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Feature Article

When patients don't follow their doctors' advice: Researchers analyze factors underlying non-adherence

Hypertension, or high blood pressure, is a condition in which the blood pressure in the arteries is chronically elevated. Every time a heart beats, the heart pumps blood through the arteries to the rest of the body. Blood pressure is a measure of the force against the walls of the arteries as the heart pumps blood through your body. If the pressure is too high, the heart has to work harder to pump, which can lead to organ damage and illnesses.

Hypertension can be treated, and it's important to do so to reduce the risk of stroke, heart attack, and heart failure. Patients diagnosed with hypertension can be treated medically, using several different types of drugs alone or in combination. They can also be treated by changing lifestyle factors, including losing weight, quitting smoking, eating a more healthful diet, reducing salt intake, exercising regularly, and limiting alcohol consumption. Often, doctors recommend a combination of the two.

Although hypertension is eminently treatable, half of hypertension patients have inadequate control of their blood pressure. Many patients have difficulty in this area simply because they don't comply with their doctors' wishes.

A VA study published online in August 2012 in the Journal of General Internal Medicine looked at the characteristics of more than 600 patients with hypertension in an attempt to determine the factors that make some of them less likely to take their medication properly; modify their diet; or exercise regularly—the key behaviors associated with self-management of hypertension.i It is among the first studies to identify factors associated with non-adherence to doctors' recommendations to all three of these key self-management behaviors.

"Clinicians have difficulty identifying patients who are unlikely to adhere to hypertension self-management," says Matthew J. Crowley MD, of the Center for Health Services Research in Primary Care at the Durham VA Medical Center, and lead author for the study. "Identifying these patients is essential to addressing suboptimal blood pressure control and the high costs of treating hypertension."

Crowley and his team, which also included researchers from Duke University, looked at data from the Take Control of Your Blood Pressure study: a five-year VA/ Duke University study designed to help health care providers better control the blood pressure of their patients with hypertension. The 636 patients in the study had a mean age of 61 years; were 49 percent African-American; and 34 percent male. Within the group, 73 percent had well-controlled blood pressure.

The team looked at each of the three aspects of hypertension self-management: medication, diet, and exercise. By administering an extensive questionnaire to participants, they identified risk factors for each area that indicated patients might not be willing or able to do what their doctors were asking of them. These included:

>Medication: Patients at risk of not taking their hypertension medication properly included African-Americans; those with low education levels; those with a lack of financial security; those with a low level of health literacy (the ability to read, understand, and use health care information to make decisions and follow instructions); and those with a high stress level.

Diet: Patients at risk of not following recommendations to modify their diet include those with a body mass index greater than 30 (body mass index, or BMI, is an index for assessing whether people are overweight or underweight); employed patients; those who are not financially secure; those who feel they accomplish less than they would like to due to psychosocial issues; and those who believe that their current lifestyle is likely to result in a heart attack.

Exercise: Patients at risk of not following recommendations to exercise include those with a BMI greater than 30 (a measure of 25 or more is considered overweight); women; those with low education levels; those who are employed; those who feel they accomplish less than they would like to due to psychosocial issues; and those who believe that a heart attack is likely, given their current lifestyle.

"Our study suggests that adhering to each of these behaviors poses different challenges for patients," explains Crowley. "For example, lack of financial security was associated with difficulty following diet recommendations, but not with difficulty following exercise recommendations."

Having assembled this data, the team created a tool that clinicians could use to identify patients who are less likely to adhere to recommendations to self-manage their hypertension. "With further study," says Crowley, "this instrument has the potential to improve identification of non-adherent patients with hypertension."

The team believes that ascertaining the likelihood that patients will take their medication properly, improve their diet, and exercise regularly, will make it easier to create targeted efforts that will improve the likelihood that these patients will follow the advice of their physicians.

"Although our results suggest ways in which the risk factors we've identified may underlie non-adherence to hypertension self-management behaviors, more study is needed to confirm the clinical utility of this instrument," concludes Crowley. "Because medication, diet, and exercise adherence are also essential to diabetes and hyperlipidemia (high blood cholesterol levels), it is possible that this instrument could be suited to assess non-adherence in these conditions as well."


i MJ Crowley, JM Grubber, MK Olsen, HB Bosworth, "Factors associated with non-adherence to three hypertension self management behaviors: preliminary data for a new instrument." J Gen Intern Med, 2012 Aug 28. (Epub ahead of print.)


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