HbA1c levels and all-cause mortality in type 2 diabetic patients: epidemiological evidence of the need for personalised therapeutic targets

Psychometric and biomedical outcomes of glycated haemoglobin target-setting in adults with type 1 and type 2 diabetes: Protocol for a mixed-methods parallel-group randomised feasibility study

BACKGROUND

The disease burden of diabetes can have wide-ranging implications on patients' psychological well-being and health-related quality of life. Glycated haemoglobin targets are commonly used to guide patient management in diabetes to reduce the future risk of developing diabetes complications, but little is known of the psychological impact of glycated haemoglobin target-setting. This protocol describes a study to determine the feasibility of evaluating psychological outcomes when setting explicit glycated haemoglobin targets in people with diabetes.

METHODS

This single-centre randomised feasibility study will follow a mixed-methods approach across four sub-studies. In sub-study A, eligible adults (aged 18 and over) with type 1 or type 2 diabetes will complete baseline validated psychometric questionnaires evaluating health-related quality of life (EuroQoL-5D-5L), diabetes-related distress (Problem Areas In Diabetes), self-care (Summary of Diabetes Self-Care Activities), well-being (Well-Being Quetionnaire-12) and diabetes-related psychosocial self-efficacy (Diabetes Empowerment Scale-Long Form). Participants will be randomised to receive explicit glycated haemoglobin intervention targets 5mmol/mol above or below current glycated haemoglobin readings. Rates of eligibility, recruitment, retention and questionnaire response rate will be measured. Psychometric outcomes will be re-evaluated 3-months post-intervention. Sub-studies B and C will use qualitative semi-structured interviews to evaluate experiences, views and opinions of diabetes patients and healthcare professionals in relation to the acceptability of study processes, the use of glycated haemoglobin targets, the impact of diabetes on psychological well-being and, in sub-study D, barriers to participation in diabetes research.

DISCUSSION

This mixed-methods study aims to provide a novel insight into the psychological implications of glycated haemoglobin target-setting for people with diabetes in secondary care, alongside testing the feasibility of undertaking a larger project of this nature.

TRIAL REGISTRATION

The study is registered with the ISRCTN (registration number: 12461724; date registered: 11th June 2021). Protocol version: 2.0.5, 26th February 2021.

The individualisation of glycaemic targets in response to patient characteristics in type 2 diabetes: a scoping review

BACKGROUND

Evidence and guidelines increasingly support an individualised approach to care for people with type 2 diabetes and individualisation of glycaemic targets in response to patient factors.

METHODS

We undertook a scoping review of the literature for evidence of factors impacting upon glycated haemoglobin target individualisation in adults with type 2 diabetes. Data were analysed thematically with the themes inductively derived from article review.

FINDINGS

Evidence suggests that presence of cardiovascular disease, hypoglycaemia unawareness, severe hypoglycaemia, limited life expectancy, advanced age, long diabetes duration, frailty, cognitive impairment, disability, extensive comorbidity, diabetes distress and patient preference should inform the setting of glycaemic targets.

CONCLUSION

The management of people with diabetes is complex. In clinical practice, many patients will have a variety of factors that should be considered when personalising their care. Approaches to personalised care and glycaemic treatment targets should be undertaken as part of a shared decision-making process between physician and patient. Use of electronic records might enable greater efficiency and more widespread use of personalised care plans for people with diabetes.

An innovative model for management of cardiovascular disease risk factors in the low resource setting of Cambodia

