Gideon D. Bahn

Follow-up of Glycemic Control and Cardiovascular Outcomes in Type 2 Diabetes

BACKGROUND The Veterans Affairs Diabetes Trial previously showed that intensive glucose lowering, as compared with standard therapy, did not significantly reduce the rate of major cardiovascular events among 1791 military veterans (median follow-up, 5.6 years). We report the extended follow-up of the study participants. METHODS After the conclusion of the clinical trial, we followed participants, using central databases to identify procedures, hospitalizations, and deaths (complete cohort, with follow-up data for 92.4% of participants). Most participants agreed to additional data collection by means of annual surveys and periodic chart reviews (survey cohort, with 77.7% follow-up). The primary outcome was the time to the first major cardiovascular event (heart attack, stroke, new or worsening congestive heart failure, amputation for ischemic gangrene, or cardiovascular-related death). Secondary outcomes were cardiovascular mortality and all-cause mortality. RESULTS The difference in glycated hemoglobin levels between the intensive-therapy group and the standard-therapy group averaged 1.5 percentage points during the trial (median level, 6.9% vs. 8.4%) and declined to 0.2 to 0.3 percentage points by 3 years after the trial ended. Over a median follow-up of 9.8 years, the intensive-therapy group had a significantly lower risk of the primary outcome than did the standard-therapy group (hazard ratio, 0.83; 95% confidence interval [CI], 0.70 to 0.99; P=0.04), with an absolute reduction in risk of 8.6 major cardiovascular events per 1000 person-years, but did not have reduced cardiovascular mortality (hazard ratio, 0.88; 95% CI, 0.64 to 1.20; P=0.42). No reduction in total mortality was evident (hazard ratio in the intensive-therapy group, 1.05; 95% CI, 0.89 to 1.25; P=0.54; median follow-up, 11.8 years). CONCLUSIONS After nearly 10 years of follow-up, patients with type 2 diabetes who had been randomly assigned to intensive glucose control for 5.6 years had 8.6 fewer major cardiovascular events per 1000 person-years than those assigned to standard therapy, but no improvement was seen in the rate of overall survival. (Funded by the VA Cooperative Studies Program and others; VADT ClinicalTrials.gov number, NCT00032487.).

Blood Pressure and Cardiovascular Disease Risk in the Veterans Affairs Diabetes Trial

OBJECTIVE Blood pressure ranges associated with cardiovascular disease (CVD) events in advanced type 2 diabetes are not clear. Our objective was to determine whether baseline and follow-up (On-Study) systolic blood pressure (SBP), diastolic blood pressure (DBP), and SBP combined with DBP predict CVD events in the Veterans Affairs Diabetes Trial (VADT). RESEARCH DESIGN AND METHODS Participants in the VADT (n = 1,791) with hypertension received stepped treatment to maintain blood pressure below the target of 130/80 mmHg in standard and intensive glycemic treatment groups. Blood pressure levels of all subjects at baseline and On-Study were analyzed to detect associations with CVD risk. The primary outcome was the time from randomization to the first occurrence of myocardial infarction, stroke, congestive heart failure, surgery for vascular disease, inoperable coronary disease, amputation for ischemic gangrene, or CVD death. RESULTS Separated SBP ≥140 mmHg had significant risk at baseline (hazards ratio [HR] 1.508, P < 0.001) and On-Study (HR 1.469, P = 0.002). DBP <70 mmHg increased CVD events at baseline (HR 1.482, P < 0.001) and On-Study (HR 1.491, P < 0.001). Combined blood pressure categories indicated high risk for CVD events for SBP ≥140 with DBP <70 mmHg at baseline (HR 1.785, P = 0.03) and On-Study (HR 2.042, P = 0.003) and nearly all SBP with DBP <70 mmHg. CONCLUSIONS Increased risk of CVD events with SBP ≥140 mmHg emphasizes the urgency for treatment of systolic hypertension. Increased risk with DBP <70 mmHg, even when combined with SBP in guideline-recommended target ranges, supports a new finding in patients with type 2 diabetes. The results emphasize that DBP <70 mmHg in these patients was associated with elevated CVD risk and may best be avoided.

