Characterisation and impact of reported and unreported exacerbations: results from ATTAIN

The frequency and impact of exacerbations identified using healthcare resource utilisation (HCRU) or the EXAcerbations of Chronic pulmonary disease Tool (EXACT) were compared prospectively in a 24-week, phase III trial (ATTAIN). Patients with moderate-to-severe chronic obstructive pulmonary disease received twice-daily adidinium 200 mu g, aclidinium 400 mu g or placebo. All HCRU events were reported to physicians. "EXACT-identified" events were categorised as "EXACT-reported" (detected by EXACT and reported to the physician) and "EXACT-unreported" (detected but not reported). Health status was measured using the St George's Respiratory Questionnaire (SGRQ). Annualised EXACT-identified event rates were higher in all study arms (placebo 1.39, adidinium 200 fig 1.00 and adidinium 400 mu g 0.98 per patient per year) versus HCRU (placebo 0.60, adidinium 200 mu g 0.43 and aclidinium 400 mu g 0.40 per patient per year). Concordance between methods was low (kappa 0.16). Adidinium reduced EXACT-identified events (rate ratio versus placebo: aclidinium 200 mu g 0.72 and aclidinium 400 mu g 0.71; both p<0.05); HCRU events were similarly reduced. At week 24, SGRQ scores improved (-6.6 versus baseline) in patients with no event during weeks 1-12; improvements were significantly smaller in patients with HCRU events (-3.4; p=0.036) or EXACT-unreported events (-3.0; p=0.002). Unreported events were more frequent than reported events. Both had similar negative impact on health status. Aclidinium reduced the frequency of both types of event.