Non-communicable diseases are increasing in developing countries and control of diabetes and hypertension is needed to reduce rates of the leading causes of morbidity and mortality, stroke and ischaemic heart disease. We evaluated a programme in Cambodia, financed by a revolving drug fund, which utilizes Peer Educators to manage diabetes and hypertension in the community. We assessed clinical outcomes and retention in the programme. For all people enrolled in the programme between 2007 and 2016, the average change in blood pressure (BP) and percentage with controlled hypertension (BP < 140/<90 mmHg) or diabetes (fasting blood glucose (BG) < 7mg/dl, post-prandial BG < 130 mg/dl, or HBA1C < 7%) was calculated every 6 months from enrolment.  Attrition rate in the nth year of enrolment was calculated; associations with loss to follow-up were explored using cox regression. A total of 9139 patients enrolled between January 2007 and March 2016. For all people with hypertension, mean change in systolic and diastolic BP within the first year was −15.1 mmHg (SD 23.6, P < 0.0001) and −8.6 mmHg (SD 14.0, P < 0.0001), respectively. BP control was 50.5% at year 1, peaking at 70.6% at 5.5 years. 41.3% of people with diabetes achieved blood sugar control at 6 months and 44.4% at 6.5 years.  An average of 2.3 years [SD 1.9] was spent in programme. Attrition rate within year 1 of enrolment ranged from 29.8% to 61.5% with average of 44.1% [SD 10.3] across 2008–15. Patients with hypertension were more likely to leave the program compared to those with diabetes and males more likely than females. The programme shows a substantial and sustained rate of diabetes and hypertension control for those who remain in the program and could be a model for implementation in other low middle-income settings, however, further work is needed to improve patient retention.

Glycaemic markers and all-cause mortality in older adults with and without diabetes: the Atherosclerosis Risk in Communities (ARIC) study

AIMS/HYPOTHESIS

There is controversy regarding the performance of HbA1c in old age. We evaluated the prognostic value of HbA1c and other glycaemic markers (fructosamine, glycated albumin, fasting glucose) with mortality risk in older adults (66-90 years).

METHODS

This was a prospective analysis of 5636 participants (31% with diagnosed diabetes, mean age 76, 58% female, 21% black) in the Atherosclerosis Risk in Communities (ARIC) study, baseline 2011-2013. We used Cox regression to examine associations of glycaemic markers (modelled in categories) with mortality risk, stratified by diagnosed diabetes status.

RESULTS

During a median of 6 years of follow-up, 983 deaths occurred. Among older adults with diabetes, 30% had low HbA1c (<42 mmol/mol [<6.0%]) and 10% had high HbA1c (≥64 mmol/mol [≥8.0%]); low (HR 1.32 [95% CI 1.04, 1.68]) and high (HR 1.86 [95% CI 1.32, 2.62]) HbA1c were associated with mortality risk vs HbA1c 42-52 mmol/mol (6.0-6.9%) after demographic adjustment. Low fructosamine and glycated albumin were not associated with mortality risk. Both low and high fasting glucose were associated with mortality risk. After further adjustment for lifestyle and clinical risk factors, high HbA1c (HR 1.81 [95% CI 1.28, 2.56]), fructosamine (HR 1.96 [95% CI 1.43-2.69]), glycated albumin (HR 1.81 [95% CI 1.33-2.47]) and fasting glucose (HR 1.81 [95% CI 1.24, 2.66]) were associated with mortality risk. Low HbA1c and fasting glucose were no longer significantly associated with mortality risk. Among participants without diabetes, associations of glycaemic markers with mortality risk were less robust.

CONCLUSIONS/INTERPRETATION

Elevated HbA1c, fructosamine, glycated albumin and fasting glucose were associated with risk of mortality in older adults with diabetes. Low HbA1c and fasting glucose may be markers of poor prognosis but are possibly confounded by health status. Our findings support the clinical use of HbA1c in older adults with diabetes. Graphical abstract.

Scientific independence and objectivity: many questions linger about treatment of type 2 diabetes, such as scientific study design, optimal glucose control and the safety of injecting exogenous insulin

Whilst clinical guidelines exist for the treatment of people with type 2 diabetes, many underlying assumptions are still not qualified by convincing evidence. In this commentary, it is argued that fundamental issues still cloud clinical practice, such as biases in the design of clinical studies, the association between glucose control & clinical outcomes, and the safety of exposure to exogenous insulin and other glucose-lowering drugs. Relevant scientific evidence and alternative opinions about important issues continue to be largely ignored, and no effort has been made to resolve these questions. This may have had serious consequences, such as stifling innovation because there are no further benefits to be achieved in relation to glucose control.

