International clinical harmonization of glycated hemoglobin in Japan: From Japan Diabetes Society to National Glycohemoglobin Standardization Program values

Distribution of and factors contributing to chronic kidney disease in a middle-aged working population

OBJECTIVES

To clarify the distribution of chronic kidney disease (CKD) and the factors contributing to its development and progression in middle-aged Japanese workers/employees.

METHODS

This was a retrospective study involving 3,964 men and 2,698 women aged 35-64 years in 2009 who had been followed-up until 2003. Data on proteinuria determined with a dipstick and glomerular filtration rate estimated from serum creatinine concentration (eGFR) were collected in the annual health check-ups.

RESULTS

Proteinuria was detected in 2.9 and 1.1 % of the men and women, respectively, and total CKD was detected in 16.0 and 16.1 % of the men and women respectively. Moderate or severe CKD associated a high risk of cardiovascular diseases and end-stage kidney disease was found mostly in the male subjects [2.0 (men) vs. 0.6 % (women)]. High-risk CKD was found in 3.3 % of the men aged 55-64 years. A body mass index (BMI) of ≥30, hypertension, diabetes mellitus (DM), current smoking and some job types were independently related to the development of proteinuria, while age, BMI, hypertriglyceridemia, and job types were related to total CKD. The development of high-risk CKD was related to preceding mild CKD signs of reduced eGFR and proteinuria as well as to hypertension, DM, smoking, and job type.

CONCLUSIONS

Chronic kidney disease was found in 16 % of middle-aged workers with an equal prevalence in both sexes, while high-risk CKD was found mostly in men, of whom 3.3 % were aged 55-64 years. Obesity, hypertension, DM, smoking and some job types were related to the development and progression of CKD.

HbA1c and the risks for all-cause and cardiovascular mortality in the general Japanese population: NIPPON DATA90

OBJECTIVE

Associations between HbA1c and cardiovascular diseases (CVD) have been reported mainly in Western countries. It is not clear whether HbA1c measurements are useful for assessing CVD mortality risk in East Asian populations.

RESEARCH DESIGN AND METHODS

The risk for cardiovascular death was evaluated in a large cohort of participants selected randomly from the overall Japanese population. A total of 7,120 participants (2,962 men and 4,158 women; mean age 52.3 years) free of previous CVD were followed for 15 years. Adjusted hazard ratios (HRs) and 95% CIs among categories of HbA1c (<5.0%, 5.0-5.4%, 5.5-5.9%, 6.0-6.4%, and ≥6.5%) for participants without treatment for diabetes and HRs for participants with diabetes were calculated using a Cox proportional hazards model.

RESULTS

During the study, there were 1,104 deaths, including 304 from CVD, 61 from coronary heart disease, and 127 from stroke (78 from cerebral infarction, 25 from cerebral hemorrhage, and 24 from unclassified stroke). Relations to HbA1c with all-cause mortality and CVD death were graded and continuous, and multivariate-adjusted HRs for CVD death in participants with HbA1c 6.0-6.4% and ≥6.5% were 2.18 (95% CI 1.22-3.87) and 2.75 (1.43-5.28), respectively, compared with participants with HbA1c <5.0%. Similar associations were observed between HbA1c and death from coronary heart disease and death from cerebral infarction.

CONCLUSIONS

High HbA1c levels were associated with increased risk for all-cause mortality and death from CVD, coronary heart disease, and cerebral infarction in general East Asian populations, as in Western populations.

Accurate method to estimate insulin resistance from multiple regression models using data of metabolic syndrome and oral glucose tolerance test

Aims/Introduction

How to measure insulin resistance (IR) accurately and conveniently is a critical issue for both clinical practice and research. In the present study, we tried to modify the β‐cell function, insulin sensitivity, and glucose tolerance test (BIGTT) in patients with normal glucose tolerance (NGT) and abnormal glucose tolerance (AGT) by oral glucose tolerance test (OGTT) and metabolic syndrome (MetS) components.

Materials and Methods

There were 327 participants enrolled and divided into NGT or AGT. Data from 75% of the participants were used to build the models, and the remaining 25% were used for external validation. Steady‐state plasma glucose (SSPG) concentration derived from the insulin suppression test was regarded as the standard measurement for IR. Five models were built from multiple regression: model 1 (MetS model with sex, age and MetS components); model 2 (simple OGTT model with sex, age, plasma glucose, and insulin concentrations at 0 and 120 min during OGTT); model 3 (full OGTT model with sex, age, and plasma glucose and insulin concentrations at 0, 30, 60, 90, 120, and 180 min during OGTT); model 4 (simple combined model): model 1 and model 2; and model 5 (full model): model 1 and 3.

Results

In general, our models had higher r² compared with surrogates derived from OGTT, such as homeostasis model assessment‐insulin resistance and quantitative insulin sensitivity check index. Among them, model 5 had the highest r² (0.505 in NGT, 0.556 in AGT, respectively).

Conclusions

Our modified BIGTT models proved to be accurate and easy methods for estimating IR, and can be used in clinical practice and research.

Degree of discrepancy between HbA1c and glycemia in variant hemoglobin is smaller when HbA1c is measured by new-type Arkray HPLC compared with old-type HPLC

OBJECTIVES

Although variant hemoglobin mainly demonstrates inappropriate HbA1c values measured by high-performance liquid chromatography (HPLC), these values differ depending on the HPLC model. In the 1990s, old-type HPLC models were replaced with new-type HPLC models which could separate stable HbA1c from labile HbA1c and modified hemoglobin. This study compared HbA1c values in subjects with variant hemoglobin measured using old-type Arkray HPLC (HA-8150) and new-type Arkray HPLC (HA-8160 or HA-8180).

DESIGN AND METHODS

This study included non-diabetic subjects with apparently low HbA1c values who had variant hemoglobins due to a β-chain heterozygous mutation. HbA1c was measured by old-type HPLC in 28 subjects with 12 variant hemoglobins (group 1) and new-type HPLC in six subjects with four variant hemoglobins (group 2). When HbA1c was measured by HPLC (HPLC-HbA1c), HbA1c measured by immunoassay (IA-HbA1c) and glycated albumin (GA) were also measured.

RESULTS

IA-HbA1c and GA did not significantly differ between both groups. However, HPLC-HbA1c in group 2 was significantly higher than that in group 1 (group 1: 2.9 ± 0.7% vs. group 2: 3.7 ± 0.2%, P = 0.006).

CONCLUSIONS

When HbA1c in subjects with variant hemoglobin is measured by new-type Arkray HPLC, the degree of discrepancy between HbA1c and glycemia is smaller compared with that measured by old-type HPLC.

The long-term coronary heart disease risk of previously obese patients with type 2 diabetes mellitus

BACKGROUND

Obesity is associated with insulin resistance, development of diabetes, and coronary heart disease. There is limited information on the contribution of previous obesity on the risk of coronary heart disease. We aimed to examine the effect of previous history of obesity on the occurrence of coronary heart disease in patients with diabetes.

METHODS

We carried out a retrospective chart analysis of 315 type 2 diabetic patients without obesity and without atherosclerotic cardiovascular events at their initial hospital visit (men/women 236/79; mean ± standard deviation; age 53.1 ± 6.6 years; maximal body mass index before enrollment (MAXBMI) 26.6 ± 3.4 kg/m2; decrease of the BMI at enrollment from MAXBMI (deltaBMI) 4.23 ± 2.62 kg/m2) to investigate the association of previous obesity (MAXBMI larger than 30 kg/m2) with the long-term incidence of cardiovascular events. Of 315 patients, forty-eight were previously obese.

RESULTS

After median follow-up of 13.9 years, 48 patients developed coronary heart disease. The Kaplan-Meier analysis exhibited that coronary heart disease occurred more frequently in previously obese patients than in subjects in the reference category (22 kg/m2 < or = MAXBMI < 25 kg/m2) and that the effect lasted proportionally over follow-up periods. Multivariate Cox regression models showed that hazard ratios and corresponding 95% confidence intervals of coronary heart disease for patients with previous obesity compared with subjects in the reference category were 2.52 and 1.15 to 5.50 (p value = 0.020) after adjustment for age, sex, smoking status, systolic blood pressure, total cholesterol and HDL cholesterol. In this cohort, deltaBMI strongly correlated with MAXBMI and also behaved as a risk factor. The hazard ratios and 95% confidence intervals by the increment of one standard deviation of deltaBMI after adjustment for age, sex, smoking status, systolic blood pressure, total cholesterol and HDL cholesterol were 1.38 and 1.08 to 1.79 (p value = 0.013).

CONCLUSIONS

Previous obesity and/or large body weight loss before admission might act as an increased risk for coronary heart disease.

Postprandial serum C-peptide to plasma glucose concentration ratio correlates with oral glucose tolerance test- and glucose clamp-based disposition indexes

OBJECTIVE

The C-peptide index (CPI), a ratio of serum C-peptide to plasma glucose levels, is a readily measured index of β-cell function. The difference in the physiological features reflected by the index measured under fasting (F-CPI) or postprandial (PP-CPI) conditions has remained unclear, however.

