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Recommendations Summary

PDM: MNT for Prevention of Type 2 Diabetes in High Risk Groups 2014

Click here to see the explanation of recommendation ratings (Strong, Fair, Weak, Consensus, Insufficient Evidence) and labels (Imperative or Conditional). To see more detail on the evidence from which the following recommendations were drawn, use the hyperlinks in the Supporting Evidence Section below.


  • Recommendation(s)

    PDM: MNT for Prevention of Type 2 Diabetes in High Risk Groups

    The registered dietitian nutritionist (RDN) should provide medical nutrition therapy (MNT) encounters for individuals who are at high risk for type 2 diabetes and increase the frequency of encounters to optimize outcomes.

    In adults with metabolic syndrome, research regarding the impact of medical nutrition therapy (MNT) reported significant improvements:

    • Decreased fasting blood glucose by 2.5mg to 9mg per dL (0.1mmol to 0.5mmol per L)
    • Decreased A1C by 0.12% to 0.23% 
    • Decreased triglycerides by 21mg to 35mg per dL (0.2mmol to 0.4mmol per L) 
    • Increased HDL cholesterol by 2.4mg per dL (0.06mmol per L)
    • Decreased body weight by 2.5kg to 4.1kg
    • Decreased waist circumference by 1.9cm to 4.8cm
    • Decreased systolic blood pressure by 4.9mm Hg.

    In individuals with prediabetes, research regarding the impact of medical nutrition therapy (MNT) reported significant improvements:

    • Decreased fasting blood glucose by 2mg to 9mg per dL (0.1mmol to 0.5mmol per L)
    • Decreased two-hour post-prandial blood glucose by 9mg to 16.2mg per dL (0.5mmol to 0.9mmol per L).
    • Decreased waist circumference by 3.8 - 5.9 cm

    In addition, studies reported that increased frequency of visits resulted in greater improvements in certain metabolic and anthropometric outcomes.

    Rating: Strong
    Imperative

    • Risks/Harms of Implementing This Recommendation

      None.

    • Conditions of Application

      None.

    • Potential Costs Associated with Application

      • The costs of medical nutrition therapy (MNT).

    • Recommendation Narrative

      • A total of eight studies (11 publications) were included in the evidence analysis for this recommendation:
        • Four positive quality randomized controlled trials (RCT) (Eriksson et al, 1999; Oldroyd et al, 2001; Lindstrom et al, 2003; Oldroyd et al, 2006; Gagnon et al, 2011 and Munakata et al, 2011)
        • Four neutral quality RCTs (Dyson et al, 1997; Mensink, Blaak et al, 2003; Mensink, Feskens et al, 2003; Corpeleijn et al, 2006 and Katula et al, 2011).

      In Adults with Metabolic Syndrome

      • Glycemic-related outcomes (FBG, random BG, two-hour post prandial BG, A1C):
        • One study regarding the impact of medical nutrition therapy (MNT) reported significant decreases in fasting blood glucose of 2.5mg to 9mg per dL (0.1mmol to 0.5mmol per L) and in A1C of 0.12% to 0.23% in adults with metabolic syndrome
        • Increased frequency of visits resulted in greater improvement in fasting blood glucose
        • Additional longer-term intervention studies are needed regarding the effect of medical nutrition therapy on glycemic-related outcomes in adults with metabolic syndrome with or without meeting the metabolic syndrome criteria for impaired glucose tolerance and impaired fasting glucose
        • Evidence is based on the following: Munakata et al, 2011.
      • Lipid outcomes (TG, HDL):
        • One study regarding the impact of medical nutrition therapy (MNT) reported decreases in triglycerides of 21mg to 35mg per dL (0.2mmol to 0.4mmol per L) and increases in HDL cholesterol of 2.4mg per dL (0.06mmol per L) in adults with metabolic syndrome
        • Additional longer-term intervention studies are needed regarding the effect of medical nutrition therapy on lipid outcomes in adults with metabolic syndrome with or without meeting the metabolic syndrome criteria for lipid levels
        • Evidence is based on the following: Munakata et al, 2011.
      • Anthropometric outcomes (WC, WHR)
        • One study regarding the impact of medical nutrition therapy (MNT) reported decreases in body weight of 2.5kg to 4.1kg and in waist circumference of 1.9cm to 4.8cm in adults with metabolic syndrome
        • Increased frequency of visits resulted in greater improvement in waist circumference
        • Additional longer-term intervention studies are needed regarding the effect of medical nutrition therapy on anthropometric outcomes in adults with metabolic syndrome with or without meeting the metabolic syndrome criteria for anthropometric measures
        • Evidence is based on the following: Munakata et al, 2011.
      • Blood pressure outcomes:
        • One study regarding the impact of medical nutrition therapy (MNT) reported decreases in systolic blood pressure of 4.9mm Hg, but not diastolic blood pressure, in adults with metabolic syndrome
        • Increased frequency of visits resulted in greater improvement in systolic blood pressure
        • Additional longer-term intervention studies are needed regarding the effect of medical nutrition therapy on blood pressure in adults with metabolic syndrome with or without meeting the metabolic syndrome criteria for blood pressure
        • Evidence is based on the following: Munakata et al, 2011. 
      • Renal outcomes:
        • There were no studies identified to evaluate the impact of medical nutrition therapy on renal outcomes in adults with metabolic syndrome
        • Intervention studies are needed regarding the effect of medical nutrition therapy on renal outcomes in adults with metabolic syndrome with or without meeting the metabolic syndrome criteria for renal measures.

