Quality of Life in Patients with Obstructive Sleep Apnea: Statistical Analysis
Apneic variations were classified using the following definitions: apnea was present when there was at least an 80% reduction in airflow for > 10 s, obstructive apnea was present when respiratory efforts were present, central apnea was present when respiratory efforts were absent, and mixed apneas occurred when there was a central component followed by an obstructive component. Hypopneas were scored when there was a 50 to 80% decrease in the airflow signal with > 4% decrease in arterial oxygen saturation. The optimal nCPAP level during the sleep study was the lowest pressure associated with the least number of respiratory events and arousals and the highest sleep efficiency.
Data are presented as mean ± SE. Each subject served as his/her own control. The baseline SF-36 parameters were compared with normative data for the same age group using an unpaired Student’s t test. The impact of comorbidity on baseline SF-36 parameters was analyzed using analysis of variance. The effects of nCPAP therapy on each patient were analyzed using a paired Student’s t test. The p value was corrected for multiple comparisons using the Bonferroni adjustment. Canadianfamilypharmacy Link A linear regression analysis was used to examine the correlation between anthropometric characteristics, indicators of sleep apnea severity, and SF-36 measures.
Twenty-nine patients (23 were male, and 6 were female) were included in this study. The average age of the patients was 44.4 ± 2.3 years old (range, 23 to 68); the average body mass index was 36.3 ± 2.0 kg/height (m)2 (range, 21.9 to 54.1). Eight patients had no comorbidities; the others had histories of coronary heart disease, hypertension, COPD, diabetes mellitus, and/or arthritis. All of the patients were medically stable at the time of their initial evaluation and on follow-up. On average, the patients had severe OSA with RDI of 77 ± 9 events/h when sleeping (range, 15 to 200). The apneas were associated with arterial oxygen desaturation, which decreased from 94.1 ± 0.3% while awake to 79.0 ± 2.1% during sleep (p < 0.001). The severity of sleep apnea and sleep fragmentation for each patient is shown in Figure 1. Sleep was markedly fragmented during the baseline period, with an increased arousal index of 67 ± 7 arousals/h.
Figure 1. Arousal index and RDI before and after nCPAP therapy. The side bars denote mean ± SE.