The leading cause of illness and death worldwide is cardiovascular disease. High cholesterol is a significant modifiable risk factor. The risk of ischemic heart disease and stroke reduces by 24% to 25% when low-density lipoprotein cholesterol (LDL) is reduced by 1 mmol/L with statins. Statins are the most widely used lipid-modifying medication. It is estimated that more than 145 million people were taking them in 2018. However, poor adherence and a delayed start to treatment are frequent. Exaggerated warnings regarding adverse effects of statins may be to blame for underuse among those at higher risk of cardiovascular events.
To maximize the benefits, when to begin and how long to continue taking statins is unclear. The study calculated the accumulation of benefits with statins according to age at therapy commencement.
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Data from 500,000 people in the UK Biobank population cohort and 118,000 participants in significant worldwide statin trials from the Cholesterol Treatment Trialists’ Collaboration was analyzed for the study.
The model simulated annual risk of heart attack, stroke, coronary revascularization, diabetes, cancer, vascular death and nonvascular mortality for every participant based on personal attributes (such as age and sex) and medical history. The effect of therapy versus no therapy was calculated using the following scenarios:
- Lifelong therapy (used until death or 110 years of age, whichever came first)
- Therapy ceased at 80 years of age
- Delayed commencement of therapy by five years among persons under the age of 45.
Lifelong Benefits of Statin Therapy
In quality-adjusted life years (QALYs), which are the duration of life adjusted by health to represent quality of life, the benefit of statins was quantified. A QALY is the same as a year of life with optimal health. Benefits were also reported separately based on baseline cardiovascular risk, which is dependent on factors like age, blood pressure, cholesterol levels, smoking status and underlying medical conditions. It measures the possibility of having a heart attack or stroke over the next 10 years.
“Our study suggests that people who start taking statins in their 50s but stop at 80 years of age instead of continuing lifelong will lose 73% of the QALY benefit if they are at relatively low cardiovascular risk and 36% if they are at high cardiovascular risk – since those at elevated risk start to benefit earlier. Women’s cardiovascular risk is generally lower than men. This means that for women, most of the lifelong benefit from statins occurs later in life and stopping therapy prematurely is likely more detrimental than for men,” said Dr. Wu.
A five-year delay in starting statin therapy had little effect on those under 45 years with low cardiovascular risk. Low risk was defined as a less than 5% likelihood of having a heart attack or stroke in the next 10 years. These people lost just 2% of the potential QALY gain from lifetime therapy. They lost 7% of the potential QALY gain from lifelong therapy. However, the impact was greater among persons under 45 with high cardiovascular risk, defined as a more than 20% likelihood of heart attack or stroke in the next 10 years.
“Again, this is because people at higher cardiovascular risk start to accrue benefit early on and have more to lose by delaying statin therapy than those at low risk,” said Dr. Wu.
Source: Medindia
