Dataset Information

The association between symptomatic, severe hypoglycaemia and mortality in type 2 diabetes: retrospective epidemiological analysis of the ACCORD study.

ABSTRACT:

Objective

To determine whether there is a link between hypoglycaemia and mortality among participants in the Action to Control Cardiovascular Risk in Diabetes (ACCORD) trial.

Design

Retrospective epidemiological analysis of data from the ACCORD trial. Setting Diabetes clinics, research clinics, and primary care clinics.

Participants

Patients were eligible for the ACCORD study if they had type 2 diabetes, a glycated haemoglobin (haemoglobin A(1C)) concentration of 7.5% or more during screening, and were aged 40-79 years with established cardiovascular disease or 55-79 years with evidence of subclinical disease or two additional cardiovascular risk factors. Intervention Intensive (haemoglobin A(1C) <6.0%) or standard (haemoglobin A(1C) 7.0-7.9%) glucose control.

Outcome measures

Symptomatic, severe hypoglycaemia, manifest as either blood glucose concentration of less than 2.8 mmol/l (<50 mg/dl) or symptoms that resolved with treatment and that required either the assistance of another person or medical assistance, and all cause and cause specific mortality, including a specific assessment for involvement of hypoglycaemia.

Results

10 194 of the 10 251 participants enrolled in the ACCORD study who had at least one assessment for hypoglycaemia during regular follow-up for vital status were included in this analysis. Unadjusted annual mortality among patients in the intensive glucose control arm was 2.8% in those who had one or more episodes of hypoglycaemia requiring any assistance compared with 1.2% for those with no episodes (53 deaths per 1924 person years and 201 deaths per 16 315 person years, respectively; adjusted hazard ratio (HR) 1.41, 95% CI 1.03 to 1.93). A similar pattern was seen among participants in the standard glucose control arm (3.7% (21 deaths per 564 person years) v 1.0% (176 deaths per 17 297 person years); adjusted HR 2.30, 95% CI 1.46 to 3.65). On the other hand, among participants with at least one hypoglycaemic episode requiring any assistance, a non-significantly lower risk of death was seen in those in the intensive arm compared with those in the standard arm (adjusted HR 0.74, 95% 0.46 to 1.23). A significantly lower risk was observed in the intensive arm compared with the standard arm in participants who had experienced at least one hypoglycaemic episode requiring medical assistance (adjusted HR 0.55, 95% CI 0.31 to 0.99). Of the 451 deaths that occurred in ACCORD up to the time when the intensive treatment arm was closed, one death was adjudicated as definitely related to hypoglycaemia.

Conclusion

Symptomatic, severe hypoglycaemia was associated with an increased risk of death within each study arm. However, among participants who experienced at least one episode of hypoglycaemia, the risk of death was lower in such participants in the intensive arm than in the standard arm. Symptomatic, severe hypoglycaemia does not appear to account for the difference in mortality between the two study arms up to the time when the ACCORD intensive glycaemia arm was discontinued.

Trial registration

NCT00000620.

SUBMITTER: Bonds DE

PROVIDER: S-EPMC2803744 | biostudies-literature |

REPOSITORIES: biostudies-literature

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Project description:Aims/hypothesisIn patients with diabetes, intensive glycaemic control reduces microvascular complications. However, severe hypoglycaemia frequently complicates intensive glycaemic control. Blood biomarkers that predict successful intensification of glycaemic control in patients with type 2 diabetes without the development of severe hypoglycaemia would advance patient care. In patients who received intensive treatment for type 2 diabetes from the Action to Control Cardiovascular Risk in Diabetes (ACCORD) study, we hypothesised that insulin deficiency and islet autoantibodies would be associated with severe hypoglycaemia and failure to achieve near-normal glycaemia (HbA1c <6.0% [42 mmol/mol]).MethodsA nested case-control design was used. Cases (n = 326) were defined as participants having severe hypoglycaemia and failure to achieve an HbA1c level of <6.0% (42 mmol/mol) prior to the ACCORD transition or death. Controls (n = 1,075) were those who achieved an HbA1c level of <6.0% (42 mmol/mol) prior to the ACCORD transition or death without severe hypoglycaemia. Each case was matched (for race, age and BMI) by up to four controls. Baseline insulin deficiency (fasting C-peptide ≤0.15 nmol/l) and islet autoantibodies (glutamic acid decarboxylase [GAD], tyrosine phosphatase-related islet antigen 2 [IA2], insulin [IAA] and zinc transporter 8 [ZnT8]) were measured. Conditional logistic regression with and without adjustment for age, BMI and diabetes duration was used on the full cohort and after removal of patients who died and their respective controls.ResultsSevere hypoglycaemia accompanied by an inability to achieve an HbA1c level of <6.0% (42 mmol/mol) was associated with insulin deficiency (adjusted OR 23.2 [95% CI 9.0, 59.5], p < 0.0001), the presence of IAA autoantibodies or baseline insulin use (adjusted OR 3.8 [95% CI 2.7, 5.3], p < 0.0001), GAD autoantibodies (OR 3.9 [95% CI 2.5, 6.0], p < 0.0001), IA2 autoantibodies (OR 16.7 [95% CI 3.9, 71.6], p = 0.0001) and ZnT8 autoantibodies (adjusted OR 3.9 [95% CI 1.2, 12.4], p = 0.02).ConclusionsC-peptide and islet autoantibodies may serve as biomarkers to predict the risk of severe hypoglycaemia during intensification of type 2 diabetes treatment.Trial registrationClinicalTrials.gov NCT00000620 (original ACCORD study).

