The clinical effectiveness and cost-effectiveness of inhaler devices used in the routine management of chronic asthma in older children: a systematic review and economic evaluation

摘要

Background:ududThis review examines the clinical effectiveness andudcost-effectiveness of hand-held inhalers to deliverudmedication for the routine management of chronicudasthma in children aged between 5 and 15 years.udAsthma is a common disease of the airways, with audprevalence of treated asthma in 5–15-year-olds ofudaround 12% and an actual prevalence in the communityudas high as 23%. Treatment for the conditionudis predominantly by inhalation of medication. Thereudare three main types of inhaler device, pressurisedudmetered dose, breath actuated, and dry powder, withudthe option of the attachment of a spacer to the firstudtwo devices under some prescribed circumstances.udTwo recent reviews have examined the clinical andudcost-effectiveness evidence on inhaler devices, butudone was for children aged under 5 years and theudcomparison in the second was made between pressurisedudmetered dose inhalers and other types only.ududObjectives:ududThis review examines the clinical effectiveness andudcost-effectiveness of manual pressurised metereduddose inhalers, breath-actuated metered doseudinhalers, and breath-actuated dry powder inhalers,udwith and without spacers as appropriate, to deliverudmedication for the routine management of chronicudasthma in children aged between 5 and 15 years.ududMethods:ududTwo previous HTA reviews have compared theudeffectiveness of inhaler devices, one focusing onudasthma in children aged under 5 years and theudother on asthma and chronic obstructive airwaysuddisease in all age groups. For the current review, audliterature search was carried out to identify alludevidence relating to the use of inhalers in olderudchildren with chronic asthma. A search of in-vitroudstudies undertaken for one of the previous reviewsudwas also updated.ududThe data sources used were: 15 electronic bibliographicuddatabases; the reference lists of one of theudprevious HTA reports and other relevant articles;udhealth services research-related internet resources;udand all sponsor submissions.ududStudies were selected according to strict inclusionudand exclusion criteria, and relevant informationudconcerning effectiveness and patient complianceudand preference was extracted directly on to anudextraction/evidence table. Quality assuranceudwas monitored.ududEconomic evaluation was undertaken by reviewingudexisting cost-effective evidence. Further economicudmodelling was carried out, and tables constructedudto determine device cost-minimisation andudincremental quality-adjusted life-year (QALY)udthresholds between devices.ududResults:ududNumber and quality of studies, anduddirection of evidence: ududFourteen randomised controlled studies wereudidentified relating to the clinical effectiveness ofudinhaler devices for delivering β2-agonists. A furtherudfive were on devices delivering corticosteroids andudone concerned the delivery of cromoglicate.udOverall, there were no differences in clinicaludefficacy between inhaler devices, but a pressurisedudmetered dose inhaler with a spacer would appearudto be more effective than one without. Theseudfindings endorse those of a previous HTA reviewudbut extend them to other inhaler devices.udSeven randomised controlled trials examined theudimpact on clinical effectiveness of using a nonchlorofluorocarbonud(CFC) propellant in place ofuda CFC propellant in metered dose inhalers, bothudpressurised and breath activated, although only oneudstudy considered the latter type. No differences wereudfound between inhalers containing either propellant.udA further 30 studies of varying quality, from 12 randomisedudcontrolled trials to non-controlled studies,udwere identified that concerned the impact of useudby, and preference for, inhaler type, and treatmentudadherence in children. Differences between theudstudies, and limitations in comparative data betweenudvarious inhaler device types, make it difficult to drawudany firm conclusions from this evidence. ududSummary of benefits:ududNo obvious benefits for one inhaler device typeudover another for use in children aged 5–15 yearsudwere identified.ududCosts and cost per quality-adjustedudlife-year:ududTwo approaches have been taken: cost-minimisationudand QALY threshold. In the QALY thresholdudapproach, additional QALYs that each device mustudproduce compared with a cheaper device to achieveudan acceptable cost per QALY were calculated. Usingudthe cheapest and most expensive devices for deliveringud200 μg of beclometasone per day, assuming noudcost offset for any device, and a threshold of £5000,udthe largest QALY needed was 0.00807. With suchuda small QALY increase, no intervention can beudcategorically rejected as not cost-effective.ududConclusions:ududGeneralisability of findings:ududOn the available evidence there are no obviousudbenefits for one inhaler device over anotherudwhen used by children aged 5–15 years withudchronic asthma. However, the evidence, in theudmajority of cases, was compiled on childrenudwith mild to moderate asthma and restrictedudto a limited number of drugs. Therefore theudfindings may not be generalisable to those atudthe more severe end of the spectrum of theuddisease or to inhaler devices delivering someudof the drugs used in the management of asthma.ududNeed for further research:ududMany of the previous studies are likely toudhave been underpowered. Further clinicaludtrials with a robust methodology, sufficientudpower and qualitative components are neededudto demonstrate any differences in clinicaludresource use and patients’ asthma symptoms.udFurther studies should also include theudbehavioural aspects of patients towards theirudmedication and its delivery mechanisms.udIt is acknowledged that sufficient power mayudprove impractical owing to the large numbersudof patients required.