HbA1c and hypoglycaemia in intensively treated type 2 diabetes: a retrospective cohort study in primary care

Objective

To establish whether low HbA1c is associated with clinical hypoglycaemia among people with type 2 diabetes prescribed insulins or sulphonylureas.

Design

Retrospective cohort study using routine electronic GP health records collected between January 2013 and December 2015.

Setting

Three east London Clinical Commissioning Groups.

Participants

Two cohorts of adults with type 2 diabetes prescribed either (i) insulins with or without other oral antidiabetic medication (n = 6788, 36.4%) or (ii) sulphonylureas with or without other oral antidiabetic medications excluding insulins (n = 11,840, 63.6%).

Main outcome measures

First clinically recorded hypoglycaemia and all-cause mortality. Hazard ratios (HR) adjusting for age, ethnicity, renal function and comorbidities were calculated using Cox regression models.

Results

Compared with an HbA1c of 53–63 mmol/mol, the adjusted HR of hypoglycaemia in those with a low HbA1c, below 53 mmol/mol, in the insulin and sulphonylurea cohorts were 1.26 (95% CI, 0.97 to 1.62) and 1.54 (95% CI, 1.27 to 1.87), respectively. Adjusted HRs of all-cause mortality from low HbA1c in the insulin and sulphonylurea cohorts were 1.54 (95% CI, 1.15 to 2.07) and 1.42 (95% CI, 1.11 to 1.81), respectively. Increasing age and renal impairment were also associated with increased hypoglycaemic risk in both cohorts.

Conclusions

HbA1c below 53 mmol/mol was associated with episodes of clinical hypoglycaemia among people with type 2 diabetes prescribed sulphonylureas, and all-cause mortality in those prescribed insulins and sulphonylureas. These findings support the need for reviewing glycaemic targets and the intensities of treatment in those with low HbA1c prescribed insulins or sulphonylureas to reduce the risk of hypoglycaemia.

Impact of differing glucose-lowering regimens on the pattern of association between glucose control and survival

AIMS

To characterize survival in relation to achieved glycated haemoglobin (HbA1c) level within alternative glucose-lowering regimens with differing risks of hypoglycaemia.

METHODS

Data were extracted from the UK Clinical Practice Research Datalink and the corresponding Hospital Episode Statistics. Patients with type 2 diabetes prescribed glucose-lowering therapy in monotherapy or dual therapy with metformin between 2004 and 2013 were identified. Risk of all-cause mortality within treatment cohorts was evaluated using the Cox proportional hazards model, introducing mean HbA1c as a quarterly updated, time-dependent covariable.

RESULTS

There were 6646 deaths in a total follow-up period of 374 591 years. Survival for lower (<7%) vs moderate HbA1c levels (≥7%, <8.5%) differed by cohort: metformin, adjusted hazard ratio (aHR) 1.03 (95% confidence interval [CI] 0.95-1.12); sulphonylurea, aHR 1.11 (95% CI 0.99-1.25); insulin, aHR 1.47 (95% CI 1.25-1.72); combined regimens with low hypoglycaemia risk, aHR 1.02 (95% CI 0.94-1.10); and combined regimens with higher hypoglycaemia risk excluding insulin, aHR 1.24 (95% CI 1.13-1.35) and including insulin, aHR 1.28 (95% CI 1.18-1.37). Higher HbA1c levels were associated with increased mortality in regimens with low hypoglycaemia risk. Post hoc analysis by HbA1c deciles revealed an elevated risk of all-cause mortality for the lowest deciles across all cohorts, but particularly in those regimens associated with hypoglycaemia. High HbA1c was associated with no difference, or a small increase in mortality risk in regimens with increased risk of hypoglycaemia.

CONCLUSIONS

The pattern of mortality risk across the range of HbA1c differed by glucose-lowering regimen. Lower HbA1c was associated with increased mortality risk compared with moderate control, especially in those regimens associated with hypoglycaemia. High levels of HbA1c were associated with the expected elevated mortality risk in regimens with low hypoglycaemia risk.