Progression of Vascular Calcification Is Increased With Statin Use in the Veterans Affairs Diabetes Trial (VADT)

OBJECTIVE To determine the effect of statin use on progression of vascular calcification in type 2 diabetes (T2DM). RESEARCH DESIGN AND METHODS Progression of coronary artery calcification (CAC) and abdominal aortic artery calcification (AAC) was assessed according to the frequency of statin use in 197 participants with T2DM. RESULTS After adjustment for baseline CAC and other confounders, progression of CAC was significantly higher in more frequent statin users than in less frequent users (mean ± SE, 8.2 ± 0.5 mm3 vs. 4.2 ± 1.1 mm3; P < 0.01). AAC progression was in general not significantly increased with more frequent statin use; in a subgroup of participants initially not receiving statins, however, progression of both CAC and AAC was significantly increased in frequent statin users. CONCLUSIONS More frequent statin use is associated with accelerated CAC in T2DM patients with advanced atherosclerosis.

Observation on Renal Outcomes in the Veterans Affairs Diabetes Trial

OBJECTIVE The Veterans Affairs Diabetes Trial (VADT) was a randomized, prospective, controlled trial of 1,791 patients with type 2 diabetes to determine whether intensive glycemic control would reduce cardiovascular events compared with standard control. The effect of intensive glycemic control and selected baseline variables on renal outcomes is reported. RESEARCH DESIGN AND METHODS Baseline mean age was 60.4 years, mean duration of diabetes was 11.5 years, HbA1c was 9.4%, and blood pressure was 132/76 mmHg. The renal exclusion was serum creatinine >1.6 mg/dL. Renal outcomes were sustained worsening of the urine albumin-to-creatinine ratio (ACR) and sustained worsening by one or more stages in the estimated glomerular filtration rate (eGFR). RESULTS Intensive glycemic control did not independently reduce ACR progression but was associated with a significant attenuation in the progression of ACR in those who had baseline photocoagulation, cataract surgery, or both. The beneficial effect of intensive glycemic control increased with increasing BMI and with decreasing diastolic blood pressure (DBP). Intensive glycemic control was associated with less worsening of eGFR with increasing baseline ACR and insulin use. Baseline systolic blood pressure, triglycerides, and photocoagulation were associated with worsening of eGFR. CONCLUSIONS Intensive glycemic control had no significant effect on the progression of renal disease in the whole cohort but was associated with some protection against increasing ACR in those with more advanced microvascular disease, lower baseline DBP, or higher baseline BMI and on worsening of eGFR in those with high baseline ACR.

Ethnicity, race, and clinically significant macular edema in the Veterans Affairs Diabetes Trial (VADT).

OBJECTIVE To determine risk factors in clinically significant macular edema (CSME) and if increased CSME in minorities is due to ethnicity or other factors in the Veterans Affairs Diabetes Trial (VADT). METHODS CSME prevalence based on 7-field stereo fundus photographs in 1268 patients with type 2 diabetes was related to ethnicity, demographics and biochemistries by univariate and multivariate analyses. RESULTS Hispanics (H) made up 17.5% and African Americans (AA) 17.7% of the cohort. CSME prevalence was 10%. In univariate analysis, CSME was more prevalent in H, 18%, and AA, 15.6% than in non-Hispanic Whites (NHW), 6.3%, p<0.01. Univariate regression of CSME associated with younger age, younger onset of diabetes; longer duration; retinopathy severity; and high HbA1c, BP, urine albumin/creatinine, and amputation, all p<0.01. In multivariate regression, CSME was associated with ethnicity/race (Hispanic White vs. non-Hispanic White, OR, (95% CI), 2.30, (1.35-3.92), p<0.01; African American vs. non-Hispanic White, 2.30, (1.33-4.00), p<0.01), diastolic BP (1.13 per 5 mm Hg, (1.02-1.23), p=0.03), amputation (3.0, (1.11-8.13), p=0.04), and retinopathy severity ( approximately 30, ( approximately 17 to approximately 59), p<0.01). CONCLUSION The prevalence of CSME in the VADT is associated with ethnicity as well as diastolic BP, amputation, and retinopathy severity.

