Effect of CPAP on insulin resistance and HbA1c in men with obstructive sleep apnoea and type 2 diabetes CPAP therapy for patients with sleep apnea and type 2 diabetes mellitus improves control of blood pressure Obstructive Sleep Apnea and Type 2 Diabetes: Is There a Link? Effect of Continuous Positive Airway Pressure on Glycemic Control in Patients with Obstructive Sleep Apnea and Type 2 Diabetes. A Randomized Clinical Trial. The Effect of Treatment of Obstructive Sleep Apnea on Glycemic Control in Type 2 Diabetes. Continuous positive airway pressure increases pulsatile growth hormone secretion and circulating insulin-like growth factor-1 in a time-dependent manner in men with obstructive sleep apnea: a randomized sham-controlled study. Obstructive sleep apnea and incident type 2 diabetes.
Background : The effects of continuous positive airway pressure ( CPAP ) for obstructive sleep apnoea ( OSA ) on insulin resistance are not clear . Trials have found conflicting results and no appropriate control groups have been used . Methods : Forty-two men with known type 2 diabetes and newly diagnosed OSA ( > 10 dips/h in oxygen saturation of > 4 % ) were r and omised to receive therapeutic ( n = 20 ) or placebo CPAP ( n = 22 ) for 3 months . Baseline tests were performed and repeated after 3 months . The study was double blind . Results : Results are expressed as mean ( SD ) . CPAP  improved the Epworth sleepiness score significantly more in the therapeutic group than in the placebo group ( −6.6 ( 4.5 ) vs −2.6 ( 4.9 ) , p = 0.01 ) . The maintenance of wakefulness test improved significantly in the therapeutic group but not in the placebo group ( + 10.6 ( 13.9 ) vs −4.7 ( 11.8 ) min , p = 0.001 ) . Glycaemic control and insulin resistance did not significantly change in either the therapeutic or placebo groups : HbA1c ( −0.02 ( 1.5 ) vs + 0.1 ( 0.7 ) , p = 0.7 , 95 % CI −0.6 % to + 0.9 % ) , euglycaemic clamp ( M/I : + 1.7 ( 14.1 ) vs −5.7 ( 14.8 ) , p = 0.2 , 95 % CI −1.8 to + 0.3 l/kg/min1000 ) , HOMA-%S ( −1.5 ( 2.3 ) vs −1.1 ( 1.8 ) , p = 0.2 , 95 % CI −0.3 % to + 0.08 % ) and adiponectin ( −1.1 ( 1.2 ) vs −1.1 ( 1.3 ) , p = 0.2 , 95 % CI −0.7 to + 0.6 & mgr;g/ml ) . Body mass index , bioimpedance and anthropometric measurements were unchanged . Hours of CPAP use per night were 3.6 ( 2.8 ) in the treatment group and 3.3 ( 3.0 ) in the placebo group ( p = 0.8 ) . There was no correlation between CPAP use and the measures of glycaemic control or insulin resistance . Conclusion : Therapeutic CPAP does not significantly improve measures of glycaemic control or insulin resistance in men with type 2 diabetes and OSA Purpose Obstructive sleep apnea ( OSA ) is highly associated with type 2 diabetes mellitus ( DM ) , and treatment of OSA may have a positive impact on cardiometabolic profile . This study investigates the effects of continuous positive airway pressure ( CPAP ) treatment on glycemic control and cardiometabolic parameters in patients with diabetes . Methods Diabetic patients , who were newly diagnosed of OSA with an apnea hypopnea index ( AHI ) ≥15 and HbA1c ≥7 % , were r and omly assigned to either CPAP treatment or no treatment ( control ) for 3 months . Measurements included HbA1c , blood pressure , fasting glucose and lipids , urinary albumin , and peripheral arterial tonometry ( to assess endothelial function ) . Results Sixty-four patients ( 52 men ) were r and omized , with mean ( ±SD ) age of 55.0 ± 9.6 years , body mass index of 29.9 ± 5.3 kg/m2 , HbA1c of 8.1 ± 1.1 % , and AHI of 45.3 ± 23.2 events/h . In the intention-to-treat analysis , no significant change in HbA1c but reduction of systolic ( 10 mmHg ( −18 to −2 ) , p < 0.05 ) and diastolic ( 6 mmHg ( −11 to −1 ) , p < 0.05 ) blood pressures were found in the CPAP group compared to the control group . Excluding those with medication changes or initiated dietary program during the study period and those who dropped out , CPAP treatment decreased HbA1c ( intervention group , n = 27 ; control group , n = 26 ) by 0.4 % ( −0.7 to −0.1 ) , p = 0.027 . Conclusions In patients with type 2 DM and moderate to severe OSA , 3 months of CPAP therapy did not decrease HbA1c but lowered systolic and diastolic blood pressures . In view of a potentially limited effect size of CPAP treatment on glycemic control , sample size estimation for future r and omized controlled studies must make adequate allowance for influence from external factors of medications/diet and CPAP use Type 2 diabetes is a chronic illness that is increasing in epidemic proportions worldwide . Major factors contributing to the development of type 2 diabetes include obesity and poor lifestyle habits ( e.g. , excess dietary intake and limited physical activity ) . Despite the proven efficacy of lifestyle interventions and the use of multiple pharmacological agents , the economic and public health burden of type 2 diabetes remains substantial .  