Comparison of four chromatographic methods used for measurement of glycated hemoglobin

This parameter’s results accuracy has a special importance in the management of diabetic patients since targets for optimal glycemic control are established using HbA1c values. Several error sources can influence the obtained value, some of them can be counteracted (ex. pipetting errors, storage), and others should be taken into consideration at the interpretation of the result (ex. presence of hemoglobin variants). The aim of this study was to compare four chromatographic methods regarding the costs and the influence of certain error sources on the accuracy of the result. Materials and methods: Samples and controls were analyzed using Variant I, Micromat II and In2it (Bio-Rad) systems, and the BIOMIDI reagent kit for HbA1c measurement. Results: Positive correlation could be observed comparing the results obtained using different methods, except the patients presenting elevated HbF. Pipetting errors modify the results up to 5% in case of Variant I, and up to 10% in case of Micromat II in the tested range. One day of improper storage at room temperature causes 3% deviation from the actual value using the Variant I analyzer and 5% in case of Micromat II and In2it equipment. As a conclusion, depending on the number of samples, automated chromatographic analyzers are the most appropriate equipments for the determination of HbA1c.

Metabolic memory and all-cause death in community-based patients with type 2 diabetes: the Fremantle Diabetes Study

AIMS

To validate the findings, in a usual care setting, of glycaemic intervention trials, which have shown that tight control in patients with recently diagnosed type 2 diabetes protects against death during post-study monitoring, but that it may be deleterious in long-duration diabetes with vascular complications.

METHODS

A subset of 531 patients with type 2 diabetes from the community-based observational Fremantle Diabetes Study Phase 1, who attended ≥5 annual reviews (mean follow-up 15.9 years), were categorized by baseline diabetes duration [<1 year (Group 1); 1 to <5 years (Group 2); and ≥5 years (Group 3)]. Glycated haemoglobin (HbA1c) trajectories over the first 5 years were determined [low, medium and high; equivalent to mean HbA1c ≤6.6% (<49 mmol/mol), 6.7-8.0% (50-64 mmol/mol) and ≥8.0% (>64 mmol/mol), respectively]. Kaplan-Meier analysis was used to assess survival by duration and HbA1c trajectory. Cox proportional hazards modelling identified predictors of all-cause death.

RESULTS

There was greater mortality in patients with a medium versus those with a low trajectory in Group 1: hazard ratio (HR) 1.99 [95% confidence interval (CI) 1.003-3.94; p = 0.049], and in patients with a high versus a low trajectory in Group 2: HR 2.02 (95% CI 1.11-3.71; p = 0.022). In Group 3, both medium [HR 0.57 (95% CI 0.35-0.92; p = 0.022)] and high [HR 0.56 (95% CI 0.32-0.96); p = 0.035] trajectories were independently and inversely associated with death.

CONCLUSIONS

In community-based patients with newly or recently diagnosed type 2 diabetes, poor glycaemic control was an adverse prognostic indicator. Tight control was independently associated with death in patients with diabetes duration ≥5 years. These data parallel intervention trial findings and support individualization of HbA1c targets.

The incidence risk of type 2 diabetes mellitus in female nurses: a nationwide matched cohort study

BACKGROUND

Diabetes is one of the most common chronic illnesses worldwide. This study was to assess whether the incidence risk of type 2 diabetes mellitus between female nurses and female non-nurses.

METHODS

Study data were obtained from the Longitudinal Health Insurance Research Database, and nurses were sampled from the Registry for medical personnel. Nurses and non-nurses with similar traits and health conditions were selected via 1:1 propensity score matching. A total of 111,670 subjects were selected (55,835 nurses and 55,835 non-nurses). Stages of diabetes development were monitored until December 31, 2009. The Cox proportional hazards model was used to discuss risks and influencing factors related to diabetes. Poisson distribution methods were used to examine the incidence rate of diabetes per 1,000 person-years.

RESULTS

The propensity matching results show that on average, female nurses who were diagnosed with diabetes were younger compared with the non-nurses (46.98 ± 10.80 vs. 48.31 ± 10.43, p <0.05). However, the results of the Cox proportional hazards model show that the nurses showed a lower risk of developing diabetes compared with the non-nurses (Adj. HR = 0.84, 95 % CI: 0.79-0.90). Factors influencing diabetes development risks among the nurses include advanced age and high Charlson Comorbidity Index levels.