The Effect of Intensive Glucose Lowering on Lipoprotein Particle Profiles and Inflammatory Markers in the Veterans Affairs Diabetes Trial (VADT)

OBJECTIVE Intensive glucose-lowering therapy (INT) did not reduce macrovascular events in the recent randomized trials, possibly because it did not improve or worsen other traditional or novel cardiovascular risk factors. RESEARCH DESIGN AND METHODS Standard plasma lipids, cholesterol content of lipoprotein subfractions, and plasma inflammatory and prothrombotic markers were determined in a subgroup of the Veterans Affairs Diabetes Trial (VADT) participants (n = 266) at baseline and after 9 months of INT or standard therapy. RESULTS INT lowered glycated hemoglobin (by a median of 2% vs. a median of 0.7% by standard treatment; P < 0.0001); increased BMI (4 vs. 1%; P < 0.001), total HDL (9 vs. 4%; P < 0.05), HDL2 (14 vs. 0%; P = 0.009), LDL2 (36 vs. 1%; P < 0.0001), and plasma adiponectin (130 vs. 80%; P < 0.01); and reduced triglycerides (−13 vs. −4%; P = 0.02) and small, dense LDL4 (−39 vs. −13%; P < 0.001), but had no effect on levels of plasma apolipoproteins B-100 and B-48, C-reactive protein, interleukin-6, lipoprotein-associated phospholipase A2, myeloperoxidase, fibrinogen, and plasminogen activator inhibitor 1. Incident macrovascular events were associated with baseline interleukin-6 (hazard ratio per each quartile increase 1.33 [95% CI 1.06–1.66]), total LDL (1.25 [1.01–1.55]), apolipoprotein B-100 (1.29 [1.01–1.65]), and fibrinogen (1.26 [1.01–1.57]) but not changes in any cardiovascular risk factors at 9 months. CONCLUSIONS INT was associated with improved adiponectin, lipid levels, and a favorable shift in LDL and HDL subfractions after 9 months. These data suggest that the failure of INT to lower cardiovascular outcomes occurred despite generally favorable changes in standard and novel risk factors early in the study.

A Link Between Hypoglycemia and Progression of Atherosclerosis in the Veterans Affairs Diabetes Trial (VADT)

OBJECTIVE To determine whether a link exists between serious hypoglycemia and progression of atherosclerosis in a substudy of the Veterans Affairs Diabetes Trial (VADT) and to examine whether glycemic control during the VADT modified the association between serious hypoglycemia and coronary artery calcium (CAC) progression. RESEARCH DESIGN AND METHODS Serious hypoglycemia was defined as severe episodes with loss of consciousness or requiring assistance or documented glucose <50 mg/dL. Progression of CAC was determined in 197 participants with baseline and follow-up computed tomography scans. RESULTS During an average follow-up of 4.5 years between scans, 97 participants reported severe hypoglycemia (n = 23) or glucose <50 mg/dL (n = 74). Serious hypoglycemia occurred more frequently in the intensive therapy group than in the standard treatment group (74% vs. 21%, P < 0.01). Serious hypoglycemia was not associated with progression of CAC in the entire cohort, but the interaction between serious hypoglycemia and treatment was significant (P < 0.01). Participants with serious hypoglycemia in the standard therapy group, but not in the intensive therapy group, had ∼50% greater progression of CAC than those without serious hypoglycemia (median 11.15 vs. 5.4 mm3, P = 0.02). Adjustment for all baseline differences, including CAC, or time-varying risk factors during the trial, did not change the results. Examining the effect of serious hypoglycemia by on-trial HbA1c levels (cutoff 7.5%) yielded similar results. In addition, a dose-response relationship was found between serious hypoglycemia and CAC progression in the standard therapy group only. CONCLUSIONS Despite a higher frequency of serious hypoglycemia in the intensive therapy group, serious hypoglycemia was associated with progression of CAC in only the standard therapy group.

Association of PAI-1 and Fibrinogen With Diabetic Retinopathy in the Veterans Affairs Diabetes Trial (VADT)

OBJECTIVE To test the hypothesis that high levels of plasminogen-activating inhibitor (PAI)-1 and fibrinogen at baseline were associated with the onset or progression of diabetic retinopathy (DR) during the Veterans Affairs Diabetes Trial (VADT). RESEARCH DESIGN AND METHODS The VADT was an open-label, prospective, randomized controlled trial to test the effect of standard glycemic control (STD) compared with intensive control (INT) on cardiovascular events in patients with advanced type 2 diabetes mellitus (T2DM). Diabetic retinopathy (DR) outcomes were also collected. Incidence and progression of DR were assessed by grading seven-field stereoscopic fundus photographs at baseline and 5 years later taken in 858 of a total of 1,791 participants who completed both eye examinations. RESULTS Assignment to INT was not independently associated with decreased risk of onset of DR. However, after adjustment for multiple covariates, baseline level of PAI-1 was an independent risk factor for the onset of DR. The risk for incidence of DR increased by 12% for each 10 ng/dL increase in baseline PAI-1 concentration (odds ratio [OR] 1.012 [95% CI 1.00–1.024], P = 0.042). Assignment to INT was not independently associated with decreased risk of progression of DR. However, there was an interaction between glycemic treatment assignment and fibrinogen level at baseline. INT was associated with decreased progression of retinopathy in those with fibrinogen <296 mg/dL (OR 0.55 [95% CI 0.31–1.00], P = 0.03). CONCLUSIONS The results require confirmation but are consistent with greater hypercoagulabilty and inflammation, as measured by higher levels of PAI-1 and fibrinogen, being related to DR and responsiveness to INT.

