Letitia H. Perdue

Effects of medical therapies on retinopathy progression in type 2 diabetes.

BACKGROUND We investigated whether intensive glycemic control, combination therapy for dyslipidemia, and intensive blood-pressure control would limit the progression of diabetic retinopathy in persons with type 2 diabetes. Previous data suggest that these systemic factors may be important in the development and progression of diabetic retinopathy. METHODS In a randomized trial, we enrolled 10,251 participants with type 2 diabetes who were at high risk for cardiovascular disease to receive either intensive or standard treatment for glycemia (target glycated hemoglobin level, <6.0% or 7.0 to 7.9%, respectively) and also for dyslipidemia (160 mg daily of fenofibrate plus simvastatin or placebo plus simvastatin) or for systolic blood-pressure control (target, <120 or <140 mm Hg). A subgroup of 2856 participants was evaluated for the effects of these interventions at 4 years on the progression of diabetic retinopathy by 3 or more steps on the Early Treatment Diabetic Retinopathy Study Severity Scale (as assessed from seven-field stereoscopic fundus photographs, with 17 possible steps and a higher number of steps indicating greater severity) or the development of diabetic retinopathy necessitating laser photocoagulation or vitrectomy. RESULTS At 4 years, the rates of progression of diabetic retinopathy were 7.3% with intensive glycemia treatment, versus 10.4% with standard therapy (adjusted odds ratio, 0.67; 95% confidence interval [CI], 0.51 to 0.87; P=0.003); 6.5% with fenofibrate for intensive dyslipidemia therapy, versus 10.2% with placebo (adjusted odds ratio, 0.60; 95% CI, 0.42 to 0.87; P=0.006); and 10.4% with intensive blood-pressure therapy, versus 8.8% with standard therapy (adjusted odds ratio, 1.23; 95% CI, 0.84 to 1.79; P=0.29). CONCLUSIONS Intensive glycemic control and intensive combination treatment of dyslipidemia, but not intensive blood-pressure control, reduced the rate of progression of diabetic retinopathy. (Funded by the National Heart, Lung, and Blood Institute and others; ClinicalTrials.gov numbers, NCT00000620 for the ACCORD study and NCT00542178 for the ACCORD Eye study.)

The Effects of Medical Management on the Progression of Diabetic Retinopathy in Persons with Type 2 Diabetes: The Action to Control Cardiovascular Risk in Diabetes (ACCORD) Eye Study

PURPOSE To report additional ocular outcomes of intensive treatment of hyperglycemia, blood pressure, and dyslipidemia in the Action to Control Cardiovascular Risk in Diabetes (ACCORD) study. DESIGN Double 2×2 factorial, multicenter, randomized clinical trials in people with type 2 diabetes who had cardiovascular disease or cardiovascular risk factors. In the glycemia trial, targets of intensive and standard treatment were: hemoglobin A1c <6.0% and 7.0% to 7.9%, respectively, and in the blood pressure trial: systolic blood pressures of <120 and <140 mmHg, respectively. The dyslipidemia trial compared fenofibrate plus simvastatin with placebo plus simvastatin. PARTICIPANTS Of the 3472 ACCORD Eye Study participants enrolled, 2856 had 4-year data (85% of survivors). METHODS Eye examinations and fundus photographs were taken at baseline and year 4. Photographs were graded centrally for retinopathy severity and macular edema using the Early Treatment Diabetic Retinopathy Study (ETDRS) methods. MAIN OUTCOME MEASURES Three or more steps of progression on the ETDRS person scale or treatment of retinopathy with photocoagulation or vitrectomy. RESULTS As previously reported, there were significant reductions in the primary outcome in the glycemia and dyslipidemia trials, but no significant effect in the blood pressure trial. Results were similar for retinopathy progression by 1, 2, and 4 or more steps on the person scale and for ≥ 2 steps on the eye scale. In the subgroup of patients with mild retinopathy at baseline, effect estimates were large (odds ratios, ∼0.30; P < 0.001), but did not reach nominal significance for participants with no retinopathy or for those with moderate to severe retinopathy at baseline. CONCLUSIONS Slowing of progression of retinopathy by intensive treatment of glycemia was observed in ACCORD participants, whose average age and diabetes duration were 62 and 10 years, respectively, and who had cardiovascular disease or cardiovascular risk factors. The effect seemed stronger in patients with mild retinopathy. Similar slowing of progression was observed in patients treated with fenofibrate, with no effect observed with intensive blood pressure treatment. This is the second study to confirm the benefits of fenofibrate in reducing diabetic retinopathy progression, and fenofibrate should be considered for treatment of diabetic retinopathy.