CONCLUSION

The low degree of diabetes development among the nurses may be attributable to the fact that nurses possess substantial knowledge on health care and on healthy behaviors. The results of this study can be used as a reference to assess occupational risks facing nursing staff, to prevent diabetes development, and to promote health education.

The effect of frailty should be considered in the management plan of older people with Type 2 diabetes

The prevalence of diabetes is increasing especially in older age due to increased life expectancy. In old age, diabetes is associated with high comorbidity burden and increased prevalence of geriatric syndromes including frailty in addition to micro- and macro-vascular complications. The emergence of frailty may change the natural history of Type 2 diabetes from a progressive to a regressive course with increased risk of hypoglycemia. This may result in normalization of blood glucose levels and lead to a state of burnt-out diabetes in frail older people with significant weight loss. Although guidelines suggest relaxed glycemic control in frail elderly with diabetes, complete withdrawal of hypoglycemic medications may be necessary in these frail populations to reduce the risk of hypoglycemia.

Lay abstract: Diabetes is a common disease especially in older people. Aging is associated with reduced appetite and reduced food intake due to lack of exercise and diminished energy consumption. In certain individuals this may be significant leading to weight loss, malnutrition and the development of frailty. As a result the doses of diabetes medications may be too strong for this frail population especially if they have organ dysfunction reducing medication clearance and increasing the risk of low blood glucose level events. Therefore, reduction or complete withdrawal of diabetes medications may be considered in this frail group.

Low HbA1c and Increased Mortality Risk-is Frailty a Confounding Factor?

Diabetes mellitus is increasingly becoming an older person disease due to the increased survival and aging of the population. Previous studies which showed benefits of tight glycemic control and a linear relationship between HbA1c and mortality have largely included younger patients newly diagnosed with diabetes and with less comorbidities. Recent studies, which included older population with diabetes, have shown a U-shaped relationship of increased mortality associated with low HbA1c. The mechanism of such relationship is unclear. There was no direct causal link between low HbA1c and mortality. It appears that malnutrition, inflammation and functional decline are characteristics shared by the populations that showed increased mortality and low HbA1c. In these studies functional status, disability or frailty was not routinely measured. Therefore, although adjustment for comorbidities was made there may be a residual confounding by unmeasured factors such as frailty. Thus, frailty or decline in functional reserve may be the main confounding factor explaining the relationship between increased mortality risk and low HbA1c.

Glucose-lowering with exogenous insulin monotherapy in type 2 diabetes: dose association with all-cause mortality, cardiovascular events and cancer

AIMS

To evaluate the association between insulin exposure and all-cause mortality, incident major adverse cardiovascular events (MACE) and incident cancer in people with type 2 diabetes treated with insulin monotherapy.

METHODS

For this retrospective study, people with type 2 diabetes who progressed to insulin monotherapy from the year 2000 were identified from the UK Clinical Practice Research Datalink. The risks of progression to serious adverse outcomes were compared using Cox proportional hazards models. In the main analysis, insulin exposure was introduced into the model as prescribed international units per kilogram per day, as a cumulative, continuous, annually updated, time-dependent covariable.

RESULTS

A total of 6484 subjects with type 2 diabetes who progressed to treatment with insulin monotherapy from the year 2000 onwards were followed for a mean of 3.3 years. The event numbers were as follows: deaths, n = 1110; incident MACE, n = 342; incident cancers, n = 382. Unadjusted event rates were 61.3 deaths per 1000 person-years, 26.4 incident MACE per 1000 person-years and 24.6 incident cancers per 1000 person-years. The adjusted hazard ratios in relation to 1-unit increases in insulin dose were 1.54 [95% confidence interval (CI) 1.32-1.78] for all-cause mortality, 1.37 (95% CI 1.05-1.81) for MACE and 1.35 (95% CI 1.04-1.75) for cancer.

CONCLUSIONS

There was an association between increasing exogenous insulin dose and increased risk of all-cause mortality, MACE and cancer in people with type 2 diabetes. The limitations of observational studies mean that this should be further investigated using an interventional study design.