Obstructive sleep apnea ( OSA ) is a treatable sleep disorder that is pervasive among overweight and obese adults , who represent about two thirds of the U.S. population today . An ever-growing number of studies have shown that OSA is associated with insulin resistance , glucose intolerance and type 2 diabetes , independent of obesity . Evidence from animal and human models that mimic OSA provides potential mechanisms for how OSA may alter glucose metabolism . Up to 83 % of patients with type 2 diabetes suffer from unrecognized OSA and increasing severity of OSA is associated with worsening glucose control . However , it is still unclear whether OSA may lead to the development of diabetes over time . More data from large-scale longitudinal studies with rigorous assessment s of diabetes and OSA are needed . In addition , there is still controversy whether continuous positive airway pressure ( CPAP ) treatment of OSA  improves glucose metabolism . Large-scale r and omized-controlled trials of CPAP treatment of OSA with well-vali date d assessment s of insulin sensitivity and glucose tolerance are needed . These studies may reveal that OSA represents a novel , modifiable risk factor for the development of prediabetes and type 2 diabetes RATIONALE Obstructive sleep apnea ( OSA ) is a risk factor for type 2 diabetes that adversely impacts glycemic control . However , there is little evidence about the effect of continuous positive airway pressure ( CPAP ) on glycemic control in patients with diabetes . OBJECTIVES To assess the effect of CPAP on glycated hemoglobin ( HbA1c ) levels in patients with suboptimally controlled type 2 diabetes and OSA , and to identify its determinants . METHODS In a 6-month , open-label , parallel , and r and omized clinical trial , 50 patients with OSA and type 2 diabetes and two HbA1c levels equal to or exceeding 6.5 % were r and omized to CPAP ( n = 26 ) or no CPAP ( control ; n = 24 ) , while their usual medication for diabetes remained unchanged . MEASUREMENTS AND MAIN RESULTS HbA1c levels , Homeostasis Model Assessment and Qualitative Insulin Sensitivity Check Index scores , systemic biomarkers , and health-related quality of life were measured at 3 and 6 months . After 6 months , the CPAP group achieved a greater decrease in HbA1c levels compared with the control group . Insulin resistance and sensitivity measurements ( in noninsulin users ) and serum levels of IL-1β , IL-6 , and adiponectin also improved in the CPAP group compared with the control group after 6 months . In patients treated with CPAP  , mean nocturnal oxygen saturation and baseline IL-1β were independently related to the 6-month change in HbA1c levels ( r(2 ) = 0.510 , P = 0.002 ) . CONCLUSIONS Among patients with suboptimally controlled type 2 diabetes and OSA  , CPAP treatment for 6 months result ed in improved glycemic control and insulin resistance compared with results for a control group . Clinical trial registered with www . clinical trials.gov ( NCT01801150 ) RATIONALE There is uncertainty about the effects of treating obstructive sleep apnea on glycemic control in patients with type 2 diabetes . OBJECTIVES To determine whether treatment of  obstructive sleep apnea in patients with type 2 diabetes improves glycemic control . METHODS In this trial , we r and omized patients with type 2 diabetes and no previous diagnosis of obstructive sleep apnea , with a glycated hemoglobin level of 6.5 - 8.5 % , and an oxygen desaturation index of 15 or more events per hour to positive airway pressure therapy or to usual care .  MEASUREMENTS AND MAIN RESULTS A total of 416 patients met the entry criteria as determined by each site and were r and omized . Of the 298 participants who met central ly adjudicated entry criteria , no differences between the study groups were seen for change in glycated hemoglobin . Furthermore , there were no between-group differences when analyses were restricted to those with poorer baseline glycemic control , those with more severe sleep apnea , or those who were adherent to therapy . A greater fall in diastolic blood pressure occurred in the positive airway pressure group than in the usual care group ( -3.5 mm Hg vs. -1.5 mm Hg ; P = 0.07 ) . This difference was significant in those who were