Metformin in adults with type 1 diabetes:Design and methods of REducing with MetfOrmin Vascular Adverse Lesions (REMOVAL): An international multicentre trial

Introduction: Cardiovascular (CV) disease is a major cause of reduced life expectancy in type 1 diabetes (T1D). Intensive insulin therapy prevents CV complications but is constrained by hypoglycaemia and weight gain. Adjunct metformin reduces insulin dose requirement and stabilises weight but there are no data on its cardiovascular effects. Aims: We have initiated an international double-blind, randomized, placebo-controlled trial (REMOVAL: REducing with MetfOrmin Vascular Adverse Lesions in type 1 diabetes) to examine whether metformin reduces progression of atherosclerosis in adults with T1D. Individuals ≥40 years of age with T1D for ≥5 years are eligible if they have ≥3 of 10 specified CV risk factors. The enrolment target is 500 participants in 17 international centres. Materials and Methods: After 12 weeks single-blind placebo-controlled run-in, participants with ≥70 % adherence are randomized to metformin or matching placebo for three years with insulin titrated towards HbA1c 7.0% (53 mmol/mol)]. The primary endpoint is progression of averaged mean far wall common carotid intima-media thickness (cIMT) measured by ultrasonography at baseline, 12, 24 and 36 months. This design provides 90% power to detect a mean difference of 0.0167 mm in cIMT progression between treatment arms (α = 0.05), assuming up to 20% withdraw or discontinue treatment. Other endpoints include HbA1c, weight, LDL cholesterol, insulin requirement, progression of retinopathy, endothelial function and frequency of hypoglycaemia. Results and Conclusions: REMOVAL is the largest clinical trial of adjunct metformin therapy in T1D to date and will provide clinically meaningful information on its potential to impact CV disease and other complications

Screening intervals for diabetic retinopathy and incidence of visual loss: a systematic review

Screening for diabetic retinopathy can help to prevent this complication, but evidence regarding frequency of screening is uncertain. This paper systematically reviews the published literature on the relationship between screening intervals for diabetic retinopathy and the incidence of visual loss. The PubMed and EMBASE databases were searched until December 2012. Twenty five studies fulfilled the inclusion criteria, as these assessed the incidence/prevalence of sight‐threatening diabetic retinopathy in relation to screening frequency. The included studies comprised 15 evaluations of real‐world screening programmes, three studies modelling the natural history of diabetic retinopathy and seven cost‐effectiveness studies. In evaluations of diabetic retinopathy screening programmes, the appropriate screening interval ranged from one to four years, in people with no retinopathy at baseline. Despite study heterogeneity, the overall tendency observed in these programmes was that 2‐year screening intervals among people with no diabetic retinopathy at diagnosis were not associated with high incidence of sight‐threatening diabetic retinopathy. The modelling studies (non‐economic and economic) assessed a range of screening intervals (1–5 years). The aggregated evidence from both the natural history and cost‐effectiveness models favors a screening interval >1 year, but ≤2 years. Such an interval would be appropriate, safe and cost‐effective for people with no diabetic retinopathy at diagnosis, while screening intervals ≤1 year would be preferable for people with pre‐existing diabetic retinopathy. A 2‐year screening interval for people with no sight threatening diabetic retinopathy at diagnosis may be safely adopted. For patients with pre‐existing diabetic retinopathy, a shorter interval ≤1 year is warranted.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/100323/1/dme12274.pd

The Long Term Effects of Angiotensin Converting Enzyme Inhibition and Metabolic Control on Cardiovascular and Renal Outcomes in Hypertensive Type 2 Diabetic Patients

