Sleep duration and snoring associate with hypertension and glycaemic control in patients with diabetes

AIMS

Few studies have analysed the effect of sleep duration and snoring on hypertension and glycaemic control in patients with diabetes. This study aims to investigate the relationship of sleep duration and snoring on prevalent hypertension and glycaemic control in people with diabetes.

METHODS

In the baseline survey of the REACTION study, 56 032 patients with diabetes were categorized into four groups according to self-reported sleep duration: < 6, 6-7.9, 8-8.9 and ≥ 9 h. Snoring frequency was evaluated as 'usually', 'occasionally' or 'never'. Hypertension was assessed by systolic blood pressure, diastolic blood pressure, self-reported previous diagnosis and antihypertensive medications. 'Good' glycaemic control was defined as HbA1c < 53 mmol/mol (7.0%) and 'poor' glycaemic control as HbA1c ≥ 53 mmol/mol (7.0%).

RESULTS

Controlling for potential confounders and intermediates, sleep ≥ 9 h relative to intermediate sleep (6-7.9 h) was significantly associated with prevalent hypertension (OR: 1.25, 95% CI: 1.18-1.32) and poor glycaemic control (OR: 1.11, 95% CI: 1.05-1.18), and a U-shaped association was found between sleep duration and prevalent hypertension (P for quadratic trend = 0.019). Usually snoring was positively associated with prevalent hypertension (OR: 1.30, 95% CI: 1.23-1.37), whereas the association between snoring and poor glycaemic control was only on the borderline of statistical significance.

CONCLUSIONS

Compared with a sleep duration of 6-7.9 h, longer sleep duration was associated with a higher prevalence of hypertension and poor glycaemic control in people with diabetes. Moreover, the relationship between sleep duration and prevalent hypertension was U-shaped. These findings may propose important public health implications for diabetes management.

The proposed terminology 'A(1c)-derived average glucose' is inherently imprecise and should not be adopted

The proposed use of a more precise standard for glycated (A(1c)) and non-glycated haemoglobin would lead to an A(1c) value, when expressed as a percentage, that is lower than that currently in use. One approach advocated to address the potential confusion that would ensue is to replace 'HbA(1c)' with a new term, 'A(1c)-derived average glucose.' We review evidence from several sources suggesting that A(1c) is, in fact, inherently imprecise as a measure of average glucose, so that the proposed terminology should not be adopted.

New therapeutic approaches to non-insulin-dependent diabetes mellitus

OBJECTIVE

To review the new treatment strategies for non-insulin-dependent diabetes mellitus (NIDDM).

METHODS

Various measures aimed at either increasing insulin secretion or decreasing insulin resistance are outlined. In addition, the management of obesity in patients with diabetes is discussed.

RESULTS

Two new sulfonylureas being investigated are repaglinide, which has a rapid onset of action, rapid reversal, and potential usefulness as a preprandial treatment of NIDDM, and glimepiride, the most potent sulfonylurea on a weight basis with an efficacy similar to that for glyburide. Metformin, an orally administered biguanide hypoglycemic agent, decreases blood glucose levels by 50 to 100 mg/dL and consistently improves triglyceride levels. Another agent for NIDDM therapy is acarbose, an a-glucosidase inhibitor. This agent avidly binds to intestinal disaccharidases and limits the postprandial increase in blood glucose. Troglitazone, a member of the thiazolidinedione class of insulin sensitizers, enhances insulin action and lowers blood glucose and blood pressure levels. In overweight patients with diabetes, fenfluramine has been the most effective centrally acting weight reduction agent.

CONCLUSION

Management of patients with NIDDM has become more complicated because of the increased variety of therapeutic options available. In each patient, nonpharmacologic treatment as well as lipid-lowering, blood pressure-lowering, and glucose-lowering agents must be considered.

Use of insulin-sensitizing agents in patients with polycystic ovary syndrome

OBJECTIVE

To review the subject of polycystic ovary syndrome and the therapeutic use of insulin-sensitizing agents in patients with this endocrinopathy.

METHODS

We present background information on this disorder and summarize the pertinent published literature.

RESULTS

Polycystic ovary syndrome affects approximately 7.5% of reproductive-age women in the United States. Although specific diagnostic criteria for this condition have not been established, the presence of three major factors-chronic anovulation, hyperandrogenemia, and clinical signs of hyperandrogenism-has been proposed as essential for consideration of the diagnosis. A high ratio of serum luteinizing hormone to follicle-stimulating hormone is found in 60 to 75% of women with this syndrome. Treatment with metformin may yield heterogeneous responses in differing populations with polycystic ovary syndrome, but most studies have shown evidence of restoration of ovulatory cycling. In addition, weight loss and decreases in free and total testosterone levels have been reported. Troglitazone therapy proved somewhat less efficacious than metformin for restoring menstrual cycles and similar to metformin in producing hormonal responses. Because troglitazone is no longer available for clinical use, studies will need to be extended to other thiazolidinediones. Patients treated with another insulin sensitizer, D-chiro-inositol, have demonstrated improved insulin sensitivity, ovulatory rates, and biochemical findings.

CONCLUSION

Current evidence suggests that the use of insulin-sensitizing agents in patients with polycystic ovary syndrome not only improves their sensitivity to the effects of insulin on glucose and lipid metabolism but also ameliorates clinical and biochemical manifestations of hyperandrogenism and increases rates of ovulation. Multicenter studies with larger numbers of patients are needed.

Troglitazone: Current Therapeutic Role in Type 2 Diabetes Mellitus

OBJECTIVE

To describe the role of troglitazone in the treatment of non-insulin-dependent diabetes mellitus.

METHODS

The potential mechanisms of action of the thiazolidinediones are outlined, and studies that have been conducted in animals and in humans are reviewed.

RESULTS

Although the precise mode of action of troglitazone, a thiazolidinedione, is unknown, this agent is an insulin sensitizer that has been shown to decrease fasting insulin, fasting plasma glucose, and blood pressure levels in humans. The effect of troglitazone is progressively greater over time; in several studies, the maximal action occurred as long as 12 weeks after initiation of treatment. The usual daily dose is 200 to 600 mg, and no dosage adjustment is necessary in patients with renal insufficiency. Adverse events, including fluid retention and hepatic dysfunction, may limit the utility of troglitazone in some clinical situations.

CONCLUSION

Both in monotherapy and in combination with sulfonylureas, insulin, or metformin, troglitazone has proved to be an effective agent for the treatment of type 2 diabetes mellitus.

Insulin resistance: current concepts

Insulin sensitivity varies greatly within the general population; factors contributing to this variability include genetic pre-disposition, obesity, unfavorable body fat distribution, and lack of physical activity. Impaired insulin sensitivity may lead to impaired glucose tolerance and, even in individuals with modest insulin deficiency, to the development of type 2 diabetes mellitus. Of equal concern in patients with impaired insulin sensitivity is the development of the insulin resistance syndrome, in which hypertension, dyslipidemia, and impaired glucose tolerance form a cluster of risk factors for cardiovascular disease. Treatment of insulin resistance includes metformin and the thiazolidinedione troglitazone. Both drugs have been shown to be effective in the treatment of insulin resistance, one of the central abnormalities in type 2 diabetes mellitus. The purpose of this study was to review the current understanding of insulin resistance and its implications for the treatment of type 2 diabetes mellitus. To do this, a MEDLINE search of the clinical literature was conducted and the content analyzed.