Correlation of daytime sleepiness with functional capacity and fatigue in obstructive sleep apnea patients

Obstructive Sleep Apnea (OSA) has been recognised as a major cause of morbidity and mortality in developing countries like India. It is characterised by repeated episode of partial (hypopnea) or complete (apnea) upper airway obstruction during sleep that lead to snoring, frequent episode of sleep interruption, hypoxemia, hypercapnia, swing in intrathoracic pressure and increased sympathetic activity. Excessive Daytime Sleepiness (EDS) is prominent symptom of Obstructive Sleep Apnea (OSA) and which is measured by Epworth sleepiness scale (ESS). Functional capacity is an important dimension in human functioning. The six- minute walk test is easier to administer, better tolerable and more representative of activities of daily living than any other walking test. Fatigue is primarily a subjective experience that includes physiological performance decrements and psychological impairments such as decreased morale, judgement and mood. Perception of fatigue measured by the Fatigue Severity Scale (FSS).

The Aim of our study was to find the correlation of epworth sleepiness scale with functional capacity and fatigue in obstructive sleep apnea patients.

It was a cross-sectional, observational, correlation study of 50 OSA patients. They were enrolled after fullfiled the inclusion criteria and were willing to participate in study. After obtaining the written consent, the participants were administrated epworth sleepiness scale, fatigue severity scale and made to perform six-minute walk test in pulmonary medicine Out Patient Department at tertiary health care hospital. The time required was 30-35 minutes.

Data was collected and analysed for normality by shapiro-wilk test. Since, the epworth sleepiness scale and fatigue severity scale are likert scale, Spearman’s rho correlation was done to find the correlation of epworth sleepiness scale with functional capacity and fatigue severity scale in obstructive sleep apnea patients.

It was observed that there is significant moderate negative correlation between Epworth Sleepiness Scale (ESS) and percentage predicted value of 6MWT (Functional Capacity) with r value of -0.597 and p value of 0.001. Also, a significant moderate positive correlation between Epworth Sleepiness Scale (ESS) and Fatigue Severity Scale (FSS) with r value of 0.492 and p value of 0.001 was observed. Thus, the alternate hypothesis was proved to be corrected.