MATERIALS/METHODS

We investigated the relationship of the two CPIs to indexes of insulin secretion measured with an oral glucose tolerance test (OGTT) or with hyperglycemic and hyperinsulinemic-euglycemic clamp analyses as well as to disposition indexes (indexes of insulin secretion adjusted for insulin sensitivity) calculated from OGTT- or clamp-based analyses. We also examined the relationship between glucose tolerance and the clamp-based disposition index.

RESULTS

The clamp-based disposition index declined progressively from normal glucose tolerance to impaired glucose tolerance to Type 2 diabetes, and it strongly correlated with the 2-h plasma glucose level during an OGTT. For patients with Type 2 diabetes, both F-CPI and PP-CPI correlated with indexes of insulin secretion including HOMA-β, the insulinogenic index, the ratio of the area under the insulin curve to that under the glucose curve during an OGTT, the serum C-peptide level after glucagon challenge, as well as early and total insulin secretion measured with a hyperglycemic clamp. PP-CPI, but not F-CPI, was significantly correlated with clamp-based and OGTT-based disposition indexes.

CONCLUSIONS

F-CPI was correlated only with unadjusted indexes of insulin secretion, whereas PP-CPI was correlated with such indexes as well as with those adjusted for insulin sensitivity. The better clinical utility of PP-CPI might be attributable to these physiological characteristics.

Efficacy of liraglutide as a follow-up therapy after resolution of glucotoxicity with intensive insulin therapy

OBJECTIVE

To assess the utility of liraglutide, a GLP-1 receptor agonist, as additional therapy following resolution of glucotoxicity with insulin therapy.

METHODS

The subjects were 13 Japanese patients with short-duration type 2 diabetes mellitus (2.0 ± 2.1 years). At first, treatment with insulin therapy consisted of bolus insulin before each meal and basal insulin at bed time commenced to improve every preprandial glucose levels below 130 mg/dL. Then, insulin therapy was replaced with liraglutide monotherapy in case in which 50% or more self-monitoring of blood glucose (SMBG) tests revealed preprandial glucose levels of less than 130 mg/dL at least for one month. Liraglutide dosing was initiated at 0.3 mg/day and increased in weekly or biweekly increments of 0.3 mg/day, to the maximum permissible dose (in Japan) of 0.9 mg/day. The participants were treated with liraglutide for 24 weeks.

RESULTS

The average insulin therapy period was 13.2 ± 5.4 weeks, and insulin therapy significantly improved HbA1c values from 12.4% ± 1.6% to 6.8% ± 0.9% (P < 0.05). After improvement of hyperglycemia with insulin therapy and switching to liraglutide monotherapy for 24 weeks, HbA1c values remained constant (6.2% ± 1.0% at week 24) and the rates of hypoglycemic episodes significantly decreased (P < 0.05).

CONCLUSIONS

These data suggest that liraglutide is proposed as an alternative follow-up therapy subsequent to eliminate glucotoxicity with insulin therapy.

Usefulness of the insulin tolerance test in patients with type 2 diabetes receiving insulin therapy

Aims/Introduction

To establish the validity of the plasma glucose disappearance rate (KITT), derived from an insulin‐tolerance test (ITT), for evaluating the insulin sensitivity of patients with type 2 diabetes after insulin therapy.

Materials and Methods

In the first arm of the study, 19 patients with poorly controlled diabetes were treated with insulin and underwent an ITT and a euglycemic clamp test (clamp‐IR). The relationship between the insulin resistance index, as assessed by both the clamp‐IR and KITT tests, was examined. In the second arm of the study, the relationships between KITT values and various clinical parameters were investigated in 135 patients with poorly controlled diabetes, after achieving glycemic control with insulin.

Results

In study 1, a close correlation between KITT and the average glucose infusion rate during the last 30 min of the standard clamp‐IR test (M‐value) was noted (P < 0.001). In study 2, body mass index (P = 0.0011), waist circumference (P = 0.0004), visceral fat area (P = 0.0011) and the log‐transformed homeostasis model assessment of insulin resistance value (P = 0.0003) were negatively correlated with the log‐transformed KITT. High‐density lipoprotein cholesterol (P = 0.0183), low‐density lipoprotein cholesterol (P = 0.0121) and adiponectin (P = 0.0384) levels were positively correlated with the log‐transformed KITT.

Conclusions

The ITT is a valid and useful test for evaluating the insulin sensitivity of patients with diabetes, even after treatment with insulin.

Serum adiponectin levels predict the risk of coronary heart disease in Japanese patients with type 2 diabetes

AIMS/INTRODUCTION

An inverse association between adiponectin and coronary heart disease (CHD) has been found in Caucasians, but it is uncertain whether this association can be extrapolated to the East Asian population. The present study aimed to investigate whether serum adiponectin levels can predict CHD in Japanese patients with type 2 diabetes as observed in Caucasians.

MATERIALS AND METHODS

This longitudinal study included 504 patients with type 2 diabetes (342 men and 162 women) who were admitted to Sumitomo Hospital between July 2005 and December 2006. We used Cox proportional hazard analysis to estimate the hazard ratio (HR) of CHD associated with serum adiponectin levels at baseline.

RESULTS

During a median follow up of 5.7 years (2177 person-years), 40 participants had new CHD and 10 had recurrent CHD. After multivariate adjustment, the highest compared with the lowest quartile of serum adiponectin levels had a significantly reduced risk of CHD (hazard ratio [HR] 0.35; 95% confidence interval [CI] 0.13-0.94; P = 0.017). The multivariate adjusted HR for the risk of CHD according to a doubling of adiponectin at baseline was 0.61 (95% CI 0.39-0.97; P = 0.037).

CONCLUSIONS

High serum adiponectin levels are significantly associated with a lower risk of CHD in Japanese patients with type 2 diabetes. This association is independent of other well-known CHD risk factors.

Very old adults with better memory function have higher low-density lipoprotein cholesterol levels and lower triglyceride to high-density lipoprotein cholesterol ratios: KOCOA Project

We cross-sectionally examined which lipid profiles are associated with better cognitive function among those aged 80 and older, free of dementia (Clinical Dementia Rating ≤0.5), functionally independent, and community-dwelling. Our cohort consisted of 193 participants from the "Keys to Optimal Cognitive Aging (KOCOA) Project", a prospective cohort study in Okinawa, Japan. Higher low-density lipoprotein cholesterol levels and lower triglyceride/high-density lipoprotein cholesterol (TG/HDL-C) ratios were associated with higher scores in memory performance after controlling for confounders. Further research is required to clarify the associations among LDL-C levels, TG/HDL-C ratios, and healthy cognitive aging.

Prediction of the presence of insulin resistance using general health checkup data in Japanese employees with metabolic risk factors

AIM

The aim of the current study was to develop a predictive model of insulin resistance using general health checkup data in Japanese employees with one or more metabolic risk factors.

METHODS

We used a database of 846 Japanese employees with one or more metabolic risk factors who underwent general health checkup and a 75-g oral glucose tolerance test (OGTT). Logistic regression models were developed to predict existing insulin resistance evaluated using the Matsuda index. The predictive performance of these models was assessed using the C statistic.

RESULTS

The C statistics of body mass index (BMI), waist circumference and their combined use were 0.743, 0.732 and 0.749, with no significant differences. The multivariate backward selection model, in which BMI, the levels of plasma glucose, high-density lipoprotein (HDL) cholesterol, log-transformed triglycerides and log-transformed alanine aminotransferase and hypertension under treatment remained, had a C statistic of 0.816, with a significant difference compared to the combined use of BMI and waist circumference (p＜0.01). The C statistic was not significantly reduced when the levels of log-transformed triglycerides and log-transformed alanine aminotransferase and hypertension under treatment were simultaneously excluded from the multivariate model (p=0.14). On the other hand, further exclusion of any of the remaining three variables significantly reduced the C statistic (all p＜0.01).

CONCLUSIONS

When predicting the presence of insulin resistance using general health checkup data in Japanese employees with metabolic risk factors, it is important to take into consideration the BMI and fasting plasma glucose and HDL cholesterol levels.

CD4⁺ CD45RA⁻ FoxP3high activated regulatory T cells are functionally impaired and related to residual insulin-secreting capacity in patients with type 1 diabetes

Accumulating lines of evidence have suggested that regulatory T cells (T(regs)) play a central role in T cell-mediated immune response and the development of type 1A and fulminant type 1 diabetes. CD4(+) forkhead box protein 3 (FoxP3)(+) T cells are composed of three phenotypically and functionally distinct subpopulations; CD45RA(+) FoxP3(low) resting T(regs) (r-T(regs)), CD45RA(-) FoxP3(high) activated T(regs) (a-T(regs)) and CD45RA(-) FoxP3(low) non-suppressive T cells (non-T(regs)). We aimed to clarify the frequency of these three subpopulations in CD4(+) FoxP3(+) T cells and the function of a-T(regs) with reference to subtypes of type 1 diabetes. We examined 20 patients with type 1A diabetes, 15 patients with fulminant type 1 diabetes, 20 patients with type 2 diabetes and 30 healthy control subjects. A flow cytometric analysis in the peripheral blood was performed for the frequency analysis. The suppressive function of a-T(regs) was assessed by their ability to suppress the proliferation of responder cells in a 1/2:1 co-culture. A flow cytometric analysis in the peripheral blood demonstrated that the frequency of a-T(regs) was significantly higher in type 1A diabetes, but not in fulminant type 1 diabetes, than the controls. Further, the proportion of a-T(regs) among CD4(+) FoxP3(+) T cells was significantly higher in patients with type 1A diabetes with detectable C-peptide but not in patients with type 1A diabetes without it and with fulminant type 1 diabetes. A proliferation suppression assay showed that a-T(regs) were functionally impaired both in fulminant type 1 diabetes and in type 1A diabetes. In conclusion, a-T(regs) were functionally impaired, related to residual insulin-secreting capacity and may be associated with the development of type 1 diabetes.

