Placebo Continuous Positive Airway Pressure Research Articles

Continuous Positive Airway Pressure Treatment in Patients with Alzheimer's Disease: A Systematic Review.

Background: Epidemiological studies have suggested a pathophysiological relationship between obstructive sleep apnea syndrome (OSAS) and Alzheimer’s disease (AD). The aim of this study is to evaluate the treatment of obstructive sleep apnea with continuous positive airway pressure (CPAP) in AD and its relationship with neurocognitive function improvement. Methods: Systematic review conducted following PRISMA’s statements. Relevant studies were searched in MEDLINE, PEDro, SCOPUS, PsycINFO, Web of Science, CINAHL and SportDicus. Original studies in which CPAP treatment was developel in AD patients have been included. Results: 5 studies, 3 RCTs (Randomized controlled trials) and 2 pilot studies. In all RCTs the CPAP intervention was six weeks; 3 weeks of therapeutic CPAP vs. 3 weeks placebo CPAP (pCPAP) followed by 3 weeks tCPAP in patients with AD and OSA. The two pilot studies conducted a follow-up in which the impact on cognitive impairment was measured. Conclusions: CPAP treatment in AD patients decreases excessive daytime sleepiness and improves sleep quality. There are indications that cognitive deterioration function measured with the Mini Mental Scale decreases or evolves to a lesser extent in Alzheimer’s patients treated with CPAP. Caregivers observe stabilization in disease progression with integration of CPAP. More research is needed on the topic presented.

Dose-dependent effects of continuous positive airway pressure for sleep apnea on weight or metabolic function: Individual patient-level clinical trial meta-analysis.

Therapeutic-continuous positive airway pressure seems to increase weight compared with placebo-continuous positive airway pressure. It is not known whether weight gain with therapeutic-continuous positive airway pressure dose is dependent or whether it causes metabolic dysfunction. Data synthesis of three randomised placebo-continuous positive airway pressure-controlled trials (2-3months) was performed to test whether there is a dose-dependent effect of continuous positive airway pressure on weight. Fasting glucose, insulin, insulin resistance (homeostatic model assessment), lipids and visceral abdominal fat were also tested to determine any effect on metabolic function. Mixed-model analysis of variance was used to quantify these effects. One-hundred and twenty-eight patients were analysed. Overall there was a small increase in weight with therapeutic-continuous positive airway pressure use compared with placebo-continuous positive airway pressure (difference: 1.17kg; 0.37-1.97, p=0.005), which was greater with high-use therapeutic-continuous positive airway pressure compared with high-use placebo-continuous positive airway pressure (1.45kg; 0.10-2.80, p=0.04). Continuous positive airway pressure use as a continuous variable was also significantly associated with weight change in continuous positive airway pressure users (0.30kghr-1 night-1 ; 0.04-0.56, p=0.001), but not in placebo users (0.04kghr-1 night-1 ; -0.22 to 0.26, p=0.76). Neither therapeutic-continuous positive airway pressure nor the dose of therapeutic-continuous positive airway pressure caused any changes to metabolic outcomes. The weight gain effects of medium-term therapeutic-continuous positive airway pressure appear modest and are not accompanied by any adverse metabolic effects.

Obstructive Sleep Apnea and Cognition in Parkinson's disease

ObjectiveObstructive sleep apnea (OSA) is very common in Parkinson's disease (PD). OSA is known to affect patients' cognition. The present study assessed whether PD patients with OSA (PD + OSA) score lower on cognitive measures than those without OSA (PD − OSA). In addition, this study evaluated whether treating the OSA with continuous positive airway pressure (CPAP) in PD + OSA patients results in an improved cognitive functioning. MethodsEighty-six patients with PD underwent an overnight polysomnography screen for OSA and were administered the Mini-Mental Status Exam (MMSE) and the Montreal Cognitive Assessment (MoCA). This resulted in 38 patients with PD + OSA who were randomly assigned to receive either therapeutic CPAP for 6 weeks (n = 19) or placebo CPAP for three weeks followed by therapeutic CPAP for three weeks (n = 19). Intervention participants completed a neurocognitive battery at baseline and 3- and 6-week time-points. ResultsPatients with PD + OSA scored significantly lower than PD − OSA on the MMSE and MoCA after controlling for age, education, and PD severity. OSA was a significant predictor of cognition (MMSE p < 0.01; MoCA p = 0.028).There were no significant changes between groups in cognition when comparing three weeks of therapeutic CPAP with 3 weeks of placebo CPAP. Comparisons between pre-treatment and 3-week post-therapeutic CPAP for the entire sample also revealed no significant changes on overall neuropsychological (NP) scores. ConclusionsFindings suggest that PD patients with OSA show worse cognitive functioning on cognitive screening measures than those without OSA. However, OSA treatment after three or six weeks of CPAP may not result in overall cognitive improvement in patients with PD.