Project description:ObjectivesTo investigate potential determinants of severe hypoglycaemia, including baseline characteristics, in the Action to Control Cardiovascular Risk in Diabetes (ACCORD) trial and the association of severe hypoglycaemia with levels of glycated haemoglobin (haemoglobin A(1C)) achieved during therapy.DesignPost hoc epidemiological analysis of a double 2x2 factorial, randomised, controlled trial.SettingDiabetes clinics, research clinics, and primary care clinics.Participants10 209 of the 10 251 participants enrolled in the ACCORD study with type 2 diabetes, a haemoglobin A(1C) concentration of 7.5% or more during screening, and aged 40-79 years with established cardiovascular disease or 55-79 years with evidence of significant atherosclerosis, albuminuria, left ventricular hypertrophy, or two or more additional risk factors for cardiovascular disease (dyslipidaemia, hypertension, current smoker, or obese). Interventions Intensive (haemoglobin A(1C) <6.0%) or standard (haemoglobin A(1C) 7.0-7.9%) glucose control.Main outcome measuresSevere hypoglycaemia was defined as episodes of "low blood glucose" requiring the assistance of another person and documentation of either a plasma glucose less than 2.8 mmol/l (<50 mg/dl) or symptoms that promptly resolved with oral carbohydrate, intravenous glucose, or glucagon.ResultsThe annual incidence of hypoglycaemia was 3.14% in the intensive treatment group and 1.03% in the standard glycaemia group. We found significantly increased risks for hypoglycaemia among women (P=0.0300), African-Americans (P<0.0001 compared with non-Hispanic whites), those with less than a high school education (P<0.0500 compared with college graduates), aged participants (P<0.0001 per 1 year increase), and those who used insulin at trial entry (P<0.0001). For every 1% unit decline in the haemoglobin A(1C) concentration from baseline to 4 month visit, there was a 28% (95% CI 19% to 37%) and 14% (4% to 23%) reduced risk of hypoglycaemia requiring medical assistance in the standard and intensive groups, respectively. In both treatment groups, the risk of hypoglycaemia requiring medical assistance increased with each 1% unit increment in the average updated haemoglobin A(1C) concentration (standard arm: hazard ratio 1.76, 95% CI 1.50 to 2.06; intensive arm: hazard ratio 1.15, 95% CI 1.02 to 1.21).ConclusionsA greater drop in haemoglobin A(1C) concentration from baseline to the 4 month visit was not associated with an increased risk for hypoglycaemia. Patients with poorer glycaemic control had a greater risk of hypoglycaemia, irrespective of treatment group. Identification of baseline subgroups with increased risk for severe hypoglycaemia can provide guidance to clinicians attempting to modify patient therapy on the basis of individual risk.Trial registrationClinicalTrials.gov number NCT00000620.

Project description:Aims/hypothesisSeveral pathophysiological mechanisms would suggest a causal link between hypoglycaemia and cardiovascular death; conversely, current knowledge would not support a causal relationship with other causes of death. To clarify the nature and the magnitude of the association between hypoglycaemia and death, we investigated the 5 year mortality risks for cardiovascular disease, cancer and other causes in individuals with type 2 diabetes admitted to hospital for a severe hypoglycaemic episode.MethodsWe defined in the UK Clinical Practice Research Datalink database a prevalent cohort of adults with type 2 diabetes diagnosed between 1 January 1998 and 1 January 2011 (index date), with available linkage to the Office for National Statistics (ONS) and the Hospital Episode Statistics (HES). A hospital admission reporting hypoglycaemia as the underlying cause was identified before the index date in the HES; date and underlying cause of death were obtained from the ONS. We quantified the 5 year risk of cause-specific death in people with and without admission to hospital for severe hypoglycaemia, adjusting for potential confounders and accounting for competing risk.ResultsOf the 74,610 subjects included in the cohort, 388 (0.5%) were admitted at least once for a severe hypoglycaemic episode; subjects admitted were older, with higher HbA1c and a greater prevalence of multimorbidity. During a median follow-up of 7.1 years, 236 (60.8%) and 18,539 (25.0%) deaths occurred in subjects with and without a previous severe hypoglycaemia, respectively. Non-cardiovascular causes accounted for 71% of all deaths in both subjects with and without hypoglycaemia. In a 60-year-old person with severe hypoglycaemia, the 5 year absolute risk of death, adjusted for age, sex, ethnicity, systolic blood pressure, total cholesterol, HbA1c, BMI, eGFR, smoking status, alcohol consumption and deprivation (Townsend score), was 6.6%, 1.1% and 13.1% for cardiovascular, cancer and other causes, respectively, while the 5 year absolute risk difference compared with a subject without severe hypoglycaemia was 4.7% (95% CI 1.0, 8.3) for cardiovascular, -1.4% (-4.1, 1.4) for cancer and 11.1% (6.1, 16.1) for other causes of death. Results were consistent in models further adjusted for medications and comorbidities (myocardial infarction, stroke, peripheral artery disease, heart failure, atrial fibrillation, cancer), with sulfonylurea and insulin associated with increased mortality rates (from cause-specific hazard ratio of 1.06 [95% CI 0.99, 1.14] for cancer death with use of sulfonylurea to 1.42 [1.29, 1.56] for cardiovascular death with use of insulin). Results were robust to missing data.Conclusions/interpretationThe results of this study indicate severe hypoglycaemia as a marker of, rather than causally linked to, an increased risk of long-term mortality. Regardless of the nature of the association, a severe hypoglycaemic episode represents a strong negative prognostic factor in patients with type 2 diabetes. Graphical abstract.