Diurnal variation of carbohydrate insulin ratio in adult type 1 diabetic patients treated with continuous subcutaneous insulin infusion

To estimate the carbohydrate‐to‐insulin ratio (CIR), a formula dividing a constant, usually 300–500, by the total daily dose (TDD) of insulin, is widely utilized. An appropriate CIR varies for each meal of the day, however. Here, we investigate diurnal variation of CIR in hospitalized Japanese type 1 diabetic patients treated with continuous subcutaneous insulin infusion. After optimization of the insulin dose, TDD and total basal insulin dose (TBD) were 34.9 ± 10.2 and 9.3 ± 2.8 units, respectively, with a percentage of TBD to TDD of 27.3 ± 6.0%. The products of CIR and TDD at breakfast, lunch and dinner were 311 ± 63, 530 ± 161, and 396 ± 63, respectively, suggesting that in the formula estimating CIR using TDD, the constant should vary for each meal of the day, and that 300, 500, and 400 are appropriate for breakfast, lunch, and dinner, respectively.

[Effect of metformin in elderly type 2 diabetes]

It has become possible in Japan to use high-dose metformin for patients with type 2 diabetes. The aim of this retrospective study was to determine the effects and safety of metformin in elderly patients with type 2 diabetes. The study subjects (98 patients who were treated with metformin) were assigned into two groups: (Ⅰ) 59 patients who were younger, aged less than 65 years, and (Ⅱ) 39 patients who were elderly, aged more than 65 years. The primary endpoint was the change in glycosylated hemoglobin A1c (HbA1c) at 12 weeks. The secondary endpoints were the safety variables, including hypoglycemic events and adverse events. Although HbA1c decreased significantly in both group Ⅰ (-0.5%) and group Ⅱ (-0.9%), the difference between the two groups in the change in HbA1c was not significant. There were no incidences of hypoglycemia or adverse events in either group. Metformin improved glycemic control in the elderly patients as well as in the non-elderly patients. It is necessary to examine what dose of metformin and serum creatinin level (Cre), eGFR is appropriate for elderly patients.

A hospital-based cross-sectional study to develop an estimation formula for 2-h post-challenge plasma glucose for screening impaired glucose tolerance

AIMS

To create and validate an estimation formula for 2-h post-challenge plasma glucose (2-hPG) as an alternative to oral glucose tolerance test (OGTT) for impaired glucose tolerance (IGT) screening.

METHODS

380 Japanese subjects (57.6% males, aged 58.5 (14.0); mean (SD) years) undergoing OGTT were included in this hospital-based cross-sectional study mainly at Kyoto University Hospital between 2000 and 2011. We determined the main predictive variables of 2-hPG from clinical variables and separated the subjects randomly into two groups: a derivation group to construct an estimation formula of 2-hPG on the basis of predictive variables and a validation group to evaluate the accuracy of the formula.

RESULTS

Fasting plasma glucose (FPG) and hemoglobin A1c (HbA1c) were highly correlated with 2-hPG measured by OGTT. Multiple linear regression analysis showed that estimated 2-hPG (e2-hPG) was calculated by the formula: e2-hPG = 1.66 × FPG (mmol/l) + 1.63 × HbA1c (%)-10.11 (R(2), coefficient of determination=60.2%). When the cut-off value was set to the diagnostic criteria of IGT, 7.8 mmol/l of e2-hPG, sensitivity, specificity, and negative predictive value (NPV) were 83.3%, 44.1%, and 74.3%, respectively. When the cut-off value was set lower (7.2 mmol/l), these values were 94.4%, 30.5%, and 85.7%, respectively. The area under the receiver operating characteristic (ROC) curve was 0.68.

CONCLUSIONS

This high-sensitive estimation formula may be a useful alternative to OGTT for IGT screening. For the levels ≤ 7.2 mmol/l, this formula may also be useful in cross-sectional study to identify people whose glucose tolerance is normal.

Impact of impaired insulin secretion and insulin resistance on the incidence of type 2 diabetes mellitus in a Japanese population: the Saku study

AIMS/HYPOTHESIS

To assess the impact of impaired insulin secretion (IIS) and insulin resistance (IR) on type 2 diabetes incidence in a Japanese population.

METHODS

This 4 year cohort study included 3,059 participants aged 30-69 without diabetes at baseline who underwent comprehensive medical check-ups between April 2006 and March 2007 at Saku Central Hospital. Based on their insulinogenic index and HOMA-IR values, participants were classified by the criteria of the Japan Diabetes Society into four categories: normal; isolated IIS (i-IIS); isolated IR (i-IR); and IIS plus IR. They were followed up until March 2011. The incidence of type 2 diabetes was determined from fasting and 2 h post-load plasma glucose concentrations and from receiving medical treatment for diabetes.

RESULTS

At baseline, 1,550 individuals (50.7%) were classified as normal, 900 (29.4%) i-IIS, 505 (16.5%) i-IR, and 104 (3.4%) IIS plus IR. During 10,553 person-years of follow-up, 219 individuals developed type 2 diabetes, with 126 (57.5%) having i-IIS at baseline. Relative to the normal group, the multivariable-adjusted HRs for type 2 diabetes in the i-IIS, i-IR and IIS plus IR groups were 8.27 (95% CI 5.33, 12.83), 4.90 (95% CI 2.94, 8.17) and 16.93 (95% CI 9.80, 29.25), respectively. The population-attributable fractions of type 2 diabetes onset due to i-IIS, i-IR, and IIS plus IR were 50.6% (95% CI 46.7%, 53.0%), 14.2% (95% CI 11.8%, 15.6%) and 12.9% (95% CI 12.3%, 13.2%), respectively.

CONCLUSIONS/INTERPRETATION

Compared with IR, IIS had a greater impact on the incidence of type 2 diabetes in a Japanese population.

Effects of weight reduction therapy on obstructive sleep apnea syndrome and arterial stiffness in patients with obesity and metabolic syndrome

AIM

Obesity and metabolic syndrome (MetS) and obstructive sleep apnea (OSA), which are often accompanied by obesity, are each independently associated with cardiovascular disease (CVD). However, the influence of OSA on arterial stiffness in obese patients remains unclear. We herein examined the relationships between the severity of OSA and CVD risk factors, including the severity of MetS and arterial stiffness, in obese patients. In addition, we evaluated the effects of weight reduction therapy on OSA and arterial stiffness.

METHODS

Among the 60 overweight or obese Japanese outpatients enrolled, 46 (76.7%) met the MetS criteria.

RESULTS

The apnea-hypopnea index (AHI) and cardio-ankle vascular index (CAVI), a new index of arterial stiffness, were significantly higher in the MetS patients than in the non-MetS patients, whereas there were no significant differences in body mass index, blood pressure or the low-density lipoprotein cholesterol level. A multivariate regression analysis revealed that waist circumference, the C-reactive protein level and CAVI were independently correlated with AHI. In addition, age, SBP, IRI and AHI were independently correlated with CAVI. Furthermore, weight reduction therapy, including diet and exercise, over a three-month period significantly decreased the AHI and CAVI values in parallel with a reduction in BMI.

CONCLUSIONS

This study demonstrated that the severity of OSA is significantly correlated with the severity of MetS and arterial stiffness in obese patients. Short-term weight reduction therapy improves not only metabolic dysfunction, but also the severity of OSA and arterial stiffness, as measured according to the CAVI. Such changes may help to prevent atherosclerosis in obese patients.

Sitagliptin added to voglibose monotherapy improves glycemic control in patients with type 2 diabetes

AIMS/INTRODUCTION

Type 2 diabetes mellitus is a progressive disease that frequently requires patients to use more than one oral antihyperglycemic agent to achieve adequate glycemic control. The present multicenter, randomized study assessed the efficacy and safety of the addition of sitagliptin to ongoing voglibose monotherapy (0.2-0.3 mg three times daily) in Japanese patients with type 2 diabetes mellitus who had inadequate glycemic control (glycated hemoglobin ≥6.9% and <10.5%).

MATERIALS AND METHODS

The present study had an initial 12-week, double-blind treatment period in which patients were randomized (1:1) to sitagliptin 50 mg/day (n = 70) or placebo (n = 63), followed by a 40-week, open-label treatment period during which all patients received sitagliptin 50 mg/day, that could have been increased to 100 mg/day for patients meeting predefined glycemic criteria.

RESULTS

After 12 weeks, treatment with sitagliptin resulted in placebo-subtracted mean changes from baseline in glycated hemoglobin (the primary end-point), fasting plasma glucose and 2-h postmeal glucose of -0.9%, -22.5 mg/dL and -51.3 mg/dL, respectively (all, P < 0.001). During the double-blind period, adverse experiences were reported with similar frequency in both treatment groups, and the occurrences of hypoglycemia and gastrointestinal adverse experiences were low. In the open-label period, sustained improvements in glycemic parameters were observed with sitagliptin treatment, and sitagliptin was generally well tolerated.

