Effectiveness of low-density lipoprotein cholesterol reduction with lipid lowering therapy for secondary prevention amongst older individuals: a nationwide cohort study

Background: Data about the clinical benefit from initial low-density lipoprotein cholesterol (LDL-C) reduction with lipid lowering treatment for secondary prevention and risk of major vascular events amongst older as compared with younger individuals treated during routine clinical care are limited. We investigated this in a nationwide cohort.Methods: Individuals aged >= 50 years with a first-time hospitalisation for a cardiovascular event (index event, including acute coronary syndrome, non-haemorrhagic stroke, transient ischaemic attack and coronary revascularisation), 1 January 2008 to 31 October 2018, who subsequently used lipid lowering treatment, and had an LDL-C measurement before and after the event were included. Hazard ratios (HRs) for major vascular events per 1 mmol/L reduction in LDL-C were estimated for the included 21,751 older and 22,681 younger individuals (>=/<70 years old) using Cox regression.Results: LDL-C lowering was associated with a 12% lower risk of major vascular events in older individuals per 1 mmol/L reduction in LDL-C (HR 0.88, 95% confidence interval [CI] 0.84-0.93), with no significant difference compared with the risk reduction amongst younger individuals (HR 0.88, 95% CI 0.83-0.93; P-value for difference between age groups: 0.86). The risk reduction was more pronounced when post hoc restricting, as a proxy for compliance, to new users with an LDL-C reduction above the lowest decile for both older (0.81, 95% CI 0.73-0.90) and younger (0.81, 95% CI 0.72-0.91) individuals.Conclusions: This study strongly supports a similar relative clinical benefit of LDL-C reduction with lipid lowering treatment for secondary prevention of major vascular events amongst individuals aged >= 70 and <70 years.