<p>Impact of symptom variability on clinical outcomes in COPD: analysis of a longitudinal cohort</p>

Abstract

PurposeWe compared clinical characteristics of COPD patients according to symptom variability and evaluated the effect of symptom variability during the first year of enrollment on clinical outcomes of COPD.MethodsWe analyzed COPD patients’ data from the Korean Obstructive Lung Disease (KOLD) cohort. Symptom variability was defined based on the value of standard deviation (SD) of mMRC scores obtained every 3 months during the follow-up period of the first year. Patients were divided into 2 groups: the consistent (SD of mMRC scores =0) and variable (SD of mMRC scores >0) groups. Clinical characteristics and outcomes were compared in terms of symptom variability.ResultsA total of 407 patients were included in the analysis. Patient age was 67.2 years and 97.8% of the subjects were male. Initial mMRC was 1.5 and the SD of mMRC scores during the first year was 0.5. There were 137 subjects (33.7%) in the consistent group and 270 (66.3%) in the variable group. The variable group showed a lower FEV1 (P=0.019) and a higher mMRC score (P=0.001). The annual incidence of acute exacerbation of COPD (AE-COPD) tended to be higher in the variable group (P=0.078) and that of severe AE-COPD was higher in the variable group than in the consistent group (P=0.002). The variable group showed a higher proportion of annual exacerbators (P=0.001) and frequent exacerbators (P=0.017). In multivariate logistic regression analysis, the variable group was significantly associated with annual exacerbators (OR =1.963, P=0.011) and frequent exacerbators (OR =2.090, P=0.055).ConclusionCOPD patients with symptom variability may have higher exacerbation risk as well as lower lung function and more severe respiratory symptoms.

Relevance of Symptom Variability for Control and Management of COPD

“…This type of exacerbations has a similar negative impact on health status as reported exacerbations 52 , so there is no way of knowing if they are real COPD exacerbations or if they just indicate a higher symptom variability period. In this context of uncertainty, some authors have suggested that symptom variability without medication change could be a risk factor for COPD exacerbation and poor prognosis, regardless of lung function and previous exacerbation history 18 .…”

“…Unfortunately, the impact of symptom variability in clinical control has not yet been studied in COPD. However, several studies have reported that early morning symptoms are associated with severe dyspnoea 16,18,43,62 , lower physical activity 43,63 , a higher use of rescue medication 39 , an increase in the number of exacerbations 12,14 or worse HRQoL 14,39 . Nighttime symptoms have also been associated with an increased risk of exacerbations and worse HRQoL 12,14,67,68 .…”

“…In a longitudinal study, Kim et al 18 found that COPD patients with symptom variability (the variable group) experienced more frequent exacerbations during the follow-up period. Furthermore, this variable setting of patients showed lower lung function, worse dyspnoea symptoms and poorer quality of life.…”

“…Several studies have reported that COPD-related symptoms are not perceived uniformly by patients, and that they show not just seasonal variation, but also changes in symptom perception over different weeks or even during a single day [9][10][11][12][13][14][15][16][17][18] . This time-dependent variability has important consequences since it has an impact on life activities, sleep quality, severity of symptoms, and exacerbations or HRQoL 10,12,[14][15][16][17][18][19] , which in turn represent a component of clinical instability within a period previously considered as relatively calm. This paper reviews in detail the symptomatic variability in COPD, its pathophysiological basis, characteristics, determinants, potential consequences and therapeutic implications.…”

Heavy shackles: The experience of symptom distress and coping behaviors of Chinese patients with chronic obstructive pulmonary disease

“…Drummond, Wise, & Hansel, 2015). Therefore, in addition to the characteristic respiratory symptoms, such as dyspnea, cough, and expectoration (Kim et al, 2019), they present other extrapulmonary symptoms, such as sleep disorders, fatigue, and muscle weakness (Goërtz et al, 2019;Muñoz, Small, Wood, Ribera, & Nuevo, 2018).…”