish National quality registers on CVD (Swedeheart, Swedvasc, Riks-stroke) and National Board of Health and Welfare registers (death, diagnosis, prescribed drug). Lp(a) was measured by two assays that report concentration in mass or molar. 
Results: 
From the KUL-database, 23664 subjects (male 48%, female 52%, median 56(0-99) years) were identified. We observed a skewed distribution, median Lp(a) 16 mg/dL or 20 nmol/L, 80:th percentile at 53 mg/dL or 119 nmol/L (Figure 1-2).
Conclusions: 
Initial analyses of routine measured Lp(a) in subjects referred to hospitals or general practitioners show similar distribution and 80:th percentile value as previously described in general population studies. Analysis of data from registers are ongoing. Results from our study will contribute to further understanding of Lp(a), its association to CVD, other diagnosis and to whether patients with elevated Lp(a) should be managed.

02 - LIPOPROTEIN (A) PLASMA LEVELS AND ASSOCIATION TO CARDIOVASCULAR DISEASE IN A STOCKHOLM COUNTY COHORT – A RETROSPECTIVE OBSERVATIONAL COHORT REGISTRY STUDY