Cardiovascular Disease, Mortality Risk, and Healthcare Costs by Lipoprotein(a) Levels According to Low-density Lipoprotein Cholesterol Levels in Older High-risk Adults

Abstract

Background: The value of lipoprotein(a) (Lp[a]) for predicting cardiovascular disease (CVD) across low-density lipoprotein cholesterol (LDL-C) is uncertain. Hypothesis: In older high-risk adults, higher LDL and Lp(a) combined would be associated with higher CVD risk and more healthcare costs. Methods: We included 3251 high-risk subjects (prior CVD, diabetes, or 10-year Framingham CVD risk >20%) age ≥65 years from the Cardiovascular Health Study and examined the relation of Lp(a) tertiles with incident CVD, coronary heart disease (CHD), and all-cause mortality within LDL-C strata (spanning <70 mg/dL to ≥160 mg/dL). We also examined 1-year all-cause and CVD healthcare costs from Medicare claims. Results: Over a 22.5-year follow-up, higher Lp(a) levels predicted CVD and total mortality (both standardized hazard ratio [HR]: 1.06, P < 0.01), whereas higher LDL-C levels predicted higher CHD (standardized HR: 1.09, P < 0.01) but lower total mortality (standardized HR: 0.94, P < 0.001). Adjusted HRs in the highest (vs lowest) tertile of Lp(a) level were 1.95 (P = 0.06) for CVD events and 2.68 (P = 0.03) for CHD events when LDL-C was <70 mg/dL. One-year all-cause healthcare costs were increased for Lp(a) ($771 per SD of 56 µg/mL [P = 0.03], $1976 for Lp(a) 25–64 µg/mL vs <25 µg/mL [P = 0.02], and $1648 for Lp(a) ≥65 µg/mL vs <25 µg/mL [P = 0.054]) but not LDL-C. Conclusions: In older high-risk adults, increased Lp(a) levels were associated with higher CVD risk, especially in those with LDL-C <70 mg/dL, and with higher healthcare costs.