Blood Pressure and Pulse Pressure Effects on Renal Outcomes in the Veterans Affairs Diabetes Trial (VADT)

OBJECTIVE Blood pressure (BP) control for renal protection is essential for patients with type 2 diabetes. Our objective in this analysis of Veterans Affairs Diabetes Trial (VADT) data was to learn whether on-study systolic BP (SBP), diastolic BP (DBP), and pulse pressure (PP) affected renal outcomes measured as albumin-to-creatinine ratio (ACR) and estimated glomerular filtration rate (eGFR). RESEARCH DESIGN AND METHODS The VADT was a prospective, randomized study of 1,791 veterans with type 2 diabetes to determine whether intensive glucose control prevented major cardiovascular events. In this post hoc study, time-varying covariate survival analyses and hazard ratios (HR) were used to determine worsening of renal outcomes. RESULTS Compared with SBP 105–129 mmHg, the risk of ACR worsening increased significantly for SBP 130–139 mmHg (HR 1.88 [95% CI 1.28–2.77]; P = 0.001) and for SBP ≥140 mmHg (2.51 [1.66–3.78]; P < 0.0001). Compared with a PP range of 40–49 mmHg, PP <40 was associated with significantly lowered risk of worsening ACR (0.36 [0.15–0.87]; P = 0.022) and PP ≥60 with significantly increased risk (2.38 [1.58–3.59]; P < 0.0001). Analyses of BP ranges associated with eGFR worsening showed significantly increased risk with rising baseline SBP and an interaction effect between SBP ≥140 mmHg and on-study A1C. These patients were 15% more likely than those with SBP <140 mmHg to experience eGFR worsening (1.15 [1.00–1.32]; P = 0.045) for each 1% (10.9 mmol/mol) A1C increase. CONCLUSIONS SBP ≥130 mmHg and PP >60 mmHg were associated with worsening ACR. The results suggest that treatment of SBP to <130 mmHg may lessen ACR worsening. The interaction between SBP ≥140 mmHg and A1C suggests that the effect of glycemic control on reducing progression of renal disease may be greater in hypertensive patients.

Advanced Glycation End Products, Oxidation Products, and the Extent of Atherosclerosis During the VA Diabetes Trial and Follow-up Study*

OBJECTIVE To determine whether plasma levels of advanced glycation end products and oxidation products play a role in the development of atherosclerosis in patients with type 2 diabetes (T2D) over nearly 10 years of the VA Diabetes Trial and Follow-up Study. RESEARCH DESIGN AND METHODS Baseline plasma levels of methylglyoxal hydroimidazolone, Nε-carboxymethyl lysine, Nε-carboxyethyl lysine (CEL), 3-deoxyglucosone hydroimidazolone and glyoxal hydroimidazolone (G-H1), 2-aminoadipic acid (2-AAA), and methionine sulfoxide were measured in a total of 411 participants, who underwent ultrasound assessment of carotid intima-media thickness (CIMT), and computed tomography scanning of coronary artery calcification (CAC) and abdominal aortic artery calcification (AAC) after an average of 10 years of follow-up. RESULTS In risk factor–adjusted multivariable regression models, G-H1 was associated with the extent of CIMT and CAC. In addition, 2-AAA was strongly associated with the extent of CAC, and CEL was strongly associated with the extent of AAC. The combination of specific advanced glycation end products and oxidation products (G-H1 and 2-AAA) was strongly associated with all measures of subclinical atherosclerosis. CONCLUSIONS Specific advanced glycation end products and metabolic oxidation products are associated with the severity of subclinical atherosclerosis over the long term and may play an important role in the “negative metabolic memory” of macrovascular complications in people with long-standing T2D.