Lack of Association Between Thiazolidinediones and Macular Edema in Type 2 Diabetes: The ACCORD Eye Substudy

OBJECTIVE To assess the cross-sectional association of thiazolidinediones with diabetic macular edema (DME). METHODS The cross-sectional association of DME and visual acuity with thiazolidinediones was examined by means of baseline fundus photographs and visual acuity measurements from the Action to Control Cardiovascular Risk in Diabetes (ACCORD) trial. Visual acuity was assessed in 9690 participants in the ACCORD trial, and 3473 of these participants had fundus photographs that were centrally read in a standardized fashion by masked graders to assess DME and retinopathy from October 23, 2003, to March 10, 2006. RESULTS Among the subsample, 695 (20.0%) people had used thiazolidinediones, whereas 217 (6.2%) people had DME. Thiazolidinedione use was not associated with DME in unadjusted (odds ratio [OR], 1.01; 95% confidence interval [CI], 0.71-1.44; P = .95) and adjusted (OR, 0.97; 95% CI, 0.67-1.40; P = .86) analyses. Significant associations with DME were found for retinopathy severity (P < .001) and age (OR, 0.97; 95% CI, 0.952-0.997; P = .03) but not for hemoglobin A(1c) (P = .06), duration of diabetes (P = .65), sex (P = .72), and ethnicity (P = .20). Thiazolidinedione use was associated with slightly greater visual acuity (0.79 letter; 95% CI, 0.20-1.38; P = .009) of uncertain clinical significance. CONCLUSIONS In a cross-sectional analysis of data from the largest study to date, no association was observed between thiazolidinedione exposure and DME in patients with type 2 diabetes; however, we cannot exclude a modest protective or harmful association. Trial Registration clinicaltrials.gov Identifier: NCT00542178.

HLA genotyping in the international Type 1 Diabetes Genetics Consortium

Background Although human leukocyte antigen (HLA) DQ and DR loci appear to confer the strongest genetic risk for type 1 diabetes, more detailed information is required for other loci within the HLA region to understand causality and stratify additional risk factors. The Type 1 Diabetes Genetics Consortium (T1DGC) study design included high-resolution genotyping of HLA-A, B, C, DRB1, DQ, and DP loci in all affected sibling pair and trio families, and cases and controls, recruited from four networks worldwide, for analysis with clinical phenotypes and immunological markers. Purpose In this article, we present the operational strategy of training, classification, reporting, and quality control of HLA genotyping in four laboratories on three continents over nearly 5 years. Methods Methods to standardize HLA genotyping at eight loci included: central training and initial certification testing; the use of uniform reagents, protocols, instrumentation, and software versions; an automated data transfer; and the use of standardized nomenclature and allele databases. We implemented a rigorous and consistent quality control process, reinforced by repeated workshops, yearly meetings, and telephone conferences. Results A total of 15,246 samples have been HLA genotyped at eight loci to four-digit resolution; an additional 6797 samples have been HLA genotyped at two loci. The genotyping repeat rate decreased significantly over time, with an estimated unresolved Mendelian inconsistency rate of 0.21%. Annual quality control exercises tested 2192 genotypes (4384 alleles) and achieved 99.82% intra-laboratory and 99.68% inter-laboratory concordances. Limitations The chosen genotyping platform was unable to distinguish many allele combinations, which would require further multiple stepwise testing to resolve. For these combinations, a standard allele assignment was agreed upon, allowing further analysis if required. Conclusions High-resolution HLA genotyping can be performed in multiple laboratories using standard equipment, reagents, protocols, software, and communication to produce consistent and reproducible data with minimal systematic error. Many of the strategies used in this study are generally applicable to other large multi-center studies. Clinical Trials 2010; 7: S75—S87. http:// ctj.sagepub.com

Persistent effects of intensive glycemic control on retinopathy in type 2 diabetes in the action to control cardiovascular risk in diabetes (ACCORD) follow-on study

