Diabetes Prevention: How About NOW?

Transcription

1 Diabetes Prevention: How About NOW? Reviewed by Claresa Levetan, MD STUDY Mokdad AH, Ford ES, Bowman BA, Nelson DE, Engelgau MM, Vinicor F, Marks JS: Diabetes trends in the U.S.: Diabetes Care 23: , 2000 SUMMARY Objective. The objective of this study was to evaluate trends in the prevalence of diabetes in the United States between 1990 and Design and Methods. The Behavioral Risk Factor Surveillance System is a standardized telephone survey operated by state health agencies in collaboration with the Centers for Disease Control Prevention. A sample of adult residents (age 18 years) with telephones from all states including the District of Columbia were asked standardized questions to provide data that could be compared across states. Diabetes status was assessed over the telephone by a trained interviewer who asked, Have you been told by a doctor that you have diabetes? Issues regarding gestational diabetes were coded separately. A total of 149,806 individuals were interviewed and completed the survey. Results. The prevalence of diagnosed diabetes in the United States increased 33% between 1990 and This rise was seen across all ages, races, educational levels, and weight levels. There was a 70% increase in diagnosed diabetes among individuals aged years. There were significant increases among Hispanics (38% increase), caucasians (29% increase), and African Americans (26% increase). For every 1-kg increase in self-reported weight, the risk of diabetes increased by 9%. Conclusions. The prevalence of diabetes continues to rise. As the prevalence of obesity also continues to increase in the United States, diabetes will become an even greater health care problem, contributing to a worldwide diabetes epidemic that is largely preventable. COMMENTARY It is proper at the present time to devote time not alone to treatment but still more to prevention of diabetes. The results may not be so striking or immediate, but they are sure to come and to be important. Elliott P. Joslin, 1921 My how we have grown! During the past several decades, we have rapidly grown in the areas of communication, technology, science, and medicine, and so, too, have we grown as individuals in our size and weight. Less than a century ago, there were no airplanes, no cars, and no fast food restaurants. Not surprisingly, this phenomenal technological growth has come at a price an expanded girth that has extended not only to adults, but also to our children. This has resulted in a 70% rise in diabetes among 30- to 40-year-olds and a doubling in the number of children with type 2 diabetes in less than a decade. 1 Since 1991, the number of obese Americans is up nearly 60%, and now nearly one in five of us are far overweight. It has been estimated that 31% of men and 35% of women are overweight. 2 4 The highest incidence occurs in those aged years, with 52% of women and 42% of men being overweight. Thirty-four percent of adults aged years are overweight. Teens are also affected, with one in five teenagers considered overweight. 3 Ironically, there are 58 million overweight adults in the United States a number almost identical to that of Americans who eat at one of the 160,000 fast-food restaurants in the United States each day. 5,6 Prevention holds the winning number, but no one will buy a ticket. A computer analysis of the Diabetes Control and Complications Trial (DCCT) found that improved glycemic control results in a mean 7.7 additional years of sight, 5.8 additional years free from end-stage renal disease, 5.6 additional years free from lower-extremity amputation, and 15.3 additional years free from onset of substantial microvascular or neurological complications. 7,8 Similar outcomes among individuals with type 2 diabetes were demonstrated by the United Kingdom Prospective Diabetes Study. 9 Yet diabetes-related complications are on the rise in the United States. 10 The prevalence of type 2 diabetes in children and adolescents is now as high as that of type 1 diabetes. Unlike chronic diseases such as hypertension and coronary disease, for which medications-for-life is the rule, the cornerstones of care for diabetes namely, medical nutrition therapy, exercise, and diabetes education have never been considered to be a lifelong medical need. The recently published Healthy People 2010 reported that only half of all Americans with diabetes have received diabetes self-management training. 10 To say that efforts to prevent complications in diabetes are cost-effective is extreme understatement. Yet few health care systems in the United States truly embrace the concept of compre- 34

