Below are links to research studies, papers and other information about sleep apnea, as well as diseases that can be affected by sleep apnea.
Terry Young, Paul E. Peppard, Daniel J. Gottlieb American Journal of Respiratory and Critical Care Medicine Vol 165 p 1217-1239; 2002
Population-based epidemiologic studies have uncovered the high prevalence and wide severity spectrum of undiagnosed obstructive sleep apnea, and have consistently found that even mild obstructive sleep apnea is associated with significant morbidity. Evidence from methodologically strong cohort studies indicates that undiagnosed obstructive sleep apnea, with or without symptoms, is independently associated with increased likelihood of hypertension, cardiovascular disease, stroke, daytime sleepiness, motor vehicle accidents, and diminished quality of life. Strategies to decrease the high prevalence and associated morbidity of obstructive sleep apnea are critically needed. The reduction or elimination of risk factors through public health initiatives with clinical support holds promise. Potentially modifiable risk factors considered in this review include overweight and obesity, alcohol, smoking, nasal congestion, and estrogen depletion in menopause. Data suggest that obstructive sleep apnea is associated with all these factors, but at present the only intervention strategy supported with adequate evidence is weight loss. A focus on weight control is especially important given the expanding epidemic of overweight and obesity in the United States. Primary care providers will be central to clinical approaches for addressing the burden and the development of cost effective case-finding strategies and feasible treatment for mild obstructive sleep apnea warrants high priority.
H. Klar Yaggi, M.D., M.P.H., John Concato, M.D., M.P.H., Walter N. Kernan, M.D., Judith H. Lichtman, Ph.D., M.P.H., Lawrence M. Brass, M.D., and Vahid Mohsenin, M.D. New England Journal of Medicine 2005; 353: 2034-41
Previous studies have suggested that the obstructive sleep apnea syndrome may be an important risk factor for stroke. It has not been determined, however, whether the syndrome is independently related to the risk of stroke or death from any cause after adjustment for other risk factors, including hypertension. METHODS: In this observational cohort study, consecutive patients underwent polysomnography, and subsequent events (strokes and deaths) were verified. The diagnosis of the obstructive sleep apnea syndrome was based on an apnea-hypopnea index of 5 or higher (five or more events per hour); patients with an apnea-hypopnea index of less than 5 served as the comparison group. Proportional-hazards analysis was used to determine the independent effect of the obstructive sleep apnea syndrome on the composite outcome of stroke or death from any cause. RESULTS: Among 1022 enrolled patients, 697 (68 percent) had the obstructive sleep apnea syndrome. At baseline, the mean apnea-hypopnea index in the patients with the syndrome was 35, as compared with a mean apnea-hypopnea index of 2 in the comparison group. In an unadjusted analysis, the obstructive sleep apnea syndrome was associated with stroke or death from any cause (hazard ratio, 2.24; 95 percent confidence interval, 1.30 to 3.86; P=0.004). After adjustment for age, sex, race, smoking status, alcohol-consumption status, body-mass index, and the presence or absence of diabetes mellitus, hyperlipidemia, atrial fibrillation, and hypertension, the obstructive sleep apnea syndrome retained a statistically significant association with stroke or death (hazard ratio, 1.97; 95 percent confidence interval, 1.12 to 3.48; P=0.01). In a trend analysis, increased severity of sleep apnea at b
Robert Wolk, Abu S.M. Shamsuzzaman, Virend K. Somers Hypertension 42:1067-1074: originally published online November 10, 2003
Obesity has a high and rising prevalence and represents a major public health problem. Obstructive sleep apnea (OSA) is also common, affecting an estimated 15 million Americans, with a prevalence that is probably also rising as a consequence of increasing obesity. Epidemiologic data support a link between obesity and hypertension as well as between OSA and hypertension. For example, untreated OSA predisposes to an increased risk of new hypertension, and treatment of OSA lowers blood pressure, even during the daytime. Possible mechanisms whereby OSA may contribute to hypertension in obese individuals include sympathetic activation, hyperleptinemia, insulin resistance, elevated angiotensin II and aldosterone levels, oxidative and inflammatory stress, endothelial dysfunction, impaired baroreflex function, and perhaps by effects on renal function. The coexistence of OSA and obesity may have more widespread implications for cardiovascular control and dysfunction in obese individuals and may contribute to some of the clustering of abnormalities broadly defined as the metabolic syndrome. From the clinical and therapeutic perspectives, the presence of resistant hypertension and the absence of a nocturnal decrease in blood pressure in obese individuals should prompt the clinician to consider the diagnosis of OSA, especially if clinical symptoms suggestive of OSA (such as poor sleep quality, witnessed apnea, excessive daytime somnolence, and so forth) are also present.
