A randomised trial of the effect and cost-effectiveness of early intensive multifactorial therapy on 5-year cardiovascular outcomes in individuals with screen-detected type 2 diabetes: the Anglo-Danish-Dutch Study of Intensive Treatment in People with Screen-Detected Diabetes in Primary Care (ADDITION-Europe) study

Blood pressure control for diabetic retinopathy

BACKGROUND

Diabetic retinopathy is a common complication of diabetes and a leading cause of visual impairment and blindness. Research has established the importance of blood glucose control to prevent development and progression of the ocular complications of diabetes. Concurrent blood pressure control has been advocated for this purpose, but individual studies have reported varying conclusions regarding the effects of this intervention.

OBJECTIVES

To summarize the existing evidence regarding the effect of interventions to control blood pressure levels among diabetics on incidence and progression of diabetic retinopathy, preservation of visual acuity, adverse events, quality of life, and costs.

SEARCH METHODS

We searched several electronic databases, including CENTRAL, and trial registries. We last searched the electronic databases on 3 September 2021. We also reviewed the reference lists of review articles and trial reports selected for inclusion.

SELECTION CRITERIA

We included randomized controlled trials (RCTs) in which either type 1 or type 2 diabetic participants, with or without hypertension, were assigned randomly to more intense versus less intense blood pressure control; to blood pressure control versus usual care or no intervention on blood pressure (placebo); or to one class of antihypertensive medication versus another or placebo.

DATA COLLECTION AND ANALYSIS

Pairs of review authors independently reviewed the titles and abstracts of records identified by the electronic and manual searches and the full-text reports of any records identified as potentially relevant. The included trials were independently assessed for risk of bias with respect to outcomes reported in this review.

MAIN RESULTS

We included 29 RCTs conducted in North America, Europe, Australia, Asia, Africa, and the Middle East that had enrolled a total of 4620 type 1 and 22,565 type 2 diabetic participants (sample sizes from 16 to 4477 participants). In all 7 RCTs for normotensive type 1 diabetic participants, 8 of 12 RCTs with normotensive type 2 diabetic participants, and 5 of 10 RCTs with hypertensive type 2 diabetic participants, one group was assigned to one or more antihypertensive agents and the control group to placebo. In the remaining 4 RCTs for normotensive participants with type 2 diabetes and 5 RCTs for hypertensive type 2 diabetic participants, methods of intense blood pressure control were compared to usual care. Eight trials were sponsored entirely and 10 trials partially by pharmaceutical companies; nine studies received support from other sources; and two studies did not report funding source. Study designs, populations, interventions, lengths of follow-up (range less than one year to nine years), and blood pressure targets varied among the included trials. For primary review outcomes after five years of treatment and follow-up, one of the seven trials for type 1 diabetics reported incidence of retinopathy and one trial reported progression of retinopathy; one trial reported a combined outcome of incidence and progression (as defined by study authors). Among normotensive type 2 diabetics, four of 12 trials reported incidence of diabetic retinopathy and two trials reported progression of retinopathy; two trials reported combined incidence and progression. Among hypertensive type 2 diabetics, six of the 10 trials reported incidence of diabetic retinopathy and two trials reported progression of retinopathy; five of the 10 trials reported combined incidence and progression. The evidence supports an overall benefit of more intensive blood pressure intervention for five-year incidence of diabetic retinopathy (11 studies; 4940 participants; risk ratio (RR) 0.82, 95% confidence interval (CI) 0.73 to 0.92; I2 = 15%; moderate certainty evidence) and the combined outcome of incidence and progression (8 studies; 6212 participants; RR 0.78, 95% CI 0.68 to 0.89; I2 = 42%; low certainty evidence). The available evidence did not support a benefit regarding five-year progression of diabetic retinopathy (5 studies; 5144 participants; RR 0.94, 95% CI 0.78 to 1.12; I2 = 57%; moderate certainty evidence), incidence of proliferative diabetic retinopathy, clinically significant macular edema, or vitreous hemorrhage (9 studies; 8237 participants; RR 0.92, 95% CI 0.82 to 1.04; I2 = 31%; low certainty evidence), or loss of 3 or more lines on a visual acuity chart with a logMAR scale (2 studies; 2326 participants; RR 1.15, 95% CI 0.63 to 2.08; I2 = 90%; very low certainty evidence). Hypertensive type 2 diabetic participants realized more benefit from intense blood pressure control for three of the four outcomes concerning incidence and progression of diabetic retinopathy. The adverse event reported most often (13 of 29 trials) was death, yielding an estimated RR 0.87 (95% CI 0.76 to 1.00; 13 studies; 13,979 participants; I2 = 0%; moderate certainty evidence). Hypotension was reported in two trials, with an RR of 2.04 (95% CI 1.63 to 2.55; 2 studies; 3323 participants; I2 = 37%; low certainty evidence), indicating an excess of hypotensive events among participants assigned to more intervention on blood pressure.

