Should we use aggressive medical treatment to stop the progression of diabetic retinopathy?

The Buzz: In type 2 diabetics, intensive glucose and lipid control (but not intensive BP control) prevents the progression of diabetic retinopathy (DR), but the approach may harm more patients than it benefits.
Citation: NEJM 363;3 July 15, 2010
Summary: As part of a sub-study of the large multi-center RCT ACCORD trial, researchers evaluated 10,251 diabetic patients randomly assigned to intensive (A1c < 6.0%) vs standard therapy (A1c < 7.0-7.9%), and were followed to monitor progression of DR, including the need for laser surgery or vitrectomy. Decreased rates of progression of DR were seen in the intensive glucose (7.3 vs 10.4%, P = 0.003) and lipid (6.5 vs 10.2%, P = 0.006) groups, but not the intensive BP group (10.4 vs 8.8%, P = 0.29). However, the trial was halted early, and a large portion of patients with higher LDL levels and alb/creat scores and lower visual acuity scores did not receive 4 year follow-up.

Commentary: These findings need to be interpreted in conjunction with the ACCORD trial, since DR is only one CV endpoint that is seen in diabetics.  In fact, the trial was stopped early when results suggested intensive glucose lowering was found to have no benefit in MI/CVA prevention and increased all-cause mortality. These findings were not replicated in the newer ADVANCE trial, which used different glucose lowering agents.  However, despite this newer trial and the benefit seen in DR, it is likely most prudent to maintain an A1c goal of 7.0-7.9%. In addition, this study suggests adding fenofibrate therapy to a statin may be useful to slow DR progression, particularly if the patient is male and has high trigylcerides or low HDL, as CV risk reduction with fenofibrate was found in these subsets.

By: Elizabeth Haskins, MD

What are the most effective lifestyle changes for improvements in lipid profiles?

The Buzz: Various lifestyle modifications can benefit lipid profiles

Citation: "Diet and Exercise in the Management of Hyperlipidemia" AFP, 81;9 May 1, 2010 1097-1101

Summary: This review article is a compilation of various primary studies and meta analysis regarding specific life style modifications and their affect on lipids. Data summarized below:

• Limit saturated fats to < 7% of calories and eliminate trans fats = LDL ↓9-12%
• Increase intake of soluble fiber (3 oz oats per day, psyllium supplement) = LDL  ↓ 5 mg/dL  
• Isocalorically increase consumption of tree nuts ( .5 oz almonds, walnuts, or pecans per day) = LDL ↓ 2-19%
• 1.5 oz soy protein per day - tofu and soy foods to replace meats = ↓ LDL 5mg/dL
  ↑ HDL 0.8 mg/dL 
•  One alcoholic drink for females, two for males = ↓  LDL 7.8 mg/dL
  ↑ HDL 9-13 mg/dL 
• 1 oz Promise, Active, or Benecol spread per day  = ↓ LDL 10% 
• Increase intake of marine omega-3 fatty acids (EPA/DHA) = ↓ Triglycerides in a dose-dependant fashion
• Mediterranian Diet = ↓ total cholesterol:HDL ratio > 12% 
• Portfolio Diet  = ↓ LDL 29-35% 
• Aerobic exercise >120 min/week = ↓ LDL 4mg/dL
  ↑ HDL 1.9 - 2.5 mg/dL

Other pearls include:

• Dietary advice from physicians results in ↓ cholesterol 6.2/ mg/dL and ↓ LDL 7.0 mg/dL.
• Dietary advice from a dietitian results in and additional ↓ cholesterol 9.7 mg/dL.
• The greatest reduction results from avoidance of saturated and trans fats, increase in polyunsaturated and monunsaturated fats, moderate ETOH intake, supplementation with plant sterols or stanols (eg Promise spread), and isocalorically increasing consumption of tree nuts

Commentary: This study helps to quantify the effects of commonly recommended lifestyle modifications on lipid levels. Some of the recommendations, although showing impressive reductions in lipids, require a motivated patient. 

By: Steven Winiarski D.O.