Continuous positive airway pressure reduces blood pressure in patients with obstructive sleep apnea; a systematic review and meta-analysis with 1000 patients

Obstructive sleep apnea (OSA) may lead to the development of hypertension and therapy with continuous positive airway pressure (CPAP) can promote reduction in blood pressure. The objective of this study is to review systematically the effects of CPAP on blood pressure in patients with OSA. The search was conducted in the following databases, from their beginning until February 2013: MEDLINE, Embase, Cochrane CENTRAL, Lilacs and PEDro. In addition, a manual search was performed on references of published studies. Randomized clinical trials (RCTs) that used CPAP compared with placebo CPAP or subtherapeutic CPAP for treatment of patients with OSA and that evaluated office SBP and DBP and 24-h ambulatory blood pressure were selected. Sixteen RCTs were included among 3409 publications, totaling 1166 patients. The use of CPAP resulted in reductions in office SBP [-3.20 mmHg; 95% confidence interval (CI) -4.67 to -1.72] and DBP (-2.87 mmHg; 95% CI -5.18 to -0.55); in night-time SBP (-4.92 mmHg; 95% CI -8.70 to -1.14); in mean 24-h blood pressure (-3.56 mmHg; 95% CI -6.79 to -0.33), mean night-time blood pressure (-2.56 mmHg; 95% CI -4.43 to -0.68) and 24-h DBP (-3.46 mmHg; 95% CI -6.75 to -0.17). However, no significant change was observed in daytime SBP (-0.74 mmHg; 95% CI -3.90 to 2.41) and daytime DBP (-1.86 mmHg; 95% CI -4.55 to 0.83). Treatment with CPAP promoted significantly but small reductions in blood pressure in individuals with OSA. Further studies should be performed to evaluate the effects of long-term CPAP and the impact on cardiovascular risk.

Serum urate levels are unchanged with continuous positive airway pressure therapy for obstructive sleep apnea: a randomized controlled trial

ObjectiveHyperuricemia is associated with the presence and severity of obstructive sleep apnea (OSA). Previous work has shown that treatment of OSA with continuous positive airway pressure (CPAP) therapy reduces urinary uric acid excretion and serum urate, but there has been no previous randomized controlled investigation on the effects of CPAP therapy on serum urate; we aimed to assess this association. MethodsSerum urate was measured in samples from participants of a previously published randomized controlled trial. Samples were taken at baseline and after 3months from men with known type 2 diabetes mellitus (T2DM) and newly diagnosed OSA, randomized to receive either therapeutic (n=19) or placebo (n=19) CPAP for 3months. ResultsBoth groups were well matched at baseline, with no significant difference in age, body mass index (BMI), glycosylated hemoglobin (HbA1c), or oxygen desaturation index (ODI). There was no significant difference in therapeutic or placebo CPAP usage. There was no significant difference in urate levels between groups at baseline (362μmol/L [standard deviation {SD}, 96] vs 413μmol/L [SD, 91] [reference range, 110–428μmol/L]) or at 3months. Baseline urate did not correlate with ODI, BMI, or HbA1c. The mean change in urate at 3months did not significantly differ between treatment groups (−7.6μmol/L [SD, 35.9] vs −6.2μmol/L [SD, 46.2]) (P=.9; [95% confidence interval, −28.7 to +25.9]). ConclusionOur randomized controlled trial has shown no significant reduction in serum urate following 3months treatment with therapeutic or placebo CPAP.