AUTHORS' CONCLUSIONS

Hypertension is a well-known risk factor for several chronic conditions for which lowering blood pressure has proven to be beneficial. The available evidence supports a modest beneficial effect of intervention to reduce blood pressure with respect to preventing diabetic retinopathy for up to five years, particularly for hypertensive type 2 diabetics. However, there was a paucity of evidence to support such intervention to slow progression of diabetic retinopathy or to affect other outcomes considered in this review among normotensive diabetics. This weakens any conclusion regarding an overall benefit of intervening on blood pressure in diabetic patients without hypertension for the sole purpose of preventing diabetic retinopathy or avoiding the need for treatment for advanced stages of diabetic retinopathy.

Determining optimal strategies for primary prevention of cardiovascular disease: systematic review of cost-effectiveness analyses in the United Kingdom

BACKGROUND

Cardiovascular diseases are the leading cause of morbidity and mortality worldwide. The aim of the study was to guide researchers and commissioners of cardiovascular disease preventative services towards possible cost-effective interventions by reviewing published economic analyses of interventions for the primary prevention of cardiovascular disease, conducted for or within the UK NHS.

METHODS

In January 2021, electronic searches of MEDLINE and Embase were carried out to find economic evaluations of cardiovascular disease preventative services. We included fully published economic evaluations (including economic models) conducted alongside randomised controlled trials of any form of intervention that was aimed at the primary prevention of cardiovascular disease, including, but not limited to, drugs, diet, physical activity and public health. Full systematic review methods were used with predetermined inclusion/exclusion criteria, data extraction and formal quality appraisal [using the Consolidated Health Economic Evaluation Reporting Standards checklist and the framework for the quality assessment of decision analytic modelling by Philips et al. (Philips Z, Ginnelly L, Sculpher M, Claxton K, Golder S, Riemsma R, et al. Review of guidelines for good practice in decision-analytic modelling in health technology assessment. Health Technol Assess 2004;8(36)].

RESULTS

Of 4351 non-duplicate citations, eight articles met the review's inclusion criteria. The eight articles focused on health promotion (n = 3), lipid-lowering medicine (n = 4) and blood pressure-lowering medication (n = 1). The majority of the populations in each study had at least one risk factor for cardiovascular disease or were at high risk of cardiovascular disease. For the primary prevention of cardiovascular disease, all strategies were cost-effective at a threshold of £25,000 per quality-adjusted life-year, except increasing motivational interviewing in addition to other behaviour change strategies. Where the cost per quality-adjusted life-year gained was reported, interventions varied from dominant (i.e. less expensive and more effective than the comparator intervention) to £55,000 per quality-adjusted life-year gained.

FUTURE WORK AND LIMITATIONS

We found few health economic analyses of interventions for primary cardiovascular disease prevention conducted within the last decade. Future economic assessments should be undertaken and presented in accordance with best practices so that future reviews may make clear recommendations to improve health policy.

CONCLUSIONS

It is difficult to establish direct comparisons or draw firm conclusions because of the uncertainty and heterogeneity among studies. However, interventions conducted for or within the UK NHS were likely to be cost-effective in people at increased risk of cardiovascular disease when compared with usual care or no intervention.

FUNDING

This project was funded by the National Institute for Health and Care Research (NIHR) Health Technology Assessment programme and will be published in Health Technology Assessment. See the NIHR Journals Library website for further project information.

