Direct renin inhibition improves parasympathetic function in diabetes.

AIM: The renin-angiotensin-aldosterone system (RAAS) and autonomic nervous system regulate the cardiovascular system. Blockade of the RAAS may slow the progression of end-organ damage. Direct renin inhibition offers a means for blocking the RAAS. The objective of this study was to examine the effect of direct renin inhibition on cardiovascular autonomic function. METHODS: In this double-blind, placebo-controlled trial, 60 individuals with diabetes were randomly assigned to 300 mg of aliskiren or placebo once daily for 6 weeks. The primary end point was a change in tests of cardiovascular autonomic function. Autonomic function was assessed by power spectral analysis and RR-variation during deep breathing [i.e. mean circular resultant (MCR), expiration/inspiration (E/I) ratio]. The MCR and E/I ratio assess parasympathetic function. Secondary measures included change in biochemical parameters [e.g. plasma renin activity, leptin and interleukin-6]. Change in cardiovascular autonomic function and blood analytes were analysed by a mixed effects model for repeated measures. RESULTS: Baseline characteristics were similar between treatment groups. In response to aliskiren compared with placebo, blood pressure was reduced as well as plasma renin activity [from 2.4 ± 3.8 (mean ± standard deviation) to 0.5 ± 0.4 µg/l/h, p < 0.001]. There was a significant interaction (aliskiren × visit) for MCR (p = 0.003) and E/I ratio (p = 0.003) indicating improvement in MCR and E/I ratio for those on aliskiren. MCR means, baseline vs. follow-up, were 41.8 ± 19.7 vs. 50.8 ± 26.1 (aliskiren) and 38.2 ± 23.6 vs. 37.5 ± 24.1 (placebo). CONCLUSIONS: Parasympathetic function (i.e. MCR and E/I ratio) was enhanced by downregulation of the RAAS.

Continuous subcutaneous insulin infusion: a comprehensive review of insulin pump therapy.

A tremendous amount of data suggest that near-normal glycemic control prevents or delays complications of diabetes, which has led to a dramatic increase in continuous subcutaneous insulin infusion (CSII) or insulin pump use. In this article, the data supporting CSII in type 1 diabetes is reviewed, and the advantages and disadvantages of CSII are analyzed. In addition, CSII use in specific situations is examined, including during childhood and pregnancy and while exercising. The published articles suggest that CSII provides better glycemic control than does conventional therapy and comparable to or slightly better control than multiple daily injections. The use of CSII may be especially indicated during pregnancy or for preconception care and for diabetes presenting in childhood or adolescence.

A cross-sectional study comparing two quantitative sensory testing devices in individuals with diabetes.

OBJECTIVE: This study was designed to compare circumference discrimination thresholds, as assessed by the Tacticon (Tacticon, Inc., Westtown, PA), a new quantitative sensory testing (QST) device, with vibratory thresholds, an assessment modality of large sensory nerve fibers, in individuals with diabetes. RESEARCH DESIGN AND METHODS: In this study, 150 individuals with diabetes were evaluated. Vibratory thresholds and circumference discrimination thresholds, evaluated with the Tacticon, were determined using a two-alternative forced-choice procedure. RESULTS: Vibratory thresholds increased with decreasing ability to discriminate differences in circumference (P < 0.001) for those below and above 50 years of age. Agreement between the two QST devices was assessed via the kappa-statistic in both age-groups (i.e., < or = 50 years old [kappa = 0.67], > 50 years old [kappa = 0.55]). In multiple logistic regression, where circumference discrimination thresholds were the dependent variable, age, duration of diabetes, and height were found to be independently associated for those > 50 years old. CONCLUSIONS: The Tacticon offers a simple method of assessing the complex function of area discrimination. Our results suggest that the Tacticon can detect neuropathy in the primary care setting. Its cost, portability, and ease of use provide some advantages over existing QST equipment.

A comparison between alternative and trade name glucose test strips.