CONCLUSIONS

Sitagliptin added on to ongoing voglibose monotherapy provided significant improvements in glycemic parameters and was well tolerated in Japanese patients with type 2 diabetes mellitus who had inadequate glycemic control. This trial was registered with ClinicalTrials.gov (no. NCT00837577).

Inverse associations between light-to-moderate alcohol intake and lipid-related indices in patients with diabetes

Background

Dyslipidemia is a common complication in patients with diabetes and is involved in being prone to cardiovascular disease. The risk of coronary artery disease is known to be lower in light-to-moderate drinkers than in abstainers. The aim of this study was to clarify whether and how alcohol drinking influences the lipid-related indices, good predictors for cardiovascular disease, such as the ratio of LDL cholesterol to HDL cholesterol (LDL-C/HDL-C ratio), the ratio of triglycerides to HDL cholesterol (TG/HDL-C ratio), and the lipid accumulation product (LAP), in patients with diabetes.

Methods

The subjects were men with diabetes (n = 1477; mean age, 54.0 years) and they were divided into non-, light (< 22 g ethanol/day), moderate (≥ 22 and < 44 g ethanol/day) and heavy (≥ 44 g ethanol/day) drinkers. The relationships between alcohol intake and the lipid-related indices were investigated by the multivariate analyses with adjustment for age, smoking, regular exercise and drug therapy for diabetes.

Results

The odds ratio (OR) vs. nondrinkers for high LDL-C/HDL-C ratio tended to be lower with an increase in alcohol intake (OR with 95% confidence interval (CI): 0.80 [0.50-1.29] in light drinkers; 0.24 [0.15-0.38] in moderate drinkers and 0.10 [0.05-0.19] in heavy drinkers). Alcohol intake showed an inverse association with a high TG/HDL-C ratio (OR with 95% CI vs. nondrinkers for high TG/HDL-C ratio: 0.54 [0.36-0.80] in light drinkers; 0.73 [0.56-0.97] in moderate drinkers and 0.72 [0.53-0.98] in heavy drinkers) and a J-shaped relationship with a high LAP (OR with 95% CI vs. nondrinkers for high LAP: 0.66 [0.43-1.02] in light drinkers; 0.82 [0.61-1.10] in moderate drinkers, and 1.29 [0.95-1.77] in heavy drinkers). Similar associations between alcohol intake and the lipid indices were obtained in a covariance analysis.

Conclusions

In patients with diabetes, light-to-moderate alcohol consumption is inversely associated with lipid-related indices, and this correlates with previous findings of cardiovascular risk reduction by modest drinking in patients with diabetes.

Morningness-eveningness questionnaire score correlates with glycated hemoglobin in middle-aged male workers with type 2 diabetes mellitus

AIMS/INTRODUCTION

'Morningness' and 'eveningness' represent the sleep-wake patterns of the circadian rhythm might also affect glycemic control in patients with type 2 diabetes. The aim of this study was to examine the relationship between the morningness-eveningness trait and metabolic parameters.

MATERIALS AND METHODS

The study participants comprised 101 Japanese male workers with type 2 diabetes treated in an outpatient clinic. Blood samples were obtained, and a morningness-eveningness questionnaire (MEQ), where a high score represents morningness; and the Pittsburg Sleep Quality Index (PSQI), where the higher the score the worse the sleep quality, were carried out.

RESULTS

MEQ correlated positively with age, and high-density lipoprotein cholesterol (HDL-C), and negatively with glycated hemoglobin (HbA1c) and PSQI. Multivariate regression analysis showed that MEQ was significantly associated with HbA1c and HDL-C. In addition, we classified the study patients into three groups: 'morning type', 'neither type' and 'evening type' according to the sum of the MEQ score, and analyzed the difference between morning type (n = 32) and evening type (n = 11). We found that HbA1c, low-density lipoprotein cholesterol and PSQI of the morning type group were significantly lower than those of the evening type group.

CONCLUSIONS

The present study suggests that 'eveningness' type male Japanese workers with type 2 diabetes suffer inadequate glycemic control.

Carotid intima-media thickness and plaque in apparently healthy Japanese individuals with an estimated 10-year absolute risk of CAD death according to the Japan Atherosclerosis Society (JAS) guidelines 2012: the Shiga Epidemiological Study of Subclinical Atherosclerosis (SESSA)

AIM

To examine whether subclinical atherosclerosis of the carotid arteries is concordant with the categories in the 2012 atherosclerosis prevention guidelines proposed by the Japan Atherosclerosis Society (JAS guidelines 2012), which adopted the estimated 10-year absolute risk of coronary artery disease (CAD) death in the NIPPON DATA80 Risk Assessment Chart.

METHODS

Between 2006 and 2008, 868 Japanese men 40 to 74 years of age without a history of cardiovascular disease were randomly selected from Kusatsu City, Japan. The intima media thickness (IMT) and plaque number from the common to internal carotid arteries were investigated using ultrasonography. The absolute risk of CAD death was estimated based on the individual risk factor data, and the mean IMT and plaque number in Categories Ⅰ, Ⅱ and Ⅲ of the guidelines were examined.

RESULTS

The estimated 10-year absolute risk of CAD was directly related to the IMT (mean IMT (mean ± SD) (mm) for a 10-year absolute risk of ≥ 2.0% and ≥ 5.0%: 0.88 ± 0.18 and 0.95 ± 0.19, respectively) and the plaque number. These results are compatible with the categories described by the guidelines (mean IMT (mean ± SD) (mm) for Categories Ⅰ, Ⅱ, and Ⅲ: 0.70 ± 0.11, 0.81 ± 0.16 and 0.88 ± 0.18, respectively; mean plaque number: 0.9, 2.1 and 3, respectively). These findings were similar for Category Ⅲ participants with or without DM and CKD.

CONCLUSIONS

Subclinical atherosclerosis of the carotid arteries is concordant with the 10-year absolute risk of CAD and the categories in the JAS guidelines 2012.

Association of chronic kidney disease and cerebral small vessel disease with cognitive impairment in elderly patients with type 2 diabetes

Background/Aims

In recent years, the relationship between chronic kidney disease (CKD) and cognitive impairment has been attracting attention. Cerebral small vessel disease (SVD) is also associated with an increased risk of cognitive impairment. However, it is still unknown whether CKD markers are associated with cognitive impairment independently of SVD in elderly diabetic patients.

Methods

Seventy-nine type 2 diabetic patients (mean age, 76.0 years) were enrolled in the present study. CKD was defined as the presence of albuminuria and/or a low estimated glomerular filtration rate (eGFR <60 ml/min/1.73 m²). SVD was evaluated by the presence and severity of silent brain infarcts (SBIs) and white matter lesions (WMLs) on brain magnetic resonance imaging. Neuropsychological tests were assessed using four validated cognitive instruments.

Results

In multiple linear regression analyses, albuminuria was associated with worse modified Stroop Color Word scores (β = 0.284, p = 0.017) and low eGFR was associated with reduced Digit Symbol Substitution scores (β = −0.224, p = 0.026) after adjustment for age, sex, education years, diabetes duration, hypertension, multiple SBIs, and advanced WMLs. In contrast, there were no significant associations between CKD markers and Mini-Mental State Examination or Word Recall scores.

Conclusion

Our findings suggest that albuminuria and low eGFR are associated with frontal lobe dysfunction independently of SVD in elderly type 2 diabetic patients.

Meaning of upper limit of normal range of post-load 1-h plasma glucose level defined by oral glucose tolerance test in Japanese subjects

Aims/Introduction

To identify upper limit post‐load 1‐h plasma glucose (1‐h PG) after 75‐g oral glucose test in a Japanese population.

Materials and Methods

A total of 918 subjects were enrolled. We divided the subjects into two groups: normal 2‐h post‐load plasma glucose (2‐h PG; <140 mg/dL) and impaired 2‐h PG group (≥140 mg/dL).

Results

A total of 417 subjects had normal 2‐h PG and 501 had impaired 2‐h PG. The receiver operating characteristic (ROC) curve showed that the optimal cut‐off value of 1‐h PG was 179 mg/dL (area under ROC curve = 0.89), providing that the sensitivity, specificity, and positive and negative predictive value were 85, 79, 82 and 83%, respectively. The subjects with 1‐h PG < 179 mg/dL consisted of 0.5% diabetes and 99.5% non‐diabetes, whereas those with 1‐h PG ≥ 179 mg/dL consisted of 26.9% diabetes and 73.1% non‐diabetes (P < 0.01). Furthermore, there was a significant correlation between 1‐h PG and 2‐h PG (r² = 0.57, P < 0.01).

Conclusions

These data suggested that 179 mg/dL is the upper limit of the normal range of post‐load of 1‐h PG in a Japanese population. Thus, the subjects with 1‐h PG ≥ 179 mg/dL might be at risk of developing future diabetes. Therefore, appropriate prospective study should be carried out to test this hypothesis.