      In Individuals with Prediabetes

      • Glycemic-related Outcomes (FBG, random BG, 2-hour post prandial BG, A1C)
        • Most studies reported that medical nutrition therapy resulted in a significant decrease in fasting blood glucose of 2 to 9 mg per dL (0.1mmol to 0.5mmol per L) and in 2-hour post prandial blood glucose of 9 to 16.2 mg/dl (0.5 - 0.9 mmol/L).
        • Of four studies (five publications) reporting A1C values, all reported no significant effect of MNT.
        • Evidence is based on the following: Dyson et al, 1997; Eriksson et al, 1999; Oldroyd et al, 2001; Lindstrom et al, 2003; Mensink, Blaak et al, 2003; Mensink, Feskens et al, 2003; Corpeleijn et al, 2006; Oldroyd et al, 2006; Gagnon et al, 2011; Katula et al, 2011.
      • Lipid Outcomes (TG, HDL)
        • Most studies reported no significant impact of medical nutrition therapy on serum triglycerides in individuals with prediabetes.
        • All studies reported no significant change in HDL cholesterol.
        • Additional intervention studies are needed regarding the effect of medical nutrition therapy on lipid outcomes (triglycerides and HDL cholesterol) in individuals with prediabetes with elevated triglycerides and/or low HDL cholesterol.
        • Evidence is based on the following: Dyson et al, 1997; Eriksson et al, 1999; Oldroyd et al, 2001; Lindstrom et al, 2003; Mensink, Blaak et al, 2003; Mensink, Feskens et al, 2003; Oldroyd et al, 2006; Gagnon et al, 2011.
      • Anthropometric Outcomes (WC, WHR)
        • Most studies reported that medical nutrition therapy (MNT) significantly reduced waist circumference by 3.8 - 5.9 cm in individuals with prediabetes.
        • Of two studies reporting waist-to-hip ratio, both reported no significant effect of MNT.
        • Evidence is based on the following: Dyson et al, 1997; Eriksson et al, 1999; Oldroyd et al, 2001; Lindstrom et al, 2003; Mensink, Feskens et al, 2003; Corpeleijn et al, 2006; Gagnon et al, 2011; Katula et al, 2011.
      • Blood Pressure Outcomes
        • Research regarding the impact of medical nutrition therapy on systolic blood pressure reported mixed results, however, the majority of research reported no significant change on diastolic blood pressure in individuals with prediabetes.
        • Additional intervention studies are needed regarding the effect of medical nutrition therapy on blood pressure in individuals with prediabetes. 
        • Evidence is based on the following: Dyson et al, 1997; Eriksson et al, 1999; Oldroyd et al, 2001; Lindstrom et al, 2003; Gagnon et al, 2011.

    • Recommendation Strength Rationale

      For Adults with Metabolic Syndrome

      • Grade III evidence is available for the conclusion statements regarding the impact of medical nutrition therapy in adults with metabolic syndrome on:
        • Glycemic-related outcomes (such as fasting blood glucose, random blood glucose, two-hour post-prandial blood glucose, A1C)
        • Lipid outcomes (TG, HDL)
        • Anthropometric outcomes (WC, WHR)
        • Blood pressure.
      • Grade V (no evidence) is available to evaluate the impact of medical nutrition therapy in adults with metabolic syndrome on renal outcomes.

      For Individuals with Prediabetes

      • Grade I evidence is available for the conclusion statements regarding the impact of medical nutrition therapy in individuals with prediabetes on:
        • Glycemic-related outcomes (such as fasting blood glucose, random blood glucose, two-hour post-prandial blood glucose, A1C)
        • Anthropometric outcomes (WC, WHR).
      • Grade II evidence is available for the conclusion statements regarding the impact of medical nutrition therapy in individuals with prediabetes on:
        • Lipid outcomes (TG, HDL)
        • Blood pressure.
       

    • Minority Opinions

      Consensus reached.