Elsevier

Sleep Medicine

Volume 10, Issue 8, September 2009, Pages 887-891
Sleep Medicine

Original Article
Markers of glycemic control and insulin resistance in non-diabetic patients with Obstructive Sleep Apnea Hypopnea Syndrome: Does adherence to CPAP treatment improve glycemic control?

https://doi.org/10.1016/j.sleep.2008.10.004Get rights and content

Abstract

Background and Aim

Obstructive Sleep Apnea Hypopnea Syndrome (OSAHS) is associated with glucose dysmetabolism and insulin resistance, therefore the amelioration of breathing disturbances during sleep can allegedly modify the levels of markers of glucose regulation and insulin resistance, such as glycated hemoglobin, fasting glucose, insulin and HOMAIR. The aim of this study was to explore the association between these parameters and sleep characteristics in non-diabetic OSAHS patients, as well as the effect of 6 months CPAP therapy on these markers, according to adherence to CPAP treatment.

Methods

Euglycemic patients (n = 56; mean age ± SD: 46.07 ± 10.67 years) with newly diagnosed OSAHS were included. Glycated hemoglobin, fasting glucose, insulin levels and HOMAIR were estimated at baseline and 6 months after CPAP application. According to CPAP adherence, patients were classified as follows: group 1 (mean CPAP use  4 h/night), group 2 (mean CPAP use < 4 h/night) and group 3 (refused CPAP treatment), and comparisons of levels of the examined parameters were performed.

Results

At baseline, average SpO2 during sleep was negatively correlated with insulin levels and HOMAIR while minimum SpO2 during sleep was also negatively correlated with insulin levels. After 6 months, only group 1 patients demonstrated a significant decrease in glycated hemoglobin (p = 0.004) accompanied by a decrease in hs-CRP levels (p = 0.002). No other statistically significant change was observed.

Conclusions

Nighttime hypoxia can affect fasting insulin levels in non-diabetic OSAHS patients. Good adherence to long-term CPAP treatment can significantly reduce HbA1C levels, but has no effect on markers of insulin resistance.

Introduction

Obstructive Sleep Apnea Hypopnea Syndrome (OSAHS) is a common disorder, affecting about 4% of middle-aged men and 2% of middle-aged women [1]. OSAHS is characterized by repetitive episodes of partial or complete obstruction of the upper airway during sleep, associated with increasing respiratory efforts, with a consequent oxyhemoglobin desaturation, sleep fragmentation and daytime symptoms (most commonly excessive sleepiness) [2]. Accumulating evidence suggests that intermittent hypoxia and oxyhemoglobin desaturation, both hallmarks of OSAHS, may independently affect energy metabolism, resulting in impaired glucose and lipid metabolism [3], as well as insulin resistance and metabolic syndrome [2], [3], [4]. Additionally, OSAHS has been proposed as an independent risk factor for type 2 diabetes [4]. The association between OSAHS and insulin resistance, independently of obesity, has been emphasized in the literature. Indeed, insulin resistance, as quantified by several techniques, mainly the homeostatic model assessment (HOMAIR) [5], has been attributed to visceral obesity, a common characteristic of OSAHS patients, as well as to the increase of sympathetic activity due to sleep fragmentation and intermittent hypoxia [6], [7].

Continuous Positive Airway Pressure (CPAP) is the primary treatment for OSAHS since it eliminates upper airway collapse during sleep and improves sleep fragmentation, daytime symptoms and quality of life [2]. Moreover, it has been demonstrated that CPAP improves several serum cardiovascular risk factors [8], [9] but its efficacy on insulin sensitivity is still not clarified [10], [11], [12] in OSAHS patients. In addition, it appears that the effect of CPAP on glycated hemoglobin (HbA1C) levels of non-diabetic OSAHS patients has not been adequately studied.

Therefore, the aim of the present study was to examine the effect of adherence to CPAP therapy on the modification of levels of markers of glucose dysmetabolism (fasting glucose levels and HbA1C) and insulin resistance (HOMAIR and fasting insulin levels) after 6 months of treatment.

Section snippets

Patients

Patients with newly polysomnographically confirmed OSAHS (Apnea Hypopnea Index [AHI]  15/h) were initially recruited. All of them had presented to the Sleep Unit of “George Papanikolaou” General Hospital, Thessaloniki, Greece, reporting symptoms suggestive of sleep-related breathing disorders and had never been previously diagnosed or treated for OSAHS. The study was approved by the Ethics Committee and all participants gave their written informed consent, after being fully informed of the study

Results

Between January and December 2006, 276 patients were referred to the Sleep Unit reporting sleep-disordered breathing. Of those patients, 64 with OSAHS (i.e., AHI  15 events per hour), who filled the inclusion criteria, consented to participate in the study. Eight patients of the 64 initially recruited, were withdrawn from the study due to significant reduction of their weight (ΔBMI, ⩾5%) (n = 3), surgery in the upper airway, (n = 2), or loss from follow-up (n = 3).

The remaining 56 patients (50 males,

Discussion

The present study evaluated the effect of adherence to CPAP treatment on glucose metabolism and insulin resistance in non-diabetic patients with OSAHS. Our main finding is that effective CPAP treatment for 6 months significantly improves HbA1C but not insulin resistance. Several studies have previously reported elevated levels of markers related to metabolic syndrome in OSAHS patients [16], [17], [18], [19]. Additionally, the effect of CPAP on insulin resistance has been the subject of several

Conflicts of interest

All authors have no conflicts to disclose.

References (43)

  • M. Smurra et al.

    CPAP treatment does not affect glucose–insulin metabolism in sleep apneic patients

    Sleep Med

    (2001)
  • S.E. Musicant et al.

    Prospective evaluation of the relationship between C-reactive protein, D-dimer and progression of peripheral arterial disease

    J Vasc Surg

    (2006)
  • T. Young et al.

    The occurrence of sleep-disordered breathing among middle-aged adults

    N Engl J Med

    (1993)
  • W.T. McNicholas et al.

    Sleep apnoea as an independent risk factor for cardiovascular disease: current evidence, basic mechanisms and research priorities

    Eur Respir J

    (2007)
  • N.M. Punjabi et al.

    Sleep-disordered breathing and insulin resistance in middle-aged and overweight men

    Am J Respir Crit Care Med

    (2002)
  • D.R. Matthews et al.

    Homeostasis model assessment: insulin resistance and beta-cell function from fasting plasma glucose and insulin concentrations in man

    Diabetologia

    (1985)
  • G.V. Robinson et al.

    Circulating cardiovascular risk factors in obstructive sleep apnoea: data from randomised controlled trials

    Thorax

    (2004)
  • I.A. Harsch et al.

    Continuous positive airway pressure treatment rapidly improves insulin sensitivity in patients with obstructive sleep apnea syndrome

    Am J Respir Crit Care Med

    (2004)
  • S.R. Coughlin et al.

    Cardiovascular and metabolic effects of CPAP in obese males with OSA

    Eur Respir J

    (2007)
  • S.D. West et al.

    Effect of CPAP on insulin resistance and HbA1c in men with obstructive sleep apnoea and type 2 diabetes

    Thorax

    (2007)
  • K. Katsouyanni et al.

    Reproducibility and relative validity of an extensive semi-quantitative food frequency questionnaire using dietary records and biochemical markers among Greek schoolteachers

    Int J Epidemiol

    (1997)
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