OBJECTIVE: To determine the reliability of seven different alternative glucose test strips manufactured for use with three different glucose meters. RESEARCH DESIGN AND METHODS: Venous blood samples were obtained from volunteers to test trade name glucose test strips on the manufacturers' glucose meters (One Touch II, Glucometer II, and Glucometer III), and the remainder of each sample was used for laboratory determination of blood glucose levels. In addition to the trade name test strips, Quick Check and First Choice test strips were tested on all meters, and Biotel test strips were also tested on the Glucometer III. RESULTS: In linear regression analysis, the R2 ranged from 0.84 to 0.97 for the test strips compared with plasma glucose values. The test strips with the highest accuracy and precision at all ranges of blood glucose levels were the One Touch II and Glucometer III trade name strips and the Quick Check and First Choice alternative strips for the One Touch II glucose meter and the First Choice alternative strip for the Glucometer II. Subgroup analysis based on ranges of blood glucose values, however, revealed that the alternative strips were not as accurate as the trade name test strips, with the exception of the First Choice alternative test strip for the Glucometer II. All of the trade name test strips were more precise than the alternative test strips designed for the individual meters. CONCLUSIONS: Alternative glucose test strips can be used to predict the actual laboratory blood glucose values but are generally not as accurate or precise as the trade name test strips.

Vibratory thresholds correlation with systolic blood pressure in diabetic women.

Previous studies have suggested a potential association of elevated blood pressure (BP) and the development of diabetic neuropathy for individuals with insulin-dependent diabetes mellitus. In this study, we examined an association between BP and vibratory thresholds (assessment modality of large sensory nerve fiber function) for 33 participants with non-insulin-dependent diabetes mellitus. There were 19 women and 14 men aged 58 +/- 7 (mean +/- SD) years, with diabetes duration of 7 +/- 6 years and a body mass index of 29 +/- 5 kg/m2. None of the individuals were taking any medications that lower BP and all were negative for the presence of microalbuminuria. Vibratory thresholds were determined at three visits using a two-alternative, forced-choice procedure. BP was assessed by 24-h ambulatory BP monitoring. As expected, vibratory thresholds were higher for men than for women (6.3 +/- 4 v 4.2 +/- 3 vibration units) but there was no statistical difference after controlling for height. In multivariate analyses with vibratory thresholds as the dependent variable, duration of diabetes (P < 0.01), age (P < .01) and systolic BP (SBP) (P < .01) explained approximately 70% of the overall variability of the gender-specific (ie, female) model. The variability was similar (ie, 70% to 73%) no matter which SBP measure was available for modeling. In terms of diastolic blood pressure (DBP) measures, only the percentage of abnormal readings (ie, > 90 mm Hg) for day DBP was found to be independently associated with vibratory thresholds for women. The association of BP and large sensory nerve fiber dysfunction for nonnephropathic diabetic women found in this cross-sectional study warrants further investigation.

Successful outcome of pregnancy in a patient with generalized lipoatrophic diabetes mellitus.

OBJECTIVE: To report the first known case of a successful outcome of pregnancy in a patient with generalized lipoatrophic diabetes. METHODS: We present a detailed case report of a patient who achieved and successfully completed a pregnancy despite having lipoatrophic diabetes. RESULTS: With careful attention to glycemic control with use of U-500 insulin and strict avoidance of dietary fat, a 23-year-old woman with lipoatrophic diabetes maintained a pregnancy to 28 weeks. The infant weighed 1,235 g and was devoid of serious metabolic complications. Three months after childbirth, the patient died of gastrointestinal bleeding. CONCLUSION: We are not aware of any previously published report of a successful pregnancy in a patient with generalized, acquired lipoatrophic diabetes. Because of the involvement of multiple organ systems in generalized lipoatrophic diabetes, female patients should be thoroughly advised of the serious pregnancy-associated risks to both the mother and the fetus and the need for extremely close monitoring.

Predicting renal disease in type I diabetics: smoke and fire or smoke and mirrors?

