Clinical Briefs

By Louis Kuritzky, MD, Clinical Assistant Professor, University of Florida, Gainesville. Dr. Kuritzky is a consultant for Abbott, AstraZeneca, Boehringer Ingelheim, Daiichi, Sankyo, Forest Pharmaceuticals, Lilly, Novo Nordisk, Takeda.

Immunochemical FOBT and low- dose aspirin

Source: Brenner H, et al. Low-dose aspirin use and performance of immunochemical fecal occult blood tests. JAMA 2010;304:2513-2520.

Immunochemical fecal occult blood testing (i-FOBT) is becoming increasingly popular as a screening tool for colorectal cancer (CRC). At the same time, the number of persons taking long-term low-dose aspirin (ASA) for CV disease risk reduction is also increasing. Concern has been expressed that the predictable increase in GI bleeding associated with ASA would decrease the specificity of i-FOBT by increasing false positives. At the same time, it has been suggested that consequences of i-FOBT to detect upper GI bleeding may have been overestimated, since the globin chains detected by i-FOBT typically are degraded progressively during passage through the GI tract, and are hence less available for i-FOBT identification than more distal bleeding in the GI tract. Finally, utilization of ASA might also increase the risk of bleeding of CRC, thus enhancing likelihood of detection.

To assess the relationship between ASA, i-FOBT, and results of CRC screening, Brenner et al reported on almost 2000 adults who underwent CRC screening, 12% of whom were regular ASA users.

Sensitivity (the number of positive tests in persons confirmed to have advanced GI neoplasms) of i-FOBT was greater in ASA users than non-users. i-FOBT specificity (the number of negative tests in persons without advanced GI neoplasms) was minimally reduced.

Chronic low-dose ASA does not appear to compromise the ability of i-FOBT to detect advanced GI neoplasia, with a modest decrease in specificity.

Capitalizing on the second-meal effect in type 2 diabetes

Source: Chen JM, et al. Utilizing the second-meal effect in type 2 diabetes: Practical use of a soya-yogurt snack. Diabetes Care 2010;33:2552-2554.

It is probably not widely known that Mom was right — at least as it pertains to diabetes — that you should NOT skip breakfast. Why? Because of the "second-meal effect," a little-recognized physiologic response that can have a potentially favorable effect on glucose.

The way the "second-meal effect" works is like this: When breakfast is eaten, the degree of hyperglycemia seen after lunch is less than if the same amount of calories are given without having eaten breakfast. It has been suggested that the improved glucose level is related to a reduction in preprandial free fatty acids, which allows for greater storage of muscle glycogen during a second meal (and hence a greater disappearance of glucose from the plasma). This phenomenon occurs in both diabetic and non-diabetic individuals. Based upon this observation, Chen at al hypothesized that perhaps providing a pre-breakfast snack would reduce post-breakfast hyperglycemia.

Diabetic subjects (n = 10) were administered a snack of soya beans and yogurt 2 hours before breakfast. For scheduling convenience, the snack was administered at 8 am, and breakfast at 10 am.

Plasma glucose 2 hours after breakfast was significantly lower in the group who received the snack. Since postprandial glucose levels have been associated with adverse cardiovascular outcomes in diabetics, it might be both desirable and possible to manipulate post-meal hyperglycemia without using medications.

Aerobic vs resistance exercise for type 2 diabetes

Source: Church T, et al. Effects of aerobic and resistance training on hemoglobin A1c in patients with type 2 diabetes. JAMA 2010;304:2253-2262.

Most persons with type 2 diabetes (DM2) are overweight or obese. Exercise is routinely advised for DM2, although whether a particular method of exercise has an advantage for optimization of glycemic control is not well defined.

Church et al compared the effects of aerobic exercise (AER), resistance training (RES), or the combination (AER + RES) vs placebo in previously sedentary mid-life DM2 adults (mean age = 56 years). Participants engaged in the prescribed activities for 9 months. The primary outcome was change in A1c from baseline.

At the conclusion of the trial, only the AER + RES provided statistically significant reduction in A1c compared to placebo; AER alone or RES alone did not.

It would be unfortunate if clinicians were to interpret this trial as indicating a lack of value of either AER or RES alone. All exercise groups had favorable changes in anthropomorphic metrics, and exercise has been shown to be associated with a favorable impact upon cardiovascular risk in large population studies, an effect that may be independent of glycemic effects.