2 hensive, preventive diabetes care for life. In a technical review of diabetes self-management education for the American Diabetes Association, Clement noted that few educational programs extended even to 1 year. 11 Perhaps when we place greater value on those who deliver preventive diabetes resources, including dietitians, certified diabetes educators, and the many other providers who are dedicated to the prevention of diabetes and its complications, self-management prevention will prevail over rising rates of diabetes and its associated complications. Diets DO work. Not surprisingly, more than 84% of Americans eat too much fat, whereas <30% eat the daily recommended five servings of fruits and vegetables. These factors contribute to the 800,000 new cases of diabetes that are diagnosed each year in the United States. 12 In 1980, 1,000 new patients were diagnosed with diabetes each day in this country. By 1998, that number had more than doubled. 13 In many cases, diet and exercise have controlled blood glucose levels to the normal range, reversed the course of the disease, 14,15 and reduced the risk for accelerated vascular disease. 16,17 Large studies have reinforced the efficacy of diet and exercise in preventing diabetes Over a 6-year period, Pan and colleagues 15 demonstrated a 31% reduction in the risk of developing diabetes among patients with impaired glucose tolerance (IGT), as compared to those who did not change their eating habits. Other studies have clearly demonstrated that diet and exercise improve glycemic control. In a subset of patients with mild type 2 diabetes, 50% of patients treated with diet and exercise without concomitant medication entered a state of remission that was maintained for at least 5 years. 14 Compliance with dietary recommendations has resulted in significant dose reduc- tions in diabetes medications, including insulin, and insulin has been completely discontinued in many patients who have complied with prescribed diet and exercise regimens. 30,31 Yes, you, too, can prevent diabetes. Among 21,271 nondiabetic American male physicians participating in the Physicians Health Study, there was an inverse relationship between physical activity and the development of diabetes. 18 The same result was found among 87,000 women in the Nurses Health Study. 19 Both studies also found that all-cause mortality was significantly reduced among study participants whose body mass index was below the national average. The 1990 National Health Interview Survey demonstrated that diabetic individuals across all age-groups were less likely to participate in regular physical exercise than were people without diabetes. Women with diabetes were significantly less likely to participate in regular exercise than were nondiabetic women and diabetic men, and African Americans with diabetes were less likely to exercise than caucasians with diabetes. 32 Physical exercise is not only a critical factor in improving glucose control by increasing peripheral glucose uptake, but also can result in an improved sense of well-being among patients. Consistent with the recommendations of Healthy People 2010, technical reviews in the field of diabetes recommend aerobic exercise at 50 70% of maximum capacity three times per week for at least 20 min each. 10 Let s review the evidence for prevention of diabetes. A landmark 6-year, randomized, prospective trial by Pan and colleagues, 15 demonstrated that exercise resulted in a 46% reduction in the incidence of diabetes among patients with IGT. Similar reductions were found among those who dieted and/or exercised. Tuomilehto 25 found that type 2 diabetes could be effectively prevented by lifestyle interventions inclusive of a lowered-fat diet and exercise during the 4-year study. The incidence of diabetes was 10% in the intervention group, compared to 22% in the control group. The intervention group lost an average of 7.7 lb compared to 1.7 lb in the control group. A similar trial, the Diabetes Prevention Program, is underway in the United States to evaluate the impact of diet, exercise, and medication on the progression to diabetes among patients with IGT. That study is scheduled to be completed in Table 1 presents a summary of the major studies related to diabetes prevention. Many other studies have demonstrated the tremendous impact of dietary modification and exercise within weeks of initiating a fitness regimen. For example, Rogers and colleagues 34 found significant improvements in glucose tolerance and reductions in insulin resistance within seven days of beginning a vigorous exercise program. 33 Wing and colleagues found significant improvements in glycemic control when as little as 2.2 kg of weight were lost. Diabetes preventive care pays, but few are collecting. A 12-week study by Testa and Simonson 35 demonstrated that improved glycemic control not only is beneficial in the long run, but also resulted in lower absenteeism from work, fewer days in bed, and a fourfold reduction in health care costs over the 3-month study period. Sadur and colleagues 36 demonstrated the benefits for adults with poorly controlled diabetes of outpatient diabetes education delivered by a diabetes nurse educator, a psychologist, a dietitian, and a pharmacist in cluster-visit settings of patients/month for 6 months. This study demonstrated not only a significant decline in HbA 1c levels CLINICAL DIABETES Volume 19, Number 1,