Statistical analysis of publicly funded cluster randomised controlled trials: a review of the National Institute for Health Research Journals Library

BACKGROUND

In cluster randomised controlled trials (cRCTs), groups of individuals (rather than individuals) are randomised to minimise the risk of contamination and/or efficiently use limited resources or solve logistic and administrative problems. A major concern in the primary analysis of cRCT is the use of appropriate statistical methods to account for correlation among outcomes from a particular group/cluster. This review aimed to investigate the statistical methods used in practice for analysing the primary outcomes in publicly funded cluster randomised controlled trials, adherence to the CONSORT (Consolidated Standards of Reporting Trials) reporting guidelines for cRCTs and the recruitment abilities of the cluster trials design.

METHODS

We manually searched the United Kingdom's National Institute for Health Research (NIHR) online Journals Library, from 1 January 1997 to 15 July 2021 chronologically for reports of cRCTs. Information on the statistical methods used in the primary analyses was extracted. One reviewer conducted the search and extraction while the two other independent reviewers supervised and validated 25% of the total trials reviewed.

RESULTS

A total of 1942 reports, published online in the NIHR Journals Library were screened for eligibility, 118 reports of cRCTs met the initial inclusion criteria, of these 79 reports containing the results of 86 trials with 100 primary outcomes analysed were finally included. Two primary outcomes were analysed at the cluster-level using a generalized linear model. At the individual-level, the generalized linear mixed model was the most used statistical method (80%, 80/100), followed by regression with robust standard errors (7%) then generalized estimating equations (6%). Ninety-five percent (95/100) of the primary outcomes in the trials were analysed with appropriate statistical methods that accounted for clustering while 5% were not. The mean observed intracluster correlation coefficient (ICC) was 0.06 (SD, 0.12; range, - 0.02 to 0.63), and the median value was 0.02 (IQR, 0.001-0.060), although 42% of the observed ICCs for the analysed primary outcomes were not reported.

CONCLUSIONS

In practice, most of the publicly funded cluster trials adjusted for clustering using appropriate statistical method(s), with most of the primary analyses done at the individual level using generalized linear mixed models. However, the inadequate analysis and poor reporting of cluster trials published in the UK is still happening in recent times, despite the availability of the CONSORT reporting guidelines for cluster trials published over a decade ago.

Screening for Prediabetes and Type 2 Diabetes: Updated Evidence Report and Systematic Review for the US Preventive Services Task Force

IMPORTANCE

Type 2 diabetes is common and is a leading cause of morbidity and disability.

OBJECTIVE

To review the evidence on screening for prediabetes and diabetes to inform the US Preventive Services Task Force (USPSTF).

DATA SOURCES

PubMed/MEDLINE, Cochrane Library, and trial registries through September 2019; references; and experts; literature surveillance through May 21, 2021.

STUDY SELECTION

English-language controlled studies evaluating screening or interventions for prediabetes or diabetes that was screen detected or recently diagnosed.

DATA EXTRACTION AND SYNTHESIS

Dual review of abstracts, full-text articles, and study quality; qualitative synthesis of findings; meta-analyses conducted when at least 3 similar studies were available.

MAIN OUTCOMES AND MEASURES

Mortality, cardiovascular morbidity, diabetes-related morbidity, development of diabetes, quality of life, and harms.

RESULTS

The review included 89 publications (N = 68 882). Two randomized clinical trials (RCTs) (25 120 participants) found no significant difference between screening and control groups for all-cause or cause-specific mortality at 10 years. For harms (eg, anxiety or worry), the trials reported no significant differences between screening and control groups. For recently diagnosed (not screen-detected) diabetes, 5 RCTs (5138 participants) were included. In the UK Prospective Diabetes Study, health outcomes were improved with intensive glucose control with sulfonylureas or insulin. For example, for all-cause mortality the relative risk (RR) was 0.87 (95% CI, 0.79 to 0.96) over 20 years (10-year posttrial assessment). For overweight persons, intensive glucose control with metformin improved health outcomes at the 10-year follow-up (eg, all-cause mortality: RR, 0.64 [95% CI, 0.45 to 0.91]), and benefits were maintained longer term. Lifestyle interventions (most involving >360 minutes) for obese or overweight persons with prediabetes were associated with reductions in the incidence of diabetes (23 RCTs; pooled RR, 0.78 [95% CI, 0.69 to 0.88]). Lifestyle interventions were also associated with improved intermediate outcomes, such as reduced weight, body mass index, systolic blood pressure, and diastolic blood pressure (pooled weighted mean difference, -1.7 mm Hg [95% CI, -2.6 to -0.8] and -1.2 mm Hg [95% CI, -2.0 to -0.4], respectively). Metformin was associated with a significant reduction in diabetes incidence (pooled RR, 0.73 [95% CI, 0.64 to 0.83]) and reduction in weight and body mass index.

