A Study of Various Predictors of COPD-Related Fatigue (COPD-RF) and its Correlation with other Established Outcome Parameters in COPD.

Abstract

Over the years approach to COPD has changed. The focus of evaluation is shifting from physiological outcome parameters to patient centered outcomes. COPD-RF is one such patient related outcome that is of considerable importance to the patients as fatigue is the second common distressing symptom in COPD & is a major concern for the patients. COPD-RF is not only a reflection of airflow limitation severity but also a result of psychological, behavioral, and physical factors. Therefore, identification of markers which determine COPD RF is essential to improve patient management. This study aims to identify the predictors of COPD Related fatigue (COPD-RF) and its correlation with other outcome tools like FEV1, 6-minute walk distance (6MWD), MMRC grade, BODE index & inflammatory markers. 50 stable COPD patients were taken in the study. MMRC grade, FEV1, 6MWD, BODE index, CRP level and sputum neutrophil % obtained. COPD-RF was assessed using 13 item (FACIT-fatigue) questionnaire. The correlation analysis was done by spearman rank correlation and ANOVA. Predictors of COPD-RF were identified by multiple linear regression. Mean age of the population was 56.53 ± 9.29. All GOLD category of severity was equally represented in the study group. The fatigue score showed significant correlation with inflammatory markers (CRP-r=-0.675; neutrophil%- r=-0.485) & 6MWD (r=-.428). Categorical variables (MMRC, FEV1 GOLD stages & BODE quartiles) also showed significant difference of fatigue among categories. BODE index & serum CRP were identified as the statistically significant predictors of fatigue, suggesting COPD-RF could reflect severity of underlying pathophysiologic process i.e. systemic inflammation. BODE index and CRP levels are the two important surrogate markers that predicts COPR-RF implying a role of systemic inflammation in the pathogenesis of fatigue. Also, COPD-RF could be an indicator of long-term prognosis of the disease & should be routinely evaluated during COPD assessment.