[Year:2012] [Month:April-June] [Volume:7] [Number:2] [Pages:7] [Pages No:55 - 61]
Objective: Primary objective of the study was to assess the prevalence of depression and anxiety among obstructive sleep apnoea (OSA) patients presenting to the sleep clinic of Safdarjung Hospital. Secondary aim was to study the correlation between and severity of depression, anxiety and respiratory disturbance index (RDI) and to see any relation with gender.
Study design: Case–control study.
Materials and Methods: One hundred seventy-two patients with OSA were evaluated before treatment and compared with controls by using the Patient Health Questionnaire-9 (PHQ-9) and anxiety on the basis of General Anxiety Disorder Assessment-7 score (GAD-7). Based on these scores, depression and anxiety were categorised as mild, moderate and severe, respectively. OSA was assessed by Epworth Sleepiness Scale, and polysomnography was used for sleep scoring and classified to mild, moderate and severe OSA by RDI.
RESULTS: Depressive symptoms were identified in 14% (25 of 172) of controls, and 36.4% (62 of 172) of patients with OSA by using PHQ-9 screening (P<0.006). Anxiety was identified in 19.2% (33 of 172) OSA patients as compared to 6.7% of controls. Evaluation of the patients with OSA compared to the control group showed depression and anxiety to be significantly more common in OSA patients than in controls (P-values 0.006 and 0.01, respectively). Overall, 41.9% and 58.1% of men and women, respectively, with OSA had elevated PHQ-9 scores; 05% and 11% of male and female control patients, respectively, exhibited depressive symptoms (P<0.001). In all, 75.75% patients were female OSA cases with symptoms of anxiety (25 of 33), while 24.25% were male (P<0.02) as screened by GAD- 7 scores. Analysis of depression scores by OSA disease severity category found significant difference in depressive symptoms between participants with mild OSA, moderate OSA and severe OSA (P-value <0.006). In this study, the association between OSA disease severity (as determined from the RDI) and PHQ-9 on univariate analysis (P ¼ .OO) was significant, with association found (P-value<0.003) on multivariable analysis, after controlling for sex. Partial linearity was noted. Analysis of anxiety scores by GAD-7 scores found no significant difference in anxiety symptoms between subgroups with mild, moderate and severe OSA (P-value <0.23) on univariate analysis, association between disease severity 0f OSA and GAD-7 scores was not significant, however, on multivariate analysis ruling out confounding factors like sex was significant (P-value <0.003).
CONCLUSIONS: Patients with OSA and daytime sleepiness are more likely to have depressive and anxiety symptoms as compared with controls. OSA disease severity, as measured with the RDI score, is a predictor of PHQ-9 score, but no correlation was seen between the severity of OSA and GAD-7 scores. These data suggest that OSA patients with symptoms of excessive sleepiness have the highest risk of associated depressive symptoms and may benefit most from depression screening.