Meta-analysis Does Not Establish Effectiveness of the Device

Abstract

This letter is regarding the article “Effects of CPAP and Mandibular Advancement Devices on Health-Related Quality of Life in OSA: A Systematic Review and Meta-analysis” by Kuhn et al1Kuhn E. Schwarz E.I. Bratton D.J. Rossi V.A. Kohler M. Effects of CPAP and mandibular advancement devices on health-related quality of life in OSA: a systematic review and meta-analysis.Chest. 2017; 151: 786-794Abstract Full Text Full Text PDF PubMed Scopus (67) Google Scholar published in CHEST (April 2017). The statement that “MADs (mandibular advancement devices) may be just as effective…” is incorrect. The current meta-analysis does not establish the effectiveness of the devices. “Decision makers making use of results of network meta-analyses will need to assess whether the differences between treatments are most likely true or whether they can be explained by bias in the analysis.” The internal validity of the analysis is contingent on three factors: appropriate identification of the studies that make up the evidence network, quality of the individual randomized controlled trials, and extent of confounding bias due to similarity and consistency violations.2Jansen J.P. Fleurence R. Devine B. et al.Interpreting indirect treatment comparisons and network meta-analysis for health-care decision making: report of the ISPOR Task Force on Indirect Treatment Comparisons Good Research Practices: part 1.Value in Health. 2011; 14: 417-428Abstract Full Text Full Text PDF PubMed Scopus (736) Google Scholar As there are no high-quality randomized controlled trials available to compare the two devices, the network analysis cannot conclude the effectiveness of the devices. The authors also state that “OSA can be effectively treated, but the decision whether to initiate therapy is primarily based on symptoms.” It is unlikely that any of the patients will be getting a polysomnogram or home sleep test in the absence of clinical symptoms, as The US Preventive Task Force has concluded that the current evidence is insufficient to assess the balance of benefits and harms of screening for OSA in asymptomatic adults.3US Preventive Services Task ForceScreening for obstructive sleep apnea in adults: US Preventive Services Task Force recommendation statement.JAMA. 2017; 317: 407-414Crossref PubMed Scopus (117) Google Scholar The guidelines do recommend treating patients with mild OSA only in the presence of symptoms. However, to state that “MADs may be just as effective…” may be a little premature without any clear evidence. Efficacy reflects the ability of treatment to prevent the occurrence of obstructive breathing events during periods when the treatment is being physically applied. This is assessed by the number of obstructive breathing events per hour of sleep or the apnea-hypopnea index (AHI). An AHI < 5 events/h indicates absence of disease or a completely efficacious treatment. In a fully compliant patient (using treatment for 100% of sleep time), efficacy measured as AHI on treatment will give an accurate reflection of OSA treatment effectiveness.4Sutherland K. Phillips C.L. Cistulli P.A. Efficacy versus effectiveness in the treatment of obstructive sleep apnea: CPAP and oral appliances.J Dental Sleep Med. 2015; 2: 175-181Crossref Google Scholar For patients with moderate to severe OSA, the odds of achieving the target AHI were significantly greater with CPAP than with oral appliances.5Ramar K. Dort L.C. Katz S.G. et al.Clinical practice guideline for the treatment of obstructive sleep apnea and snoring with oral appliance therapy: an update for 2015.J Clin Sleep Med. 2015; 11: 773-827Crossref PubMed Scopus (424) Google Scholar However, it is reasonable to offer OA as an alternative treatment when the patients have tried or are intolerant to CPAP therapy, especially in mild to moderate OSA. Effects of CPAP and Mandibular Advancement Devices on Health-Related Quality of Life in OSA: A Systematic Review and Meta-analysisCHESTVol. 151Issue 4PreviewUntreated OSA is associated with impaired health-related quality of life (QoL) and excessive daytime sleepiness, which have been shown to improve with treatment. The aim was to compare the effects of CPAP and a mandibular advancement device (MAD) on health-related QoL in OSA. Full-Text PDF ResponseCHESTVol. 152Issue 5PreviewWe would like to thank Dr Hunasikatti for his interest in our study.1 He raised some concerns about the validity and interpretation of our network meta-analysis. In this regard he argues that because “there are no high-quality randomized controlled trials available to compare the two devices, the network analysis cannot conclude the effectiveness of the devices.” However, an important point has been missed: Networks of randomized controlled trials can be evaluated in the context of a network meta-analysis, which permits inferences into the comparative effectiveness of interventions that have not been evaluated directly against each other. Full-Text PDF