Changes in Diet and Exercise Can Make a Big Difference Within Six Months of ACS

Reed Miller

February 5, 2010 (Hamilton, Ontario) — Changes to a patient's eating, exercise, and smoking habits should be prioritized as high as adherence to a drug regimen following an acute coronary syndrome (ACS), according to the authors of a new international study on lifestyle changes following ACS [1].

The study shows that the benefits of improving diet, exercising more, and quitting smoking are additive and can reduce a patient's risk within six months if the patient sticks with it, "justifying a significant investment in establishing programs that systematically enhance early lifestyle modification and secondary prevention," study authors Dr Clara Chow (McMaster University, Hamilton, ON) and colleagues report in the February 1, 2010 issue of Circulation.

The study included 18 809 patients from 41 countries enrolled in the Organization to Assess Strategies in Acute Ischemic Syndromes (OASIS) randomized clinical trial. Patients reported their adherence to diet, physical-activity, and smoking-cessation advice at 30 days. MI, stroke, cardiovascular death, and all-cause mortality were recorded out to six months.

About one-third of patients in the study continued to smoke, almost 30% did not adhere to either the diet or exercise recommendations, and just under 30% adhered to both the diet and exercise advice for at least 30 days. By contrast, over 96% of subjects continued to take antiplatelet drugs, 79% stayed on statins, and about 72% maintained an ACE-inhibitor/angiotensin-receptor-blocker regimen.

Quitting smoking cut the risk of MI by almost half compared with persistent smoking (odds ratio 0.57; 95% CI 0.36–0.89). Diet and exercise adherence also reduced the risk of MI by nearly half compared with nonadherence (odds ratio 0.52; 95% CI 0.4–0.69). On the other hand, patients who continued to smoke and did not adhere to diet and exercise regimens were 3.8 times (95% CI 2.5–5.9) more likely to suffer an MI, stroke, or death within six months than nonsmokers who modified diet and exercise.

In addition to the direct cardiovascular health benefits of healthy diet, exercise, and smoking cessation, it is also possible that some unknown characteristic of the kind of people who stick to their doctor's advice also improves cardiovascular health. "That is, the effects seen with lifestyle behaviors here are not [only] a true effect of diet and exercise per se but are related to characteristics of adherers," Chow et al point out. The study did not find any substantial difference in drug treatments or other baseline characteristics of adherers to diet, exercise, or smoking advice vs nonadherers. However, the data show that "good lifestyle behaviors appear to cluster (eg, persons who quit smoking had higher rates of adherence to diet and exercise)."

Still Lots of Room for Improvement

In addition to showing the short-term benefits of lifestyle improvement, the study adds to the growing body of evidence showing that patients are much less likely to follow their doctor's advice on smoking, diet, and exercise than they are to stick with a drug regimen, although lots of patients do neither.

Commenting on the study, American Heart Association (AHA) spokesperson and cardiologist Dr Nieca Goldberg (New York University, NY) told heartwire , "This study is consistent with other studies that show improvement in cardiovascular risk profiles with lifestyle counseling. However, the biggest problem is not so much our beliefs in reducing risk for cardiovascular disease though participation in modification of lifestyle, it's really getting the patients to participate in their care and actively lower their risk factors."

The study also found that adherence rates for each type of lifestyle advice as well as compliance with medications varied greatly from place to place. For example, 47.2% of North Americans adhered to their recommended diet for at least 30 days after ACS, compared with 88.1% of Indians and 83.3% of South Americans. Of the eight regions evaluated, Australians had the best rate of exercise compliance, but it was still only 60.7%. The worst rate of exercise compliance was reported by South Africans (25.7%), who also were near the bottom of the table in diet adherence (39%) and smoking cessation (39.4%). Western Europe had the worst rate of smoking cessation (38.8%), while India had the best (90.5%).

"What we should learn from that is that [coronary disease] is an international problem, and it would be really interesting if we could do an international sharing of data and investigate what is it about some populations that make them more likely to consistently adhere to a dietary or exercise program [than others,]" Goldberg said.

Medication compliance varied from region to region as well, although it was generally higher than adherence to lifestyle modifications in every region. Every region had at least 95% compliance with antiplatelet drugs and at least 89% compliance with blood-pressure-lowering medication.

However, beta-blocker compliance ranged from 36.4% in Latin America to 75.3% in India. Statin compliance was lowest in South Africa (55.1%) and East Asia (68.8%) and highest in Australia (89.9%) and India (88.3%).

Goldberg pointed out that the low adherence rates in the study are particularly disappointing, given that the study only looked at the first six months after ACS, and many patients tend to backslide after six months. "Everyone has good intentions, but somewhere along the way they fall off the wagon. The biggest challenge for all healthcare providers is to help their patients maintain a healthy lifestyle."

Chow told heartwire that her group plans to further investigate these regional differences. "There may be something that makes certain behavioral change easier or more difficult in different communities or regions," she said. For example, "Indians do not have a culture of exercising during leisure time, whereas Australians are a nation very interested in outdoor activity. Clearly, this is an interesting area for future research regarding what, if any, are the system-level factors that cause these regional variations and if indeed they are exportable."

The differences in medication compliance are also probably due to the "system-level" factors of access and availability of medications, Chow said. For example, beta blockers are still the primary blood-pressure-lowering option in some economically less well-off regions, whereas in richer countries they are just one of numerous blood-pressure-lowering therapies to choose from. Also, high cost limits the use of statins in many parts of the world, she said.

CRSP Programs Can Only Help if They're Used

In an accompanying editorial [2], Dr Neal Patel and Dr Gary J Balady (Boston University, MA) explain that "the difficulty of lifestyle modification after hospital discharge resides in the daunting task of conversion of counseling into actual behavior change." Unfortunately, direct contact between physician and patient after hospital discharge is usually limited, and patients' feelings of isolation as they try to change their lifestyle generally lead to poor results. Therefore, cardiac-rehabilitation/secondary-prevention (CRSP) programs are critical to "bridging the gap from successful guideline-focused in-hospital care to lifelong-sustained behavioral change."

The AHA recommends that CRSP programs include nutritional counseling, risk-factor management (lipids, blood pressure, weight, diabetes mellitus, and smoking), exercise and physical-activity counseling, and psychosocial interventions. Clinical studies show that programs with these components can improve post-MI survival up to 56%, but despite the clear benefits of CRSP programs, "use of such programs remains dismally low," Patel and Balady report--around 14% of Medicare patients hospitalized for acute MI are enrolled in a CRSP program, and the rates are even lower for women, minorities, and patients with comorbidities.

They also cite a study that found that in a center that referred 55% of acute-MI patients to a CRSP program, only 33% of those referred ever enrolled in the program after discharge. "Although a successful CRSP program can lay the foundation for beneficial change, the process of behavior modification is lifelong and requires a concerted and cohesive effort from the patient, cardiologist, and primary-care provider," Patel and Balady conclude.

Heartwire © 2010