Plasma glucose regulation and mortality in Korea: a pooled analysis of three community-based cohort studies

Abnormal Fasting Glucose Increases Risk of Unrecognized Myocardial Infarctions in an Elderly Cohort

OBJECTIVES

To investigate glucose levels as a risk factor for unrecognized myocardial infarctions (UMIs).

DESIGN

Cohort SETTING: Cardiovascular Health Study.

PARTICIPANTS

Individuals aged 65 and older with fasting glucose measurements (N=4,355; normal fasting glucose (NFG), n = 2,041; impaired fasting glucose (IFG), n = 1,706; DM: n = 608; 40% male, 84% white, mean age 72.4 ± 5.6).

MEASUREMENTS

The relationship between glucose levels and UMI was examined. Participants with prior coronary heart disease (CHD) or UMI on initial electrocardiography were excluded. Using Minnesota codes, UMI was identified according to the presence of pathological Q-waves or minor Q-waves with ST-T abnormalities. Crude and adjusted hazard ratios (HRs) were calculated. Analyses were adjusted for age, sex, body mass index (BMI), hypertension, antihypertensive and lipid-lowering medication use, total cholesterol, high-density lipoprotein cholesterol, and smoking status.

RESULTS

Over a mean follow-up of 6 years, there were 459 incident UMIs (NFG, n=202; IFG, n=183; DM, n=74). Participants with IFG were slightly more likely than those with NFG to experience a UMI (hazard ratio (HR)=1.11, 95% confidence interval (CI)=0.91-1.36, p = .30), and those with DM were more likely than those with NFG to experience a UMI (HR=1.65, 95% CI=1.25-2.13, p < .001). After adjustment HR for UMI in IFG those with IFG were no more likely than those with NFG to experience a UMI (HR=1.01, 95% CI=0.82-1.24, p = .93), whereas those with DM were more likely than those with NFG to experience a UMI (HR=1.37, 95% CI=1.02-1.81, p = .03). The 2-hour oral glucose tolerance test was not statistically significantly associated with UMI.

CONCLUSION

Fasting glucose status, particularly in the diabetic range, forecasted UMI during 6 years of follow-up in elderly adults. Further studies are needed to clarify the level of glucose at which risk is greater. J Am Geriatr Soc 67:43-49, 2019.

Increased Vascular Disease Mortality Risk in Prediabetic Korean Adults Is Mainly Attributable to Ischemic Stroke

Background and Purpose—

Prediabetes is a known risk factor for vascular diseases; however, its differential contribution to mortality risk from various vascular disease subtypes is not known.

Methods—

The subjects of the National Health Insurance Service in Korea (2002–2013) nationwide cohort were stratified into normal glucose tolerance (fasting glucose <100 mg/dL), impaired fasting glucose (IFG) stage 1 (100–109 mg/dL), IFG stage 2 (110–125 mg/dL), and diabetes mellitus groups based on the fasting glucose level. A Cox regression analysis with counting process formulation was used to assess the mortality risk for vascular disease and its subtypes—ischemic heart disease, ischemic stroke, and hemorrhagic stroke.

Results—

When adjusted for age, sex, and body mass index, IFG stage 2, but not stage 1, was associated with significantly higher all-cause mortality (hazard ratio [HR], 1.26; 95% confidence interval [CI], 1.18–1.34) and vascular disease mortality (HR, 1.27; 95% CI, 1.08–1.49) compared with normal glucose tolerance. Among the vascular disease subtypes, mortality from ischemic stroke was significantly higher (HR, 1.60; 95% CI, 1.18–2.18) in subjects with IFG stage 2 but not from ischemic heart disease and hemorrhagic stroke. The ischemic stroke mortality associated with IFG stage 2 remained significantly high when adjusted other modifiable vascular disease risk factors (HR, 1.51; 95% CI: 1.10–2.09) and medical treatments (HR, 1.75; 95% CI, 1.19–2.57).

Conclusions—

Higher IFG degree (fasting glucose, 110–125 mg/dL) was associated with increased all-cause and vascular disease mortality. The increased vascular disease mortality in IFG stage 2 was attributable to ischemic stroke, but not ischemic heart disease or hemorrhagic stroke in Korean adults.

β-Cell Function and Insulin Sensitivity in Normal Glucose-Tolerant Subjects Stratified by 1-Hour Plasma Glucose Values

AIM

This study was designed to assess β-cell function and insulin sensitivity indices among normal glucose tolerance (NGT) subjects stratified by 1-h plasma glucose (1hPG) values during an oral glucose tolerance test (OGTT).

