Decision making for position-dependent obstructive sleep apnea syndrome on the basis of patient information and physical examinations of the upper airway, acquired on an outpatient basis.

CONCLUSIONS

Patients with body mass index (BMI) < 25 kg/m2 and obstructive sleep apnea syndrome (OSAS) are highly suspicious for position-dependent OSAS. Diagnosis of position-dependent/position-independent OSAS can be difficult in patients satisfying both 'BMI >25 kg/m2' and 'any of tongue enlargement (TE), palatine tonsil hypertrophy (PTH) and obstruction by Muller's maneuver (OMM)'. Polysomnography is warranted in such patients.

OBJECTIVES

The objective was to retrospectively elucidate criteria for differentiating position-dependent OSAS on the basis of patient information and physical examinations of the upper airway obtainable in clinics.

METHODS

The 643 patients were categorized as positional patients (PPs) or non-positional patients (NPPs). The patient background factors examined were sex, age, BMI, and hypertension. TE, PTH, pharyngeal tonsil hypertrophy, and OMM were evaluated. Cross-validation was performed using even-numbered registrations as the training set group (Group A) and odd-numbered registrations as the test case group (Group B).

RESULTS

In Group A, patients with BMI <25 kg/m2 were clearly more frequent among PP than among NPP. In Group A with BMI ≥25 kg/m2, significant differences were found for TE, PTH and OMM. Significant differences were found between 0 and 1/2/3 for number of factors. Results generated from Group A were validated in Group B.