Esra Tasali, Babak Mokhlesi and Eve Van Cauter Chest 2008; 133; p 496-506
Type 2 diabetes is a major public health concern with high morbidity, mortality, and health-care costs. Recent reports have indicated that the majority of patients with type 2 diabetes also have obstructive sleep apnea (OSA). There is compelling evidence that OSA is a significant risk factor for cardiovascular disease and mortality. Rapidly accumulating data from both epidemiologic and clinical studies suggest that OSA is also independently associated with alterations in glucose metabolism and places patients at an increased risk of the development of type 2 diabetes. Experimental studies in humans and animals have demonstrated that intermittent hypoxia and reduced sleep duration due to sleep fragmentation, as occur in OSA, exert adverse effects on glucose metabolism. Based on the current evidence, clinicians need to address the risk of OSA in patients with type 2 diabetes and, conversely, evaluate the presence of type 2 diabetes in patients with OSA. Clearly, there is a need for further research, using well-designed studies and long-term follow-up, to fully demonstrate a causal role for OSA in the development and severity of type 2 diabetes. In particular, future studies must carefully consider the confounding effects of central obesity in examining the link between OSA and alterations in glucose metabolism. The interactions among the rising epidemics of obesity, OSA, and type 2 diabetes are likely to be complex and involve multiple pathways. A better understanding of the relationship between OSA and type 2 diabetes may have important public health implications.
Mary S. M. IP, Bing Lam, Matthew M.T. NG, Wah Kit Lam, Kenneth W.T. Tsang, Karen S. L. Lam American Journal of Respiratory and Critical Care Medicine Vol 165. pp 670–676, 2002
Epidemiological studies have implicated obstructive sleep apnea (OSA) as an independent comorbid factor in cardiovascular and cerebrovascular diseases. It is postulated that recurrent episodes of occlusion of upper airways during sleep result in pathophysiological changes that may predispose to vascular diseases. Insulin resistance is a known risk factor for atherosclerosis, and we postulate that OSA represents a stress that promotes insulin resistance, hence atherogenesis. This study investigated the relationship between sleep-disordered breathing and insulin resistance, indicated by fasting serum insulin level and insulin resistance index based on the homeostasis model assessment method (HOMA-IR). A total of 270 consecutive subjects (197 male) who were referred for polysomnography and who did not have known diabetes mellitus were included, and 185 were documented to have OSA defined as anapnea–hypopnea index (AHI)5. OSA subjects were more insulin resistant, as indicated by higher levels of fasting serum insulin (p_0.001) and HOMA-IR (p_0.001); they were also older and more obese. Stepwise multiple linear regression analysis showed that obesity was the major determinant of insulin resistance but sleep disordered breathing parameters (AHI and minimum oxygen saturation) were also independent determinants of insulin resistance (fasting insulin: AHI, p_0.02, minimum O2, p_0.041; HOMA-IR:AHI, p_0.044, minimum O2, p_0.022); this association between OSA and insulin resistance was seen in both obese and nonobese subjects. Each additional apnea or hypopnea per sleep hour increased the fasting insulin level and HOMA-IR by about 0.5%. Further analysis of the relationship of insulin resistance and hypertension confirmed that insulin resistance was a significant factor for hyper
Jo-Dee L. Lattimore, MBCHB, FRACP, David S. Celermajer, MBBS, MSC, PHD, FRACP, Ian Wilcox, BMEDSCI, MBBS, PHD, FRACP, FCCP Journal of the American College of Cardiology Vol. 41, No. 9, 2003
Obstructive sleep apnea (OSA) is a common disorder associated with an increased risk of cardiovascular disease and stroke. As it is strongly associated with known cardiovascular risk factors, including obesity, insulin resistance, and dyslipidemia, OSA is an independent risk factor for hypertension and has also been implicated in the pathogenesis of congestive cardiac failure, pulmonary hypertension, arrhythmias, and atherosclerosis. Obesity is strongly linked to an increased risk of OSA, and weight loss can reduce the severity of OSA. The current standard treatment for OSA—nasal continuous positive airway pressure (CPAP)—eliminates apnea and the ensuing acute hemodynamic changes during sleep. Long-term CPAP treatment studies have shown a reduction in nocturnal cardiac ischemic episodes and improvements in daytime blood pressure levels and left ventricular function. Despite the availability of effective therapy, OSA remains an underdiagnosed and undertreated condition. A lack of physician awareness is one of the primary reasons for this deficit in diagnosis and treatment.
