Respiratory disturbance index: an independent predictor of mortality in coronary artery disease.

Cardiovascular mortality was prospectively investigated in consecutive coronary artery disease (CAD) patients with versus without obstructive sleep apnea (OSA) during a follow-up period of 5 yr. An overnight sleep/ventilatory study was performed in patients requiring intensive care (n = 62, mean age 67.6 +/- 10.4 yr, range 44 to 86) during a stable condition (New York Heart Association [NYHA] functional class I-II) 4 to 21 mo after discharge from the hospital. OSA, defined as a respiratory disturbance index (RDI) of 10/h or more was found in 19 patients (mean RDI 17.5 +/- 8.3). Three OSA subjects who were successfully treated with continuous positive airway pressure (CPAP) during the observation period were excluded from the final analysis. There was no statistically significant difference (Fisher two-tailed exact test) between the OSA and non-OSA patient groups in terms of number of elderly subjects (age >/= 65 yr), gender, obesity (body mass index [BMI] >/= 30 kg/m(2)), smoking history, presence of hypertension, diabetes mellitus, hypercholesterolemia, or history of myocardial infarction at the study start. During the follow-up period, cardiovascular death occurred in six of 16 OSA patients (37.5%) compared with 4 (9.3%) in the non-OSA group (p = 0.018). The univariate predictors of cardiovascular mortality were RDI (p = 0.007), OSA (p = 0.014), age at baseline (p = 0.028), hypertension at baseline (p = 0.036), history of never-smoking (p = 0.031), and digoxin treatment during the follow-up period (p = 0.013). In a Cox multiple conditional regression model, RDI remained as an independent predictor of cardiovascular mortality (exp beta = 1.13, 95% confidence interval [CI] 1.05 to 1.21, two-sided p < 0.001). We conclude that untreated OSA is associated with an increased risk of cardiovascular mortality in patients with CAD. Furthermore, it appears appropriate that RDI is taken into consideration when evaluating secondary prevention models in CAD.

[1]  R. Grunstein,et al.  Sleep-related breathing disorders. 5. Nasal continuous positive airway pressure treatment for obstructive sleep apnoea. , 1995, Thorax.

[2]  D. Kripke,et al.  Morbidity, mortality and sleep-disordered breathing in community dwelling elderly. , 1996, Sleep.

[3]  D. Hillman,et al.  Association of sleep apnoea with myocardial infarction in men , 1990, The Lancet.

[4]  O. Polo,et al.  Respiratory variation of the ballistocardiogram during increased respiratory load and voluntary central apnoea. , 1992, The European respiratory journal.

[5]  J. Hedner,et al.  Effect of nasal continuous positive airway pressure during sleep on 24-hour blood pressure in obstructive sleep apnea. , 1993, Sleep.

[6]  Philippe Amouyel,et al.  A European Society of Cardiology survey of secondary prevention of coronary heart disease: Principal results. , 1997 .

[7]  P. McLaughlin,et al.  Cardiac output response to continuous positive airway pressure in congestive heart failure. , 1992, The American review of respiratory disease.

[8]  A. Besset,et al.  The validity of the static charge sensitive bed in detecting obstructive sleep apnoeas. , 1988, The European respiratory journal.

[9]  N. E. Breslow.  Statistical Methods in Cancer Research , 1986 .

[10]  A. Odén,et al.  Myxofibrosarcoma. A malignant soft tissue tumor of fibroblastic-histiocytic origin. A clinicopathologic and prognostic study of 110 cases using multivariate analysis. , 1983, Acta pathologica, microbiologica, et immunologica Scandinavica. Supplement.

[11]  Treatment of hyperlipidaemia. , 1990, British medical bulletin.

[12]  T. Gislason,et al.  Increased mortality among sleepy snorers: a prospective population based study , 1998, Thorax.

[13]  M. Partinen,et al.  Obstructive sleep apnoea syndrome in morbidly obese patients , 1991, Journal of internal medicine.

[14]  J. Hedner,et al.  An independent association between obstructive sleep apnoea and coronary artery disease. , 1999, The European respiratory journal.

[15]  L. Peterson,et al.  High prevalence of hypertension in sleep apnea patients independent of obesity. , 1994, American journal of respiratory and critical care medicine.

[16]  M Partinen,et al.  Long-term outcome for obstructive sleep apnea syndrome patients. Mortality. , 1988, Chest.

[17]  N. Douglas,et al.  Long-term use of CPAP therapy for sleep apnea/hypopnea syndrome. , 1999, American journal of respiratory and critical care medicine.

[18]  M. Partinen,et al.  Sleep apnea and mortality in an aged cohort. , 1988, American journal of public health.

[19]  L. Goldman,et al.  The recent decline in mortality from coronary heart disease, 1980-1990. The effect of secular trends in risk factors and treatment. , 1997, JAMA.

[20]  K. Franklin,et al.  Sleep apnoea and nocturnal angina , 1995, The Lancet.

[21]  M. Kryger,et al.  Mortality and apnea index in obstructive sleep apnea. Experience in 385 male patients. , 1988, Chest.

[22]  J. Herman.  An instance of sleep paralysis in Moby-Dick. , 1997, Sleep.

[23]  J. Hedner,et al.  Reduced hospitalization with cardiovascular and pulmonary disease in obstructive sleep apnea patients on nasal CPAP treatment. , 1997, Sleep.

[24]  J. Ménard,et al.  1993 guidelines for the management of mild hypertension: memorandum from a WHO/ISH meeting. , 1993, Bulletin of the World Health Organization.

[25]  S. Ancoli-Israel.  Epidemiology of sleep disorders. , 1989, Clinics in geriatric medicine.

[26]  I. Deary,et al.  Randomized placebo-controlled crossover trial of continuous positive airway pressure for mild sleep Apnea/Hypopnea syndrome. , 1999, American journal of respiratory and critical care medicine.

[27]  N. Saunders,et al.  Four-year follow-up of mortality and sleep-related respiratory disturbance in non-demented seniors. , 1995, Sleep.

[28]  A J Block,et al.  Do patients with sleep apnea die in their sleep? , 1988, Chest.

[29]  D. Kripke,et al.  Sleep apnea in female patients in a nursing home. Increased risk of mortality. , 1989, Chest.

[30]  M. Partinen,et al.  Sudden death and sleeping history among Finnish men , 1991, Journal of internal medicine.