Diabetes in Japan: a review of disease burden and approaches to treatment

Association of sleep duration with untreated diabetes in Japanese men

OBJECTIVE

We assessed the cross-sectional association between sleep duration and untreated diabetes in Japanese men.

METHODS

Participants included 20,744 men aged 30-64 years who first visited the general hospital in Tokyo for routine health assessments during 2003-2007. Untreated diabetes was defined as not being under diabetes treatment and fasting blood glucose of ≥126 mg/dL or hemoglobin A(1c) of ≥6.5%. Sleep duration (≤5, 6, 7, or ≥8 h) and confounders were assessed using a questionnaire. Logistic regression was used to calculate odds ratios (ORs) for diabetes after adjustment for confounders.

RESULTS

The prevalence of untreated diabetes was 3.4% in all men. The prevalence of untreated diabetes by sleep duration was as follows: ≤5 h: 3.5%; 6 h: 3.3%; 7 h: 3.2%; and ≥8 h: 5.1%. Men who reported sleeping for ≤5 h (OR: 1.52, 95% confidential interval [CI]: 1.22-1.90) and ≥8 h (OR: 1.39, 95% CI: 1.05-1.85) were significantly more likely to have untreated diabetes compared with those who reported sleeping for 7 h. In stratified analyses by obesity (body mass index ≥25.0 kg/m(2)), the association between long sleep duration (≥8 h) and untreated diabetes remained significant only in obese men.

CONCLUSION

Short sleep duration was significantly associated with untreated diabetes in both nonobese and obese men. Regarding long sleep duration, a significant association was observed in obese men only.

[Challenge of studies on the development of new Zn complexes to treat diabetes mellitus]

In recent years, people all over the world have suffered from various diseases such as cancer, myocardial infarction, osteoporosis, hypertension, and diabetes mellitus (DM). Especially, DM, well-known as one of lifestyle-related diseases, has been regarded as a serious problem, because it is difficult to fully recover. The number of patients suffering from DM in 2007 was reported to be approximately 200 million people worldwide. However, insulin preparations and synthetic therapeutics, which are clinically used treatment of DM, have been associated with problems such as physical and mental pain due to daily injections and certain severe side effects, respectively. Zn, which is an essential trace element in animals and humans and plays an important role in maintenance of their lives, has been indicated to exhibit insulin-like activity. Since the finding of insulin-like effects of Zn, several Zn complexes have been proposed as a new type of anti-diabetic therapeutics which is differ from existing medicines. In this symposium, we introduce the anti-diabetic effect, complication relieving effect, and action mechanism of bis(2-mercaptopyridine-N-oxidato)Zn complex with Zn(S(2)O(2)) coordination mode.

Comparative efficacy of vildagliptin and sitagliptin in Japanese patients with type 2 diabetes mellitus: a matching-adjusted indirect comparison of randomized trials

BACKGROUND AND OBJECTIVE

Vildagliptin and sitagliptin are oral dipeptidyl peptidase 4 inhibitors approved in Japan for the treatment of type 2 diabetes mellitus when adequate glycaemic control is not achieved with diet, exercise or sulphonylureas. The aim of this study was to compare 12-week glycaemic control with vildagliptin 50 mg twice daily versus sitagliptin 50 or 100 mg once daily in Japanese patients with type 2 diabetes.

METHODS

Randomized trials of vildagliptin or sitagliptin in Japanese patients were identified from the literature. Individual patient data were obtained for vildagliptin trials. In the absence of a head-to-head randomized trial, a matching-adjusted indirect comparison was conducted by weighting individual patients from vildagliptin trials to match average baseline characteristics published for sitagliptin trials, including age, sex, body mass index, glycosylated haemoglobin (HbA(1c)), fasting plasma glucose (FPG) and diabetes duration. After matching, HbA(1c) change from baseline to week 12, the primary endpoint in each trial, was compared between balanced populations treated with vildagliptin and sitagliptin. Separate comparisons were conducted for vildagliptin 50 mg twice daily versus sitagliptin 50 mg and 100 mg once daily.

RESULTS

Two trials of vildagliptin and three trials of sitagliptin were identified for Japanese patients. Across all included trials, a total of 264 patients were treated with vildagliptin 50 mg twice daily, 235 were treated with sitagliptin 50 mg once daily and 145 were treated with sitagliptin 100 mg once daily. Mean baseline HbA(1c) ranged from 7.4% to 7.8% per trial. Before matching, significant (p < 0.05) cross-trial differences included lower mean HbA(1c) (by 0.2-0.3%) and higher FPG (by 5-13 mg/dL) in vildagliptin trials. After matching, all baseline characteristics were balanced between treatment groups. Combining matched trials, vildagliptin 50 mg twice daily was associated with significantly greater absolute HbA(1c) reduction by 0.28% compared with sitagliptin 50 mg once daily (95% CI 0.15, 0.41; p < 0.001) and by 0.35% compared with sitagliptin 100 mg once daily (95% CI 0.07, 0.62; p = 0.013).