MATERIALS AND METHODS

One hundred sixty-six NGT subjects underwent a five-point OGTT, and glucose and insulin levels were estimated. We calculated the following indices: (a) β-cell function (homeostasis assessment model-β-cell function [HOMA-β] and Insulinogenic Index [IGI]) and (b) insulin sensitivity (homeostasis assessment model-insulin resistance [HOMA-IR], Matsuda Index, and Insulin Sensitivity Index [ISI]).

RESULTS

NGT subgroups with elevated 1hPG values (i.e., 1hPG ≥143 to <155 mg/dL and 1hPG ≥155 mg/dL) did not differ from those with 1hPG <143 mg/dL by HOMA-β (P = 0.236) but had significantly lower IGIs (367 ± 239 vs. 257 ± 243 vs. 246 ± 239; P = 0.019). With respect to ISIs, HOMA-IR was not significantly different among the groups (P = 0.103). However, the Matsuda Index (11.2 ± 5.0 vs. 7.4 ± 4.8 vs. 5.5 ± 4.9; P < 0.001) and ISI (0.015 ± 0.010 vs. 0.012 ± 0.006 vs. 0.011 ± 0.011; P = 0.028) were significantly lower in subjects with elevated 1hPG values.

CONCLUSIONS

NGT subjects with elevated 1hPG levels have alterations in β-cell function and insulin sensitivity compared with those with normal 1hPG levels.

The Population-Based Risk of Need for Coronary Revascularization According to the Presence of Type 2 Diabetes Mellitus and History of Coronary Heart Disease in the Korean Population

BACKGROUND

Whether diabetic patients without a history of coronary heart disease (CHD) have the same risk of CHD events as non-diabetic patients with a history of CHD remains controversial. This study aimed to determine whether type 2 diabetes mellitus (T2DM) is a coronary heart disease (CHD) equivalent in the need for coronary revascularization procedures (RVs) in the Korean population.

METHODOLOGY/PRINCIPAL FINDINGS

We followed 2,168,698 subjects who had oral anti-diabetic drugs (OADs)-taking T2DM in 2008 and/or CHD in 2007-2008 (i.e., recent CHD). We used systematic datasets from the nationwide claims database of the Health Insurance Review and Assessment service of Korea, which is representative of the whole population of Korea, from January 2007 to December 2012. The primary study endpoint was the development of need for RVs (i.e., incident CHD) after January 2009 among three groups based on their status of T2DM and recent CHD, i.e., T2DM only, recent CHD only, and both T2DM and recent CHD. After adjustment for age and sex, patients with recent CHD only had 2.14 times the risk of incident CHD (95% CI, 2.11-2.18, P<0.001) compared with patients with T2DM only. Patients with both T2DM and recent CHD demonstrated approximately 2-fold increased risk of incident CHD compared with subjects with recent CHD only (95% CI, 1.75-1.82), while 4-fold increased risk compared with subjects with T2DM only (95% CI, 3.71-3.87). The risk of incident CHD also differed according to sex and age.

CONCLUSIONS/SIGNIFICANCE

This analysis of data from the nationwide claims database revealed that T2DM did not have a recent CHD equivalent risk in the Korean population. These results suggest that an appropriate strategy for the CHD risk stratification in diabetic patients should be adopted to manage this population.

Effect of socio-economic status on the prevalence of diabetes

PURPOSE

As Korean society has become industrialized and westernized, the prevalence of diabetes has increased rapidly. Environmental factors, especially socio-economic status (SES), may account for the increased prevalence of diabetes. We evaluated the associations between the prevalence of diabetes and SES as reflected by household income and education level.

MATERIALS AND METHODS

This study was based on data obtained from the fifth Korea National Health and Nutrition Examination Survey, conducted in 2010-2012. Diabetes referred to a fasting plasma glucose ≥126 mg/dL in the absence of known diabetes, previous diagnosis of diabetes made by a physician, and/or current use of oral hypoglycemic agents or insulin.

RESULTS

Household income and education level were inversely associated with the prevalence of diabetes among individuals aged 30 years or older. These associations were more prominent in females aged 30-64 years. According to household income, the odds ratio (OR) [95% confidence interval (CI)] for the lowest quartile group versus the highest quartile group was 4.96 (2.87-8.58). According to education level, the OR (95% CI) for the lowest quartile group versus the highest quartile group was 8.02 (4.47-14.4).

CONCLUSION

Public policies for the prevention and management of diabetes should be targeted toward people of lower SES, especially middle-aged females.