LDL-cholesterol Predicts a First CHD Event in Senior Citizens, Especially So in Those With Elevated Lipoprotein(a): Dubbo Study of the Elderly

Objective: The analysis was designed to explore the combined effects of LDL-cholesterol and lipoprotein(a) (Lp(a)) in predicting incident coronary heart disease (CHD) in senior citizens without prior CHD. Methods: This is a prospective cohort study in Dubbo NSW which has followed 2805 men and women 60 years and older for 16 years since 1988–1989. Subjects with prior CHD (n = 607) were excluded from this analysis. Incident CHD events were identified by hospital record linkage. The contributions of LDL and Lp(a) to CHD events and their combined effects were evaluated in proportional hazards regression models. Results: There were 689 CHD events over 16 years in a cohort of 2198 men and women without prior CHD. LDL-cholesterol (corrected for cholesterol content of Lp(a)) and Lp(a) modelled in quartile categories each independently predicted CHD, but exclusively in Quartile 4 (Q4) for each parameter. Using the combination of LDL Q1 and Lp(a) Q1 as a reference group, LDL Q4 (>4.90 mmol/L) most clearly predicted CHD in combination with Lp(a) Q4 (>276 mg/L), hazard ratio 1.95 (95%CI 1.31–2.90). Conclusion: The present findings may have important practical implications in clinical management. If Lp(a) is assessed in senior citizens without prior CHD and found to be genuinely low, elevated LDL-cholesterol may not require active intervention.