adherent to positive airway pressure therapy ( -4.4 mm Hg vs. -1.6 mm Hg ; P = 0.02 ) . There was a significant reduction in sleepiness in the positive airway pressure therapy group ( P < 0.0001 ) . Quality of life assessment revealed improvements in vitality , mental health , and mental component summary scores in the positive airway pressure therapy group . CONCLUSIONS This trial showed no effect of positive airway pressure therapy on glycemic control in patients with relatively well-controlled type 2 diabetes and obstructive sleep apnea . Clinical trial registered with www . clinical trials.gov ( NCT00509223 ) STUDY OBJECTIVES To assess the time-dependent effect of continuous positive airway pressure ( CPAP ) , on insulin-like growth factor-1 ( IGF-1 ) , IGF binding proteins ( IGFBPs ) and pulsatile growth hormone ( GH ) secretion . DESIGN A r and omized , double-blind , sham-controlled , parallel group study . PARTICIPANTS Sixty-five middle-aged men with moderate to severe obstructive sleep apnea . INTERVENTION Active ( n = 34 ) or sham ( n = 31 ) CPAP for 12 weeks , followed by 12 weeks of active CPAP ( n = 65 ) . MEASUREMENTS AND RESULTS Fasting morning IGF-1 , IGFBP-3 , and IGFBP-1 blood levels at 0 , 6 , 12 , and 24 weeks . Overnight GH secretion was calculated by mathematical deconvolution of serial GH measurements from serum sample s collected every 10 min ( 22:00 - 06:00 ) during simultaneous polysomnography in a subset of 18 men ( active n = 11 , sham n = 7 ) at week 12 . Active , compared with sham , CPAP  increased IGF-1 at 12 weeks ( P = 0.006 ) , but not at 6 weeks ( P = 0.44 ) . Changes in IGFBP-3 and IGFBP-1 were not different between groups at 6 or 12 weeks ( all P ≥ 0.15 ) . At week 24 , there was a further increase in IGF-1 and a decrease in IGFBP-1 in the pooled group ( P = 0.0001 and 0.046 , respectively ) . In the subset , total ( P = 0.001 ) and pulsatile ( P = 0.002 ) GH secretion , mean GH concentration ( P = 0.002 ) , mass of GH secreted per pulse ( P = 0.01 ) and pulse frequency ( P = 0.04 ) were all higher after 12 weeks of CPAP compared with sham . Basal secretion , interpulse regularity , and GH regularity were not different between groups ( all P > 0.11 ) . CONCLUSIONS Twelve weeks , but not 6 weeks , of CPAP increases IGF-1 , with a further increase after 24 weeks . Total and pulsatile GH secretion , secretory burst mass and pulse frequency are also increased by 12 weeks . CPAP improves specific elements of the GH/IGF-1 axis in a time-dependent manner . CLINICAL TRIALS REGISTRATION Australia New Zeal and Clinical Trials Network , www.anzctr.org.au , number ACTRN12608000301369 OBJECTIVES To determine whether severity of obstructive sleep apnea is associated with incident diabetes in middle-aged and older adults . METHODS A prospect i ve analysis of 1453 non-diabetic participants of both the Atherosclerosis Risk in Communities Study and the Sleep Heart Health Study ( mean age 63 years , 46 % male ) had in-home polysomnography ( 1996 - 1998 ) and was followed up for incident diabetes . Using the apnea-hypopnea index derived from home polysomnography , study participants were categorized as follows : < 5.0 ( normal ) , 5.0 - 14.9 ( mild ) , 15.0 - 29.9 ( moderate ) , and ≥30.0 events/h ( severe ) . Incident diabetes was ascertained during annual follow-up telephone calls through 2013 . RESULTS During a median follow-up of 13 years , there were 285 incident diabetes cases among the 1453 participants . Participants with severe obstructive sleep apnea  were at greater risk of incident diabetes compared to persons classified as normal after adjustment for confounders including body mass index and waist circumference ( 1.71 [ 1.08 , 2.71 ] ) . The association between severe obstructive sleep apnea and incident diabetes was similar when analyses were restricted to obese individuals . CONCLUSIONS Severe obstructive sleep apnea was associated with greater risk of incident diabetes , independent of adiposity in a community-based sample . Healthcare professionals should be cognizant of the high prevalence of OSA in the general population and the potential link to incident diabetes
Obstructive sleep apnea ( OSA ) has many serious consequences , and one of these may be the exacerbation of type 2 diabetes mellitus ( T2DM ) .
Reports on the effect of continuous positive airway pressure ( CPAP ) on glucose metabolism in people with T2DM and OSA are conflicting .
Therefore , the purpose of this review was to examine the effect of CPAP treatment on glucose metabolism by synthesizing findings from r and omized controlled trials .