The use of oximetry and a questionnaire in primary care enables safe exclusion of a subsequent obstructive sleep apnea diagnosis

Inleiding

Obstructive sleep apnea (OSA) is a common sleep disorder that causes patients to stop breathing during sleep. Diagnosis and treatment of OSA requires specialized care that is generally only available in sleep clinics. In the Netherlands, the number of referrals to sleep clinics for OSA approached 100.000 in 2017 and has increased rapidly. However, of all patients referred, up to 30% eventually does not have OSA upon final poly(somno)graphy. Therefore, a strategy to increase the pre-test probability in the general practice was desired.

Onderzoeksvraag

We hypothesized that overnight oximetry alone, or combined with a previously published questionnaire in a two-step strategy, could be used to safely rule out OSA in patients visiting their general practitioner with potentially OSA-related complaints, thereby reducing the number of patients requiring referral for sleep testing.

Methode

A total of 140 subjects with suspected OSA were included from 54 participating primary care practices in the Netherlands. All subjects completed the Philips questionnaire and underwent one night of oximetry prior to referral to a sleep center, the so-called OSAsense strategy. The prognostic value of two strategies was evaluated against the diagnosis of the sleep center as the gold standard: 1) assume OSA and subsequently refer to a sleep center if the oxygen desaturation index (ODI) is ≥ 5; and 2) assume OSA and refer to a sleep center if the Philips questionnaire score is ≥ 55% (regardless of the ODI), or if the Philips questionnaire score is < 55% and the ODI is ≥ 5.

Resultaten

OSA was diagnosed in the sleep centers in 100 (71%) of the included subjects. Using ODI ≥ 5 alone resulted in a sensitivity of 99.0%, a specificity of 50.0%, a negative predictive value of 95.2%, and a positive predictive value of 83.2%. Using the two-step strategy, oximetry would be performed on 39% of the subjects. This strategy resulted in a sensitivity of 100%, a specificity of 35.0%, a negative predictive value of 100%, and a positive predictive value of 79.4%.

Conclusie

The use of oximetry alone or combined in a two-step strategy with a questionnaire using OSAsense in primary care enables safe exclusion of a sleep center diagnosis of OSA.

Context huisarts-patiënt

The researched ‘OSAsense strategy’ (both the oximetry as well as the questionnaire) may be used in primary care practices. OSAsense is already implemented in several general practices in both Twente as well as Groningen. During the presentation, we will discuss the study as well as the implementation process in these regions.