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DM: Effectiveness of MNT Provided by RD/RDN (2015)

Intervention
In adults with type 1 and type 2 diabetes, how effective is MNT provided by an RD/RDN on glycemia (A1C or glucose)?
- Conclusion
  In adults with type 2 diabetes, 21 study arms from 18 studies reported that MNT provided by RDNs significantly lowered HbA1c levels. At three months, HbA1c levels decreased by 0.3% to 2.0% and with ongoing MNT support decreases in HbA1c levels were maintained or improved for more than 12 months. An initial series of RDN encounters (three to 11; a total of two to 16 hours) with continued RDN encounters throughout the studies were reported. Although nutrition therapy interventions were effective throughout disease duration, the decrease in HbA1c was largest in studies in which participants were newly diagnosed or had higher baseline HbA1c levels. RDNs implemented a variety of nutrition therapy interventions all resulting in a reduced energy intake.
  In adults with type 1 diabetes, three studies reported that MNT provided by RDNs contributed to significantly decreased HbA1c levels. At six months, HbA1c levels decreased by 1.0% to 1.9%. An initial series of RDN encounters (four to six) were reported. Ongoing MNT support resulted in maintenance of the reduced HbA1c levels at one year and in the Diabetes Control and Complications Trial (DCCT) throughout the 6.5 years of the trial.
  
  In adults with type 1 and type 2 diabetes, nine studies reported that MNT provided by RDNs decreased fasting blood glucose levels at three months by 18mg to 61mg per dL. With ongoing MNT support, decreased levels were maintained to 12 months and in the DCCT throughout the 6.5 years of the trial.
- Grade: I
  - Grade I means there is Good/Strong evidence supporting the statement;
  - Grade II is Fair;
  - Grade III is Limited/Weak;
  - Grade IV is Expert Opinion Only;
  - Grade V is Not Assignable.
  - High (A) means we are very confident that the true effect lies close to that of the estimate of the effect;
  - Moderate (B) means we are moderately confident in the effect estimate;
  - Low (C) means our confidence in the effect estimate is limited;
  - Very Low (D) means we have very little confidence in the effect estimate.
  - Ungraded means a grade is not assignable.
- Evidence Summary: In adults with type 1 and type 2 diabetes, how effective is MNT provided by an RD or nutritionist on glycemia (A1C or glucose)?
- Search Plan and Results: DM: Medical Nutrition Therapy 2013
In adults with type 1 and type 2 diabetes, what impact does MNT provided by an RD/RDN have on medication usage (insulin or other glucose-lowering medications)?
- Conclusion
  In adults with type 2 diabetes, 12 study arms from 11 studies reported that MNT provided by RDNs resulted in decreases in doses or the number of glucose-lowering medications used. An initial series of RDN encounters (three to 10; a total two to six hours) with continued RDN encounters throughout the studies were reported. The United Kingdom Prospective Diabetes Study (UKPDS) reported significantly improved glucose outcomes for approximately two years. However, due to the normal progression of type 2 diabetes, additional medications were needed to achieve optimal glycemic control. Weight gain with medication use can be ameliorated by an intensive intervention provided by RDNs.
  In two studies of adults with type 1 diabetes, RDNs implemented carbohydrate-counting for the adjustment of pre-meal insulin doses. In both studies, a series of RDN encounters (four to six) were reported. Although the number of insulin injections increased, HbA1c improved without an increase in total insulin doses.
- Grade: I
  - Grade I means there is Good/Strong evidence supporting the statement;
  - Grade II is Fair;
  - Grade III is Limited/Weak;
  - Grade IV is Expert Opinion Only;
  - Grade V is Not Assignable.
  - High (A) means we are very confident that the true effect lies close to that of the estimate of the effect;
  - Moderate (B) means we are moderately confident in the effect estimate;
  - Low (C) means our confidence in the effect estimate is limited;
  - Very Low (D) means we have very little confidence in the effect estimate.
  - Ungraded means a grade is not assignable.
- Evidence Summary: In adults with type 1 diabetes and type 2 diabetes, what impact does MNT provided by an RD or nutritionist have on medication usage (insulin or other glucose-lowering medications)?
- Search Plan and Results: DM: Medical Nutrition Therapy 2013
In adults with type 1 and type 2 diabetes, how effective is MNT provided by an RD/RDN on CVD risk factors (lipids or blood pressure)?
- Conclusion
  In adults with type 2 diabetes and normal to mildly elevated cholesterol levels, 19 study arms in 16 studies reported that MNT provided by RDNs had mixed effects on cholesterol levels. Eight study arms reported significant decreases in cholesterol ranging from eight mg to 28mg per dL.
  In adults with type 2 diabetes and normal to mildly elevated LDL-cholesterol levels, 17 study arms in 15 studies reported that MNT provided by RDNs had mixed effects on LDL-cholesterol levels. Seven study arms reported significant decreases in LDL-cholesterol ranging from eight mg to 22mg per dL.
  
  In adults with type 2 diabetes and normal to mildly low HDL-cholesterol levels, 19 study arms in 16 studies reported that MNT provided by RDNs had mixed effects on HDL-cholesterol levels. Three studies reported significant increases in HDL-cholesterol ranging from 2.4mg to six mg per dL.
  