CPAP and Hypertension in Nonsleepy Patients

Is continuous positive airway pressure (CPAP) therapy better than no therapy in reducing the incidence of hypertension or cardiovascular (CV) events in a cohort of nonsleepy patients with obstructive sleep apnea (OSA)? Randomized, controlled trial; no placebo CPAP used. ClinicalTrials.gov Identifier: NCT00127348. Randomization was performed using a computer generated list of random numbers in the coordinating center and results were mailed to participating centers in numbered opaque envelopes. Primary outcome was evaluated by individuals not involved in the study and who were blinded to patient allocation. Patients, investigators, and the statistician were not blinded. median 4 (interquartile range, 2.7-4.4) years. 14 academic medical centers in Spain. 725 adults (mean age 51.8 y, 14% women) who were diagnosed with OSA with apnea hypopnea index (AHI) ≥ 20 events per hour and Epworth sleepiness score (ESS) ≤ 10 were randomized. Subjects with previous CV events were excluded. However, patients with a history of hypertension were not excluded (50% of the sample were hypertensive at baseline). Patients were randomized to receive CPAP treatment or no active intervention. All participants received dietary counseling and advice about sleep hygiene. The primary outcome was the incidence of either systemic hypertension (among participants who were normotensive at baseline) or CV events (among all participants). The secondary outcome was the association between the incidence of hypertension or CV events (nonfatal myocardial infarction, nonfatal stroke, transient ischemic attack, hospitalization for unstable angina or arrhythmia, heart failure, and CV death) and the severity of OSA assessed by the AHI and oxygen saturation. The sample size was calculated assuming that the incidence of hypertension or new CV event in this population over a period of 3 years would be 10% annually; 345 patients per group were needed to detect a 60% reduction in incidence of new hypertension or CV events (90% power, 2-sided α = 0.05, assuming 10% study dropout). 83% complete (only patients who received the allocated intervention were included in analysis of primary outcome). A total of 147 patients with new hypertension and 59 cardiovascular events were identified (Table). In the CPAP group, there were 68 patients with incident hypertension and 28 CV events. Of the 357 participants in the CPAP group, 127 used CPAP < 4 hours/night (36%). In the control group, there were 79 patients with new hypertension and 31 CV events. There was no statistically significant difference between the groups in the primary outcome. TableRisk for incident hypertension or cardiovascular event In adults with moderate to severe OSA and no symptoms of daytime sleepiness, CPAP therapy did not reduce incident hypertension or CV event compared with no active therapy. Instituto de Salud Carlos III (PI 04/0165) (Fondo de Investigaciones Sanitarios, Ministerio de Sanidad y Consumo, Spain), Spanish Respiratory Society (SEPAR) (Barcelona), Resmed (Bella Vista, Australia), Air Products-Carburos Metalicos (Barcelona), Respironics (Murrysville, Pennsylvania), and Breas Medical (Madrid, Spain).

Effects of CPAP on &amp;quot;vascular&amp;quot; risk factors in patients with obstructive sleep apnea and arterial hypertension