This review has demonstrated that DN is common and can occur in one-third to one-half of IDDM patients. DN has a strong metabolic component, but there is also a component of genetic susceptibility. Persistent microalbuminuria is currently the most convenient and reliable predictor of nephropathy. Finally, Na/LiCTT, an experimental (and not yet commercially available) blood test, is felt to be a predictor of familial susceptibility to hypertension, and may be a marker of the risk of nephropathy in IDDM.

Over-the-counter yellow ultraviolet light protective lenses: any benefit for individuals with diabetes mellitus?

The use of yellow UV protective lenses did improve some individual's ability to see even under artificial and controlled circumstances. Each test, although given in random order, cannot be interpreted to demonstrate the full range of benefit. The improvement for most was modest. Any improvement was most likely due to increased contrast. Light of a short wavelength is scattered more than long wavelength light. The yellow UV protective lenses block light of a short wavelength, thus reducing scatter and increasing contrast. Therefore, patients with visual problems of increased scatter would be expected to demonstrate the greatest improvement. We did not test for the duration of benefit. Subjective reports, from other patients, who have routinely used these lenses (only yellow lens-naive patients were included in the trial) suggest that the benefit increased with duration of use. Patients who routinely use the yellow UV protective lenses state that due to the increased contrast, they squint less. This seems to be most true at dusk. These regular users note that both their eyes are less tired and driving, in particular, is less stressful with the use of yellow lenses. The small benefit might conceivably be magnified in a real world setting. Given that the lenses cost only $10 to $15 and can be purchased in any sporting goods store, even our small measured improvement is likely to be worthwhile. Finally, patients were tested with "off-the-shelf" yellow lenses. To benefit patients the study was designed for their convenience and the low purchase price. The color of the lenses can be chosen to maximize the desired effect. We did not test various wavelength yellow lenses. Consequently, there may be better, albeit more expensive, yellow/orange lenses which might be designed explicitly for this purpose. In summary, the use of these yellow "sunglasses" might provide some improvement in sight for diabetic patients while keeping expense to a minimum.

The new diagnosis and classification of diabetes mellitus.

We are in the midst of an epidemic of diabetes, and the prevalence appears to be especially marked within Delaware. To prevent tragic long-term complications of diabetes, and to minimize the enormous costs associated with treating them, an emphasis must be placed on the early diagnosis and aggressive management of diabetes. The changes in the classification, diagnosis and screening for diabetes should help to redirect the focus to one of preventive care.

Obesity is not a confounding factor for performing autonomic function tests in individuals with diabetes mellitus.

AIM: Cardiovascular autonomic neuropathy is a serious complication of diabetes mellitus. Previous studies have revealed conflicting results with regard to the role of obesity and its effect on the performance of tests (e.g. RR-variation during deep breathing) for the determination of the presence of cardiovascular autonomic dysfunction. The objective of this study was to determine if obesity affects the performance and the reproducibility of autonomic function tests. METHODS: This cross-sectional study included 159 diabetic individuals. Autonomic function tests included: RR-variation during deep breathing and the Valsalva ratio. These tests were assessed using the ANS2000 ECG Monitor and Respiration Pacer. RR-variation was measured by vector analysis (i.e. mean circular resultant, MCR). Reproducibility of the autonomic function tests was assessed by determining the coefficient of variation (CV) on repeat testing. RESULTS: Using cut-off points to describe normal weight (body mass index (b.m.i.) < or = 25 kg/m(2)), overweight (b.m.i. 25.01-30 kg/m(2)), obese (b.m.i. 30.01-40 kg/m(2)), and morbidly obese (b.m.i. > or = 40.1 kg/m(2)), no difference was found for the MCR, Valsalva ratio, CV of the MCR, or CV of the Valsalva ratio among the various weight levels for individuals with type 1 or type 2 diabetes. CONCLUSIONS: The results of this study indicate that obesity is not a confounding factor in the performance of autonomic function tests. Likewise, the reproducibility of autonomic function testing is not affected by obesity. Assessment of autonomic function is important for obese and non-obese individuals given that reduced RR-variation is associated with exercise intolerance, intraoperative cardiovascular lability and increased risk of mortality.