  In adults with type 2 diabetes and normal to elevated triglyceride levels, 19 study arms in 16 studies reported that MNT provided by RDNs had mixed effects on triglyceride levels. Seven study arms reported significant decreases in triglycerides ranging from 15mg to 153mg per dL.
  
  In adults with type 2 diabetes and with near-normal blood pressure levels, 12 study arms in 10 studies reported that MNT provided by RDNs had mixed effects on blood pressure levels. Seven study arms reported significant decreases in systolic and diastolic blood pressure of 3.2 to 9.0mmHg/2.5 to 5.3mmHg.
  
  In adults with type 1 diabetes and near normal lipid and blood pressure levels, two studies reported that MNT provided by RDNs led to non-significant changes in total cholesterol, HDL-cholesterol, triglycerides and blood pressure. The Diabetes Control and Complications Trial (DCCT) at five years, reported that LDL-cholesterol was significantly decreased.
  
  Subjects did not have or were not described as having any disorders of lipid metabolism or hypertension. The effectiveness of MNT may have been confounded by lipid-lowering or anti-hypertensive medications. Additional long-term studies are needed to ascertain the effectiveness of MNT on lipid profiles and blood pressure in adults with diabetes and disorders of lipid metabolism and hypertension.
- Grade: II
  - Grade I means there is Good/Strong evidence supporting the statement;
  - Grade II is Fair;
  - Grade III is Limited/Weak;
  - Grade IV is Expert Opinion Only;
  - Grade V is Not Assignable.
  - High (A) means we are very confident that the true effect lies close to that of the estimate of the effect;
  - Moderate (B) means we are moderately confident in the effect estimate;
  - Low (C) means our confidence in the effect estimate is limited;
  - Very Low (D) means we have very little confidence in the effect estimate.
  - Ungraded means a grade is not assignable.
- Evidence Summary: In adults with type 1 and type 2 diabetes, how effective is MNT provided by an RD/nutritionist on CVD risk factors (lipids or blood pressure)?
- Search Plan and Results: DM: Medical Nutrition Therapy 2013
In adults with type 1 and type 2 diabetes, how effective is MNT provided by an RD/RDN on quality of life?
- Conclusion
  In six studies in which RDNs implemented MNT, improvements in quality of life were reported. An initial series of three to six RDN encounters (2.5 hours to six hours) with long-term RDN encounters were reported.
- Grade: I
  - Grade I means there is Good/Strong evidence supporting the statement;
  - Grade II is Fair;
  - Grade III is Limited/Weak;
  - Grade IV is Expert Opinion Only;
  - Grade V is Not Assignable.
  - High (A) means we are very confident that the true effect lies close to that of the estimate of the effect;
  - Moderate (B) means we are moderately confident in the effect estimate;
  - Low (C) means our confidence in the effect estimate is limited;
  - Very Low (D) means we have very little confidence in the effect estimate.
  - Ungraded means a grade is not assignable.
- Evidence Summary: In adults with type 1 and type 2 diabetes, how effective is MNT provided by an RD or nutritionist on quality of life?
- Search Plan and Results: DM: Medical Nutrition Therapy 2013
In adults with type 1 and type 2 diabetes, how effective is MNT provided by an RD/RDN on weight management (pounds, waist circumference or BMI)?
- Conclusion
  In adults with type 2 diabetes, body weight outcomes from MNT provided by RDNs were mixed. At study end, 11 study arms reported MNT provided by RDNs significantly decreased baseline body weights by 2.4kg to 6.2kg, whereas six study arms reported non-significant weight changes at study end. In persons with type 1 diabetes, weight outcomes were also mixed.
  In adults with type 2 diabetes, body mass index (BMI) outcomes from MNT provided by RDNs were mixed. At study end, nine study arms reported significant decreases in baseline BMIs by 0.3kg/m² to 2.1kg/m², whereas eight study arms reported non-significant changes in BMI at study end. In persons with type 1 diabetes, one study reported a significantly decreased BMI of 0.3kg/m² from MNT provided by RDNs.
  
  In adults with type 2 diabetes, waist circumference outcomes from MNT provided by RDNs were mixed. At study end, nine study arms reported decreases of 1.0cm to 5.5cm, whereas three study arms reported non-significant changes in waist circumference at study end. In persons with type 1 diabetes, one study reported a significantly decreased waist circumference of one cm from MNT provided by RDNs.
- Grade: II
  - Grade I means there is Good/Strong evidence supporting the statement;
  - Grade II is Fair;
  - Grade III is Limited/Weak;
  - Grade IV is Expert Opinion Only;
  - Grade V is Not Assignable.
  - High (A) means we are very confident that the true effect lies close to that of the estimate of the effect;
  - Moderate (B) means we are moderately confident in the effect estimate;
  - Low (C) means our confidence in the effect estimate is limited;
  - Very Low (D) means we have very little confidence in the effect estimate.
  - Ungraded means a grade is not assignable.
- Evidence Summary: In adults with type 1 and type 2 diabetes, how effective is MNT provided by an RD or nutritionist on weight management (pounds, waist circumference or BMI)?
- Search Plan and Results: DM: Medical Nutrition Therapy 2013