BackgroundThe aim of this study was to assess the effects of continuous positive airway pressure (CPAP) on arterial stiffness, central blood pressure, and reflected pulse wave characteristics in patients with severe obstructive sleep apnea (OSA) and stage 2–3 arterial hypertension.MethodsForty-four patients with hypertension and severe OSA (apnea/hypopnea index > 30) received stepped dose titration of antihypertensive treatment, consisting of valsartan 160 mg + amlodipine 5–10 mg + hydrochlorothiazide 25 mg. CPAP therapy was added after 3 weeks of continuous antihypertensive treatment with BP < 140/90 mmHg or after adjusting triple treatment in patients with resistant arterial hypertension. The patients were randomized to effective CPAP (4–15 mm H2O) or placebo CPAP (pressure 4 mm H2O) for three weeks, then crossed over to the alternative treatment in a single-blind manner. Office blood pressure (BP), ambulatory BP monitoring, ambulatory arterial stiffness index (AASI), aortic BP, carotid-femoral pulse wave velocity (cfPWV), and systolic wave augmentation index were measured using a Sphygmocor® device at baseline, after antihypertensive treatment, placebo CPAP, and effective CPAP.ResultsBaseline cfPWV was above the normal range in 94% of patients. After reaching target BP, the cfPWV decreased by 1.9 ± 1.0 msec (P = 0.007). Effective CPAP achieved a further cfPWV reduction of 0.7 msec (P = 0.03). Increased arterial stiffness (pulse wave velocity > 12 msec) persisted in 35% of patients on antihypertensive treatment and effective CPAP, in 56% of patients on antihypertensive treatment alone, and in 53% of patients on placebo CPAP. Only the combination of antihypertensive treatment with effective CPAP achieved a significant reduction in augmentation index and AASI, along with a further reduction in aortic and brachial BP.ConclusionEffective CPAP for 3 weeks resulted in a significant additional decrease in office BP, ambulatory BP monitoring, central BP, and augmentation index, together with an improvement in arterial stiffness parameters, ie, cfPWV and AASI, in a group of hypertensive patients with OSA.

Erratum to McEwen et al. "Diurnal changes and levels of fibrin generation are not altered by continuous positive airway pressure (CPAP) in obstructive sleep apnoea (OSA). A randomised, placebo-controlled crossover study" (Thromb Haemost 2012; 108: 701–709)

SummaryIn the original article by McEwen BJ, Phillips CL, et al. "Diurnal changes and levels of fibrin generation are not altered by continuous positive airway pressure (CPAP) in obstructive sleep apnoea (OSA). A randomised, placebo-controlled crossover study. (Thromb Haemost 2012; 108: 701–709) the authors recently realised that a statistical analysis error has resulted in minor data errors in Table 1. They also realised that no data on the Epworth Sleepiness Score (ESS) was listed despite the table legend listing the meaning of ESS.The correct (mean ± SD) baseline data are: AHI (events/h): 37.7 ± 24.4; ODI (events/h): 30.7 ± 22.6; SaO2-T90 (%TST): 5.9 ± 10.1; Min SaO2 (%) 79.3 ± 9.8; ESS 10.2 ± 4.9.The correct (mean ± SEM) CPAP vs Placebo CPAP data are: AHI (events/h): 5.7 ± 1.7 vs 40.2 ± 5.2, p&lt;0.00001; ODI (Events/h): 4.2 ± 1.7 vs 39.6 ± 4.4, p&lt;0.00001; SaO2-T90 (%TST): 0.6 ± 0.3 vs 9.8 ± 2.3, p&lt;0.001; Min SaO2 (%) 90 ± 1.2 vs 79 ± 1.4, p&lt;0.00001; Treatment Compliance (h/night) 4.3 ± 0.4 vs 3.4 ± 0.4, p&lt;0.05; Epworth Sleepiness Score (ESS) 7.4 ± 0.8 vs 8.7 ± 0.7, p&lt;0.05.Although this new data is very similar to the original data, the authors felt it important to correct. Importantly, these errors had no influence on the main coagulation outcomes and study interpretation.

P269 CPAP Therapy Does Not Reduce Serum Uric Acid Levels in Obstructive Sleep Apnoea

Obstructive Sleep Apnoea (OSA) is associated with a high prevalence of hyperuricaemia, which occurs in up to 57% of men with severe OSA, most likely due to increased oxidative stress....

The effect of continuous positive airway pressure usage on sleepiness in obstructive sleep apnoea: real effects or expectation of benefit?

RationalePlacebo responses are complex psychobiological phenomena and often involve patient expectation of benefit. With continuous positive airway pressure (CPAP) treatment of obstructive sleep apnoea, greater hours of CPAP use are...

