Are Health Care Professionals Advising Patients With Diabetes or At Risk for Developing Diabetes to Exercise More?

RESEARCH DESIGN AND METHODS

The Medical Expenditure Panel Survey (MEPS) is cosponsored by the Agency for Healthcare Research and Quality and the National Center for Health Statistics. The MEPS Household Component (HC), a nationally representative survey of the U.S. civilian noninstitutionalized population, collects detailed information on demographic characteristics, health conditions, health status, and use of medical care services, income, and employment (22). The sampling frame for the MEPS-HC is drawn from respondents to the National Health Interview Survey. National Health Interview Survey provides a nationally representative sample of the U.S. civilian noninstitutionalized population, with oversampling of Hispanics and blacks. The MEPS Medical Provider Component supplements and validates information on medical care and pharmacy events at the person level. Medical condition diagnoses are based on ICD-9 clinical modification codes (23,24). The sample design of the MEPS-HC survey includes stratification, clustering, multiple stages of selection, and disproportionate sampling (25). MEPS sampling weights incorporate adjustment for the complex sample design and reflect survey nonresponse and population totals from the current population survey (25).

Adult respondents to the year 2002 survey who reported about physician advice to exercise were eligible for this study sample. All adult respondents (≥18 years) were asked, “Has a doctor or other health professional ever advised you to exercise more?” Of 27,243 adult participants in the year 2002 survey, 26,878 responded when asked about ever receiving exercise advice.

Ascertainment of diabetes and diabetes risk factors

Self-reported information from the MEPS-HC survey was used to ascertain whether a respondent had diabetes or risk factors for developing type 2 diabetes. Respondents were asked if they had ever been diagnosed with diabetes (excluding gestational diabetes). For type 2 diabetes risk factors, we selected clinical and demographic variables available in the MEPS-HC survey that were included in the American Diabetes Association’s list of risk factors (26). Risk factors included age ≥45 years, non-Caucasian ethnicity, BMI ≥25 kg/m², physical inactivity, diagnosis of hypertension (diagnosed on two or more different medical visits with high blood pressure), and history of cardiovascular disease (diagnosed with angina or angina pectoris, heart attack or myocardial infarction, stroke, or any other kind of heart disease or condition).

In the analyses, we defined cardiovascular risk factors as the presence of one or more of the following clinical conditions: history of cardiovascular disease, a diagnosis of hypertension, and/or hyperlipidemia. MEPS mapped medical conditions to three-digit ICD-9 codes based on medical and pharmacy utilization and self-report. Then 259 mutually exclusive clinical classification categories were mapped from ICD-9 codes in order to provide clinically homogenous groupings. The ICD-9 to clinical classification category cross-walk is available at www.meps.ahrq.gov (24). The current research used clinical classification category 053, “Disorders of Lipid Metabolism,” to identify individuals with hyperlipidemia.

Assessment of BMI, physical activity, and other covariates

We used self-reported information from the MEPS-HC survey for the assessment of BMI, physical activity, and other covariates. Respondents were asked to estimate their current body weight and height; if they “spend half an hour or more in moderate or vigorous physical activity at least three times a week;” if they had “difficulties walking, climbing stairs, grasping objects, reaching overhead, lifting, bending or stooping, or standing for long periods of time;” and to report on current smoking status, age, sex, race, ethnicity, years of schooling, and income level (24). The Centers for Disease Control and Prevention formula was used to calculate BMI (27), and the National Heart, Lung, and Blood Institute classification scheme was used to define normal, overweight, and obese categories (28).

Data analysis

To incorporate adjustment for the complex sample design, the current research used MEPS person-level and variance adjustment weights using STATA 8.1 in all analyses to ensure nationally representative estimates. χ² tests were conducted to test for variation in rates of exercise advice across selected subgroups. Multiple logistic regression analysis was used to estimate the adjusted odds of receiving health professional advice to exercise more.

