Continuous positive-airway pressure improved mild sleep-disordered breathing
ACP J Club. 1998 Sep-Oct;129:44. doi:10.7326/ACPJC-1998-129-2-044
Redline S, Adams N, Strauss ME, et al. Improvement of mild sleep-disordered breathing with CPAP compared with conservative therapy. Am J Respir Crit Care Med. 1998 Mar;157: 858-65.
In patients with mild sleep-disordered breathing (SDB), is treatment with continuous positive-airway pressure (CPAP) more effective than conservative treatment (CT) for well-being, mood, and functional status?
8-week randomized controlled trial.
Cleveland, Ohio, United States.
111 volunteers recruited by fliers, by practitioner contact, and from general medical clinics and other studies. Eligibility criteria were age 25 to 65 years; respiratory disturbance index (number of apneas and hypopneas/h) between 5 and 30; and absence of pathologic sleepiness, sleep disorders other than SDB, and underlying conditions that could interfere with study protocol adherence. 87.4% of patients (mean age 48 y, 62% European Americans, 52% men) completed the study.
59 patients were allocated to nasal CPAP with a prescribed pressure based on the level that eliminated snoring and most respiratory events (mean 7.4 cm H2O). 52 patients allocated to CT received mechanical nasal dilators. Patients in both groups received counseling about sleep posture and hygiene, those with a body mass index > 29 kg/m2 received weight loss counseling from a dietitian, and those with nasal congestion were given a nasal steroid spray (Beconase). Patients received telephone calls every 2 weeks reminding them to use the prescribed therapy every night.
Main outcome measures
Response scores of ≥ 2 (improvement in ≥ 2 areas: mood, fatigue, or general health and functional status, with no deterioration in any domain).
Compared with patients allocated to CT, more patients allocated to CPAP had improvements in ≥ 2 areas (P < 0.05) (Table). Subgroup analysis showed beneficial effects of CPAP over CT for patients with diabetes or hypertension (P < 0.05) and patients who did not report sinus problems (P < 0.01). No serious adverse effects were reported for either group.
Among patients with mild sleep-disordered breathing, more patients who received continuous positive-airway pressure treatment had improvements in at least 2 areas: mood, fatigue, or general health and functioning at 8 weeks, compared with patients who received conservative treatment with mechanical nasal dilators.
Sources of funding: National Heart, Lung and Blood Institute; Department of Veterans Affairs; CPAP units provided by Puritan Bennett and Healthdyne, Beconase by Glaxo, and Breath-Right nasal dilators by CNS Co.
For correspondence: Dr. S. Redline, Rainbow Babies Children's Hospital, 11100 Euclid Avenue, Cleveland, OH 44106, USA. FAX 216-844-6265.
Table. Continuous positive-airway pressure (CPAP) vs conservative treatment (CT) for sleep-disordered breathing at 8-week follow-up*
|Outcome||CPAP||CT||RBI (95% CI)||NNT (CI)|
|Improvement in ≥ 2 of mood, fatigue, or general health and functioning||49%||26%||88% (10 to 234)||5 (2 to 28)|
*Abbreviations defined in Glossary; RBI, NNT, and CI calculated from data in article.
The most effective treatment for reducing or abolishing obstructive apnea and hypopnea in SDB is nasal CPAP. The long-term cardiovascular and cerebrovascular morbidity and mortality of SDB and any influence of treatment on these are poorly documented. However, neuropsychological tests, subjective sleepiness, measures of the tendency to sleep, or ability to stay awake improve with CPAP treatment. Control for CPAP is difficult, but reasonable attempts to study parallel groups show a worthwhile effect. In most studies of moderate to severe SDB, 70% to 85% of patients use CPAP for an average of 5 hours per night.
Redline and colleagues recruited volunteers who snored but not those who attended a sleep clinic; the latter group would be more likely to have prominent daytime symptoms. Persons who fell asleep while driving or in other dangerous situations were excluded, but study patients still had high Epworth sleepiness scale scores of 10 to 11 out of 24. Control treatment involving nasal dilator strips, advice, and inhaled steroids could be regarded as reasonable conventional therapy.
It is not surprising that nocturnal apnea and snoring were controlled by CPAP. Well-being, mood, fatigue, and functional status also improved. Whether this is worth the cost and inconvenience of CPAP will depend on the patient, the degree of the problem, and the motivation. In these closely evaluated volunteers, CPAP use was quite low, averaging 3.1 hours per night while patients were asleep.
These findings do not mean that all persons who snore or have mild-to-moderate SDB need CPAP. It does reinforce the effectiveness of CPAP on daytime functioning and shows the difficulties in establishing minimum levels of apnea and hypopnea for treatment policies. SDB should be considered for persons who snore and have mild daytime symptoms. Active treatment with advice on position and weight loss, attention to the nose, and perhaps mandibular advancement devices might be tried initially, with CPAP considered in some patients with residual daytime symptoms.
P. John Rees, MD
Guy's HospitalLondon, England, UK