Association between alkaline phosphatase and hypertension in a rural Japanese population: the Nagasaki Islands study

BACKGROUND

Although serum alkaline phosphatase (ALP) levels have been associated with hypertension, and ALP is known as an enzyme affected by alcohol consumption, no study has been published on the associations between ALP and the risk of hypertension in relation to drinking status.

METHODS

We conducted a cross-sectional study of 2,681 participants (837 men and 1,846 women) aged 30 to 89 years undergoing a general health check-up to investigate the associations between ALP and hypertension in relation to drinking status.

RESULTS

Of the 2,681 participants, 1,549 (514 men and 1,035 women) were diagnosed with hypertension. A sex difference was observed for the relationship between ALP and hypertension. While no significant association was observed for men, the association was significantly positive for women. The multivariable adjusted odds ratio and 95% coincidence interval (CI) of hypertension per increment of 1-log ALP were 0.95 (95% CI: 0.56 to 1.59) for men and 1.57 (95% CI: 1.07 to 2.33) for women. When this analysis was restricted to nondrinkers, a significantly elevated risk of hypertension was observed for men and remained significant for women; that is, 3.32 (95% CI: 1.38 to 8.02) for men and 1.68 (95% CI: 1.11 to 2.55) for women.

CONCLUSION

ALP is associated with hypertension for both male and female nondrinkers, but not for drinkers. For analyses of associations between ALP and blood pressure, alcohol consumption should thus be considered a potential confounder.

Retrospective analysis of safety and efficacy of insulin-to-liraglutide switch in Japanese type 2 diabetes: A caution against inappropriate use in patients with reduced β-cell function

Aims/Introduction

The safety and efficacy of insulin‐to‐liraglutide switch in type 2 diabetes has not been studied adequately. Here, we retrospectively characterize clinical parameters that might predict insulin‐to‐liraglutide treatment switch without termination due to hyperglycemia, and examine the effects of switching the therapies on glycated hemoglobin (HbA_1c) and bodyweight in Japanese type 2 diabetes.

Materials and Methods

Japanese type 2 diabetes patients who underwent the switch of therapy were evaluated for their clinical data including β‐cell function‐related indices, such as increment of serum C‐peptide during glucagon stimulation test (GST‐ΔCPR). HbA_1c and bodyweight were analyzed in patients continuing with liraglutide after switching from insulin for 12 weeks.

Results

Of 147 patients, 28 failed in the switch due to hyperglycemia, nine failed because of other reasons and 110 continued with liraglutide for the 12‐week period. Patients failing in the switch due to hyperglycemia showed longer duration and higher daily insulin dose, as well as lower GST‐ΔCPR. Receiver–operating characteristic analysis showed that GST‐ΔCPR of 1.34 ng/mL is a cut‐off point for insulin‐to‐liraglutide switch without termination due to hyperglycemia. In patients continuing liraglutide for 12 weeks, the switch significantly reduced HbA_1c and bodyweight with no severe hypoglycemia, irrespective of sulfonylurea co‐administration, body mass index, duration and total daily insulin dose. The switch also significantly reduced the percentage of body fat and visceral fat areas.

Conclusions

Insulin‐to‐liraglutide switch can improve glycemic control and reduce bodyweight in Japanese type 2 diabetes patients. However, caution must be taken with the switch in patients with reduced insulin secretory capacity as predicted by GST‐ΔCPR.

Vascular complications and changes in body mass index in Japanese type 2 diabetic patients with abdominal obesity

Background

Although many Asian type 2 diabetic patients have been considered to be not obese and have low capacity of insulin secretion, the proportion of obese patients with visceral fat accumulation has increased in recent years. We found previously considerable number of Japanese non-obese subjects (body mass index (BMI) < 25 kg/m²) with visceral fat accumulation and multiple cardiovascular risk factors. The aim of the study was to investigate the difference in clinical features of type 2 diabetic patients with and without visceral fat accumulation, focusing on vascular complications and changes in BMI.

Methods

We enrolled 88 Japanese hospitalized type 2 diabetic patients. Abdominal obesity represented waist circumference (WC) of ≥85 cm for males and ≥90 cm for females (corresponding to visceral fat area of 100 cm²). Subjects were divided into two groups; with or without abdominal obesity.

Results

Hypertension, dyslipidemia and cardiovascular diseases were significantly more in the patients with abdominal obesity. The prevalence of cardiovascular disease in the non-obese patients (BMI < 25 kg/m²) with abdominal obesity were similar in obese patients (BMI ≥25 kg/m²). The mean BMI of the patients with abdominal obesity was < 25 kg/m² at 20 years of age, but reached maximum to more than 30 kg/m² in the course. Furthermore, substantial portion of the type 2 diabetic patients (52% in males and 43% in females) were not obese at 20 year-old (BMI < 25 kg/m²), but developed abdominal obesity by the time of admission.

Conclusion

These results emphasize the need to control multiple risk factors and prevent atherosclerotic disease in patients with abdominal obesity. The significant weight gain after 20 years of age in patients with abdominal obesity stresses the importance of lifestyle modification in younger generation, to prevent potential development of type 2 diabetes and future atherosclerotic cardiovascular disease.

Validity of diabetes self-reports in the Saku diabetes study

BACKGROUND

Diabetes is an important risk factor for cardiovascular disease, certain types of cancer, and death, and self-reports are one of the most convenient methods for ascertaining diabetes status. We evaluated the validity of diabetes self-reports among Japanese who participated in a health checkup.

METHODS

Self-reported diabetes was cross-sectionally compared with confirmed diabetes among 2535 participants aged 28 to 85 years in the Saku cohort study. Confirmed diabetes was defined as the presence of at least 1 of the following: fasting plasma glucose (FPG) level of 126 mg/dL or higher, 2-hour post-load glucose (2-hPG) level of 200 mg/dL or higher after a 75-gram oral glucose tolerance test, glycated hemoglobin (HbA1c) level of 6.5% or higher, or treatment with hypoglycemic medication(s).

RESULTS

Of the 251 participants with self-reported diabetes, 121 were taking hypoglycemic medication(s) and an additional 69 were classified as having diabetes. Of the 2284 participants who did not self-report diabetes, 80 were classified as having diabetes. These data yielded a sensitivity of 70.4%, a specificity of 97.3%, a positive predictive value of 75.7%, and a negative predictive value of 96.5%. The frequency of participants with undiagnosed diabetes was 3.0%. Of these, 64.2% had FPG within the normal range and were diagnosed by 2-hPG and/or HbA1c.

CONCLUSIONS

Our findings provide additional support for the use of self-reported diabetes as a measure of diabetes in epidemiologic studies performed in similar settings in Japan if biomarker-based diagnosis is difficult.

Seasonal variation in critical limb ischemia requiring endovascular therapy: an analysis of a multicenter database of Japanese patients with critical limb ischemia undergoing endovascular therapy

AIM

We investigated whether any seasonal variation is observed in the incidence, severity and prognosis of critical limb ischemia (CLI) requiring endovascular therapy.

METHODS

We analyzed a multicenter database of 1,568 consecutive CLI cases undergoing primary endovascular therapy for infrainguinal lesions between July 2004 and June 2011. The monthly incidence was assessed according to the cumulative number of cases in each month, using a simple moving average. The data were fitted to a nonlinear regression model with a cosine function. The monthly proportion of cases in each Rutherford classification among the overall CLI population was assessed using a multinomial logistic regression model. The monthly risk of major amputation was evaluated using a Cox proportional hazard regression model.

RESULTS

Significant seasonal variation was observed in the incidence of CLI (p＜0.01). It was higher in the period from winter to spring, with a peak in March, and lower in the period from summer to autumn, with a trough in September; the fold difference between the peak and trough was 2.2. The seasonal variation was more markedly observed in the cases with a more severe Rutherford class. The proportion of cases in each Rutherford class among the overall CLI population also exhibited significant seasonal variation (p＜0.01). In addition, the risk of major amputation demonstrated significant seasonal variation (p=0.03); however, the statistical significance was lost following adjustment for the Rutherford classification (p=0.10).

CONCLUSIONS

Seasonal variation is observed in the incidence and severity of CLI. The seasonality of the limb prognosis is likely explained by that of the CLI severity.

Association of automated carotid IMT measurement and HbA1c in Japanese patients with coronary artery disease

AIMS

The purpose of this study was to evaluate whether carotid IMT (cIMT) identified using automated software is associated with HbA1c in Japanese patients with coronary artery disease.

METHODS

370 consecutive patients (males 218; median age 69 years ± 11) who underwent carotid-US and first coronary angiography were prospectively analyzed. After ultrasonographic examinations were performed, the plaque score (PS) was calculated and automated IMT analysis was obtained with a dedicated algorithm. Pearson correlation analysis was performed to calculate the association between automated IMT, PS and HbA1c.

RESULTS

The mean value of cIMT was 1.00 ± 0.47 mm for the right carotid and 1.04 ± 0.49 mm for the left carotid; the average bilateral value was 1.02 ± 0.43 mm. No significant difference of cIMT was detected between men and women. We found a direct correlation between cIMT values and HbA1c (p=0.0007) whereas the plaque score did not correlate with the HbA1c values (p>0.05) CONCLUSION: The results of our study confirm that automated cIMT values and levels of HbA1c in Japanese patients with coronary artery disease are correlated whereas the plaque score does not show a statistically significant correlation.