K. Banno, C. Ramsey, R. Walld, MH. Kryger Sleep. (32)2. 1-FEB-2009. pp 247-52.
STUDY OBJECTIVES: To determine the effect of obesity and sleep apnea on health care expenditure in women over 10 years. DESIGN: Retrospective observational study SETTING: Tertiary university-based medical center PATIENTS AND CONTROLS: Three groups of age-matched women: 223 obese women with OSAS (body mass index: 39.3 +/- 0.6 kg/m2), and from the general population, 223 obese controls (BMI 36.3 +/- 0.4) and 223 normal weight controls (BMI 23.9 +/- 0.4). INTERVENTIONS: None. MEASUREMENTS AND RESULTS: We examined health care utilization in the 3 matched groups for the 10 years leading up to the documentation of OSAS. The mean physician fees and the number of physician visits were significantly higher in obese controls than in normal weight controls during the observed period. Physician fees and physician visits progressively increased in the 10 years before diagnosis in the OSAS cases and were significantly higher than in the matched obese controls. Physician fees, in Canadian dollars, one year before diagnosis in the OSAS cases were higher than in obese controls: $547.49 +/- 34.79 vs $246.85 +/- 20.88 (P<0.0001). More was spent for OSAS cases on physician fees for circulatory, endocrine and metabolic diseases, and mental disorders than the obese controls. Physician visits one year before diagnosis in the OSAS cases were more frequent than in the obese controls: 13.2 +/- 0.73 visits vs 7.26 +/- 0.49 visits (P<0.0001). CONCLUSIONS: Obese women are heavier users of health services than normal weight controls. Obese women with OSAS use significantly more health services than obese controls. Since OSAS imposes a greater financial burden, treatment of OSAS may reduce other comorbidities and lower overall medical costs.
Albarrak M; Banno K; Sabbagh AA; Delaive K; Walld R; Manfreda J; Kryger MH SLEEP. (28)10. 2005. pp 1306-1311.
Study Objectives: Patients with untreated obstructive sleep apnea syndrome (OSAS) have higher healthcare utilization than matched controls. However, the long-term impact of continuous positive airway pressure (CPAP) use on healthcare utilization is unknown. Design: Retrospective observational cohort study. Subjects: There were 342 eligible men with OSAS and matched controls on whom there were utilization data for 5 years prior to initial OSAS diagnosis and for the 5 years on CPAP treatment of the cases. Interventions: Patients were treated with CPAP. Results: Patients with OSAS were typical cases (mean±SD): age, 48.2±0.6 years; body mass index, 35.6±0.4 kg/m2; Epworth Sleepiness Scale score, 14.2±0.3; apnea-hypopnea index, 47.1±1.8 events per hour. The number of physician visits were higher by 3.46±0.2 (95% confidence interval [CI]:2.57 to 4.36) in cases in the year before diagnosis, compared with the fifth year before diagnosis, then decreased over the next 5 years by 1.03±0.49 (95% CI: -1.99 to -0.07)(P<.0001). Physician fees, in Canadian dollars, were higher by $148.65±$27.27(95% CI: 95.12 to 202.10) in cases in the year before diagnosis, compared with the fifth year before diagnosis, and then decreased over the next 5 years by $13.92±$27.94(95%CI: -68.68 to 40.83)(P=.0009). Preexisting ischemic heart disease at the time of OSAS diagnosis predicted about a 5-fold increase in healthcare utilization between the second and fifth year of treatment. Conclusions: Treatment of OSAS reversed the trend of increasing healthcare utilization seen prior to diagnosis. Preexisting ischemic heart disease results in a negative impact on healthcare utilization. CPAP results in a long-term health benefit, as measured by the use of healthcare services.
