Longitudinal assessment of serum albumin levels with the risk of coronary artery calcification progression in an asymptomatic population of Korean adults: an observational cohort study.

Objectives: This study evaluated the association between serum albumin levels and coronary artery calcification (CAC) progression in asymptomatic adults without hypoalbuminaemia at baseline.

Design: Observational cohort study.

Setting: Data from the Korea Initiatives on Coronary Artery Calcification (KOICA) which is a retrospective, single ethnicity, multicentre and observational registry were analysed.

Participants: A total of 12 344 Korean adults with baseline albumin level of ≥3.5 g/dL (51.7±8.5 years; 84.3% male) were included. The median interscan period was 3.0 (2.0-4.8) years. All participants were stratified into three groups based on serum albumin tertile.

Primary And Secondary Outcome Measures: Association of serum albumin with the risk of CAC progression was analysed using multivariate logistic regression models with adjustment of interscan period. CAC progression was defined as a square root (√) transformed difference between the baseline and follow-up coronary artery calcium score (CACS) (Δ√transformed CACS) of ≥2.5. Annualised Δ√transformed CACS was defined as Δ√transformed CACS divided by interscan period.

Results: With increasing serum albumin tertiles, the annualised Δ√transformed CACS (I (lowest): 0.16 (0-1.24) vs II: 0 (0-1.09) vs III (highest): 0 (0-1.01)) and the incidence of CAC progression (I: 36.6% vs II: 31.3% vs III: 25.0%) were decreased despite higher prevalence of hypertension, diabetes and hyperlipidaemia (all p<0.05). Serum albumin levels were inversely related to the annualised Δ√transformed CACS and the risk of CAC progression among overall participants. After adjusting for age, sex, hypertension, diabetes, hyperlipidaemia, obesity, current smoking, alcohol consumption, serum creatinine levels, baseline CACS and interscan period, this inverse association between serum albumin levels (per-1 g/dL increase) and the risk of CAC progression was consistently observed, especially in baseline CACS of 1-10 (OR: 0.392, 95% CI: 0.234 to 0.658) and 11-100 (OR: 0.580, 95% CI: 0.381 to 0.883) (all p<0.05).

Conclusions: Serum albumin levels were inversely associated with the risk of CAC progression. This phenomenon was predominantly observed in CACS of 1-100 at baseline.