Adherence - Keeping up the Statin Usage Through the Years
Drugs don’t work unless the patient takes them. Do people continue to use their statins?
Words thrown about among public health professionals here include compliance and adherence. Compliance is how closely the patient did what the doctor told him or her to. It suggests passivity. The word adherence implies more agency on the part of the patient. If we want patients to be an active part of their own health care team, we tend to prefer the word adherence. The word “persistence” is sometimes used as a straightforward description of how long the patient continues to use a medication.
A meta-study back back in 1995 showed 65% compliance among statin patients. (This was when the pool of patients prescribed statins was smaller. It is reasonable to think the adherence level has declined with expanded usage.) As with other drugs, compliance levels drop as time goes by after the first prescription. A Finnish study found a 10-year compliance level rate of 44%. People over age 74 and under age 45 had lower compliance rates than those in between those ages.
A more recent study found half of statin patients stop taking the medicine in the first year, and it gets worse as time goes by.
A study of patients in Finland found 48% discontinued use at some point (at least a 6-month time-out in their therapy), but that of those who took a time-out, 47% restarted the therapy within a year and 85+% were taking the medicine at the time the researchers stopped following them (which could be more than 10 years after the start of treatment.) So although by a simple definition compliance was low, a more nuanced look at the data gives a cheerier picture.
Causes of Low Adherence Rates
Why do people quit taking statins? Boredom, expense, forgetfulness, side effects. Even if the side effects are not real or are caused by something other than statins (e.g. memory loss can have many causes), the patient may be looking for something to blame his or her maladies on and any medication taken can be blamed.
When queried about why they quit taking their medications, the most common response was side effects
However, it’s hard to know if these patients were actually experience side effects, and if they were, how bad those effects were. "Side effects" may just be an excuse for other reasons (such as forgetfulness) or one of several factors that resulted in quitting.
A study published in the Journal of Clinical Lipidology in 2012 found that most statin users surveyed had switched medication at some time. This may be due to the expiration of the patent status of simivistatin as cost was cited most often as the reason for switching.
Among the 12% of patients who quit statins altogether 62% blamed adverse effects. This is a higher number that clinical trials would suggest. It is hard to say whether that many people actually had the side effects or if the design of the clinical trials did not accurately predict adverse side effects, or a combination of both factors.
Another study found patients with coronary arterial disease who were prescribed a combination regimen had a long-term adherence rate of using aspirin at 71 %, ß-blockers 46 %, and statins 44 %. Now these are people who actually have been told by doctors they have CAD (coronary arterial disease), not people who were being given the drug for primary prevention. If these patients were not scared straight into high adherence numbers, who will be?
Who is Better at Adherence?
Are some groups more likely to follow doctor’s orders than others? Analysis has shown age is a decent predictor of adherence to a regimen, with a U-shaped distribution. People over 70 and under 50 are less likely to be compliant than people in the 50-69 range. Women and people with lower incomes are also less likely to be compliant. Patients with a history of cardiovascular problems or also diagnosed with high blood pressure were more likely to keep taking their statins in the long run.
People who have had coronary events (e.g. a heart attack), are more likely to stay on their statin medication. They have been "scared straight" into following doctors’ orders. People who are taking another cardiovascular medication have higher compliance levels than those who are not.
People who are taking statins for preventative reasons see less visible short-term benefits and may tend to stop taking the drugs. This may put a wrinkle in plans to vastly expand administration of statins to people with low risk for prophylactic purposes. Although public health authorities may feel widespread statin use is a good idea, the compliance level will probably fall as the share of the population using them increases.
Costs of not adhering
Indeed, predictions of millions of lives impacted by statin drugs are predicated on the efficacy shown in clinical trials. The actual impact on public health, while considerable, is not a great as predicted and the disparity may be due to the fact that people don’t take their pills.
A study of US patients who were prescribed statins, called the Understanding Statin Use in America and Gaps in Education (USAGE) surveyed over 10,000 statin users. The patients were self reporting whether they were continuing to take the statin. Among current users, 95% took a statin alone, and 70% had not missed a dose in the past month. Although ~70% reported that their physicians had explained the importance of cholesterol levels for their heart health former users were less satisfied with the discussions (65% vs. 83%, P < .05). Muscle-related side effects were reported by 60% and 25% of former and current users, respectively (P < .05). Nearly half of all respondents switched statins at least once. The primary reason for switching by current users was cost (32%) and the primary reason for discontinuation was side effects (62%).
Tactics for Improving Adherence
The low rate of compliance is a major reason for the daily regimen. Trials with every-other-day usage and weekly usage found reduced compliance at 50% and 29% respectively. Encouraging patients to make taking the pill a habit before bed is designed to raise usage. Although the drug makers recommend taking statins in the evening, there is only a small benefit to taking the pills then compared to other times of day. The most important thing is to take the pill every day, and if a patient takes more than one medication daily (as many do), adherence rates are higher if all pills are taken at the same time.
A British study concluded that simplifying the regimen resulted in greater adherence, and that reminders were still the best way of keeping patients on their drugs for the long run A US study by the pharmaceutical industry found that genetic testing of patients for certain genes and regular testing of cholesterol levels resulted in better adherence. Other ideas that have been proposed include follow-on contact from nurses to remind patients and inserting reminders into patients’ electronic calendars (either daily, weekly, monthly, or random reminders). Anyone who can come up with a low-cost way of improving adherence will be doing society a great benefit.
Health Care Costs and Patient Involvement
If patients keep up their adherence, health care costs decline. That’s why many are trying to find ways to keep people using their statins. Proposals, some of which have been tried, include regular refills of medications (without patient prompting the pharmacy), mail order prescription filling, and combining multiple medicines into one pill. Involving the patient and letting the patient feel he or she is an active part of the decision-making process work for many patients. Different patients have different personalities, and some enthusiastically get involved with their treatment and may even resent doctors who come across as paternalistic or who appear to think they know everything. Reports from many doctors and nurses suggest that involving the patient and making patients an active part of shared-decision making may in fact be the best way to achieve adherence to statin regimens.