Impact of continuous positive airway pressure treatment on right ventricle performance in patients with obstructive sleep apnoea, assessed by three-dimensional echocardiography

Obstructive sleep apnoea (OSA) is a predictor of right ventricle (RV) impairment. However, there is scant information on the effect of OSA treatment on RV performance. We sought to evaluate the impact of OSA treatment with a continuous positive airway pressure (CPAP) device on RV volume and function, as well as on variables related to pulmonary vascular haemodynamics. Fifty-six OSA patients and 50 controls were studied. All individuals underwent three-dimensional echocardiogram (3DE) to estimate RV volumes, function, pulmonary vascular resistance, and tricuspid regurgitation velocity. A total of 30 patients with apnoea-hypopnoea index greater than 20 were randomly selected to receive placebo (n=15) or effective CPAP (n=15) for 24 weeks. They underwent 3DE examination on three different occasions: at baseline, after 12 weeks, and after 24 weeks of CPAP or placebo. Higher pulmonary vascular resistance (2.1 Wood's ± 0.5 vs. 1.8 Wood's ± 0.4), larger end-diastolic RV volume index (52.2 mL/m(2) ± 7.3 vs. 49.9 mL/m(2) ± 6.0), larger end-systolic RV volume index (18.7 mL/m(2) ± 4.3 vs. 15.4 mL/m(2) ± 3.6), and lower RV ejection fraction (64.3% ± 6.8 vs. 68.4% ± 5.9) were observed in the OSA group compared to non-OSA controls (P<0.05, all). In the effective CPAP group we observed the following changes from the baseline to the 24-week echo evaluation: (A) reduction in pulmonary vascular resistance (2.2 Wood's ± 0.3 to 1.8 Wood's ± 0.3); (B) reduction in the RV end-systolic volume index (20.3 mL/m(2) ± 4.5 to 16 mL/m(2) ± 2.1); and (C) increase in RV ejection fraction (63.0% ± 7.2 to 70.8% ± 0.9) (P<0.05 for all). Twenty-four-week treatment with CPAP improved RV performance but did not change RV structural variables.

Effects of continuous positive airway pressure on coagulability in obstructive sleep apnoea: a randomised, placebo-controlled crossover study

IntroductionObstructive sleep apnoea (OSA) is associated with increased cardiovascular risk, however the mechanisms are not well established.ObjectivesThis study aimed to determine whether treatment of OSA with nasal continuous positive airway...

Mood Predicts Response to Placebo CPAP.

Study Objectives. Continuous positive airway pressure (CPAP) therapy is efficacious for treating obstructive sleep apnea (OSA), but recent studies with placebo CPAP (CPAP administered at subtherapeutic pressure) have revealed nonspecific (or placebo) responses to CPAP treatment. This study examined baseline psychological factors associated with beneficial effects from placebo CPAP treatment. Participants. Twenty-five participants were studied with polysomnography at baseline and after treatment with placebo CPAP. Design. Participants were randomized to either CPAP treatment or placebo CPAP. Baseline mood was assessed with the Profile of Mood States (POMS). Total mood disturbance (POMS-Total) was obtained by summing the six POMS subscale scores, with Vigor weighted negatively. The dependent variable was changed in apnea-hypopnea index (ΔAHI), calculated by subtracting pre- from post-CPAP AHI. Negative values implied improvement. Hierarchical regression analysis was performed, with pre-CPAP AHI added as a covariate to control for baseline OSA severity. Results. Baseline emotional distress predicted the drop in AHI in response to placebo CPAP. Highly distressed patients showed greater placebo response, with a 34% drop (i.e., improvement) in AHI. Conclusion. These findings underscore the importance of placebo-controlled studies of CPAP treatment. Whereas such trials are routinely included in drug trials, this paper argues for their importance even in mechanical-oriented sleep interventions.

