Case Study: The Benefits of Making a Dietitian Referral for Pre-diabetes Free

Initial consultation. D.G., a 54-year-old white man, was referred to a registered dietitian (RD) for pre-diabetes. He had been identified as having pre-diabetes 8 months earlier and was trying to lose weight on his own.

The initial assessment indicated that his height was 67″ and current weight was 185 lb (BMI 29 kg/m²). His waist measurement was 35″, and a 3-year weight history indicated weight fluctuations between 173 and 191 lb.

Recent laboratory tests showed a fasting blood glucose (FBG) of 123 mg/dl,total cholesterol of 249 mg/dl, triglyceride level of 297 mg/dl, HDL cholesterol of 42 mg/dl, and LDL cholesterol of 148 mg/dl. D.G. reported taking atenolol for hypertension and daily aspirin. The referring health care provider stated that D.G. was at increased health risk because of“probable metabolic syndrome.”

The RD reviewed with D.G. his diabetes risk factors: age, personal medical history of hypertension, dyslipidemia, pre-diabetes, and BMI > 25 kg/m². He reported engaging in aerobic exercise five times each week for 35-60 minutes per session, but said he had been unsuccessful at eating less fat to lower his cholesterol.

After obtaining information on his usual food intake, the RD recommended that D.G. limit his food intake to 1,800 cal/day, his total fat intake to 25-30% of calories (50-60 g), and his saturated fat intake to 7-10% of calories (14-20 g). They discussed ways to lower calories by eating smaller portions, making lower-fat food choices, and limiting foods high in sugar,such as regular soda. The RD encouraged him to maintain his aerobic exercise routine.

D.G. was assessed to be at the “action” stage of the readiness-to-change behavior change model for physical activity and at the“preparation” stage for managing weight and choosing low-fat foods. He was very motivated to live a healthy lifestyle and reduce his risk of developing diabetes and heart disease. He had strong support from his wife.

D.G. enrolled in a phone-based lifestyle counseling program and received nutrition and disease-prevention information. He agreed to track his food intake using an online food log and nutritional analysis program and to participate in regular follow-up with the RD for several months.

RD follow-up at 6 months. D.G. reported that his weight was 165 lb. He had lost 20 lb and reduced his BMI to 25.8 kg/m². He was keeping a food log and meeting his fat and calorie goals. Laboratory results at the 6-month follow-up showed an FBG of 109 mg/dl (down 14 mg/dl), a total cholesterol of 226 mg/dl (down 23 mg/dl), a triglyceride level of 154 (down 143 mg/dl), an HDL cholesterol level of 46 (up 4 mg/dl), and an LDL cholesterol level of 149 (up 1 mg/dl). D.G. reported that he wanted to lose an additional 10 lb for a goal weight of 155 lb. He reported being more confident in his ability to make healthy food choices and to maintain his aerobic exercise program. He felt positive about his support system.

The RD congratulated D.G. for the progress he had made and assessed him to be at the “action” stage of change for making food choices that were low in fat and saturated fat and at the “maintenance” stage for continuing with his aerobic exercise. The RD noted that reducing saturated fat further (to 7%) could lower LDL cholesterol but that sometimes a cholesterol-lowering medication may also be necessary.

D.G. decided that he had the tools he needed to continue on his own. He planned to maintain his aerobic exercise program and work at further reducing total fat and saturated fat intake, portion sizes, and foods high in sugar,while increasing his fruit and vegetable intake. He agreed to follow up with his health care provider to have his blood glucose and cholesterol level checked on a regular basis.

Clinic visit 9 months after initial RD consultation. D.G.'s care provider started him on atorvastatin because, even with dietary changes,his blood lipids remained outside of goal: total cholesterol of 241 mg/dl,triglyceride level of 185 mg/dl, HDL cholesterol level of 52 mg/dl, and LDL cholesterol level of 152 mg/d. His FBG was 112 mg/dl, and his weight was 171 lb (up 6 lb).