Postprandial serum C-peptide value is the optimal index to identify patients with non-obese type 2 diabetes who require multiple daily insulin injection: Analysis of C-peptide values before and after short-term intensive insulin therapy

Aims/Introduction

Type 2 diabetes is a progressive disease characterized by a yearly decline in insulin secretion; however, no definitive evidence exists showing the relationship between decreased insulin secretion and the need for insulin treatment. To determine the optimal insulin secretory index for identifying patients with non‐obese type 2 diabetes who require multiple daily insulin injection (MDI), we evaluated various serum C‐peptide immunoreactivity (CPR) values.

Materials and Methods

We near‐normalized blood glucose with intensive insulin therapy (IIT) over a 2‐week period in 291 patients with non‐obese type 2 diabetes, based on our treatment protocol. After improving hyperglycemia, we challenged with oral hypoglycemic agent (OHA), and according to the responsiveness to OHA, patients were classified into three therapy groups: OHA alone (n = 103), basal insulin plus OHA (basal insulin‐supported oral therapy [BOT]; n = 56) and MDI (n = 132). Glucagon‐loading CPR increment (ΔCPR), fasting CPR (FCPR), CPR 2 h after breakfast (CPR2h), the ratio of FCPR to FPG (CPI), CPI 2 h after breakfast (CPI2h) and secretory unit of islets in transplantation (SUIT) were submitted for the analyses. Receiver operating characteristic (ROC) and multiple logistic analyses for these CPR indices were carried out.

Results

Many CPR values were significantly lower in the MDI group compared with the OHA alone or BOT groups. ROC and multiple logistic analyses disclosed that post‐prandial CPR indices (CPR2h and CPI2h) were the most reliable CPR markers to identify patients requiring MDI.

Conclusions

Postprandial CPR level after breakfast is the most useful index for identifying patients with non‐obese type 2 diabetes who require MDI therapy.

Effects of soybean product intake on fasting and postload hyperglycemia and type 2 diabetes in Japanese men with high body mass index: The Saku Study

AIMS/INTRODUCTION

The inverse association between soybean intake and type 2 diabetes mellitus has been reported. We investigated the effects of soybean product intake on the incidence of type 2 diabetes mellitus considering fasting and postload hyperglycemia.

MATERIALS AND METHODS

The present 4-year, cohort study included 1,738 men and 1,301 women, aged 30-69 years, without diabetes mellitus at baseline who underwent comprehensive medical check-ups between April 2006 and March 2007 at Saku Central Hospital. Participants were stratified by sex and body mass index (BMI), and further classified into three groups based on soybean product intake: group 1 (0-1 time/week), group 2 (2-3 times/week) and group 3 (four or more times per week). Participants underwent annual standard 75-g oral glucose tolerance testing during follow-up periods until March 2011. Main outcomes were incidence of fasting hyperglycemia, postload hyperglycemia and type 2 diabetes mellitus.

RESULTS

During 10,503 person-years of follow up, 204 participants developed type 2 diabetes mellitus, including 61 who developed fasting hyperglycemia and 147 who developed postload hyperglycemia. Among men with a high BMI, group 3 had significantly lower risk for the incidence of type 2 diabetes mellitus, fasting hyperglycemia and postload hyperglycemia than group 1, and multivariable-adjusted hazard ratios and 95% confidence intervals were 0.44 (0.22-0.89), 0.36 (0.15-0.96) and 0.40 (0.18-0.92), respectively. Similar results were not observed among men with low BMI or women.

CONCLUSIONS

Soybean product intake prevented fasting and postload hyperglycemia and type 2 diabetes mellitus in men with a high BMI. Further long-term observation is necessary.

Morphometric features of corneal epithelial basal cells, and their relationship with corneal nerve pathology and clinical factors in patients with type 2 diabetes

AIMS/INTRODUCTION

We compared the morphometric features of corneal epithelial basal cells between patients with type 2 diabetes mellitus and healthy controls, and analyzed the relationship of these features with corneal nerve fiber pathology and clinical factors in the patients.

MATERIALS AND METHODS

Corneal epithelial basal cells and corneal nerve fibers were visualized by corneal confocal microscopy in 75 patients with type 2 diabetes and 42 age-matched controls. Density, area and area variability of corneal epithelial basal cells, as well as the width of the intercellular space between neighboring cells, were evaluated for both groups.

RESULTS

Patients showed decreased density (P < 0.02) and area (P < 0.0001), larger area variability (P < 0.0001) and a wider intercellular space (P < 0.0001) compared with controls. Density correlated inversely with area (P < 0.0001), width of intercellular space (P < 0.03) and beading frequency (P < 0.03), whereas it correlated directly with prothrombin time (P < 0.002) and activated partial thromboplastin time (P < 0.03). Area correlated inversely with duration of diabetes (P < 0.05) and coefficient of variation of area (P < 0.01), whereas it correlated directly with beading frequency (P < 0.05). Area variability correlated inversely with area (P < 0.01) and prothrombin time (P < 0.01), whereas it correlated directly with fibrinogen level (P < 0.0001).

CONCLUSIONS

Type 2 diabetes induces morphometric changes in corneal epithelial basal cells; this seems to be related to the morbid period of diabetes, beading frequency of corneal nerve fibers and blood coagulation state.

Twenty-year trend of increasing obesity in young patients with poorly controlled type 2 diabetes at first diagnosis in urban Japan

Aims/Introduction

To investigate trends over the past 20 years for the prevalence of obesity and glycemic control in association with a patient's first hospital visit for type 2 diabetes mellitus.

Materials and Methods

This was a historical, cross‐sectional, time‐series, single‐center study carried out at Marunouchi Hospital. Data from type 2 diabetic patients who were never treated until their first hospital visit were analyzed for the following periods: 1986–1987 (group A, n = 453), 1996–1997 (group B, n = 547) and 2006–2008 (group C, n = 443). Data on each patient's body mass index (BMI), age, untreated duration and glycated hemoglobin levels were also collected.

Results

Obesity in younger patients (below age 40 years and ages 40–49 years in group C) with poor glycemic control increased over time. Patients with a BMI of <21.0 kg/m² or ≥23.0 kg/m² showed worse glycemic control than those with a BMI of 21.0–23.0 kg/m² in group C. Younger patients had worse glycemic control and shorter untreated durations in group C. A BMI ≥23.0 kg/m² was an independent risk factor for glycated hemoglobin levels ≥8.4% in group C, even after correction for sex, age, untreated duration and symptoms.

Conclusions

In recent years, glycemic control has worsened in young, obese patients in urban Japan. Obesity is rapidly increasing in younger patients, and patients with a BMI ≥23.0 kg/m² might be candidates for diabetes screening. This trial was registered with the University Medical Information Network Clinical Trials Registry (no. UMIN000005725).

Effects of lifestyle education program for type 2 diabetes patients in clinics: a cluster randomized controlled trial

BACKGROUND

The prevalence of type 2 diabetes is rising worldwide, as has been the global mean fasting plasma glucose level. This study aimed to evaluate the effectiveness of a structured individual-based lifestyle education (SILE) program to reduce the hemoglobin A1c (HbA1c) level in type 2 diabetes patients delivered by registered dietitians in primary care clinical settings.

METHODS

This was a 6-month prospective cluster randomized controlled trial in a primary care setting with randomization at the practice level. Twenty general practitioners in 20 clinics in Kanagawa prefecture, Japan, were involved. 193 adults (51% men, mean age 61.3 years) with type 2 diabetes and HbA1c ≥6.5% who received treatment in medical clinics were the participants. A SILE program was implemented through 4 sessions with trained registered dietitians during the 6-month study period. Results were compared with those of a control group who received usual care. The primary endpoint was the change in HbA1c levels at 6 months from baseline. Secondary endpoints were the changes at 6 months from baseline in fasting plasma glucose, lipid profile, blood pressure, BMI, energy, and nutrient intakes (whole day and each meal). Intention-to-treat analysis was conducted. Mixed-effects linear models were used to examine the effects of the treatment.

RESULTS

The mean change at 6 months from baseline in HbA1c was a 0.7% decrease in the intervention group (n = 100) and a 0.2% decrease in the control group (n = 93) (difference -0.5%, 95%CI: -0.2% to -0.8%, p = 0.004). After adjusting for baseline values and other factors, the difference was still significant (p = 0.003 ~ 0.011). The intervention group had a significantly greater decrease in mean energy intake at dinner compared with the control group and a greater increase in mean vegetable intake for the whole day, breakfast, and lunch as shown in crude and adjusted models. A tendency toward improvement was observed in the other secondary endpoints but the improvement was not statistically significant. These results were confirmed by several sensitivity analyses.

CONCLUSIONS

The SILE program that was provided in primary care settings for patients with type 2 diabetes resulted in greater improvement in HbA1c levels than usual diabetes care and education.

TRIAL REGISTRATION

http://UMIN000004049.