Vishesh Kapur MD, MPH, David K. Blough PhD, Robert E. Sandblom MD, Richard Hert MD, James B. de Maine MD, Sean D. Sullivan PhD, Bruce M. Psaty MD PhD SLEEP, Vol. 22, No. 6, 1999 749-755
Obstructive sleep apnea is an under-diagnosed, but common disorder with serious adverse consequences. Cost data from the year prior to the diagnosis of sleep-disordered breathing in a consecutive series of 238 cases were used to estimate the potential medical cost of undiagnosed sleep apnea and to determine the relationship between the severity of sleep-disordered breathing and the magnitude of medical costs. Among cases, mean annual medical cost prior to diagnosis was $2720 versus $1384 for age and gender matched controls (p<0.01). Regression analysis showed that the reciprocal of the apnea hypopnea index among cases was significantly related to log-transformed annual medical costs after adjusting for age, gender, and body mass index (p<0.05). We conclude that patients with undiagnosed sleep apnea had considerably higher medical costs than age and sex matched individuals and that the severity of sleep-disordered breathing was associated with the magnitude of medical costs. Using available data on the prevalence of undiagnosed moderate to severe sleep apnea in middle-aged adults, we estimate that untreated sleep apnea may cause $3.4 billion in additional medical costs in the U.S. Whether medical cost savings occur with treatment of sleep apnea remains to be determined.
Ahmed Bahammam, MD, MRCP†, Kenneth Delaive, BSc, John Ronald BSc, Jure Manfreda, MD, Les Roos, PhD* and Meir H. Kryger, MD, FRCPC SLEEP, Vol. 22, No. 6, 1999
Objective: To document changes in health care utilization (physician claims and hospitalizations) two years after diagnosis and treatment of patients with OSAS. Design: Prospective observational cohort study. Setting: The study was done in the Canadian Province of Manitoba. OSAS patients were selected from a University-based sleep disorders center. Control subjects were selected from the general population. Patients and controls: There were 344 OSAS patients on whom there was utilization data for the period of the study. They were matched to controls from the general population by gender, age, and geographic location. Measurements and results: The difference in physician claims between the patients and their matched controls two years after diagnosis and treatment ($174±32.4 (SE) per year in Canadian dollars) was significantly less than the difference in the year before diagnosis ($260±35.7 (SE), p=0.038). Examining the subgroups of patients adhering (PAT) or not adhering (PNAT) to treatment revealed that the changes were only significant in the patients adhering to treatment. Hospital stays for the entire OSAS group decreased from 1.27 days+0.25(SE) per patient per year one year before diagnosis to 0.54+0.13 per patient per year (p=0.01). The changes in the PAT group (1.25+0.28 per patient per year one year before diagnosis to 0.53+0.14 per patient per year (p=0.034) were significant while in the PNAT group they were not. Conclusions: Adherence to treatment in patients with OSAS results in a significant reduction in physician claims and hospital stays.
