Nonparametric Rank-Based Methods for Group Sequential Monitoring of Paired Censored Survival Data

This research gives methods for nonparametric sequential monitoring of paired censored survival data in the two-sample problem using paired weighted log-rank statistics with adjustments for dependence in survival and censoring outcomes. The joint asymptotic closed-form distribution of these sequentially monitored statistics has a dependent increments structure. Simulations validating operating characteristics of the proposed methods highlight power and size consequences of ignoring even mildly correlated data. A motivating example is presented via the Early Treatment Diabetic Retinopathy Study.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/65768/1/j.0006-341X.2000.0984.x.pd

Risk of diabetic retinopathy at first screen in children at 12 and 13 years of age

AIMS: \ud \ud To investigate the relationships between age at diagnosis of diabetes, age at diabetic eye screening and severity of diabetic retinopathy at first and subsequent screenings in children aged 12 or 13 years.\ud \ud METHODS: \ud \ud Data were extracted from four English screening programmes and from the Scottish, Welsh and Northern Irish programmes on all children with diabetes invited for their first and subsequent screening episodes from the age of 12 years. Retinopathy levels at first and subsequent screens, time from diagnosis of diabetes to first screening and age at diagnosis in years were calculated.\ud \ud RESULTS: \ud \ud Data were available for 2125 children with diabetes screened for the first time at age 12 or 13 years. In those diagnosed with diabetes at 2 years of age or less, the proportion with retinopathy in one or both eyes was 20% and 11%, respectively, decreasing to 8% and 2% in those diagnosed between 2 and 12 years (P < 0.0001). Only three children (aged 8, 10 and 11 years at diagnosis of diabetes) had images graded with referable retinopathy and, of these, two had non-referable diabetic retinopathy at all subsequent screenings. Of 1703 children with subsequent images, 25 were graded with referable diabetic retinopathy over a mean follow-up of 3.1 years, an incidence rate of 4.7 (95% confidence interval, 3.1-7.0) per 1000 per year.\ud \ud CONCLUSIONS: \ud \ud In this large cohort of children, the low prevalence and incidence rates of referable diabetic retinopathy suggest that screening earlier than age 12 is not necessary

Development of an evidence-based checklist for the detection of drug related problems in type 2 diabetes

Objective To develop an evidence-based checklist to identify potential drug related problems (PDRP) in patients with type 2 diabetes. Setting The evidence based checklist was applied to records of ambulatory type 2 diabetes patients in New South Wales, Australia. Method After comprehensive review of the literature, relevant medication groups and potential drug related problems in type 2 diabetes were identified. All the relevant information was then structured in the form of a checklist. To test the utility of the evidence-based checklist a cross-sectional retrospective study was conducted. The PDRP checklist was applied to the data of 148 patients with established type 2 diabetes and poor glycaemic control. The range and extent of DRPs in this population were identified, which were categorized using the PCNE classification. In addition, the relationship between the total as well as each category of DRPs and several of the patients’ clinical parameters was investigated. Main outcome measure: Number and category of DRPs per patient. Results The PDRP checklist was successfully developed and consisted of six main sections. 682 potential DRPs were identified using the checklist, an average of 4.6 (SD = 1.7) per patient. Metabolic and blood pressure control in the study subjects was generally poor: with a mean HbA1c of 8.7% (SD = 1.5) and mean blood pressure of 139.8 mmHg (SD = 18.1)/81.7 mmHg (SD = 11.1). The majority of DRPs was recorded in the categories ‘therapy failure’ (n = 264) and ‘drug choice problem’ (n = 206). Potentially non-adherent patients had a significantly higher HbA1c than patients who adhered to therapy (HbA1c of 9.4% vs. 8.5%; P = 0.01). Conclusion This is the first tool developed specifically to detect potential DRPs in patients with type 2 diabetes. It was used to identify DRPs in a sample of type 2 diabetes patients and demonstrated the high prevalence of DRPs per patient. The checklist may assist pharmacists and other health care professionals to systematically identify issues in therapy and management of their type 2 diabetes patients and enable earlier intervention to improve metabolic control

The ChromaTest, a digital color contrast sensitivity analyzer, for diabetic maculopathy: a pilot study

BACKGROUND: To assess the ability of the Chromatest in investigating diabetic maculopathy. METHOD: Patients with Type 2 diabetes and no concurrent ocular pathology or previous laser photocoagulation were recruited. Visual acuities were assessed followed by colour contrast sensitivity testing of each eye using Chromatest. Dilated fundoscopy with slit lamp biomicroscopy with 78 D lens was then performed to confirm the stage of diabetic retinopathy according to the Early Treatment Diabetic Retinopathy Study. RESULTS: 150 eyes in 150 patients were recruited into this study. 35 eyes with no previous laser photocoagulation were shown to have clinically significant macular oedema (CSMO) and 115 eyes with untreated non-proliferative diabetic retinopathy (NPDR) on fundus biomicroscopy. Statistical significant difference was found between CSMO and NPDR eyes for protan colour contrast threshold (p = 0.01). Statistical significance was found between CSMO and NPDR eyes for tritan colour contrast threshold (p = 0.0002). Sensitivity and specificity for screening of CSMO using pass-fail criterion for age matched TCCT results achieved 71% (95% confidence interval: 53-85%) and 70% (95% confidence interval: 60-78%), respectively. However, threshold levels were derived using the same data set for both training and testing the effectiveness since this was the first study of NPDR using the Chromatest CONCLUSION: The ChromaTest is a simple, cheap, easy to use, and quick test for colour contrast sensitivity. This study did not achieve results to justify use of the Chromatest for screening, but it reinforced the changes seen in tritan colour vision in diabetic retinopathy

