[Risk for sleep apnea syndrome and excessive daily sleepiness in chronic hemodialysis patients].

UNLABELLED

Sleeping disorders are common among chronic hemodialysis (HD) patients and obstructive sleep apnea (OSA) syndrome frequency is often underestimated.

AIM

fo examine the risk for OSA in chronic HD patients.

METHOD

The study included all chronic HD patients in University Hospital Osijek (N=180), mean age 63 years, 92 men. They were treated by maintenance HD for median 3 years (0-26). The patients fulfilled the Croatian version of STOP and Epworth Sleepiness Scale (ESS) questionnaires.

RESULTS

According to the STOP questionnaire, 80.6% of the patients have the risk for OSA, with significant difference in gender distribution (P=0.002). 27.2% of the patients declared excessive daytime sleepiness. The patients at risk for OSA have significantly more expressed excessive daytime sleepiness in comparison with the patients without the risk (P=0.017). 55% of the patients were obese, without more expressed excessive daytime sleepiness. Mean daytime sleepiness score was 4.41. According to the ROC analysis, the cutoff score for the risk for OSA assessed by STOP questionnaire at ESS was 2, with sensitivity 71% and specificity 57,1% (AUC 0.644, P=0.003). OSA related risks and comorbidities were present in the forms of snoring in 43,3%, excessive daytime sleepiness in 77,2%. observed apnea during sleep in 6.7%, arterial hypertension in 90%, diabetes mellitus in 6.7%, asthma in 7.8%, depression in 10.6% and gastroesophageal reflux in 38% patients.

DISCUSSION

Chronic HD patients in the University Hospital Osijek have high risk for OSA, with significant gender related difference more frequent in women). Epidemiologic studies of OSA to date showed higher prevalence in men. Increase in the global prevalence of obesity goes along with OSA prevalence. Our study did not find obesity to be a risk for OSA. Furthermore, our study showed lower value of cut-off score in excessive daytime sleepiness as the risk for OSA according to the STOP questionnaire than was officially recommended for ESS. Mean daytime sleepiness score determined by our study of 4.41 was obviously lower than in several other studies on thc patients diagnosed with sleeping disorders. The survey performed in the Centre for Sleeping Medicine in Split proposed ethnicity, life habits, sociologic and cultural factors as reasons for such broad variations in the results of mean daytime sleepiness obtained in their and other authors' studies Both the STOP questionnaire and the ESS can successfully discriminate healthy from OSA subjects. However, STOP questionnaire showed to be better predictor for OSA than ESS in the Centre for Sleeping Medicine in the Split survey. While our study found significantly less patients with excessive daytime sleepiness (according to the results of ESS) than the proportion of the patients at risk for OSA by STOP questionnaire (with significantly higher daytime sleepiness in the patients at risk or OSA), polysomnography should be performed in the patients at risk and the results compared afterwards. Objective measurements are needed, but this does not change the fact that there is still a need for studies aimed to find clinical predictors for OSA for different countries with distinct life habits and different languages. Therefore, standardized questionnaire version is necessary.

CONCLUSION

The patients on chronic HD in University Hospital Centre Osijek had high frequency of risk for sleep apnea syndrome, especially women. The risk related risks and comorbidities in those patients were also common. Excessive daytime sleepiness was significantly higher in those with risk for OSA and the risk related cut-off score for excessive daily sleepiness was lower than the official for ESS. Polysomnography should be performed in the patients at risk also to assess specificity of STOP and ESS questionnaires in the patients at maintenance HD.