James A. Reichert, Daniel A. Block, Elizabeth Cundiff, Bernhard A Votteri Sleep Medicine. 2003; 4:213-218
Obstructive sleep apnea (OSA) is a serious, common, and underdiagnosed disorder that challenges health care resources. While polysomnography (PSG) represents the standard diagnostic test for OSA, portable devices provide an alternative diagnostic tool when issues of cost, time, geographic availability, or other constraints pose impediments to in-lab testing. This study compares the NovaSom QSG, a new sleep apnea home diagnostic system, to PSG both in the laboratory and in the home. Fifty-one consecutive adults referred to the sleep lab for suspicion of OSA underwent one night of in-lab, simultaneous recording of PSG and NovaSom QSG in addition to using the NovaSom QSG at home for three nights. Two separate comparisons were made using the apnea–hypopnea index (AHI): in-lab PSG to in-lab NovaSom QSG and in-lab PSG to home NovaSom QSG. Using a clinical cut-off of AHI ¼ 15, the sensitivity and specificity of the in-lab NovaSom QSG vs. PSG were 95% and 91%, respectively. For home NovaSom QSG vs. in-lab PSG, the sensitivity was 91% and specificity was 83%. The intra-class correlation coefficient for the agreement between three separate nights of NovaSom QSG home data was 0.88. In a patient population suspected of having OSA, the NovaSom QSG demonstrated acceptable sensitivity and specificity both in the lab and self-administered in the home, when compared to PSG.
David Claman, Andrew Murr, Kimberly Trotter Otolaryngology- Head and Neck Surgery. 2001; 125: 227-230
Objective: To validate the accuracy of the Bedbugg™, a new home monitoring device for diagnosis of sleep apnea. Study design and setting: Simultaneous sleep monitoring was performed by formal polysomnography and by Bedbugg. Monitoring was performed in a university sleep center in 42 subjects who had previously been scheduled for polysomnography. Results: The correlation for the apnea-hypopnea index (AHI) between polysomnography and Bedbugg was r= 0.96. The sensitivity of Bedbugg for detecting an AHI >15 was 85.7%. the specificity of Bedbugg for detecting an AHI < 15 was 95.2%. Conclusion: The Bedbugg device provides an accurate assessment of the apnea-hypopnea index. Significance: Accurate home monitoring for sleep apnea may provide access to care for a higher proportion of undiagnosed sleep apnea patients.
Moreira and Flávio Danni Fuchs, Costa Fuchs, Miguel Gus, Erlon Oliveira de Abreu-Silva, Leila Beltrami Vasconcelos, Sandro Cadaval Gonçalves, Maria do Carmo Lenz, Sandra Ana Claudia Tonelli de Oliveira, Denis Martinez, Luiz Felipe T. Chest 2009; 135; 330-336
The use of portable respiratory monitoring (PM) has been proposed for the diagnosis of obstructive sleep apnea syndrome (OSAS), but most studies that validate PM accuracy have not followed the best standards for diagnostic test validation. The objective of the present study was to evaluate the accuracy of PM performed at home to diagnose OSAS and its outcomes after first validating PM in the laboratory setting by comparing it to polysomnography (PSG). Methods: Patients with suspected OSAS were submitted, in random order, to PM at the sleep laboratory concurrently with PSG (lab-PM) or at home-PM. The diagnostic performance was assessed by sensitivity, specificity, positive and negative predictive values, positive likelihood ratio (_LR), negative likelihood ratio (_LR), intraclass correlation coefficients, _ statistic, and Bland-Altman plot. Results: One hundred fifty-seven subjects (73% men, mean age _ SD, 45 _ 12 yr) with an apnea-hypopnea index (AHI) of 31 (SD _ 29) events/h were studied. Excluding inadequate recordings, 149 valid comparisons with lab-PM and 121 with unattended home-PM were obtained. Compared to PSG for detecting AHI > 5, the lab-PM demonstrated sensitivity of 95.3%, specificity of 75%, _LR of 3.8, and _LR of 0.11; the home-PM exhibited sensitivity of 96%, specificity of 64%, _LR of 2.7, and _LR of 0.05. Kappa statistics indicated substantial correlation between PSG and PM results. Bland-Altman plot showed smaller dispersion for lab-PM than for home-PM. Pearson product moment correlation coefficients among the three AHIs and clinical outcomes were similar, denoting comparable diagnostic ability. Conclusions: This study used all available comparison methods to d
Eugene C. Fletcher, MD; Jacqueline Stich, RN; Karl L. Yang, MD Archives of Family Medicine. 2000; 9: 168-174