CONCLUSION

After adjusting for baseline differences among trials of vildagliptin and sitagliptin in Japanese patients with type 2 diabetes, vildagliptin 50 mg twice daily was associated with significantly greater HbA(1c) reduction than sitagliptin 50 mg or 100 mg once daily.

Long-term outcome of living donor liver transplantation for primary biliary cirrhosis

In living donor liver transplantation (LDLT) for primary biliary cirrhosis (PBC), the majority of donors are genetically related to their recipients, leading to concerns of an earlier recurrence of PBC and a poorer prognosis due to genetic susceptibility. Totally 81 patients who underwent LDLT for PBC were the subjects of the present study. Immunosuppressive agents consisted of tacrolimus and methylprednisolone. In the outpatient clinic, when the aspartate and alanine aminotransferase level exceeded the upper limit of the normal range, the dose of methylprednisolone was increased from 4 to 6 mg/day for several months. Blood was examined every 2 weeks for 3 months and a liver biopsy was performed when aminotransferase levels did not decrease to the upper limit of the normal range after more than 3 months. Five-year survival and recurrence rates were estimated and the prognostic factors were analyzed. The mean observation period was 6.2 years. Five years after LDLT for PBC, the biopsy-proven PBC recurrence rate was 1%. The 5-year patient survival rate was 80%. The nonrelated or blood-related donor factor and number of human leukocyte antigen matches did not correlate with prognosis. PBC recurrence rate after LDLT in our series was lower than that in previous studies.

Association between insomnia symptoms and hemoglobin A1c level in Japanese men

BACKGROUND

The evidence for an association between insomnia symptoms and blood hemoglobin A(1c) (HbA(1c)) level has been limited and inconclusive. The aim of this study was to assess whether each symptom of initial, middle, and terminal insomnia influences HbA(1c) level in Japanese men.

METHODS

This cross-sectional study examined 1,022 male workers aged 22-69 years with no history of diabetes at a Japanese company's annual health check-up in April 2010. High HbA(1c) was defined as a blood level of HbA(1c) ≥6.0%. Three types of insomnia symptoms (i.e., difficulty in initiating sleep, difficulty in maintaining sleep, and early morning awakening) from the previous month were assessed by 3 responses (i.e., lasting more than 2 weeks, sometimes, and seldom or never [reference group]).

RESULTS

The overall prevalence of high HbA(1c) was 5.2%. High HbA(1c) was positively and linearly associated with both difficulty in maintaining sleep (P for trend  = .002) and early morning awakening (P for trend  = .007). More specifically, after adjusting for potential confounding factors, high HbA(1c) was significantly associated with difficulty in maintaining sleep lasting more than 2 weeks (adjusted odds ratio, 6.79 [95% confidence interval, 1.86-24.85]) or sometimes (2.33 [1.19-4.55]). High HbA(1c) was also significantly associated with early morning awakening lasting more than 2 weeks (3.96 [1.24-12.59]).

CONCLUSION

Insomnia symptoms, particularly difficulty in maintaining sleep and early morning awakening, were found to have a close association with high HbA(1c) in a dose-response relationship.

Influence of dietary therapy appraisal on future perceived control of type 2 diabetes

We sought to elucidate the causal effect of patients’ self-appraisal of their dietary regimen on their control beliefs among adults with type 2 diabetes. Data from 176 outpatients were assessed using a two-wave cross-lagged panel model. We found that a cross-lagged path connecting dietary appraisal at baseline to perceived control at one year (β = .30, p = .003) was larger than a path connecting perceived control at baseline to dietary appraisal at one year (β = —.16, p = .07). We conclude that dietary appraisal has a feedback effect on the future perceived control of type 2 diabetes.

The cost effectiveness of rapid-acting insulin aspart compared with human insulin in type 2 diabetes patients: an analysis from the Japanese third-party payer perspective

OBJECTIVES

The Nippon Ultra-Rapid Insulin and Diabetic Complication Evaluation Study (NICE Study) (NCT00575172) was a 5-year, open-label, randomised controlled trial which compared cardiovascular outcomes in Japanese type 2 diabetes patients intensively treated with regular human insulin or insulin aspart (NovoRapid; Novo Nordisk A/S, Bagsvaerd, Denmark), a rapid-acting insulin analogue. The aim of the present analysis was to evaluate the cost effectiveness of insulin aspart versus regular human insulin from the perspective of a Japanese third-party healthcare payer.