Three ileus cases associated with the use of dipeptidyl peptidase-4 inhibitors in diabetic patients

Dipeptidyl peptidase (DPP)-4 inhibitors are a new class of antidiabetic drugs that increase incretin hormone levels to enhance blood sugar level-dependent insulinotropic effects, suppress glucagon action, and reduce bowel motility. These incretin effects are ideal for blood sugar control. However, the safety profile of DPP-4 inhibitors is not yet established. Herein, we present three cases of ileus, considered to be closely related to the use of DPP-4 inhibitors, in diabetic patients. Each of the three patients exhibited some risk of a deficiency in bowel movement; the onset of ileus was within 40 days after strengthened inhibition of DPP-4. The use of a DPP-4 inhibitor could be safe, although the cases presented herein enable us to inform the scientific community to some of the potential adverse effects of the use of DPP-4 inhibitors in select populations.

Combined examination of glyceryl trinitrate-mediated vascular dilation with flow-mediated vascular dilation is essential for assessment of vascular function in type 2 diabetes

Aims/Introduction

In order to characterize the impaired vascular function in type 2 diabetes (DM) patients, we evaluated the flow‐mediated vascular dilation (FMD) with glyceryl trinitrate‐mediated vascular dilation (NMD) using ultrasonography.

Materials and Methods

A total of 111 DM patients and 42 healthy control participants were studied. The maximal dilatation of FMD and NMD (%FMD and %NMD, respectively), the beginning time (T) of dilatation after stimulation and the velocity (V) of the vascular dilatation were also measured.

Results

Among DM patients, 49% had impaired %NMD, which affects the results of %FMD. In DM patients with normal %NMD, the %FMD was also significantly lower than that in control participants, although the T and the V were not impaired. In contrast, both the T and the V were disturbed in the DM patients with low %NMD. Multiple linear regression analysis showed that %NMD was independently correlated with albuminuria. Our results indicate that the impaired FMD in DM is be affected by low NMD, and impaired endothelial function already exists even in DM patients whose vascular smooth muscle function is still retained, and also albuminuria is the clinical feature of DM with low %NMD.

Conclusions

Examination of NMD, not only FMD, should be carried out as it offers the possibility of clarifying vascular function in DM patients.

Comparison of effects of pitavastatin and atorvastatin on glucose metabolism in type 2 diabetic patients with hypercholesterolemia

AIMS/INTRODUCTION

The distinct effects of different statins on glycemic control have not been fully evaluated. In this open-label, prospective, cross-over clinical trial, we compared the effects of pitavastatin and atorvastatin on glycemic control in type 2 diabetic patients with hypercholesterolemia.

MATERIALS AND METHODS

A total of 28 Japanese type 2 diabetics with hypercholesterolemia treated with rosuvastatin (2.5 mg/day) for at least 8 weeks were recruited to this quasi-randomized cross-over study. At study entry, the patients assigned to sequence 1 received pitavastatin (2 mg/day) for 12 weeks in period 1 and atorvastatin (10 mg/day) for another 12 weeks in period 2, whereas patients assigned to sequence 2 received atorvastatin (10 mg/day) for 12 weeks in period 1 and pitavastatin (2 mg/day) for another 12 weeks in period 2. Blood samples were collected at three visits (baseline, after 12 and 24 weeks).

RESULTS

Lipid control was similar in both statins. The difference in glycated hemoglobin between pitavastatin and atorvastatin treatments was -0.18 (95% confidence interval -0.34 to -0.02; P = 0.03). Compared with atorvastatin, pitavastatin treatment significantly lowered the levels of glycoalbumin, fasting glucose and homeostasis model assessment of insulin resistance.

CONCLUSIONS

Our results showed that treatment with pitavastatin had a more favorable outcome on glycemic control in patients with type 2 diabetes compared with atorvastatin. This trial was registered with UMIN (no. 000003554).

Prediabetes and impaired lung function in asymptomatic adults

Diabetes and metabolic syndrome are associated with impaired lung function. However, it is unknown whether this is also true in prediabetes. In a cross-sectional study of 1237 asymptomatic adults, we found that diabetes and prediabetes were both significantly associated with low vital capacity, even after adjustment for relevant confounding factors.

Evaluation of a minimally invasive system for measuring glucose area under the curve during oral glucose tolerance tests: usefulness of sweat monitoring for precise measurement

AIMS

We developed a system for measuring glucose area under the curve (AUC) using minimally invasive interstitial fluid extraction technology (MIET). Sweat contamination during interstitial fluid glucose (IG) extraction affects the accuracy of glucose AUC measurement, because this technology uses extracted sodium ion levels as an internal standard. Therefore, we developed a sweat monitoring patch to reduce this effect and investigated its efficacy in volunteers undergoing oral glucose tolerance tests (OGTTs).

MATERIALS AND METHODS

Fifty diabetes mellitus inpatients and 10 healthy subjects undergoing the 75 g OGTT were included. Two sites on the forearm were pretreated with microneedle arrays, then hydrogels for interstitial fluid extraction were placed on the treated sites. Simultaneously, hydrogels for sweat monitoring were placed on untreated sites near the treated sites. Plasma glucose (PG) levels were measured every 30 min for 2 h to calculate reference AUC values. Using MIET, IG AUC was calculated from extracted glucose and sodium ion levels after attachment of the hydrogel for 2 h.

RESULTS

Good correlation between IG AUC measurements using MIET and reference AUCs measured using PG levels was confirmed over a wide AUC range (202-610 mg/h/dl) after correction for the sweat-induced error detected by the hydrogel patches on the nonpretreated skin. Strong correlation between IG AUC and peak glucose levels indicates that glucose spikes can be easily detected by this system.

CONCLUSION

We confirmed the effectiveness of a sweat monitoring patch for precise AUC measurement using MIET. This novel, easy-to-use system has potential for glucose excursion evaluation in daily clinical practice.

Comparison of annual variability in HbA1c and glycated albumin in patients with type 1 vs. type 2 diabetes mellitus

OBJECTIVE

It has been suggested that plasma glucose (PG) levels per se and long-term variations in PG levels are associated with diabetic vascular complications. Glycated albumin (GA) reflects shorter-term glycemic control, as well as postprandial PG levels, as compared to HbA1c. In this study, we hypothesized that GA more strongly reflects long-term variations in PG levels than HbA1c, and compared the variability of HbA1c and that of GA in patients with type 1 diabetes mellitus (T1DM) and type 2 diabetes mellitus (T2DM).

METHODS

This study included 8 T1DM patients and 48 T2DM patients. Over a 1-year period, HbA1c and GA were measured every month and the mean values and coefficients of variation (CV) for each patient were calculated.

RESULTS

In both T1DM and T2DM patients, the CV of GA was significantly higher than the CV of HbA1c. Both the CV of HbA1c and the CV of GA were significantly higher in the T1DM patients than in the T2DM patients.

CONCLUSION

The annual variability in GA was greater than that in HbA1c. In addition, the annual variability in HbA1c and that in GA in the T1DM patients were greater than in the T2DM patients. Our findings suggest that GA more accurately reflects long-term variations in PG levels than HbA1c.

Effects of insulin changes on quality of life and glycemic control in Japanese patients with type 2 diabetes mellitus: The insulin-changing study intending to gain patients' insights into insulin treatment with patient-reported health outcomes in actual clinical treatments (INSIGHTs) study

Aims/Introduction

Our primary objective was to assess changes in quality of life (QOL) associated with changes in insulin regimen in patients with type 2 diabetes mellitus. Secondary objectives were to assess the reasons for and patterns of changes in insulin regimen, and the effects on glycemic control.

Materials and Methods

This 12‐week, observational study included patients with type 2 diabetes mellitus (n = 625) who planned to change insulin regimen (type of insulin, injection device and/or number of injections). The primary outcome measure was a change from baseline in QOL assessed by the Insulin Therapy‐Related (ITR) QOL questionnaire. The secondary outcome measures included change from baseline in plasma glycated hemoglobin (HbA_1c) level, the reasons for and pattern of insulin regimen change, and change from baseline in QOL assessed by Diabetes Treatment Satisfaction Questionnaire (DTSQ).

Results

QOL did not worsen during the study. Improvements were seen in the ITR‐QOL ‘daily activities’ subscale score (baseline: 12.7 ± 2.3; week 12: 12.9 ± 2.3; P = 0.038, n = 568) and the DTSQ ‘perceived frequency of hyperglycemia’ subscale score (baseline: 3.4 ± 1.6; week 12: 3.0 ± 1.7; P < 0.001, n = 573). Glycemic control improved, as evidenced by decreased plasma HbA_1c levels (baseline: 8.21 ± 1.47%; week 12: 7.85 ± 1.31%; P < 0.001, n = 606).

Conclusions

It was suggested that insulin regimen changes might improve glycemic control in Japanese patients with type 2 diabetes mellitus without worsening QOL. This trial was registered with ClinicalTrials.gov (no. NCT01055808).

Defining criteria for the introduction of liraglutide using the glucagon stimulation test in patients with type 2 diabetes

Aims/Introduction

To define a set of criteria using indices of β‐cell function, including results from the glucagon stimulation test, for liraglutide introduction in patients with type 2 diabetes.

Materials and Methods

In the present retrospective cohort study, patients were included in our analysis if their β‐cell function had been evaluated with a glucagon stimulation test and a 24‐h urinary C‐peptide (U‐CPR) excretion test before switching from insulin therapy to liraglutide monotherapy. The efficacy of liraglutide was determined by the extent to which glycemic control was achieved or if glycated hemoglobin levels were maintained at <7.0% after liraglutide monotherapy for 24 weeks.

