Purpose: Many Veterans Affairs Medical Centers (VAMCs) have implemented home sleep apnea testing (HSAT) in lieu of traditional in-lab testing to establish a timely and cost-sensitive diagnosis of obstructive sleep apnea (OSA). However, concern remains for the sensitivity and specificity of said technology in this population as many veterans are at increased risk for many of the comorbid conditions that can limit the accuracy of HSAT results. Hence, the purpose of this study is to evaluate rate of incongruent outcomes (e.g., negative HSAT results despite high clinical symptomology) as well as differences in study quality metrics and predictors of OSA between veteran sleep patients and general sleep patients being evaluated by a home sleep test.
Methods: A random sample of HSAT outcomes from 1500 veterans and 1500 general sleep clinic patients was retrieved from a repository of anonymized HSAT outcomes from 2009 to 2013. General sleep clinic data were from patients referred for home sleep testing from a variety of clinical practices across North America, whereas VAMC patients were tested using a central dissemination process. All patients were tested for OSA using the Apnea Risk and Evaluation System (ARES), an HSAT that simultaneously records airflow, pulse oximetry, snoring, accelerometry, and EEG. Sample differences and rates of comorbidities, HSAT outcomes, predictors of OSA, and pretest OSA risk information were evaluated between groups. The presence of OSA was defined as an apnea-hypopnea index (AHI; using 4% desaturation criterion) of ≥5 and ≥15 events per hour. Sample differences in predictors of OSA were evaluated using logistic multiple regression.
Results: Veterans (91.3% male) were more likely to report comorbidities, especially depression, insomnia, hypertension, diabetes, restless legs syndrome (RLS), and use of sleep and pain medications compared to general sleep clinic patients (57.1% male). Despite differences in the rate of medical comorbidities, no differences were observed between groups with regard to rates of positive studies, study integrity indicators, or predictors of OSA. Veterans, on average, had 30 min less recording time compared to those in the general clinic sample (p < .01). However, these differences did not impact the amount of the record that was deemed valid nor were veterans more likely to have wakefulness after sleep onset. Predictors of OSA for both groups included advancing age, and increased measures of adiposity (neck circumference and BMI). Mean AHI and respiratory disturbance index (RDI) were statistically similar for both groups and were similar for sleep stage and position.
Conclusions: Home sleep apnea testing for the diagnosis of OSA appears to yield similar results for VAMC patients deemed at high risk for OSA as it does with general sleep clinic patients.
Keywords: HSAT; Home sleep test; Portable monitor; Veteran.