Improving implementation of OSA screening: patient-performed neck encirclement within the NoSAS score

Technical Summary: Improving Implementation of OSA Screening via Patient-Performed Neck Encirclement

Problem Statement
Obstructive sleep apnea (OSA) remains substantially underdiagnosed globally, necessitating pragmatic screening strategies for primary care and non-specialized settings. The NoSAS score is a validated screening tool that includes neck circumference >40 cm as a key variable. However, in routine clinical practice, the measurement of neck circumference is often inconsistently recorded due to the need for specific equipment (measuring tape), operator-dependent technique, and the limitations of fixed thresholds in accounting for inter-individual morphological variability. This inconsistency leads to missing data, which hinders the calculation of the NoSAS score and limits its real-world implementation. The study addresses whether a simplified, equipment-free adaptation of the NoSAS score—replacing measured neck circumference with a patient-performed neck encirclement maneuver—can improve feasibility without compromising diagnostic performance.

Methodology
The authors conducted a retrospective analysis of prospectively collected routine clinical data from 449 consecutive adults referred to a tertiary sleep center in Lyon, France, between September and December 2025.

• Data Collection: During routine outpatient assessments, medical students (blinded to the study objective) recorded both standard neck circumference measurements and patient-performed neck encirclement at the same anatomical level.
• The Maneuver: Patient-performed neck encirclement involves the patient attempting to surround their own neck with both hands, bringing the thumb and middle finger of each hand into contact. A positive result (indicating a risk factor) is defined as the inability to completely encircle the neck.
• Scoring: A modified "NoSAS hand" score was calculated by substituting the standard neck circumference criterion with the encirclement result.
• Reference Standard: OSA severity was determined by polysomnography according to standard AASM criteria, with thresholds set at AHI ≥15 events·h⁻¹ (moderate-to-severe) and AHI ≥30 events·h⁻¹ (severe).
• Statistical Analysis: Diagnostic performance was assessed using sensitivity, specificity, predictive values, McNemar paired comparisons, and Cohen's κ to evaluate agreement and differences between the standard and modified approaches.

Key Results

• Feasibility and Data Availability: Patient-performed neck encirclement was substantially more available than measured neck circumference (94.0% vs. 71.3%). Consequently, replacing the neck circumference item increased the overall availability of a calculable NoSAS score from 68.8% to 91.3%.
• Agreement: There was substantial agreement between measured neck circumference and patient-performed encirclement (κ = 0.635).
• Diagnostic Performance:
  • As an isolated criterion, neck encirclement showed numerically higher sensitivity and comparable specificity for identifying both moderate-to-severe and severe OSA compared to measured circumference, though these differences were not statistically significant in paired analyses.
  • At the score level, the "NoSAS hand" preserved the diagnostic performance of the standard NoSAS score. Sensitivity and specificity for both AHI thresholds remained similar, with no significant differences observed in paired comparisons.
• Missing Data Analysis: Patients with missing neck circumference measurements exhibited higher AHI values and a greater prevalence of severe OSA compared to those with available measurements, suggesting that missingness in routine practice is not random and may disproportionately affect high-risk patients.

Significance and Claims
The paper claims that substituting measured neck circumference with patient-performed neck encirclement represents a pragmatic, equipment-free alternative that substantially improves the feasibility of OSA screening in routine clinical practice. The authors argue that this simple maneuver facilitates the implementation of the NoSAS score by reducing missing data, particularly in settings constrained by time or operator variability.

Crucially, the study demonstrates that this adaptation preserves the overall diagnostic performance of the NoSAS score. The authors suggest that the encirclement maneuver may offer a more individualized assessment of neck morphology by relating neck size to the patient's own hand dimensions, potentially overcoming the limitations of fixed anthropometric thresholds. While the study acknowledges limitations—including its single-center, tertiary referral design and the potential infeasibility of the maneuver for patients with upper-limb disabilities—it concludes that the approach offers a meaningful advantage for improving case detection and screening implementation without requiring specific equipment.