OBJECTIVES This study investigated whether the beneficial effects of intensive glycemic control and fenofibrate treatment of dyslipidemia in reducing retinopathy progression demonstrated in the Action to Control Cardiovascular Risk in Diabetes (ACCORD) Eye Study persisted beyond the clinical trial. RESEARCH DESIGN AND METHODS The ACCORD Study (2003–2009) randomized participants with type 2 diabetes to intensive or standard treatment for glycemia (A1C level at <6.0% [42 mmol/mol] vs. 7.0–7.9% [53–63 mmol/mol]), systolic blood pressure (<120 vs. 140 mmHg), and dyslipidemia (fenofibrate [160 mg] plus simvastatin or placebo plus simvastatin). ACCORD Eye Study participants, who had baseline and year 4 eye examinations and fundus photographs, were reexamined in the ACCORD Follow-On (ACCORDION) Eye Study (2010–2014) 4 years after the ACCORD trial closeout. The outcome measure was diabetic retinopathy progression of three or more steps on the Early Treatment Diabetic Retinopathy Study scale. RESULTS Diabetic retinopathy progressed in 5.8% with intensive glycemic treatment versus 12.7% with standard (adjusted odds ratio [aOR] 0.42, 95% CI 0.28–0.63, P < 0.0001), 7.5% with intensive blood pressure treatment versus 6.0% for standard (aOR 1.21, 95% CI 0.61–2.40, P = 0.59), and 11.8% with fenofibrate versus 10.2% with placebo (aOR 1.13, 95% CI 0.71–1.79, P = 0.60) in ACCORDION Eye participants (n = 1,310). CONCLUSIONS Prior intensive glycemic control continued to reduce diabetic retinopathy progression, despite similar A1C levels, when the ACCORD Study ended. This is the first study in people with type 2 diabetes of 10 years’ duration and established cardiovascular disease, unlike the newly diagnosed participants of the UK Prospective Diabetes Study, to demonstrate this effect. The benefit of fenofibrate, however, did not persist. Intensive blood pressure control had no effect.

Designing and implementing sample and data collection for an international genetics study: the Type 1 Diabetes Genetics Consortium (T1DGC)

Background and Purpose The Type 1 Diabetes Genetics Consortium (T1DGC) is an international project whose primary aims are to: (a) discover genes that modify type 1 diabetes risk; and (b) expand upon the existing genetic resources for type 1 diabetes research. The initial goal was to collect 2500 affected sibling pair (ASP) families worldwide. Methods T1DGC was organized into four regional networks (Asia-Pacific, Europe, North America, and the United Kingdom) and a Coordinating Center. A Steering Committee, with representatives from each network, the Coordinating Center, and the funding organizations, was responsible for T1DGC operations. The Coordinating Center, with regional network representatives, developed study documents and data systems. Each network established laboratories for: DNA extraction and cell line production; human leukocyte antigen genotyping; and autoantibody measurement. Samples were tracked from the point of collection, processed at network laboratories and stored for deposit at National Institute for Diabetes and Digestive and Kidney Diseases (NIDDK) Central Repositories. Phenotypic data were collected and entered into the study database maintained by the Coordinating Center. Results T1DGC achieved its original ASP recruitment goal. In response to research design changes, the T1DGC infrastructure also recruited trios, cases, and controls. Results of genetic analyses have identified many novel regions that affect susceptibility to type 1 diabetes. T1DGC created a resource of data and samples that is accessible to the research community. Limitations Participation in T1DGC was declined by some countries due to study requirements for the processing of samples at network laboratories and/or final deposition of samples in NIDDK Central Repositories. Re-contact of participants was not included in informed consent templates, preventing collection of additional samples for functional studies. Conclusions T1DGC implemented a distributed, regional network structure to reach ASP recruitment targets. The infrastructure proved robust and flexible enough to accommodate additional recruitment. T1DGC has established significant resources that provide a basis for future discovery in the study of type 1 diabetes genetics. Clinical Trials 2010; 7: S5—S32. http://ctj.sagepub.com

Design of the Value of Imaging in Enhancing the Wellness of Your Heart (VIEW) trial and the impact of uncertainty on power

Background Although observational evidence has suggested that the measurement of coronary artery calcium (CAC) may improve risk stratification for cardiovascular events and thus help guide the use of lipid-lowering therapy, this contention has not been evaluated within the context of a randomized trial. The Value of Imaging in Enhancing the Wellness of Your Heart (VIEW) trial is proposed as a randomized study in participants at low intermediate risk of future coronary heart disease (CHD) events to evaluate whether CAC testing leads to improved patient outcomes. Purpose To describe the challenges encountered in designing a prototypical screening trial and to examine the impact of uncertainty on power. Methods The VIEW trial was designed as an effectiveness clinical trial to examine the benefit of CAC testing to guide therapy on a primary outcome consisting of a composite of nonfatal myocardial infarction, probable or definite angina with revascularization, resuscitated cardiac arrest, nonfatal stroke (not transient ischemic attack (TIA)), CHD death, stroke death, other atherosclerotic death, or other cardiovascular disease (CVD) death. Many critical choices were faced in designing the trial, including (1) the choice of primary outcome, (2) the choice of therapy, (3) the target population with corresponding ethical issues, (4) specifications of assumptions for sample size calculations, and (5) impact of uncertainty in these assumptions on power/sample size determination. Results We have proposed a sample size of 30,000 (800 events), which provides 92.7% power. Alternatively, sample sizes of 20,228 (539 events), 23,138 (617 events), and 27,078 (722 events) provide 80%, 85%, and 90% power. We have also allowed for uncertainty in our assumptions by computing average power integrated over specified prior distributions. This relaxation of specificity indicates a reduction in power, dropping to 89.9% (95% confidence interval (CI): 89.8–89.9) for a sample size of 30,000. Samples sizes of 20,228, 23,138, and 27,078 provide power of 78.0% (77.9–78.0), 82.5% (82.5–82.6), and 87.2% (87.2–87.3), respectively. Limitations These power estimates are dependent on form and parameters of the prior distributions. Conclusions Despite the pressing need for a randomized trial to evaluate the utility of CAC testing, conduct of such a trial requires recruiting a large patient population, making efficiency of critical importance. The large sample size is primarily due to targeting a study population at relatively low risk of a CVD event. Our calculations also illustrate the importance of formally considering uncertainty in power calculations of large trials as standard power calculations may tend to overestimate power.