RESEARCH DESIGN AND METHODS

A discrete event-simulation model was developed in Microsoft Excel to assess the within-trial cost effectiveness and make longer-term clinical projections in patients treated with regular human insulin or insulin aspart. In addition to severe hypoglycaemia, the model captured myocardial and cerebral infarction events and percutaneous coronary intervention and coronary artery bypass graft procedures. Within-trial mortality, incidence of severe hypoglycaemia and cardiovascular event probabilities were derived from the annual rates observed during the trial period, while post-trial outcomes were calculated using the event rates from the trial, adjusted for increasing patient age. Event costs were accounted from the healthcare payer perspective and expressed in 2008 Japanese yen (JPY), while health-related quality of life (HRQoL) was captured using event and state utilities. Future costs and clinical benefits were discounted at 3% annually. Life expectancy, quality-adjusted life expectancy, cardiovascular event rates and costs were evaluated over 5- and 10-year time horizons and sensitivity analyses were performed to assess variability in model outcomes.

RESULTS

Over 5 years of treatment, insulin aspart dominated human insulin both in incremental life expectancy and in incremental quality-adjusted life-years (QALYS). Insulin aspart was associated with a small improvement in discounted life expectancy of 0.005 years (4.688 vs. 4.684 years) and an increase of 0.023 quality-adjusted life-years (QALYs) (3.800 vs. 3.776 QALYs) when compared with regular human insulin. Insulin aspart also incurred lower costs (JPY 481,586 vs. 594,717, difference -113,131) which resulted from the decreased incidence of cardiovascular events with insulin aspart (0.013 events per patient year vs. 0.030 on regular human insulin). Breakdown of costs indicated that pharmacy costs were higher with insulin aspart (JPY 346,608 vs. 278,468), but these costs were more than offset by the reduced costs associated with cardiovascular complications and hypoglycaemia over 5 years of treatment (JPY 134,978 vs. 316,249). Sensitivity analysis showed that insulin aspart was still cost-effective in the case where only 18% of the within-trial cardiovascular and mortality benefit over regular human insulin was captured in the model (assuming a willingness-to-pay threshold of JPY 5,000,000).

LIMITATIONS

The NICE study cohort was relatively small (n = 325), meaning that caution should be exercised when calculating and interpreting the incremental cost-effectiveness ratio. Also, despite the differences in cardiovascular risk profile between the Japanese and UK populations, UKPDS-derived risk equations were used to project MI outcomes and PCI and CABG procedures and UKPDS HRQoL scores were applied to all health states. While these risk formulas and HRQoL utilities may not be directly applicable to the Japanese population, no equivalent Japanese-specific data are currently available.

CONCLUSIONS

In a Japanese type 2 diabetes population, prescribing rapid-acting insulin aspart significantly reduced cardiovascular complications over 5- and 10-year time horizons, resulting in increased quality of life and decreased costs when compared with human insulin.

Glucagon-like peptide analogues for type 2 diabetes mellitus: systematic review and meta-analysis

BACKGROUND

Glucagon-like peptide (GLP-1) analogues are a new class of drugs used in the treatment of type 2 diabetes. They are given by injection, and regulate glucose levels by stimulating glucose-dependent insulin secretion and biosynthesis, suppressing glucagon secretion, and delaying gastric emptying and promoting satiety. This systematic review aims to provide evidence on the clinical effectiveness of the GLP-1 agonists in patients not achieving satisfactory glycaemic control with one or more oral glucose lowering drugs.

METHODS

MEDLINE, EMBASE, the Cochrane Library and Web of Science were searched to find the relevant papers. We identified 28 randomised controlled trials comparing GLP-1 analogues with placebo, other glucose-lowering agents, or another GLP-1 analogue, in patients with type 2 diabetes with inadequate control on a single oral agent, or on dual therapy. Primary outcomes included HbA1c, weight change and adverse events.

RESULTS

Studies were mostly of short duration, usually 26 weeks. All GLP-1 agonists reduced HbA1c by about 1% compared to placebo. Exenatide twice daily and insulin gave similar reductions in HbA1c, but exenatide 2 mg once weekly and liraglutide 1.8 mg daily reduced it by 0.20% and 0.30% respectively more than glargine. Liraglutide 1.2 mg daily reduced HbA1c by 0.34% more than sitagliptin 100 mg daily. Exenatide and liraglutide gave similar improvements in HbA1c to sulphonylureas. Exenatide 2 mg weekly and liraglutide 1.8 mg daily reduced HbA1c by more than exenatide 10 μg twice daily and sitagliptin 100 mg daily. Exenatide 2 mg weekly reduced HbA1c by 0.3% more than pioglitazone 45 mg daily.Exenatide and liraglutide resulted in greater weight loss (from 2.3 to 5.5 kg) than active comparators. This was not due simply to nausea. Hypoglycaemia was uncommon, except when combined with a sulphonylurea. The commonest adverse events with all GLP-1 agonists were initial nausea and vomiting. The GLP-1 agonists have some effect on beta-cell function, but this is not sustained after the drug is stopped.

CONCLUSIONS

GLP-1 agonists are effective in improving glycaemic control and promoting weight loss.