title: Pitfalls in processing home electronic spirometric data in asthma.
abstract: Electronic spirometers offer the prospect of paperless home monitoring, but data quality is not automatically better than from conventional monitoring. The aim of this study was to determine the extent to which the quality and processing of self-recorded spirometric data from patients with asthma complied with international guidelines for spirometry. Data were from 33 subjects with poorly controlled asthma who had completed the first 9 weeks of a clinical budesonide trial. MicroMedical DiaryCard electronic spirometers were used to record three spirometric manoeuvres in twice-daily sessions. Confounding events were recorded in a paper diary. Within-session reproducibility was calculated for forced expiratory volume in one second (FEV1), forced vital capacity (FVC) and peak expiratory flow (PEF) during the first week of run-in and week 9 of budesonide treatment. Geometric means of within-session reproducibility (mean difference between highest and second-highest value from each session over a one-week period) for FEV1, FVC and PEF were 76 mL, 116 mL and 18 L x min(-1), respectively, during run-in. Times of spirometric sessions varied widely, with some overlap between morning and evening session times. Manoeuvre-induced falls in PEF and FEV1 occurred only as often as expected by chance. Nonasthma events including equipment faults and painful conditions caused changes in spirometric results. Home spirometric monitoring can be carried out with excellent reproducibility in patients with asthma. However, quality-control issues are complex and an accompanying paper diary remains essential.
authors.affiliation: Institute of Respiratory Medicine, Royal Prince Alfred Hospital and Dept of Medicine, University of Sydney, Camperdown, NSW, Australia.
authors.forename: H K
authors.initials: HK
authors.lastname: Reddel
authors.forename: S I
authors.initials: SI
authors.lastname: Ware
authors.forename: C M
authors.initials: CM
authors.lastname: Salome
authors.forename: C R
authors.initials: CR
authors.lastname: Jenkins
authors.forename: A J
authors.initials: AJ
authors.lastname: Woolcock
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000893:Anti-Inflammatory Agents / Q000008:administration & dosage*; D001249:Asthma / Q000175:diagnosis* / Q000188:drug therapy*; D019819:Budesonide / Q000008:administration & dosage*; D004582:Electronics, Medical; D005260:Female; D006701:Home Nursing; D006801:Humans; D008297:Male; D008875:Middle Aged; D008991:Monitoring, Physiologic / Q000295:instrumentation; D010366:Peak Expiratory Flow Rate / Q000187:drug effects; D015203:Reproducibility of Results; D012648:Self Care / Q000592:standards*; D012680:Sensitivity and Specificity; D013147:Spirometry / Q000379:methods / Q000592:standards*
chemical_list: D000893:Anti-Inflammatory Agents; D019819:Budesonide