CONCLUSIONS AND RELEVANCE

Trials of screening for diabetes found no significant mortality benefit but had insufficient data to assess other health outcomes; evidence on harms of screening was limited. For persons with recently diagnosed (not screen-detected) diabetes, interventions improved health outcomes; for obese or overweight persons with prediabetes, interventions were associated with reduced incidence of diabetes and improvement in other intermediate outcomes.

Screening for Prediabetes and Type 2 Diabetes: US Preventive Services Task Force Recommendation Statement

IMPORTANCE

An estimated 13% of all US adults (18 years or older) have diabetes, and 34.5% meet criteria for prediabetes. The prevalences of prediabetes and diabetes are higher in older adults. Estimates of the risk of progression from prediabetes to diabetes vary widely, perhaps because of differences in the definition of prediabetes or the heterogeneity of prediabetes. Diabetes is the leading cause of kidney failure and new cases of blindness among adults in the US. It is also associated with increased risks of cardiovascular disease, nonalcoholic fatty liver disease, and nonalcoholic steatohepatitis and was estimated to be the seventh leading cause of death in the US in 2017. Screening asymptomatic adults for prediabetes and type 2 diabetes may allow earlier detection, diagnosis, and treatment, with the ultimate goal of improving health outcomes.

OBJECTIVE

To update its 2015 recommendation, the USPSTF commissioned a systematic review to evaluate screening for prediabetes and type 2 diabetes in asymptomatic, nonpregnant adults and preventive interventions for those with prediabetes.

POPULATION

Nonpregnant adults aged 35 to 70 years seen in primary care settings who have overweight or obesity (defined as a body mass index ≥25 and ≥30, respectively) and no symptoms of diabetes.

EVIDENCE ASSESSMENT

The USPSTF concludes with moderate certainty that screening for prediabetes and type 2 diabetes and offering or referring patients with prediabetes to effective preventive interventions has a moderate net benefit.

CONCLUSIONS AND RECOMMENDATION

The USPSTF recommends screening for prediabetes and type 2 diabetes in adults aged 35 to 70 years who have overweight or obesity. Clinicians should offer or refer patients with prediabetes to effective preventive interventions. (B recommendation).

Association of weight loss and weight loss maintenance following diabetes diagnosis by screening and incidence of cardiovascular disease and all-cause mortality: An observational analysis of the ADDITION-Europe trial

AIMS

Short-term weight loss may lead to remission of type 2 diabetes but the effect of maintained weight loss on cardiovascular disease (CVD) is unknown. We quantified the associations between changes in weight 5 years following a diagnosis of diabetes, and incident CVD events and mortality up to 10 years after diagnosis.

MATERIALS AND METHODS

Observational analysis of the ADDITION-Europe trial of 2730 adults with screen-detected type 2 diabetes from the UK, Denmark and the Netherlands. We defined weight change based on the maintenance at 5 years of weight loss achieved during the year after diabetes diagnosis, and as 5-year overall change in weight. Incident CVD events (n = 229) and all-cause mortality (n = 225) from 5 to 10 years follow-up were ascertained from medical records.

RESULTS

Gaining >2% weight during the year after diabetes diagnosis was associated with higher hazard of all-cause mortality versus maintaining weight [hazard ratio (95% confidence interval): 3.18 (1.30-7.82)]. Losing ≥5% weight 1 year after diagnosis was also associated with mortality, whether or not weight loss was maintained at 5 years: 2.47 (0.99-6.21) and 2.72 (1.17-6.30), respectively. Losing ≥10% weight over 5 years was associated with mortality among those with body mass index <30 kg/m² [4.62 (1.87-11.42)]. Associations with CVD incidence were inconclusive.