Measurement of islet cell antibodies in the Type 1 Diabetes Genetics Consortium: efforts to harmonize procedures among the laboratories.

Background and Purpose Three network laboratories measured antibodies to islet autoantigens. Antibodies to glutamic acid decarboxylase (GAD65 [GADA]) and the intracellular portion of protein tyrosine phosphatase (IA-2ic [IA-2A]) were measured by similar, but not identical, methods in samples from participants in the Type 1 Diabetes Genetics Consortium (T1DGC). Methods All laboratories used radiobinding assays to detect antibodies to in vitro transcribed and translated antigen, but with different local standards, calibrated against the World Health Organization (WHO) reference reagent. Using a common method to calculate WHO units/mL, we compared results reported on samples included in the Diabetes Autoantibody Standardization Program (DASP), and developed standard methods for reporting in WHO units/mL. We evaluated intra-assay and inter-assay coefficient of variation (CV) in blind duplicate samples and assay comparability in four DASP workshops. Results Values were linearly related in the three laboratories for both GADA and IA-2A, and intra-assay technical errors for values within the standard curve were below 13% for GADA and below 8.5% for IA-2A. Correlations in samples tested 1—2 years apart were >97%. Over the course of the study, internal CVs were 10—20% with one exception, and the laboratories concordantly called samples GADA or IA-2A positive or negative in 96.7% and 99.6% of duplicates within the standard curve. Despite acceptable CVs and general concordance in ranking samples, the laboratories differed markedly in absolute values for GADA and IA-2A reported in WHO units/mL in DASP over a large range of values. Limitations With three laboratories using different assay methods (including calibrators), consistent values among them could not be attained. Conclusions Modifications in the assays are needed to improve comparability of results expressed as WHO units/mL across laboratories. It will be essential to retain high intra- and inter-assay precision, sensitivity and specificity and to confirm the accuracy of harmonized methods. Clinical Trials 2010; 7: S56—S64. http:// ctj.sagepub.com

Biobanking, consent, and commercialization in international genetics research: the Type 1 Diabetes Genetics Consortium

Background and Purpose This article describes several ethical, legal, and social issues typical of international genetics biobanking, as encountered in the Type 1 Diabetes Genetics Consortium (T1DGC). Methods By studying the examples set and lessons learned from other international biobanking studies and by devoting considerable time and resources to identifying, addressing, and continually monitoring ethical and regulatory concerns, T1DGC was able to minimize the problems reported by some earlier studies. Conclusions Several important conclusions can be drawn based on the experience in this study: (1) Basic international standards for research ethics review and informed consent are broadly consistent across developed countries. (2) When consent forms are adapted locally and translated into different languages, discrepancies are inevitable and therefore require prompt central review and resolution before research is initiated. (3) Providing separate ‘check-box’ consent for different elements of a study creates confusion and may not be essential. (4) Creating immortalized cell lines to aid future research is broadly acceptable, both in the US and internationally. (5) Imposing some limits on the use of stored samples aids in obtaining ethics approvals worldwide. (6) Allowing potential commercial uses of donated samples is controversial in some Asian countries. (7) Obtaining government approvals can be labor-intensive and time-consuming, and can require legal and diplomatic skills. Clinical Trials 2010; 7: S33—S45. http:// ctj.sagepub.com

Frequent self‐weighing as part of a constellation of healthy weight control practices in young adults

Frequent self‐weighing is linked with weight management success, but concern has been raised about its possible association with unhealthy practices. This study examined the association of self‐weighing with other weight control behaviors in a sample for whom frequent weighing might be questioned—namely, normal‐weight or overweight (BMI of 21‐29.9) young adults (age 18‐35).