RESULTS

Overall, 34% of adults reported they had ever been told by a health care professional to exercise more (Table 1). Among all adults, the unadjusted proportion of the participants who had received advice to exercise more increased with increasing BMI and with age up to 70 years, after which the proportion declined. A higher unadjusted proportion of individuals who reported ever receiving advice were female, were white or black, had higher education and income levels, reported being physically inactive, and had limitations in physical functioning. Significant variation in physician advice existed across geographic region although the absolute differences were small.

Among adults with diabetes, 73% reported they had been told by a health care professional to exercise more compared with 31% of those without diabetes (Table 2). Of those respondents not reporting a diagnosis of diabetes, 30% had three or more risk factors for the development of type 2 diabetes. The proportion of participants without diabetes who reported receiving advice increased as the number of type 2 diabetes risk factors increased, until reaching approximately the same prevalence as reported among people with diabetes when five risk factors were present. Among people with diabetes, the prevalence of receiving advice was significantly higher if an individual also had heart disease (76%) versus if they did not (62%).

Among factors associated with ever having received advice to exercise more, the most notable for both individuals with and without diabetes were the strong associations between measures of health and the reported receipt of advice (Table 3). People with cardiovascular conditions versus those without and people who were overweight versus normal had two to three times the odds of ever receiving advice. Those people who were obese had four to eight times the odds of ever receiving advice to exercise more compared with normal weight individuals.

The adjusted associations between sociodemographic factors and the reported receipt of advice were different among individuals with versus without diabetes. Among those without diabetes, the likelihood of receiving advice increased with age up to 80 years and increased with higher education and income levels. Among individuals with diabetes, the likelihood of ever receiving advice did not vary significantly by age, education, or income but did by ethnicity. Hispanics with diabetes were 40% less likely to report receiving advice to exercise than non-Hispanics.

Among people without diabetes, limitations in physical functioning were positively associated with being advised to exercise more, and currently being physically active was negatively associated with past exercise advice from a health professional. Among people with diabetes, physical limitations and physical activity were not significantly associated with whether the respondent had ever received advice to exercise more or not.

CONCLUSIONS

The good news from this study is that health care professionals seem to recognize the importance of exercise for individuals with diabetes and with severe obesity. The majority of patients with these diseases report that they have been advised by a health care professional to exercise more. Similarly, as the established risk factors for type 2 diabetes increase, advice to exercise is more likely. More patients understand the need for physical activity than was apparent in earlier studies examining past-year advice only (from 51 to 73%) (20) and may reflect a very positive change in the behavior of health care professionals since the late 1990s.

The not so good news from this study is that there has not been an increase overall in those patients who report being advised to exercise. In 1995 and in the current study, 34% of the total sample had been advised to exercise (20). This suggests that health care professionals may not adequately recognize the importance of exercise for prevention of chronic disease and for overall health in those without disease. Since health care professionals are already providing exercise advice to some patients, there may be an opportunity to raise their awareness about opportunities to provide this advice to all patients, even those who are not obese or with many risk factors for type 2 diabetes.

Another reason for concern is that while more patients with diabetes are being advised to exercise, exercise rates among those with diabetes remain low and are lower than for the general population (12). Consistent with other findings, these data suggest that physician advice may not be sufficient to produce the desired behavior change, at least in this group (29,30). Physician advice has been shown to be a strong predictor of attempts to change lifestyle habits (13–15); however, the U.S. Preventive Services Task Force found insufficient evidence to conclude that advising patients in primary care settings to be physically active is sufficient alone to sustain long term increases in activity levels (29).

As others have also noted, health professionals may not take the time nor provide enough specific information to help patients successfully change their physical activity behaviors (31,32). Podl et al. (33) reported that exercise counseling by community family physicians was brief ranging from <1 to 6 min per patient. Glasgow et al. (34) found only 40% of patients receiving counseling from physicians also received assistance in planning an exercise routine or follow-up support. Mutual goal setting, readiness for change, and tailored interventions will be important for increasing clinical effectiveness in lifestyle modification strategies with diabetic patients (35).