CONCLUSIONS

Both weight loss and weight gain after screen-detected diabetes diagnosis were associated with higher mortality, but not CVD events, particularly among participants without obesity. The clinical implications of weight loss following a diagnosis of diabetes probably depend on its magnitude and timing, and may differ by body mass index status. Personalization of weight loss advice and support may be warranted.

Screening for type 2 diabetes mellitus

BACKGROUND

Diabetes mellitus, a metabolic disorder characterised by hyperglycaemia and associated with a heavy burden of microvascular and macrovascular complications, frequently remains undiagnosed. Screening of apparently healthy individuals may lead to early detection and treatment of type 2 diabetes mellitus and may prevent or delay the development of related complications.

OBJECTIVES

To assess the effects of screening for type 2 diabetes mellitus.

SEARCH METHODS

We searched CENTRAL, MEDLINE, LILACS, the WHO ICTRP, and ClinicalTrials.gov from inception. The date of the last search was May 2019 for all databases. We applied no language restrictions.

SELECTION CRITERIA

We included randomised controlled trials involving adults and children without known diabetes mellitus, conducted over at least three months, that assessed the effect of diabetes screening (mass, targeted, or opportunistic) compared to no diabetes screening.

DATA COLLECTION AND ANALYSIS

Two review authors independently screened titles and abstracts for potential relevance and reviewed the full-texts of potentially relevant studies, extracted data, and carried out 'Risk of bias' assessment using the Cochrane 'Risk of bias' tool. We assessed the overall certainty of the evidence using the GRADE approach.

MAIN RESULTS

We screened 4651 titles and abstracts identified by the search and assessed 92 full-texts/records for inclusion. We included one cluster-randomised trial, the ADDITION-Cambridge study, which involved 20,184 participants from 33 general practices in Eastern England and assessed the effects of inviting versus not inviting high-risk individuals to screening for diabetes. The diabetes risk score was used to identify high-risk individuals; it comprised variables relating to age, sex, body mass index, and the use of prescribed steroid and anti-hypertensive medication. Twenty-seven practices were randomised to the screening group (11,737 participants actually attending screening) and 5 practices to the no-screening group (4137 participants). In both groups, 36% of participants were women; the average age of participants was 58.2 years in the screening group and 57.9 years in the no-screening group. Almost half of participants in both groups were on antihypertensive medication. The findings from the first phase of this study indicate that screening compared to no screening for type 2 diabetes did not show a clear difference in all-cause mortality (hazard ratio (HR) 1.06, 95% confidence interval (CI) 0.90 to 1.25, low-certainty evidence). Screening compared to no screening for type 2 diabetes mellitus showed an HR of 1.26, 95% CI 0.75 to 2.12 (low-certainty evidence) for diabetes-related mortality (based on whether diabetes was reported as a cause of death on the death certificate). Diabetes-related morbidity and health-related quality of life were only reported in a subsample and did not show a substantial difference between the screening intervention and control. The included study did not report on adverse events, incidence of type 2 diabetes, glycosylated haemoglobin A1c (HbA1c), and socioeconomic effects.

AUTHORS' CONCLUSIONS

We are uncertain about the effects of screening for type 2 diabetes on all-cause mortality and diabetes-related mortality. Evidence was available from one study only. We are therefore unable to draw any firm conclusions relating to the health outcomes of early type 2 diabetes mellitus screening. Furthermore, the included study did not assess all of the outcomes prespecified in the review (diabetes-related morbidity, incidence of type 2 diabetes, health-related quality of life, adverse events, socioeconomic effects).

Evaluation of the Diabetes Screening Component of a National Cardiovascular Risk Assessment Programme in England: a Retrospective Cohort Study

Type 2 Diabetes (T2D) is increasing but the effectiveness of large-scale diabetes screening programmes is debated. We assessed associations between coverage of a national cardiovascular and diabetes risk assessment programme in England (NHS Health Check) and detection and management of incident cases of non-diabetic hyperglycaemia (NDH) and T2D. Retrospective analysis employing propensity score covariate adjustment method of prospectively collected data of 348,987 individuals aged 40-74 years and registered with 455 general practices in England (January 2009-May 2016). We examined differences in diagnosis of NDH and T2D, and changes in blood glucose levels and cardiovascular risk score between individuals registered with general practices with different levels (tertiles) of programme coverage. Over the study period 7,126 cases of NDH and 12,171 cases of T2D were detected. Compared with low coverage practices, incidence rate of detection in medium and high coverage practices were 15% and 19% higher for NDH and 10% and 9% higher for T2D, respectively. Individuals with NDH in high coverage practices had 0.2 mmol/L lower mean fasting plasma glucose and 0.9% lower cardiovascular risk score at follow-up. General practices actively participating in the programme had higher detection of NDH and T2D and improved management of blood glucose and cardiovascular risk factors.