Continuous Positive Airway Pressure Reduces Postprandial Lipidemia in Obstructive Sleep Apnea

Dyslipidemia is common in Obstructive Sleep Apnea (OSA). Postprandial lipidemia (PPL) is a strong marker of cardiovascular risk. Evidence that OSA treatment improves PPL is lacking. To investigate the effect of continuous positive airway pressure (CPAP) treatment on postprandial lipidemia (PPL) in patients with obstructive sleep apnea (OSA) in the upper moderate or severe range. In this randomized, placebo-controlled crossover trial, we compared the effects of 2 months each of therapeutic and placebo CPAP on PPL. PPL was determined from the area under the 24-hour triglyceride concentration curve (TAG-AUC(24)) using seven blood samples drawn across both the wake and sleep periods. Secondary outcomes were the difference in other 24-hour lipid profiles. Thirty-eight eligible patients were randomly assigned to a treatment order and 29 patients completed the trial. CPAP reduced PPL compared with placebo with a mean TAG-AUC(24) difference of -357 mmol/L/d (95% confidence interval [CI], -687.3 to -26.8; P = 0.035). During both the CPAP and placebo studies, TAG levels peaked during both wakefulness (2:00 p.m.) and sleep (3:00 a.m.). Both peaks were lower during CPAP than placebo: 2:00 p.m., -0.49 mmol/L (95% CI, -0.74 to -0.24; P < 0.0005) and 3:00 a.m., -0.40 mmol/L (95% CI, -0.65 to -0.15; P = 0.002). Moreover, mean 24-hour total cholesterol was -0.19 mmol/L lower on CPAP (95% CI, -0.27 to -0.11; P < 0.00001). This randomized trial demonstrated that treatment of severe OSA with CPAP improves postprandial TAG and total cholesterol levels. These effects may reduce the risk for cardiovascular events. The results imply that the association between OSA and cardiovascular disease may, in part, be caused by direct effects on dyslipidemia. Clinical trial registered with the Australian and New Zealand Clinical Trials Registry at www.anzctr.org.au (ACTRN 12605000066684).

Effects of continuous positive airway pressure on fatigue and sleepiness in patients with obstructive sleep apnea: data from a randomized controlled trial.

Complaints of fatigue are frequent in patients with obstructive sleep apnea (OSA); however, the impact of continuous positive airway pressure (CPAP) on fatigue remains unclear. Fifty-nine men and women with OSA were randomly assigned to therapeutic or placebo CPAP in a double-blind fashion for a 3-week intervention period. Four outcome measures were assessed: (1) fatigue/vigor measured with the Multidimensional Fatigue Symptom Inventory--Short Form (MFSI-sf), the (2) fatigue and (3) vigor subscales of the Profile of Mood States--Short Form (POMS), and (4) the Epworth Sleepiness Scale (ESS). Data were analyzed using repeated-measures analysis of variance. Compared with patients receiving placebo CPAP, those patients treated with therapeutic CPAP showed significant reductions in the apnea-hypopnea index, as well as decreases in both measures of fatigue and increases in vigor (P values < 0.05). The beneficial effect of therapeutic treatment was most pronounced in patients with high levels of fatigue at study onset. Significant treatment effects in sleepiness scores were not observed in the entire sample (P > 0.05); however, in a subset of patients with excessive sleepiness at the onset of treatment, ESS scores were significantly reduced with use of therapeutic CPAP (P < 0.05). Results suggest that 3 weeks of therapeutic CPAP significantly reduced fatigue and increased energy in patients with OSA. Therapeutic CPAP significantly reduced daytime sleepiness in patients who reported excessive sleepiness at the onset of treatment.

Continuous positive airway pressure deepens sleep in patients with Alzheimer’s disease and obstructive sleep apnea

Objective Patients with Alzheimer’s disease (AD) and obstructive sleep apnea (OSA) experience disrupted sleep. This study examined the effect of continuous positive airway pressure (CPAP) on sleep parameters in AD patients with OSA. Methods A randomized placebo-controlled trial of 3 weeks of therapeutic CPAP (tCPAP) vs. 3 weeks placebo CPAP (pCPAP) followed by 3 weeks tCPAP in patients with AD and OSA. Polysomnography data from screening after one night and after 3 weeks of treatment were analyzed. Records were scored for percent of each sleep stage, total sleep time (TST), sleep efficiency (SE), sleep period (SP), time in bed (TIB), sleep onset (SO), wake time after sleep onset (WASO), and arousals. A randomized design comparing one night of pCPAP to tCPAP and a paired analysis combining 3 weeks of tCPAP were performed. Results Fifty-two participants (mean age = 77.8 years, SD = 7.3) with AD and OSA were included. After one treatment night, the tCPAP group had significantly less % Stage 1 ( p = 0.04) and more % Stage 2 sleep ( p = 0.02) when compared to the pCPAP group. In the paired analysis, 3 weeks of tCPAP resulted in significant decreases in WASO ( p = 0.005), % Stage 1 ( p = 0.001), arousals ( p = 0.005), and an increase in % Stage 3 ( p = 0.006). Conclusion In mild to moderate AD patients with OSA, the use of tCPAP resulted in deeper sleep after just one night, with improvements maintained for 3 weeks.

