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

PURPOSE: The study aims to prospectively validate the prognostic value of oximetry alone or combined in a two-step strategy with a questionnaire for the exclusion of obstructive sleep apnea (OSA) in primary care. METHODS: A total of 140 subjects with suspected OSA were included from 54 participating primary care practices. All subjects completed the Philips questionnaire and underwent one night of oximetry prior to referral to a sleep center. 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. RESULTS: 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 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%. CONCLUSIONS: In a Dutch primary care population with a clinical suspicion of OSA and low frequency of cardiovascular comorbidities, the use of oximetry alone or combined in a two-step strategy with a questionnaire enables exclusion of a sleep center diagnosis of OSA.

Validation of the oxygen desaturation index in the diagnostic workup of obstructive sleep apnea.

INTRODUCTION: Obstructive sleep apnea (OSA) is common, and diagnosis requires expensive and laborious testing to assess the apnea hypopnea index (AHI). We performed an analysis to explore the relationship between the oxygen desaturation index (ODI) as measured with pulse oximetry and the AHI in our large portable monitoring (PM) database to find an optimal cutoff value for the ODI in order to be able to exclude AHI ≥ 5 on PM. METHODS: Three thousand four hundred thirteen PM recordings were randomly divided into a training set (N = 2281) and a test set (N = 1132). The optimal cutoff for the ODI to exclude an AHI ≥ 5 on PM was determined in the training set and subsequently validated in the test set. RESULTS: Area under the curve of the ODI to exclude an AHI ≥ 5 on PM was 0.997 in the training set and 0.996 in the test set. In the training set, the optimal cutoff to predict an AHI < 5 was an ODI < 5. Using this cutoff in the test set provided a sensitivity of 97.7%, a specificity of 97.0%, a positive predictive value of 99.2%, and a negative predictive value of 91.4%. CONCLUSION: An ODI < 5 predicts an AHI < 5 with high sensitivity and specificity when measured simultaneously using the same oximeter during PM recording.