3 Table 1. Studies Demonstrating How Diabetes Can Be Prevented Authors Tuomilehto et al. 25 Uuistupa et al. 24 Pan et al. 15 Eriksson et al. 14 Helmrich et al. 24 Burchfiel et al. 22 Folsom et al. 21 Hu et al. 20 Manson et al. 19 Manson et al. 18 Salmeron et al. 17 Wannamethee and Shaper 16 Summary 523 overweight individuals with IGT were randomized to regular dietary and exercise program or a control group that met only yearly with a dietitian and a physician. After 4 years, the incidence of diabetes was 10% in the intervention group and 22% in the control group. The intervention group lost an average of 7.7 lb compared to 1.7 lb in the control group. 523 Finnish individuals with IGT were randomized into an intervention or a control group. Intervention included dietary advice and individually guided exercise program. After 1 year, there was a 3.7-kg greater weight loss among intervention patients, which was sustained at 2-year follow-up. Significant reductions in fasting and 2-h glucose and insulin levels were seen at 1- and 2-year follow-ups. At 2-year follow-up, 42% of intervention patients had sustained a 5-kg weight loss compared to 12% in the control group. 577 individuals with IGT were randomized into one of four groups (control, diet only, exercise only, or diet plus exercise) and followed for 6 years. In the control group, 67.7% developed diabetes, whereas 43.5% in the intervention groups developed diabetes. Diet resulted in a 31% risk reduction of diabetes; exercise led to a 46% reduction; and diet plus exercise resulted in a 42% reduction. 181 patients with IGT and 41 with newly diagnosed diabetes were randomized into lifestyle protocol with diet/and or exercise and followed for 5 years. Glucose tolerance normalized in >50% of patients with IGT, and >50% of those with diabetes were in remission at 6 years. Questionnaires evaluating the patterns of physical activity among 5,990 male alumni of the University of Pennsylvania during a 14-year follow-up period found that leisure time physical activity in walking, stair climbing, and sports was inversely related to the development of type 2 diabetes. For every 500-kcal increment of activity, risk was reduced 6%. The protective effect was strongest among people at highest risk for diabetes. Weight gain since college was also an independent risk predictor of diabetes. In 6,815 Japanese-American men in the Honolulu Heart Program aged years who were initially free of diabetes, physical activity was inversely associated with the incidence of diabetes after adjusting for age, BMI, body fat, blood pressure, lipids, and family history of diabetes. The study involved 34,257 postmenopausal women aged years. After 12 years of follow-up, the relative risk of diabetes after adjusting for age, smoking, estrogen use, dietary variables, and family history of diabetes was 0.69 (31% lower) for those who exercised compared to sedentary women. The study included 70,102 female nurses aged years who did not have diabetes, cardiovascular disease, or cancer at baseline. Physical activity was determined based on time spent per week on each of eight common physical activities including walking. Adjusting for age, smoking, hypertension, lipids, and other covariates, the study found a relative risk as much as 46% lower for those who exercised. Faster walking pace was independently associated with a decreased risk. 87,253 U.S. women aged years and free of diabetes, cardiovascular disease, and cancer at baseline were followed for 8 years. Women who engaged in vigorous exercise at least once per week, after adjusting for age, family history, BMI, and other factors, had a relative risk of diabetes of 0.67 (33% lower) than those who did not exercise weekly. The study involved 21,271 male physicians aged who did not have a history of diabetes, cardiovascular disease, or cancer at baseline. Following a 5-year follow-up period, men who exercised at least once per week, after adjusting for smoking, hypertension, family history, and other covariates, had a 0.64 relative risk (36% lower) of developing diabetes. Greater frequency of exercise per week was associated with even lower risks. The study involved 65,173 U.S. women free of diabetes, cardiovascular disease, and cancer at baseline. At 6-year follow-up, after adjusting for covariates including BMI and family history, cereal fiber intake was inversely associated with risk of diabetes. Those who consumed the most fiber had a relative risk of 0.72 (28% lower) compared with those with the lowest fiber intake. The combination of high glycemic load and low fiber intake more than doubled the risk of developing diabetes (relative risk = 2.50). The study involved 7,100 British men with no history of diabetes. After 5 years, those who had a weight gain of >10% had a relative risk of 1.61 (61% higher) after adjusting for covariates. Men who lost >4% of their total body weight reduced their risk for developing diabetes by 35%. *Randomized, prospective trials. 36