Obstructive Sleep Apnea (OSA) is recognized as a frequent cause of symptomatic daytime sleepiness in the general population. The importance of this disorder as a contributor to cardiovascular disease, including systemic hypertension, stroke, and coronary artery disease, is being increasingly recognized as a cause of early morbidity and mortality in patients with OSA. As many as 4% of middle-aged men and 2% of middle-aged women may have sleep apnea syndrome, which is defined as the presence of apnea during sleep with pathologic daytime sleepiness. Thus, diagnosing and treating OSA is becoming a major health problem in the United States from the standpoint of physician education and vigilance as well as cost. Polysomnography(PSMGY)with electroencephalographic sleep staging, oximetry, and respiratory monitoring is a criterion standard for the diagnosis of OSA and for continuous positive airway pressure (CPAP) titration. Disadvantages are that PSMGY is labor intensive, requiring continuous technician monitoring; is not readily available in some rural areas; and long scheduling delays may occur. Intrapatient night-to-night variability may give divergent respiratory disturbance indices (RDIs), causing reclassification of the diagnosis in up to 43% of patients with lower RDIs (5-15 respiratory events per hour).Through new technology, unattended home monitoring now offers an alternative to PSMGY in diagnosing patients with OSA, while automatic titrating (auto)-CPAP machines may provide an alternative to in-laboratory PSMGY in the pre- diction of the correct CPAP pressure. Our objective was to show that in-home, unattended diagnosis and treatment of OSA with a single device is technically feasible in that measurement of airflow interruption at night is sufficiently accurate to establish this diagnosis in patients with classic symptoms.
Benjamin Hoffman, MD, MPH, Dustin D. Wingenbach, MBA, Amy N. Kagey, MS, Justin L. Schaneman, MS, David Kasper Journal of Occupational and Environmental Medicine Volume 52, Number 5, May 2010
To assess the impact on health plan and disability costs associated with continuous positive airway pressure or bi-level positive airway pressure treatment of obstructive sleep apnea in a commercial motor vehicle driver population. Methods: A retrospective, pre/post claims-based comparison analysis was performed. Health plan and disability costs, in addition to disability claimant rates and missed workdays were compared for the 12 months before treatment to the 24 months after treatment. Results: Health plan costs were significantly lower in both the first and second years after treatment. Short-term disability metrics also exhibited favorable results, with approximately half as many using the benefit, lower costs, and fewer missed workdays in the postperiod. Conclusions: Effective treatment of obstructive sleep apnea in drivers is associated with lower health care and disability costs and fewer missed workdays.
Carol M. Baldwin RN, PhD,1 Kent A. Griffith MPH,2 F. Javier Nieto MD, PhD,3 George T. O’Connor MD, MS,4 Joyce A. Walsleben PhD,5 and SusanRedline MD, MPH6 SLEEP, Vol. 24, No. 1, 2001
This study assessed the extent to which sleep-disordered breathing (SDB), difficulty initiating and maintaining sleep (DIMS), and excessive daytime sleepiness (EDS) were associated with impairment of quality of life (QoL) using the SF-36. Participants (n=5,816; mean age=63 years; 52.5% women) were enrolled in the nation-wide population-based Sleep Heart Health Study (SHHS) implemented to investigate sleep-disordered breathing as a risk factor in the development of cardiovascular disease. Each transformed SF-36 scale was analyzed independently using multiple logistic regression analysis with sleep and other potential confounding variables (e.g., age, ethnicity) included as independent variables. Men (11.6%) were significantly more likely to have SDB compared to women (5.6%), while women (42.4%) were significantly more likely to report DIMS than men (32.5%). Vitality was the sole SF-36 scale to have a linear association with the clinical categories of SDB (mild, moderate, severe SDB). However, individuals with severe SDB indicated significantly poorer QoL on several SF-36 scales. Both DIMS and EDS were strongly associated with reduced QoL even after adjusting for confounding variables for both sexes. Findings suggest 1) mild to moderate SDB is associated with reduced vitality, while severe SDB is more broadly associated with poorer QoL 2) subjective sleep symptoms are comprehensively associated with poorer QoL, and 3) SF-36 mean score profiles for SDB and sleep symptoms are equivalent to other chronic diseases in the U.S. general population.
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