Aspirin for Primary Prevention of Cardiovascular Events in People With Diabetes: A position statement of the American Diabetes Association, a scientific statement of the American Heart Association, and an expert consensus document of the American College of Cardiology Foundation

The burden of cardiovascular disease (CVD) among patients with diabetes is substantial. Individuals with diabetes are at two- to fourfold increased risk of cardiovascular events compared with age- and sex-matched individuals without diabetes. In diabetic patients over the age of 65 years, 68% of deaths are from coronary heart disease (CHD) and 16% are from stroke (1). A number of mechanisms for the increased cardiovascular risk with diabetes have been proposed, including increased tendency toward intracoronary thrombus formation (2), increased platelet reactivity (3), and worsened endothelial dysfunction (4). The increased risk for cardiovascular events and mortality in patients with diabetes has led to considerable interest in identifying effective means for cardiovascular risk reduction. Aspirin has been shown to be effective in reducing cardiovascular morbidity and mortality in high-risk patients with myocardial infarction (MI) or stroke (secondary prevention) (5). The Food and Drug Administration has not approved aspirin for use in primary prevention, and its net benefit among patients with no previous cardiovascular events is more controversial, for both patients with and without a history of diabetes (5). The U.S. Preventive Services Task Force recently updated its recommendation about aspirin use for primary prevention. The Task Force recommended encouraging aspirin use in men age 45–79 years and women age 55–79 years and not encouraging aspirin use in younger adults. They did not differentiate their recommendations based on the presence or absence of diabetes (6,7). In 2007, the American Diabetes Association (ADA) and the American Heart Association (AHA) jointly recommended that aspirin therapy (75–162 mg/day) be used as a primary prevention strategy in those with diabetes at increased cardiovascular risk, including those who are over 40 years of age or who have additional risk factors (family history of CVD, hypertension, smoking, dyslipidemia, or albuminuria) (8). These recommendations were

Impact of changes in metabolic control on progression to photocoagulation for clinically significant macular oedema:a 20 year study of type 1 diabetes

AIMS/HYPOTHESIS: Although increasing hyperglycaemia, arterial hypertension and longer duration of diabetes raise the risk of progression of diabetic retinopathy, short-term benefits in terms of improved metabolic control and lowered blood pressure have not been demonstrated. We therefore examined the effect of changes in glycaemia and arterial blood pressure on the incidence of clinically significant macular oedema in a population of diabetic patients. METHODS: We performed a retrospective review of all patients with type 1 diabetes who attended the retinopathy screening clinic at the Steno Diabetes Center from 1988 to 2008, using the endpoint referral to first photocoagulation treatment for clinically significant diabetic macular oedema. The analysis included 1,878 patients (median observation, 8 years). Changes were defined as the inter-visit change; in the case of an event the last event-free interval before referral, where the median screening interval was 6 months. RESULTS: Risk of progression to photocoagulation for macular oedema increased with duration of diabetes (p < 0.001), current HbA(1c) (p < 0.0001) and with the magnitude of changes in HbA(1c) (p = 0.0002) and systolic blood pressure (p < 0.0001) in a multiple regression model. A recent decrease of ≥0.5 percentage points or an increase in HbA(1c) of >0.5 percentage points per 6 months was associated with HRs of 3.04 and 1.28, respectively, compared with lesser changes in HbA(1c). CONCLUSIONS/INTERPRETATION: In this study, large recent changes in metabolic control and systolic blood pressure, irrespective of direction, were independent risk factors for progression to photocoagulation for diabetic macular oedema. The effects of metabolic and haemodynamic stability on diabetic retinopathy should be examined in prospective studies

Use of aspirin for primary and secondary prevention of cardiovascular disease in diabetic patients in an ambulatory care setting in Spain

<p>Abstract</p> <p>Background</p> <p>This study was conducted in order to determine the use of aspirin and to assess the achievement of therapeutic targets in diabetic patients according to primary (PP) or secondary prevention (SP).</p> <p>Methods</p> <p>This is a retrospective, observational study including patients ≥18 years with diabetes mellitus followed in four primary care centers. Measurements included demographics, use of aspirin and/or anticoagulant drugs, co-morbidities, clinical parameters and proportion of patient at therapeutic target (TT). Descriptive statistics, chi-square test and logistic regression model were used for significance.</p> <p>Results</p> <p>A total of 4,140 patients were analyzed, 79.1% (95% confidence intervals [CI]: 77.7–80.5%) in PP and 20.9% (95% CI: 18.2–23.7%) in SP. Mean age was 64.1 (13.8) years, and 49.3% of patient were men (PP: 46.3, SP: 60.7, p = 0.001). Aspirin was prescribed routinely in 20.8% (95% CI: 19.4–22.2%) in PP and 60.8% (95% CI: 57.6–64.0%) in SP. Proportion of patient at TT was 48.0% for blood pressure and 59.8% for cholesterol. Use of aspirin was associated to increased age [OR = 1.01 (95% CI: 1.00–1.02); p = 0.011], cardiovascular-risk factors [OR = 1.14 (95% CI: 1.03–1.27); p = 0.013], LDL-C [OR = 1.42 (95% CI: 1.06–1.88); p = 0.017] and higher glycated hemoglobin [OR = 1.51 (95% CI: 1.22–1.89); p = 0.000] were covariates associated to the use of aspirin in PP.</p> <p>Conclusion</p> <p>Treatment with aspirin is underused for PP in patients with diabetes mellitus in Primary Care. Achievement of TT should be improved.</p