For patients with suspected obstructive sleep apnea (OSA), a previous sleep study may not be required to indicate the need for continuous positive airway pressure (CPAP) treatment, according to a simulated intention-to-treat study published in Sleep and Breathing.

Because undiagnosed and untreated OSA has serious medical consequences, simpler strategies are needed that allow CPAP therapy to be initiated in more symptomatic patients with a high clinical probability of severe OSA. Thus, researchers evaluated the performance of clinical criteria for diagnosis and initiation of empiric treatment with CPAP in patients with suspected OSA compared with treatment decisions based on sleep studies, guidelines, and experience of the participating physicians.

The researchers created a simulated intention-to-treat study in retrospective and prospective cohorts. Independent observers formed 2 groups and were blinded to each other’s opinions. These 10 observers based their decision about CPAP treatment on the guidelines of either the Spanish Society of Pulmonology and Thoracic Surgery (SEPAR) or the American Academy of Sleep Medicine (AASM), while factoring in their clinical opinion. Patients completed sleep questionnaires, which were reviewed by 4 observers who indicated CPAP if the patients had snoring, frequent apneas (≥3-4/wk), body mass index (BMI) >25 kg/m2, sleepiness (Epworth Sleepiness Scale >11), or tiredness (≥3-4/wk).

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A total of 653 patients (264 women, 40%) were included. In the retrospective cohort, the patients’ median age was 54 years with a median BMI of 27.8 kg/m2 and a median apnea hypopnea index (AHI) of 16.5 events per hour. In the prospective cohort, the patients’ median age was 51 years with a median BMI of 29.8 kg/m2 and an AHI of 15 events per hour.

In a pooled analysis of both cohorts, CPAP indication without a previous sleep study showed low sensitivity (22.4%) but specificity of 97.1% in patients with high pretest probability for OSA (based on reports of snoring, frequent apneas, BMI >25 kg/m2, and sleepiness or tiredness). Indication for CPAP therapy based strictly on SEPAR or AASM recommendations was on average 66% (retrospective cohort: 64.5% and prospective cohort: 69%) while the 10 observers suggested CPAP in 48% of the cases (retrospective cohort, 48.7%; prospective cohort, 46.7%; P <.01). Application of the simple questionnaire and clinical criteria resulted in CPAP indication with a low chance of error as there were fewer than 5% false positives.

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“Our observations have clinical relevance since patients suspected of OSA with tiredness and vascular comorbidities or sleepiness, who for some reason have delays or inaccessibility to diagnostic tests, could initiate empirical treatment with CPAP safely with little chance of error,” the researchers wrote. They added that this strategy could potentially lower healthcare costs because it could avoid conducting a sleep study in 20% of patients have symptoms suspicious for OSA.


Nigro CA, Borsini E, Dibur E, et al. Indication of CPAP without a sleep study in patients with high pretest probability of obstructive sleep apnea [published online on November 12, 2019]. Sleep Breath. doi:10.1007/s11325-019-01949-6