The effect of continuous positive airway pressure treatment on physical activity in patients with obstructive sleep apnoea: A randomised controlled trial

Background Continuous positive airway pressure (CPAP) improves daytime sleepiness in patients with obstructive sleep apnoea (OSA). The effect of CPAP on physical activity is unclear. We hypothesized that activity would increase after CPAP treatment. Methods A double blind, parallel, randomised, controlled trial using therapeutic and placebo CPAP was performed in men with newly diagnosed OSA (more than 10 > 4% SaO 2 dips/hour and Epworth Sleepiness Score [ESS] ⩾9). Activity was measured by wrist actigraphy before and after three months of CPAP therapy. Results Thirty-six men completed 1 week of continuous actigraphy before and after therapeutic CPAP ( n = 16) or placebo CPAP ( n = 20). The two groups were well-matched at baseline, with no significant differences in mean age, body mass index, ESS and SaO 2 dips/hour. Mean (SD) ESS and modified maintenance of wakefulness test (OSLER) improved significantly after CPAP. ESS change in the therapeutic group was −6.1 (4.4), compared to placebo, −2.8 (5.0); difference between groups p = 0.04; OSLER (minutes), therapeutic +10.4 (14.4), placebo −5.0 (12.0), p = 0.003. There was no significant difference between groups in mean hourly activity levels for the seven days at baseline; activity levels did not significantly change in either group after CPAP [daytime activity (arbitrary units): therapeutic −13.9 (93.1) vs. placebo +8.3 (62.9), p = 0.4]. There was no correlation between change in activity and CPAP use. Conclusion Activity does not increase after CPAP in men with OSA, despite improvements in daytime sleepiness. The reasons for this are not clear, but may be due to longstanding, habitual patterns of activity.

Cognitive effects of treating obstructive sleep apnea in Alzheimer's disease: a randomized controlled study.

To examine whether treatment of obstructive sleep apnea (OSA) with continuous positive airway pressure (CPAP) in patients with Alzheimer's disease (AD) results in better cognitive function. Randomized double-blind placebo-controlled trial. Participants were randomized to therapeutic CPAP for 6 weeks or placebo CPAP for 3 weeks followed by therapeutic CPAP for 3 weeks. General clinical research center. Fifty-two men and women with mild to moderate AD and OSA. CPAP. A complete neuropsychological test battery was administered before treatment and at 3 and at 6 weeks. A comparison of subjects randomized to 3 weeks of therapeutic versus placebo CPAP suggested no significant improvements in cognition. A comparison of pre- and posttreatment neuropsychological test scores after 3 weeks of therapeutic CPAP in both groups showed a significant improvement in cognition. The study was underpowered to make definitive statements about improvements within specific cognitive constructs, although exploratory post hoc examination of change scores for individual tests suggested improvements in episodic verbal learning and memory and some aspects of executive functioning such as cognitive flexibility and mental processing speed. OSA may aggravate cognitive dysfunction in dementia and thus may be a reversible cause of cognitive loss in patients with AD. OSA treatment seems to improve some cognitive functioning. Clinicians who care for patients with AD should consider implementing CPAP treatment when OSA is present.

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

West et al are to be commended for the laborious study of the impact of continuous positive airway pressure (CPAP) on insulin resistance and glycaemic control in males with obstructive...

Effect of CPAP on insulin resistance and HbA1c in men with obstructive sleep apnoea and 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...