Results

Liraglutide was effective in 36 of 77 patients. In the liraglutide‐effective cases, the following parameters were higher: fasting C‐peptide (CPR0) levels, C‐peptide levels 6 min after glucagon stimulation (CPR6), the C‐peptide index (CPI; CPR0 × 100/fasting plasma glucose) and stimulated C‐peptide index (S‐CPI; CPR6 × 100/plasma glucose 6 min after glucagon stimulation). U‐CPR did not differ between liraglutide‐effective and liraglutide‐ineffective cases. Using receiver operating characteristic analysis adjusted for baseline characteristics, the independent cut‐off value for effective liraglutide introduction was 0.72 for CPI and 1.92 for S‐CPI.

Conclusions

Evaluation of β‐cell function using the glucagon stimulation test is useful for determining the efficacy of liraglutide introduction in patients with type 2 diabetes.

Diabetes mellitus and risk of dementia: A meta-analysis of prospective observational studies

AIMS/INTRODUCTION

The aim of the present study was to investigate the association between diabetes and the risk of all type dementia (ATD), Alzheimer's disease (AD) and vascular dementia (VaD).

MATERIALS AND METHODS

Prospective observational studies describing the incidence of ATD, AD and VaD in patients with diabetes mellitus were extracted from PubMed, EMBASE and other databases up to January 2012. Pooled relative risk (RR) estimates and 95% confidence intervals (CIs) were calculated using the random-effects model. Subgroup analyses and sensitivity analysis were also carried out.

RESULTS

A total of 28 studies contributed to the analysis. Pooled RR of developing ATD (n = 20) was 1.73 (1.65-1.82, I (2) = 71.2%), AD (n = 20) was 1.56 (1.41-1.73, I (2) = 9.8%) and VaD (n = 13) was 2.27 (1.94-2.66, I (2) = 0%) in patients with diabetes mellitus. Higher and medium quality studies did not show any significant difference for pooled RR for ATD, AD or VaD. Sensitivity analyses showed robustness of pooled RR among ATD, AD and VaD, showing no single study had a major impact on pooled RR.

CONCLUSIONS

The results showed a 73% increased risk of ATD, 56% increase of AD and 127% increase of VaD in diabetes patients.

Serum arylhydrocarbon receptor transactivating activity is elevated in type 2 diabetic patients with diabetic nephropathy

Aims/Introduction

Evidence is emerging that exposure to persistent organic pollutants (POPs) is a risk factor for obesity‐related diseases and for diabetes mellitus (DM). We found that POPs could be measured by a cell‐based arylhydrocarbon receptor (AhR)‐dependent reporter assay. We tested if serum AhR transactivating (AHRT) activities are a risk factor for diabetic nephropathy in people with type 2 diabetes.

Materials and Methods

We enrolled diabetic patients with normoalbuminuria (n = 36), microalbuminuria (n = 29), macroalbuminuria (n = 8) and end‐stage renal disease (n = 31). Sera were tested for their AHRT activities, which were standardized by an AhR ligand, 2,3,7,8‐tetrachlorodibenzo‐p‐dioxin (TCDD) and expressed as TCDD equivalents (TCDDeq pmol/L).

Results

Mean serum AHRT activities were higher in patients with microalbuminuria (40.1 ± 7.1 pmol/L), macroalbuminuria (37.4 ± 5.5 pmol/L) and end‐stage renal disease (59.1 ± 20.0 pmol/L) than in subjects with normoalbuminuria (12.7 ± 5.4 pmol/L; P < 0.05 for all comparisons). Serum AhR ligands showed a correlation with estimated glomerular filtration rate (eGFR; r = −0.663, P < 0.001), serum creatinine level (r = 0.635, P < 0.001), systolic blood pressure (r = 0.223, P = 0.026), glycated hemoglobim (r = 0.339, P < 0.001) and diabetic duration (r = 0.394, P < 0.001). In a multiple regression analysis, diabetic nephropathy was found to be an independent risk factor for higher AHRT activity after controlling for the confounding factors.

Conclusions

The present findings suggest serum AHRT activity, thus serum AhR ligands, is a risk factor for diabetic nephropathy. Further studies are required to clarify if an accumulation of POPs in the body is causally related to diabetic nephropathy.

Weight reduction is associated with improvement of glycemic control in Japanese men, whose hemoglobin A1C is 5.6-6.4%, with visceral fat accumulation, but not without visceral fat accumulation

Aims/Introduction

The aim of the present study was to determine whether weight reduction is associated with improvement of glycemic control in non‐obese and obese subjects with or without visceral fat accumulation, whose hemoglobin A1c (A1C) is 5.6–6.4%.

Materials and Methods

A total of 798 male subjects whose A1C levels were between 5.6% and 6.4% were divided into subgroups based on body mass index (BMI) and/or estimated visceral fat area (eVFA), and were analyzed with respect to the relationships between 1‐year changes in BMI (ΔBMI) and A1C (ΔA1C).

Results

In both the BMI ≥25 and BMI <25 groups, ΔA1C correlated positively with ΔBMI (BMI ≥25 (n = 321): r = 0.236, P < 0.0001; BMI <25 (n = 477): r = 0.095, P = 0.0387) although the r‐value was very small for the latter group. In addition, for the group with eVFA ≥100 cm² (n = 436), ΔA1C correlated positively with ΔeVFA (r = 0.150, P = 0.0017), but this correlation was not found for the eVFA <100 cm² group (n = 339, P = 0.3505). Furthermore, ΔA1C positively correlated with ΔBMI for the groups in BMI ≥25 with eVFA >100 cm² (n = 293, r = 0.256, P < 0.0001) and BMI <25 with eVFA ≥100 cm² (n = 145, r = 0.250, P = 0.0024), but not for the groups in BMI ≥25 with eVFA <100 cm² (n = 28, P = 0.6401) nor BMI <25 with eVFA <100 cm² (n = 332, P = 0.6605).

Conclusions

These results suggest that the assessment of visceral fat, rather than BMI, might be more important in identifying subjects in whom lifestyle intervention aiming at weight reduction could be effective to prevent diabetes. This trial was registered with University Hospital Medical Information Network Clinical Trials Registry (no. UMIN 000002391).

Kir6.2 E23K polymorphism is related to secondary failure of sulfonylureas in non-obese patients with type 2 diabetes

Aims/Introduction

The Kir6.2 E23K polymorphism was studied with a special reference to secondary sulfonylurea (SU) failure in non‐obese patients with type 2 diabetes.

Materials and Methods

We recruited 278 non‐obese (body mass index ≤30.0 kg/m²) Japanese patients with type 2 diabetes who had a history of SU treatment (for 11.2 ± 6.3 years) and compared the frequency of the secondary SU failure among the genotypes of the polymorphism. Genotyping of the Kir6.2 E23K was carried out by polymerase chain reaction‐restriction fragment length polymorphism.

Results

The genotype frequencies of the polymorphism were similar to those previously reported in Japanese patients with type 2 diabetes. The frequency with which patients deteriorated into secondary SU failure was significantly higher in those with the KK genotype than those with EE or EK genotypes. Among 214 patients who eventually received insulin therapy because of secondary SU failure, the period of SU treatment in those with the KK genotype was significantly shorter than those with the EE or EK genotype, although the period from diagnosis to the start of SU treatment was not significantly different.

Conclusions

These data suggest that the Kir6.2 E23K polymorphism is related to the acceleration of secondary SU failure in non‐obese Japanese patients with type 2 diabetes.

Sugar-sweetened beverage and diet soda consumption and the 7-year risk for type 2 diabetes mellitus in middle-aged Japanese men

PURPOSE

This cohort study investigated the association between sugar-sweetened beverage (SSB) and diet soda consumption and the incidence of type 2 diabetes in Japanese men.

METHODS

The participants were 2,037 employees of a factory in Japan. We measured consumption of SSB and diet soda using a self-administered diet history questionnaire. The incidence of diabetes was determined in annual medical examinations over a 7-year period. Hazard ratios (HRs) with 95 % confidence intervals (CIs) for diabetes were estimated after adjusting for age, body mass index, family history, and dietary and other lifestyle factors.

RESULTS

During the study, 170 participants developed diabetes. The crude incidence rates (/1,000 person-years) across participants who were rare/never SSB consumers, <1 serving/week, ≥ 1 serving/week and <1 serving/day, and ≥ 1 serving/day were 15.5, 12.7, 14.9, and 17.4, respectively. The multivariate-adjusted HR compared to rare/never SSB consumers was 1.35 (95 % CI 0.80-2.27) for participants who consumed ≥ 1 serving/day SSB. Diet soda consumption was significantly associated with the incident risk of diabetes (P for trend = 0.013), and multivariate-adjusted HRs compared to rare/never diet soda consumers were 1.05 (0.62-1.78) and 1.70 (1.13-2.55), respectively, for participants who consumed <1 serving/week and ≥ 1 serving/week.

CONCLUSIONS

Consumption of diet soda was significantly associated with an increased risk for diabetes in Japanese men. Diet soda is not always effective at preventing type 2 diabetes even though it is a zero-calorie drink.