Lonneke M. Boer

Validity of an automated telephonic system to assess COPD exacerbation rates

Current tools for recording chronic obstructive pulmonary disease (COPD) exacerbations are limited and often lack validity testing. We assessed the validity of an automated telephonic exacerbation assessment system (TEXAS) and compared its outcomes with existing tools. Over 12 months, 86 COPD patients (22.1% females; mean age 66.5 yrs; mean post-bronchodilator forced expiratory volume in 1 s 53.4% predicted) were called once every 2 weeks by TEXAS to record changes in respiratory symptoms, unscheduled healthcare utilisation and use of respiratory medication. The responses to TEXAS were validated against exacerbation-related information collected by observations made by trained research assistants during home visits. No care assistance was provided in any way. Diagnostic test characteristics were estimated using commonly used definitions of exacerbation. Detection rates, compliance and patient preference were assessed, and compared with paper diary cards and medical record review. A total of 1,824 successful calls were recorded, of which 292 were verified by home visits (median four calls per patient, interquartile range three to five calls per patient). Independent of the exacerbation definition used, validity was high, with sensitivities and specificities between 66% and 98%. Detection rates and compliance differed extensively between the different tools, but were highest with TEXAS. Patient preference did not differ. TEXAS is a valid tool to assess COPD exacerbation rates in prospective clinical studies. Using different tools to record exacerbations strongly affects exacerbation occurrence rates.

'Exacerbation-free time' to assess the impact of exacerbations in patients with chronic obstructive pulmonary disease (COPD): a prospective observational study

COPD exacerbations are commonly quantified as rate per year. However, the total amount of time a patient suffers from exacerbations may be stronger related to his or her disease burden than just counting exacerbation episodes. In this study, we examined the relationship between exacerbation frequency and exacerbation-free time, and their associations with baseline characteristics and health-related quality of life. A total of 166 COPD patients reported symptom changes during 12 months. Symptom-defined exacerbation episodes were correlated to the number of exacerbation-free weeks per year. Analysis of covariance was used to examine the effects of baseline characteristics on annual exacerbation frequency and exacerbation-free weeks, Spearman’s rank correlations to examine associations between the two methods to express exacerbations and the Chronic Respiratory Questionnaire (CRQ). The correlation between exacerbation frequency and exacerbation-free weeks was −0.71 (p < 0.001). However, among frequent exacerbators (i.e., ≥3 exacerbations/year, n = 113) the correlation was weak (r = −0.25; p < 0.01). Smokers had less exacerbation-free weeks than non-smokers (β = −5.709, p < 0.05). More exacerbation-free weeks were related to better CRQ Total (r = 0.22, p < 0.05), Mastery (r = 0.22, p < 0.05), and Fatigue (r = 0.23, p < 0.05) scores, whereas no significant associations were found between exacerbation frequency and CRQ scores. In COPD patients with frequent exacerbations, there is substantial variation in exacerbation-free time. Exacerbation-free time may better reflect the burden of exacerbations in patients with COPD than exacerbation frequency does.Chronic lung disease: The importance of exacerbation durationTime spent exacerbation-free may provide a stronger indication of disease burden than exacerbation frequency for patients with chronic lung disease. Exacerbations in chronic obstructive pulmonary disease (COPD) are marked by a sudden decline in lung function, potential hospitalisation and a need to increase medication. Exacerbation frequency is used as a marker in COPD management, but this does not consider the duration of exacerbations or the impact this has on patients’ lives. Lonneke Boer at Radboud University Medical Center, the Netherlands, and co-workers questioned 166 patients every two weeks for a year about their experiences of exacerbation duration and frequency. There was substantial variation in exacerbation-free time between patients, with smokers most likely to suffer longer periods of poorer health. Exacerbation-free time was better correlated with health-related quality of life than exacerbation frequency.

Validation of ACCESS: an automated tool to support self-management of COPD exacerbations

Background To support patients with COPD in their self-management of symptom worsening, we developed Adaptive Computerized COPD Exacerbation Self-management Support (ACCESS), an innovative software application that provides automated treatment advice without the interference of a health care professional. Exacerbation detection is based on 12 symptom-related yes-or-no questions and the measurement of peripheral capillary oxygen saturation (SpO2), forced expiratory volume in one second (FEV1), and body temperature. Automated treatment advice is based on a decision model built by clinical expert panel opinion and Bayesian network modeling. The current paper describes the validity of ACCESS. Methods We performed secondary analyses on data from a 3-month prospective observational study in which patients with COPD registered respiratory symptoms daily on diary cards and measured SpO2, FEV1, and body temperature. We examined the validity of the most important treatment advice of ACCESS, ie, to contact the health care professional, against symptom- and event-based exacerbations. Results Fifty-four patients completed 2,928 diary cards. One or more of the different pieces of ACCESS advice were provided in 71.7% of all cases. We identified 115 symptom-based exacerbations. Cross-tabulation showed a sensitivity of 97.4% (95% CI 92.0–99.3), specificity of 65.6% (95% CI 63.5–67.6), and positive and negative predictive value of 13.4% (95% CI 11.2–15.9) and 99.8% (95% CI 99.3–99.9), respectively, for ACCESS’ advice to contact a health care professional in case of an exacerbation. Conclusion In many cases (71.7%), ACCESS gave at least one self-management advice to lower symptom burden, showing that ACCES provides self-management support for both day-to-day symptom variations and exacerbations. High sensitivity shows that if there is an exacerbation, ACCESS will advise patients to contact a health care professional. The high negative predictive value leads us to conclude that when ACCES does not provide the advice to contact a health care professional, the risk of an exacerbation is very low. Thus, ACCESS can safely be used in patients with COPD to support self-management in case of an exacerbation.