Mortality of Sleep Apnoea Patients Treated by Nasal Continuous Positive Airway Pressure Registered in the ANTADIR Observatory

[ANTADIR: Association Nationale pour le Traitement A Domicile de l'Insufficance Respiratoire chronique]
D. Veale, E. Chailleux, A. Hoorelbeke-Ramon, O. Reybet-Degas, M.P. Humeau-Chapuis, F. Alluin-Algous, B. Fleury, O. Jonquet, P. Michard
ANTADIR, Paris, France
Published in European Respiratory Journal 2000; 15: 326-331

Summary

In the 1970's, ANTADIR [National Association for the Home Treatment of Chronic Respiratory Insufficiency] was set up in France. Since then, it has collected data on patients from 25 of the 33 associations in the network, covering 79% of the total group of patients under treatment. Data includes information from a form completed by the provider: age, sex, height, weight, Forced Expiratory Volume [FEV] on pulmonary function testing, Vital Capacity [VC] of the lungs, and arterial blood gases [ABG] while breathing room air. Also recorded were later treatment modification and death.

The group available for study included 5,669 patients prescribed CPAP over the 9 years between 1/1/85 and 12/31/93, from which 311 were excluded because of requiring additional oxygen, signifying more complicated conditions. At the time of this analysis (1/1/96), 276 patients (4.9%) had died over a 10-year period. Another 1,487 patients (26%) had been lost to follow-up, having had treatment stopped mostly due to non-compliance.

Those variables mentioned in the first paragraph were examined as potential predictors of survival. Neither sex nor body mass predicted mortality. Those patients who died were older (62 versus 56 years) and had poorer respiratory function on all recorded variables.

A subgroup of 124 patients who died were compared with a control group, matched for age and sex, who started CPAP at about the same time. Results were similar, in that patients who died had poorer pulmonary function test results. Though they did not differ from controls on the Apnea Hypopnea Index (AHI), they did spend more of their sleep time with low blood oxygen saturations (below 90%). Also, the CPAP compliance of those who died was much worse than that of survivors--only 57% of the deceased used CPAP for at least 5 hours per night, versus 77% of the controls. Moreover, those who died had a more extensive history of heart arrhythmias, heart attacks, strokes, peripheral vascular disease, heart failure, respiratory illnesses, and neurological and psychiatric problems

Nevertheless, the CPAP patients' death rate over six years was identical to that of the general French population for the 18-69 year age range. Yet they had an excess of deaths related to cardiovascular disease, especially sudden deaths and cardiac arrests, as well as to accidents, poisoning, suicide, and surgery.

Findings relevant to clinicians, the authors felt, were that patients who died had more severe sleep apnea as measured by extent of nighttime blood oxygen desaturation, and poorer compliance with CPAP. Impaired respiratory function while awake is another danger sign. Cardiovascular problems, another possible consequence of sleep apnea, also warns of higher mortality risk. Depression and suicide may represent yet another potentially fatal complication of sleep apnea: 8 of their fatalities had resulted from suicide, a higher proportion than in the general population. Accidents may represent another cause of mortality increased with sleep apnea.

Comments

By and large, I believe, this study speaks for itself, and tells a story that all people with sleep apnea should listen to with attention. They have, overall, no higher mortality risk, with treatment, than the general population. Without treatment, this no longer appears to hold true: noncompliance is a significant predictor of death.

Those who have other predictors of mortality risk should take special care with treatment: people who know themselves to have cardiac or respiratory disease apart from sleep apnea, those with impaired respiratory function as tested while awake, those with substantial oxygen desaturation while asleep, those with bouts of depression and suicidal ideas, those who have had auto accidents or near-misses. Everyone with sleep apnea, but especially those with these indicators of high mortality risk, should do their utmost to get treatment and continue treatment.

"Life is one long process of getting tired."
Samuel Butler, 1835-1902

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