Treat-to-target HbA1c and lipid profile to prolong β-cell mass/function and optimize treatment goal attainment

BACKGROUND

To evaluate the relation between different serum lipid fractions and other known barriers to attain the HbA_1c  ≤ 7.0% (53 mmol/mol) target.

METHODS

Data on 2719 patients with type 2 diabetes were collected from the five waves of the International Diabetes Mellitus Practice Study implemented in Argentina (2006 to 2012) including demographic/socioeconomic profile, clinical, metabolic (HbA_1c and serum lipids) data, and treatment type and also, percentage of treatment goal attainment. Descriptive statistical analyses included ANOVA, χ² test, and Fisher exact test and univariate and multivariate logistic regression analyses, which identified predictive factors for HbA_1c  ≤ 7% (53 mmol/mol).

RESULTS

The average age was 63 years, primary/secondary education, health insurance, 10-year type 2 diabetes duration, most associated with cardiovascular risk factors and some microvascular/macrovascular complications; 94.5% received antihyperglycaemic drugs. Percentage of people on target: HbA_1c 51.2%, blood pressure 23.5%, total cholesterol 62.6%, low-density lipoprotein (LDL) cholesterol 38.9%, and triglycerides 61.1%. HbA_1c on target depended markedly on treatment type: more of those treated with lifestyle changes and significantly fewer of those receiving insulin. Only 4.1% had all parameters simultaneously on target. Multivariate logistic regression analyses showed that achieving HbA_1c  ≤ 7.0% (53 mmol/mol) was associated with higher educational level, shorter diabetes duration, and having reached goals for LDL cholesterol and triglycerides, whereas opposite results were obtained with insulin treatment and longer diabetes duration.

CONCLUSIONS

High LDL cholesterol and triglyceride levels simultaneously potentiate development/progression of chronic complications, exerting this effect in the long term by decreasing β-cell mass/function, thereby making it more difficult to reach HbA_1c values able to prevent complications.

Type 2 diabetes in general practice in Norway 2005-2014: moderate improvements in risk factor control but still major gaps in complication screening

OBJECTIVE

To assess the status of type 2 diabetes care in general practice and changes in the quality of care between 2005 and 2014, and to identify areas of diabetes care requiring improvement.

RESEARCH DESIGN AND METHODS

Two cross-sectional surveys were performed that included patients with type 2 diabetes in selected areas (n=9464 in 2014, n=5463 in 2005). Quality of care was assessed based on key recommendations in national guidelines. Differences in clinical performance between 2005 and 2014 were assessed in regression models adjusting for age, sex, counties and clustering within general practices.

RESULTS

Treatment targets were achieved in a higher proportion of patients in 2014 compared with 2005: hemoglobin A1c ≤7.0% (≤53 mmol/mol) in 62.8% vs 54.3%, blood pressure ≤135/80 mm Hg in 44.9% vs 36.6%, and total cholesterol ≤4.5 mmol/L in 49.9% vs 33.5% (all adjusted P≤0.001). Regarding screening procedures for microvascular complications, fewer patients had recorded an eye examination (61.0% vs 71.5%, adjusted P<0.001), whereas more patients underwent monofilament test (25.9% vs 18.7%, adjusted P<0.001). Testing for albuminuria remained low (30.3%) in 2014. A still high percentage were current smokers (22.7%).

CONCLUSIONS

We found moderate improvements in risk factor control for patients with type 2 diabetes in general practice during the last decade, which are similar to improvements reported in other countries. We report major gaps in the performance of recommended screening procedures to detect microvascular complications. The proportion of daily smokers remains high. We suggest incentives to promote further improvements in diabetes care in Norway.