Measurement properties of a screening questionnaire of obstructive sleep apnea risk: Little information, great prediction?☆

Abstract

IntroductionPrevious research had shown the suitability of several questionnaires predicting the obstructive sleep apnea syndrome. Measurement properties of an online screening questionnaire were studied.MethodsThe sample consisted of 184 Portuguese adults (89 men and 95 women); 46 of them were polysomnographically diagnosed with the untreated obstructive sleep apnea syndrome. The participants were assessed with an online questionnaire of sleep apnea risk, from University of Maryland.ResultsA principal component factor analysis was performed, revealing a single factor (49.24% of the total variance). Internal consistency was minimally adequate (α=0.74). The mean of inter-item correlation was of 0.35 (0.12<r>0.61), whereas the item-total correlations were considered good (0.52<r>0.81). The total score for patients was significantly higher than for healthy participants (p<0.000), but no significant statistical differences between severity groups of patients were found (p>0.05).Furthermore, the ability of the measure in discriminating between healthy subjects and OSA subjects was good. Overall data from the Rasch analysis was consistent with the guidelines of Linacre, scores show good model fit and psychometric adequacy.ConclusionsThe measure showed an adequate structural, internal and criterion validity, suggesting this as a useful and effective screening for sleep apnea risk in Portuguese adults.

Sensitivity and specificity of Frontal Assessment Battery in newly diagnosed and untreated obstructive sleep apnea patients

“…With a simple and rapid application but with adequate discriminative power for ED in patients diagnosed with OSA, the FAB is an instrument that provides clinicians with a more informed decision about the need for more thorough neuropsychological examination. Our study presents a methodological limitation, derived from the fact that all OSA patients were evaluated by full-night PSG and QSAR while the testimony group was assessed only through QSAR using the normative values for the Portuguese population [42]. It is therefore desirable that in future studies, all participants are evaluated through PSG.…”

“…The total score is computed through the sum of item responses and represents a measure of sleep apnea risk (range 5e20, with higher results indicating greater sleep apnea risk). This measure showed adequate metric properties, with a cutoff point of 10.5 [42].…”

“…This consultation took place, on average, two weeks after the PSG. The remaining 20 participants (15 males and 5 females) had no symptoms of OSA (M ¼ 51.60 years old, SD ¼ 10.70) and scored below the cut-off score in a screening measure for the risk of OSA (Questionnaire for Sleep Apnea Risk [QSAR] [42]; and in a measure of excessive daytime sleepiness (Epworth Sleepiness Scale [ESS]; [66]. None of the participants used psychotropic drugs or presented a psychiatric diagnosis and concerning mood disorders, although 27.5% of patient group scored >13 in Beck Depression Inventory II (presence of mild to moderate depressive symptoms; [67].…”

“…The QSAR is a self-report questionnaire, freely available online [42], developed by the sleep disorders center of the University of Maryland as a screening tool for the risk of OSA. This instrument consists of five items describing the main features of the disorder, including symptoms observed by the patients or by others, anthropometric characteristics, daytime sleepiness (global score of ESS), and previous clinical conditions.…”

Use of the rasch model on nursing treatment of sleep disorders for cardiovascular post-surgery patients

“…The items used in the questionnaire follow the rating scale analysis (RSA), that according to the Rasch-Andrich model it is possible to construct measures from observations based on an ordinal rating scale according to this expression: The categories of the RSA must follow some guidelines for Andrich rating scales, 10,11 in particular they must show that thresholds (points with equal probability for two adjacent categories) are ordered, distinctly located and that no categories are missing or exceed the construct needs. In this analysis we used the Andrich rating scale model as usual in similar projects, 12,13 instead of the Masters Partial Credit used by other authors, 14 considering that it is a more parsimonious model and simpler to use by nurses because the categories are more evident for the complete instrument. In addition, the Andrich rating scale makes easier to assess unidimensionality of the scale and the structure of the data, in consequence each category has a real probability to be selected by the nurse for the patient's evaluation.…”