London Chronic Obstructive Pulmonary Disease Research Articles

Detection and severity grading of COPD exacerbations using the exacerbations of chronic pulmonary disease tool (EXACT).

Uncertainty exists over the ability of the exacerbations of chronic pulmonary disease tool (EXACT) patient-reported outcome diary to quantify exacerbation severity and frequency. To clarify this, we investigated the ability of the EXACT to assess severity of exacerbations and examined the relationship between exacerbations diagnosed using London chronic obstructive pulmonary disease (COPD) cohort diary cards, physician review and symptom-defined events using the EXACT. 58 patients enrolled in the London Chronic Obstructive Pulmonary Disease (COPD) cohort prospectively completed the EXACT during 128 cohort diary card-defined exacerbations between January 2010 and April 2012. Mean ± sd EXACT scores increased from 42.6 ± 8.6 at baseline to 48.0 ± 8.6 at exacerbation onset (p<0.001), and rose further to a maximum score of 54.1 ± 8.9. Maximum EXACT scores were significantly higher in treated than untreated events. Time taken for EXACT scores to return to baseline was significantly related to symptom recovery time as judged by London COPD cohort diary cards, and to peak expiratory flow rate recovery. ∼50% of both diary card-defined and healthcare utilisation exacerbations crossed the EXACT event threshold. However, only 27.9% of diary card-defined and 34.6% of healthcare utilisation exacerbations fully met the criteria for an EXACT event. Patients exhibited smaller rises in the EXACT score at exacerbation as baseline disease severity increased. The EXACT is an effective method of evaluating chronic obstructive pulmonary disease exacerbation severity. However, concerns remain about the ability of the EXACT to accurately detect exacerbations.

Temporal Clustering of Exacerbations in Chronic Obstructive Pulmonary Disease

Exacerbations are important events in chronic obstructive pulmonary disease. Preventing exacerbations is a key treatment goal. Observational data suggest that after a first exacerbation, patients may be at increased risk of a second exacerbation, but this has not been specifically studied. We hypothesized that exacerbations may cluster together in time, a finding that would have important implications for targeting preventative interventions and the analysis of clinical trial data. To assess whether exacerbations are random events, or cluster in time. A total of 297 patients in the London chronic obstructive pulmonary disease cohort recorded daily symptoms and were assessed for a total of 904 patient-years. The observed timing of second exacerbations after an initial exacerbation was compared with that expected should exacerbations occur randomly. The observed timing distribution of second exacerbations differed significantly (P < 0.001) from the expected exponential function (shape parameter of the fitted Weibull function, 0.966 [95% confidence interval, 0.948-0.985]), suggesting that more second exacerbations occurred sooner than later and that exacerbations cluster together in time. Twenty-seven percent of first exacerbations were followed by a second recurrent event within 8 weeks. Approximately one third of exacerbations were recurrent exacerbations. Although initial exacerbations were milder than isolated events, they were not less likely to receive treatment, and under-treatment of initial events is not a plausible explanation for exacerbation recurrence. Recurrent exacerbations contribute significantly to overall exacerbation frequency (rho = 0.81; P < 0.0001). Exacerbations are not random events but cluster together in time such that there is a high-risk period for recurrent exacerbation in the 8-week period after an initial excerbation.

Temporal Clustering of Exacerbations in Chronic Obstructive Pulmonary Disease

Rationale: Exacerbations are important events in chronic obstructive pulmonary disease. Preventing exacerbations is a key treatment goal. Observational data suggest that after a first exacerbation, patients may be at increased risk of a second exacerbation, but this has not been specifically studied. We hypothesized that exacerbations may cluster together in time, a finding that would have important implications for targeting preventative interventions and the analysis of clinical trial data.Objectives: To assess whether exacerbations are random events, or cluster in time.Methods: A total of 297 patients in the London chronic obstructive pulmonary disease cohort recorded daily symptoms and were assessed for a total of 904 patient-years. The observed timing of second exacerbations after an initial exacerbation was compared with that expected should exacerbations occur randomly.Measurements and Main Results: The observed timing distribution of second exacerbations differed significantly (P < 0.001) from the...