The Effects Of Heated Humidification On Compliance And Subjective Daytime Sleepiness In Patients With Obstructive Sleep Apnea Syndrome:a Meta-analysis

Background:The benefits of heated humidification during PAP on upper airway side effects,particularly on reducing the dryness of nose,mouth,throat and complaints of nasal congestion are well established.Other than attenuating of symptoms,whether heated humidification can improve PAP compliance and subjective daytime sleepiness remain unclear since previous studies yielded inconsistent results.Objective:To perform a systematic review and meta-analysis in patients with obstructive sleep apnea syndrome,evaluating the effects of heated humidification on PAP compliance and subjective daytime sleepiness.Methods:We searched PubMed,EMBASE,Medline,Cochrane Library,Clinical Trials,Web of Science and Scopus from inception to Oct,2017.The randomized controlled trials which assessed effects of heated humidification on PAP compliance and subjective daytime sleepiness were included.Results:A total of ten eligible randomized controlled trials were evaluated finally in this meta-analysis.We put emphasis on two outcomes from included studies,PAP usage time and Epworth sleepiness scale score.When all the studies were pooled,heated humidification did not improve PAP usage time in both APAP subgroup(WMD = 22.34,95%CI:-21.08～65.77,P = 0.31)and CPAP subgroup(WMD = 11.09,95%CI:-10.21～32.40,P = 0.31).And it was also ineffective in enhancing compliance among patients with upper airway symptoms prior to PAP therapy(WMD = 28.90,95%CI:-14.55～72.35,P = 0.19)or patients without upper airway symptoms prior to PAP therapy(WMD = 4.95,95%CI:-29.83～39.73,P = 0.78).In terms of ESS score,heated humidification did not reduce ESS scores in both APAP subgroup(WMD =-1.59,95%CI:-3.81～0.64,P=0.16)and CPAP subgroup(WMD =-0.38,95%CI:-1.08～0.33,P =0.29).And it was also unhelpful in reducing ESS scores among patients with upper airway symptoms prior to PAP therapy(WMD =-1.72,95%CI:-5.05～1.61,P = 0.31)or patients without upper airway symptoms prior to PAP therapy(WMD =-0.58,95%CI:-1.90～0.74,P = 0.39).Conclusion:Current studies indicated heated humidification during PAP therapy improved neither the compliance nor ESS scores in OSAS patients,no matter what types of PAP or whether the patients had upper airway symptoms prior to PAP therapy or not.But conclusion based on population with upper airway symptoms was limited because of small sample size and possible selection bias.In future,more attentions are needed to concentrate on OSAS patients with upper airway symptoms so that work may be targeted on potentially possible benefited subgroup.