Some social demographic factors typically associated with higher rates of health professional counseling, such as sex and higher education and income levels (15,20,21), were not observed among people with diabetes in this study, suggesting that fewer disparities in physical activity recommendations may be occurring in this high-risk patient group. However, some ethnic disparity was seen since respondents with diabetes who were Hispanic were 40% less likely to have ever received advice to exercise more than non-Hispanic respondents. One limitation with this study is that information was not available to determine whether the quality of health care professional advice to exercise differed by social demographic factors or by the presence of health conditions. On average, though, awareness of the need to exercise more is high among patients with diabetes and most at risk for developing type 2 diabetes.

Data from this study also suggest a missed opportunity for primary prevention among patients without diabetes. Rates of advice to exercise more were high among obese patients (54–74%) and patients with cardiovascular risk factors (∼60%) but were low among younger (16–27%) or sedentary (40%) adults. Based on estimates from National Health and Nutrition Examination Survey and the longitudinal Coronary Artery Risk Development in Young Adults Study, young adults (aged 20–40 years) gain on average an estimated 2 lb per year or 20 lb over a decade (36). Data from the Framingham Heart Study indicate the long-term (30-year) risk of becoming overweight exceeds 50% (37). Reinforcing the value of life-long physical activity for young, sedentary adults can help curb the rising obesity and diabetes epidemics.

The results of this research are subject to limitations. All variables relied on self-reports, including the receipt of exercise advice and the diagnosis of diabetes. While the diabetes and risk factor estimates presented here are consistent with other survey-based national-level estimates in the U.S.(20,38), it is likely that the rates of exercise advice, diabetes, and diabetes risk factors in this study are underestimates of national prevalence. Recall of health professional counseling on exercise has been shown to underestimate actual observed rates of counseling (33). Alternatively, those with health conditions may have overreported information about the receipt of health care professional advice to exercise, particularly if they are already aware that exercise could help their condition.

There is also evidence that self-reported conditions may be underreported in general (39), and blacks, whites, and Hispanics differ in reporting of disease labeling and levels of illness and disability (40,41). Previous studies (42,43) have also shown that overweight respondents tend to underestimate their weight and overestimate their height, so BMI scores are underestimated. Unlike the National Health and Nutrition Examination Survey, MEPS does not contain information on undiagnosed diabetes. Recent estimates suggest that ∼30% of individuals with diabetes have not been diagnosed (44). Respondents in the present study with multiple risk factors for developing diabetes may have undiagnosed diabetes, which may explain why their rates of exercise counseling were similar to those patients recalling a diagnosis of diabetes.

Caution should also be taken in directly comparing results from this study with other studies as part of the apparent differences in the prevalence of physician advice may be attributable to differences in how the receipt of physician advice was ascertained. For example in an earlier national study by Wee et al. (20), annual exposure to advice was determined by asking “During your last (medical) check-up, did the doctor recommend that you begin or continue to do any type of exercise or physical activity?” Whereas in the present study, a cumulative exposure to advice was determined by asking “Has a doctor or other health professional ever advised you to exercise more?” That is, results from the present study should be interpreted as suggesting that the cumulative effect of past medical visits has led to most individuals with diabetes or at highest risk of developing type 2 diabetes knowing they need to exercise more.

The dramatically increasing epidemics of obesity, an outcome of inactivity, and diabetes are well-known threats in the U.S. The results of this research indicate that most adults with diabetes or at greatest risk for developing type 2 diabetes have been advised by a health professional to become more active and that rates of advice to exercise more are increasing over time. This is good news, as it indicates more patients are aware of the need for greater physical activity. Another positive trend suggested in these results is that the importance of physical activity for people with diabetes may have broken through some of the typical barriers associated with sociodemographic disparities, as the results suggest that people with diabetes who have lower levels of income and education were no less likely to receive advice to exercise more (as opposed to those without diabetes). These preliminary findings call for additional future research. Despite these positive trends, the proportion of adults with diabetes engaging in regular physical activity is low (12). The challenge is to ensure that not only are people with diabetes or at high risk for developing type 2 diabetes advised to exercise more but that they are also given the education, resources, and supportive environment to succeed.