Patients that stop taking statins could have an increased risk of being admitted to hospital with heart or blood vessel problems during an average follow-up period of 2.4 years, according to a new study.
The nationwide study included 120,173 people in France, who were aged 75 between 2012 and 2014 and had been taking statins continuously for two years.
The study, which is published in the European Heart Journal, is the first to evaluate the impact of discontinuing statins taken for primary prevention in older people. It has not been clear how effective their use is in preventing such events occurring in healthy people with no previous history of cardiovascular disease.
Misconceptions around statin use have long been documented. On area of controversy is whether statin use is appropriate in patients aged over 75 years. The risk of heart attacks and strokes increases markedly with age, and yet statins are not utilised as widely in older people as they should be.
Dr Philippe Giral, an endocrinologist specialist in prevention of cardiovascular disease at Pitié-Salpêtrière Hospital (part of Assistance Publique-Hôpitaux de Paris), Paris, France, who led the research said that although further, randomised studies are needed before guidelines can be updated, he would advise elderly people who are taking statins to prevent cardiovascular disease to continue taking them.
He said: "To patients, we would say that if you are regularly take statins for high cholesterol, we would recommend you don't stop the treatment when you are 75. To doctors, we would recommend not stopping statin treatment given for primary prevention of cardiovascular diseases in your patients aged 75."
The researchers analysed data from the French national health insurance claims database and information on hospital diagnoses and clinical procedures. They were able to get comprehensive information on statin use, especially as statins are available by prescription only, for the whole of the French population.
They looked specifically at all patients who had turned 75 between 2012 and 2014, who had been taking statins for at least 80% of the time in the previous two years. They included only people with good cardiovascular health in the analysis. They excluded all those who had been diagnosed with cardiovascular disease and anyone who was taking other medications to treat or prevent heart or blood vessel problems.
Patients were followed for a maximum of four years (an average of 2.4 years) and during this time, 14.3% (17,204 people) stopped taking statins for at least three consecutive months, and 4.5% (5,396 people) were admitted to hospital for a cardiovascular problem.
Increased risk of cardiovascular events
Those who discontinued their statins had a 33% increased risk of any cardiovascular event. The association was stronger for admissions to hospital for heart problems; there was a 46% increased risk of a coronary event, while the increased risk of a blood vessel problem, such as stroke, was 26%.
Dr Giral said: "We estimated that an extra 2.5 cardiovascular events per 100 people would occur within four years among those who discontinued their statins at the age of 75 years compared to those who continued taking their statins."
The researchers stress that this is an observational, retrospective, non-randomised study and therefore cannot show that discontinuing statins can cause a heart attack or stroke, only that it is associated with it. However, they say that extensive health-related patient information was used to improve their estimates of the association and their results are consistent with the known relationship between cholesterol levels and cardiovascular risk.
The researchers found an unexpectedly low statin discontinuation rate (14.3%) among the people they studied, but believe this is probably due to the fact that they included only people who had been taking statins continuously for the previous two years. A recent meta-analysis of data from 40 countries found a 40% non-adherence rate among statin users aged 65 years and older, and the overall French population of 75-year-olds, from which the people in this study were derived, had a similar rate of non-adherence among statin users: 44% had not taken statins for at least 80% of the time in at least one of the preceding two years.
Limitations of the study include the fact that statin use was defined by prescriptions dispensed, although the researchers point out that as the patients regularly had prescriptions dispensed to them, they would be unlikely not to take the medication; the researchers did not have information on patients' socio-economic status, their lifestyles, cholesterol levels at the start of the period being studied, tobacco use, obesity and frailty; and they did not have precise information on the reasons why people stopped taking statins.