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It is unknown whether heterogeneity in effects of self-management interventions in patients with chronic obstructive pulmonary disease (COPD) can be explained by differences in programme characteristics. This study aimed to identify which characteristics of COPD self-management interventions are most effective.Systematic search in electronic databases identified randomised trials on self-management interventions conducted between 1985 and 2013. Individual patient data were requested for meta-analysis by generalised mixed effects models.14 randomised trials were included (67% of eligible), representing 3282 patients (75% of eligible). Univariable analyses showed favourable effects on some outcomes for more planned contacts and longer duration of interventions, interventions with peer contact, without log keeping, without problem solving, and without support allocation. After adjusting for other programme characteristics in multivariable analyses, only the effects of duration on all-cause hospitalisation remained. Each month increase in intervention duration reduced risk of all-cause hospitalisation (time to event hazard ratios 0.98, 95% CI 0.97-0.99; risk ratio (RR) after 6 months follow-up 0.96, 95% CI 0.92-0.99; RR after 12 months follow-up 0.98, 95% CI 0.96-1.00).Our results showed that longer duration of self-management interventions conferred a reduction in all-cause hospitalisations in COPD patients. Other characteristics are not consistently associated with differential effects of self-management interventions across clinically relevant outcomes., (The content of this work is not subject to copyright. Design and branding are copyright ©ERS 2016.)

Not all exacerbations are captured by reliance on healthcare contacts. Symptom-based exacerbation definitions have shown to provide more adequate measures of exacerbation rates, severity and duration. However, no consensus has been reached on what is the most useful method and algorithm to identify these events. This article provides an overview of the existing symptom-based definitions and tests the hypothesis that differences in exacerbation characteristics depend on the algorithms used. We systematically reviewed symptom-based methods and algorithms used in the literature, and quantified the impact of the four most referenced algorithms on exacerbation-related outcome using an existing chronic obstructive pulmonary disease (COPD) cohort (n = 137). We identified 51 studies meeting our criteria using 14 widely varying symptom algorithms to define onset, severity and recovery. The most (71%) frequently referenced algorithm (modified Anthonisen) identified an incidence rate of 1.7 episodes·patient-yr⁻¹ (95% CI 1.4-2.1), while for requiring only one major or two major symptoms this was 1.9 episodes·patient-yr⁻¹ (95% CI 1.6-2.3) and 1.5 episodes·patient-yr⁻¹ (95% CI 0.6-1.0), respectively. Studies were generally lacking methods to enhance validity and accuracy of symptom recording. This review revealed large inconsistencies in definitions, methods and accuracy to define symptom-based COPD exacerbations. We demonstrated that minor changes in symptom criteria substantially affect incidence rates, clustering type and classification of exacerbations.