4 in the intervention subjects, compared to a decline of 0.2% in control subjects, but also significant reductions in both hospitalizations (P = 0.04) and utilization of outpatient medical services (P < 0.01). In a similar 6-month randomized intervention, my colleagues and I demonstrated that a computer-generated personalized diabetes education poster designed to be hung on a refrigerator and a personalized wallet card bearing the same information resulted in a decrease in HbA 1c twice as large as the decrease for control subjects, who did not receive these materials. 37 The poster and card stated the patient s diabetes status, goals, and self-care recommendations. Unfortunately, even after important studies such as these end and their results are published in peer-reviewed journals, there is often no preventive infrastructure to carry out the costeffective strategies they recommend. Talk is cheap, and it pays. In 1969, the diabetes section at the Los Angeles County/University of Southern California Medical Center implemented a telephone-answering service for clinic patients with diabetes as an alternative entry point for patients who would ordinarily have gone directly to the emergency room. 38 The phone line was staffed by a designated diabetes nurse practitioner or a diabetes-service resident who screened all patients being considered for hospital admission rather than having that decision made in the emergency room. Within 1 year of initiation of the phone line, the diabetes population served increased by 50%, whereas emergency admissions decreased from 2,680 to 1,250, with a two-thirds reduction in diabetic ketoacidosis. But although the estimated cost savings of this program was $3.4 million, the minimal costs of such an advice line could not be absorbed by the health care system over the long run. The value of a simple intervention such as telephone access to diabetes professionals has been lost in our current health care system. How many hospitalizations could be prevented if physicians and diabetes health care professionals were given the time to talk to patients? How many office visits could be avoided if time on the telephone was encouraged rather than discouraged by our current system of reimbursement? The DCCT was successful in sustaining improved HbA 1c results over a 10-year period in large part because of the regular telephone contact between members of the research team and patients. 7 Patients in the intervention group received on average 32 phone calls per year, but the payoff in terms of additional years of complication-free living was staggering. The intensive services provided during the DCCT, including the phone calls) were well within cost-efficacy range for the current standards we provide for many other chronic diseases. Who will pay for diabetes prevention? Although we have the scientific knowhow and data demonstrating our ability to reduce the rising rates of diabetes and its devastating complications, the current health care system in the United States provides a paucity of the preventive diabetes resources that are truly the lifelines for those with or at risk for this disease. Not uncommonly, both physicians and patients are weighed down by conundrums posed by insurers, such as being denied reimbursement for diagnostic testing unless a patient already has a diagnosis of a disease when the disease cannot be diagnosed until a test is performed. We have yet to shift our focus to beginning prevention long before adulthood, when our formative habits develop. By 2025, it is estimated that more than 300 million people throughout the world will have diabetes. The time has come for diabetes prevention, both in the United States and around the world. But the question remains: Who will pay this small price for prevention of diabetes? Perhaps a better question would be: Will our health care system continue to be a reactive one that would rather pay for costly procedures such as amputation or dialysis than cover the much lower costs of preventing complications? As we think about new technological and pharmacological developments for combating disease, we need to take a few steps back and begin to value those health care systems that promote healthier lifestyles and provide more complex and ongoing care but reap much greater benefits in the long run. When we demonstrate to society that disease prevention is valued as much as medical and surgical treatment of a disease after preventable complications arise, then we will begin to prevent diabetes. REFERENCES 1 Centers for Disease Control and Prevention National Center for Chronic Disease Prevention and Health Promotion: Diabetes threat on the rise among U.S. children. 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Arch Intern Med 147: , Testa MA, Simonson DC: Health economic benefits and quality of life during improved glycemic control in patients with type 2 diabetes mellitus. JAMA 280: , Sadur CN, Moline N, Costa M, Michalik D, Mendlowitz D, Roller S, Watson R, Swain BE, Selby JV, Javorski WC: Diabetes management in a health maintenance organization: efficacy of care management using cluster visits. Diabetes Care 22: , Levetan CS, Dawn KR, Robbins DC, Ratner RE: Impact of customized automation on hemoglobin A1c (Late-breaking abstract 11). American Diabetes Association 60 th Scientific Sessions, San Antonio, TX. Alexandria, Va., American Diabetes Association, Miller LV, Goldstein BA: More efficient care of diabetic patients in a county-hospital setting. N Engl J Med 286: , 1972 Claresa Levetan, MD, is director of diabetes education at MedStar Research Institute in Washington, D.C. She is an associate editor of Clinical Diabetes. 38