Long-term effects of angiotensin-converting enzyme inhibition and metabolic control in hypertensive type 2 diabetic patients.BackgroundIn hypertensive type 2 diabetic patients, treatment with angiotensin-converting enzyme (ACE) inhibitors is associated with a lower incidence of cardiovascular events than those treated with calcium channel-blocking agents. However, the long-term renal effects of ACE inhibitors in these patients remain inconclusive. In 1989, we commenced a placebo-controlled, double-blind, randomized study to examine the anti-albuminuric effects of enalapril versus nifedipine (slow release) in 102 hypertensive, type 2 diabetic patients. These patients have been followed up for a mean trial duration of 5.5 ± 2.2 years. We examined the determinants, including the effect of ACE inhibition on clinical outcomes in these patients.MethodsAfter a six-week placebo-controlled, run-in period, 52 patients were randomized double-blind to receive nifedipine (slow release) and 50 patients to receive enalapril. After the one-year analysis, which confirmed the superior anti-albuminuric effects of enalapril (-54%) over nifedipine (+11%), all patients were continued on their previously assigned treatment with informed consent. They were subdivided into normoalbuminuric (N = 43), microalbuminuric (N = 34), and macroalbuminuric (N = 25) groups based on two of three 24-hour urinary albumin excretion (UAE) measurements during the run-in period. Renal function was shown by the 24-hour UAE, creatinine clearance (CCr), and the regression coefficient of the yearly plasma creatinine reciprocal (β-1/Cr). Clinical endpoints were defined as death, cardiovascular events, and/or renal events (need for renal replacement therapy or doubling of baseline plasma creatinine).ResultsIn the whole group, patients treated with enalapril were more likely to revert to being normoalbuminuric (23.8 vs. 15.4%), and fewer of them developed macroalbuminuria (19.1 vs. 30.8%) compared with the nifedipine-treated patients (P < 0.05). In the microalbuminuric group, treatment with enalapril (N = 21) was associated with a 13.0% (P < 0.01) reduction in 24-hour UAE compared with a 17.3% increase in the nifedipine group (N = 13). In the macroalbuminuric patients, enalapril treatment (N = 11) was associated with stabilization compared with a decline in renal function in the nifedipine group, as shown by the β-1/Cr (0.65 ± 4.29 vs. -1.93 ± 2.35 1/μmol × 10-3, P < 0.05) after adjustment for baseline values. Compared with the normoalbuminuric and microalbuminuric patients, those with macroalbuminuria had the lowest mean CCr (75.5 ± 24.1 vs. 63.5 ± 21.3 vs. 41.9 ± 18.5 mL/min, P < 0.001) and the highest frequency of clinical events (4.7 vs. 5.9 vs. 52%, P < 0.001). On multivariate analysis, β-1/Cr (R2 = 0.195, P < 0.001) was independently associated with baseline HbA1c (β = -0.285, P = 0.004), whereas clinical outcomes (R2 = 0.176, P < 0.001) were independently related to the mean low-density lipoprotein cholesterol (β = 2.426, P = 0.018), high-density lipoprotein cholesterol (β = -8.797, P = 0.03), baseline UAE (β = 0.002, P = 0.04), and mean CCr during treatment (β = -0.211, P = 0.006).ConclusionIn this prospective cohort analysis involving 102 hypertensive, type 2 diabetic patients with varying degrees of albuminuria followed up for a mean duration of five years, we observed the importance of good metabolic and blood pressure control on the progression of albuminuria and renal function. Treatment with enalapril was associated with a greater reduction in albuminuria than with nifedipine in the entire patient group, and especially in those with microalbuminuria. In the macroalbuminuric patients, the rate of deterioration in renal function was also attenuated by treatment with enalapril

Diagnostic criteria for diabetes revisited: making use of combined criteria

BACKGROUND: Existing cut-offs for fasting plasma glucose (FPG) and post-load glucose (2hPG) criteria are not equivalent in the diagnosis of diabetes and glucose intolerance. Adjusting cut-offs of single measurements have not helped so we undertook this project to see if they could be complementary. METHODS: We performed oral glucose tolerance tests and mean levels of hemoglobin A1c (HbA1c) measurements on 43 patients referred to a diabetes clinic for possible diabetes. Results of single and combined use of the FPG and 2hPG criteria were evaluated against the levels of HbA1c and results re-interpreted in the light of existing reports in the literature. RESULTS: Our results confirm that the FPG and the 2hPG, being specific and sensitive respectively for the presence of glucose intolerance or diabetes, are not equivalent. They are shown to be indeed complementary and a re-definition of diagnostic criteria based on their combined use is proposed. CONCLUSIONS: We conclude that altering single measurement cut-offs for the diagnosis of diabetes and altered glucose tolerance will not result in better outcomes. We present the case for a combined criteria in the diagnosis and definition of diabetes with a FPG≥7 mmol/L AND 2-hour glucose ≥7.8 mmol/L being used to define diabetes while a FPG<7 mmol/L AND 2-hour glucose <7.8 mmol/L being used to define normality. Discordant values will define impaired glucose tolerance (IGT). This proposal requires prospective evaluation in a large cohort

HbA1c levels in schoolchildren with type 1 diabetes are seasonally variable and dependent on weather conditions

Aims/hypothesis: We evaluated seasonal HbA$_{1c}$ changes in children with type 1 diabetes and its relation with measures of weather conditions. Methods: HbA$_{1c}$ changes over more than 3 years were evaluated in type 1 diabetic patients who were younger than 18 years and had diabetes duration of more than 12 months, and correlated with measures of weather conditions (ambient temperature, hours of sunshine and solar irradiance). After comparison of autocorrelation patterns, patterns of metabolic control and meteorological data were evaluated using Spearman rank correlation. Results: A total of 3,935 HbA$_{1c}$ measurements in 589 school (≥7 years) and 88 preschool (<7 years) children were analysed. Mean (±SD) HbA$_{1c}$ level for the whole study period was 7.65±1.12%. The lowest HbA$_{1c}$ levels were observed in late summer and the highest in winter months, with differences consistently exceeding 0.44%. Autocorrelation analysis of HbA$_{1c}$ levels in schoolchildren showed a sine-wave pattern with a cycle length of roughly 12 months, which mirrored changes in ambient temperature. Strong negative correlations of HbA$_{1c}$ with ambient temperature (R=−0.56; p=0.0002), hours of sunshine (R=−0.52; p=0.0007) and solar irradiance (R=−0.52; p=0.0006) were present in schoolchildren, but not in preschoolers (p≥0.29 for each correlation). Conclusions/interpretation: Seasonal changes of HbA$_{1c}$ levels in schoolchildren with type 1 diabetes are a significant phenomenon and should be considered in patient education and diabetes management. They may potentially affect the results of clinical trials using HbA$_{1c}$ levels as their primary outcome, as well as HbA$_{1c}$-based diagnosis of diabetes