Impaired glucose metabolism among those with and without diagnosed diabetes and mortality: a cohort study using Health Survey for England data

BACKGROUND

The extent that controlled diabetes impacts upon mortality, compared with uncontrolled diabetes, and how pre-diabetes alters mortality risk remain issues requiring clarification.

METHODS

We carried out a cohort study of 22,106 Health Survey for England participants with a HbA1C measurement linked with UK mortality records. We estimated hazard ratios (HRs) of all-cause, cancer and cardiovascular disease (CVD) mortality and 95% confidence intervals (CI) using Cox regression.

RESULTS

Average follow-up time was seven years and there were 1,509 deaths within the sample. Compared with the non-diabetic and normoglycaemic group (HbA1C <5.7% [<39 mmol/mol] and did not indicate diabetes), undiagnosed diabetes (HbA1C ≥6.5% [≥48 mmol/mol] and did not indicate diabetes) inferred an increased risk of mortality for all-causes (HR 1.40, 1.09-1.80) and CVD (1.99, 1.35-2.94), as did uncontrolled diabetes (diagnosed diabetes and HbA1C ≥6.5% [≥48 mmol/mol]) and diabetes with moderately raised HbA1C (diagnosed diabetes and HbA1C 5.7-<6.5% [39-<48 mmol/mol]). Those with controlled diabetes (diagnosed diabetes and HbA<5.7% [<39 mmol/mol]) had an increased HR in relation to mortality from CVD only. Pre-diabetes (those who did not indicate diagnosed diabetes and HbA1C 5.7-<6.5% [39-<48 mmol/mol]) was not associated with increased mortality, and raised HbA1C did not appear to have a statistically significant impact upon cancer mortality. Adjustment for BMI and socioeconomic status had a limited impact upon our results. We also found women had a higher all-cause and CVD mortality risk compared with men.

CONCLUSIONS

We found higher rates of all-cause and CVD mortality among those with raised HbA1C, but not for those with pre-diabetes, compared with those without diabetes. This excess differed by sex and diabetes status. The large number of deaths from cancer and CVD globally suggests that controlling blood glucose levels and policies to prevent hyperglycaemia should be considered public health priorities.

HbA1c is associated with increased all-cause mortality in the first year after acute ischemic stroke

OBJECTIVES

To assess the association between baseline HbA1c and the poor outcomes within 1 year after acute ischemic stroke.

METHODS

Acute ischemic stroke patients with HbA1c values at baseline (n  =  2186) were selected from the abnormal glucose regulation in patients with acute stroke across China study (ACROSS). Logistic regressions were performed to assess the association between HbA1c quartiles (<5.5% [37 mmol/mol], 5.5 to <6.1% [37 to <43 mmol/mol], 6.1 to <7.2% [43 to <55 mmol/mol], and ≥ 7.2% [≥ 55 mmol/mol]) and the poor outcomes within 1 year. Poor outcomes were defined as all-cause mortality (modified Rankin scale [mRS]  =  6) and poor functional outcome (mRS [2-6]).

RESULTS

The risk for all-cause mortality was significantly increased in HbA1c level >5.5% [>37 mmol/mol] when compared to HbA1c quartile <5.5% [<37 mmol/mol] and dramatically increased to two to three times higher in the highest HbA1c quartile ≥ 7.2% [>55 mmol/mol] (1-year all-cause mortality model, odds ratios [ORs] were 1.07, 1.01, and 2.45, P for trend 0.009). After the further analysis with previous diabetes mellitus (DM) and post-stroke insulin use stratified, the risk of mortality was increased across the HbA1c levels (P for trend 0.020) and dramatically augmented in HbA1c ≥ 7.2% [>55 mmol/mol] in patients without a history of DM and without post-stroke insulin use.

DISCUSSION

Elevated HbA1c (from 5.5% [37 mmol/mol]) presenting pre-stroke glycemia status has a significant trend in increasing the risk of 1-year all-cause mortality. HbA1c ≥ 7.2% (>55 mmol/mol) is an independent risk predictor for 1-year all-cause mortality after acute first-ever ischemic stroke. Such an association might be altered by glycometabolism status.