Clinic visit 1 year after initial RD consultation. With sustained weight loss, a low-fat diet, and cholesterol-lowering medication,D.G.'s metabolic outcomes were at goal: total cholesterol of 123 mg/dl (down 118 mg/dl), triglyceride level of 117 mg/dl (down 68 mg/dl), HDL cholesterol level of 49 mg/dl (down 3 mg/dl), and LDL cholesterol level of 51 (down 101 mg/dl). His FBG was 99 mg/dl (down 13 mg/dl), and his weight was 166 lb (down 5 lb).

By losing weight and keeping it off, D.G. has been able to prevent type 2 diabetes for the past 1.5 years, and his FBG has returned to normal. If he does not gain weight and remains physically active, he will likely continue to prevent or delay the development of diabetes.

1. How is pre-diabetes identified, and what are the current recommendations for its treatment?

2. How can patients with pre-diabetes benefit from being referred to an RD?

3. Is lowering FBG enough when treating patients with pre-diabetes?

Pre-diabetes is identified through either the FBG test or the oral glucose tolerance test (OGTT) (Table 1). Either test should be repeated on another day to confirm the presence of the condition.¹ 

The Diabetes Prevention Program (DPP) showed that as little as a 5%sustained weight loss (∼ 10 lb) and 30 minutes of exercise 5 days a week(150 minutes/week) can reduce type 2 diabetes risk by 58%.²  DPP researchers found that diet and exercise were more effective than metformin therapy. Participants who were treated with metformin reduced their diabetes risk by only 31%.² 

Because weight management is the primary treatment recommendation for pre-diabetes, referral to an RD would benefit patients with this condition. An RD can assess a patient's current food intake, activity level, and readiness to change, and then make recommendations for lifestyle change. Nutrition recommendations for pre-diabetes include calorie reduction, reduced intake of total fat (particularly saturated fat), and increased intake of whole grains and dietary fiber.³ Physical activity recommendations include 2.5 hours of moderate physical activity (such as brisk walking) per week.² 

Based on an individual's readiness to change and current lifestyle behaviors, the RD can tailor these recommendations to each patient. One way to do this is through use of the Transtheoretical Model.⁴  For example,an individual in the “preparation” stage (i.e., planning to make changes within the 30 days) may know what to do (eat healthier), but may not know where to begin changing their food choices. An RD can help this individual develop an eating plan and teach specific how-to skills, such as using nutrition labels choosing lower-fat foods.

Pre-diabetes is associated with the metabolic syndrome—the clustering of obesity, dyslipidemia, and hypertension. An RD can also make nutrition recommendations that will help patients who need to lower their cholesterol and blood pressure. The medical nutrition therapy goals for prevention of diabetes in high-risk individuals include:

• Moderate sustained weight loss of ∼ 5%

• Achievement and maintenance of optimal metabolic outcomes, including normal blood lipid, blood pressure, and blood glucose levels

• Modification of nutrient intake for the treatment of comorbidities (i.e.,obesity, dyslipidemia, cardiovascular disease, and hypertension)

• Improvement in health through nutritious food choices

• Development of plans to address individual nutritional needs while taking into consideration patients' personal and cultural preferences and lifestyles and respecting their wishes and willingness to change.³ 

Patients with pre-diabetes often have other related medical conditions, so treating pre-diabetes itself is not enough. Metabolic outcomes should be monitored on a regular basis. Changes in lifestyle and, if necessary, the addition or adjustment in medications should be made to maintain optimal blood glucose, blood lipid, and blood pressure levels.^5,6 

• Sustained weight loss of at least 5% is necessary to prevent type 2 diabetes in high-risk patients.

• Patients with pre-diabetes may benefit from a nutrition consultation because an RD can conduct a comprehensive nutrition assessment and provide lifestyle counseling for cholesterol and blood pressure management in addition to management of prediabetic glucose levels.

• The focus of the interventions should not be limited to blood glucose. Because of the association between pre-diabetes and the metabolic syndrome,treating hypertension and dyslipidemia is equally important.

• To reach optimal metabolic outcomes, medications for blood pressure and cholesterol-lowering may be needed in addition to a healthier lifestyle.

• Individuals with pre-diabetes can get valuable benefits from an RD referral including behavior change counseling (i.e., tailored counseling based on an individual's motivational readiness to change), individualized nutrition recommendations, and assistance with developing a realistic action plan for diabetes prevention.