title: Dyspnea in Chronic Fatigue Syndrome (CFS): comparison of two prospective cross-sectional studies.
abstract: Chronic Fatigue Syndrome (CFS) subjects have many systemic complaints including shortness of breath. Dyspnea was compared in two CFS and control cohorts to characterize pathophysiology. Cohort 1 of 257 CFS and 456 control subjects were compared using the Medical Research Council chronic Dyspnea Scale (MRC Score; range 0-5). Cohort 2 of 106 CFS and 90 controls answered a Dyspnea Severity Score (range 0-20) adapted from the MRC Score. Subsets of both cohorts completed CFS Severity Scores, fatigue, and other questionnaires. A subset had pulmonary function and total lung capacity measurements. Results show MRC Scores were equivalent between sexes in Cohort 1 CFS (1.92 [1.72-2.16]; mean [95% C.I.]) and controls (0.31 [0.23-0.39]; p&lt;0.0001). Receiver-operator curves identified 2 as the threshold for positive MRC Scores in Cohort 1. This indicated 54% of CFS, but only 3% of controls, had significant dyspnea. In Cohort 2, Dyspnea Score threshold of 4 indicated shortness of breath in 67% of CFS and 23% of controls. Cohort 2 Dyspnea Scores were higher for CFS (7.80 [6.60-9.00]) than controls (2.40 [1.60-3.20]; p&lt;0.0001). CFS had significantly worse fatigue and other complaints compared to controls. Pulmonary function was normal in CFS, but Borg scores and sensations of chest pain and dizziness were significantly greater during testing than controls. General linear model of Cohort 2 CFS responses linked Dyspnea with rapid heart rate, chest pain and dizziness. In conclusion, sensory hypersensitivity without airflow limitation contributed to dyspnea in CFS. Correlates of dyspnea in controls were distinct from CFS suggesting different mechanisms.
authors: Georgetown University Medical Cente, Washingnton, DC, USA. r. mkr33@georgetown.edu
authors: Murugan
authors: M
authors: Ravindran
authors: Oluwatoyin
authors: O
authors: Adewuyi
authors: Yin
authors: Y
authors: Zheng
authors: Rakib U
authors: RU
authors: Rayhan
authors: Uyenphuong
authors: U
authors: Le
authors: Christian
authors: C
authors: Timbol
authors: Samantha
authors: S
authors: Merck
authors: Rania
authors: R
authors: Esteitie
authors: Charles
authors: C
authors: Read
authors: Michelle
authors: M
authors: Cooney
authors: James
authors: J
authors: Baraniuk
mesh_terms: D000328:Adult; D015331:Cohort Studies; D003430:Cross-Sectional Studies; D004417:Dyspnea / Q000150:complications* / Q000453:epidemiology / Q000523:psychology; D015673:Fatigue Syndrome, Chronic / Q000150:complications* / Q000453:epidemiology / Q000523:psychology; D005260:Female; D006304:Health Status; D006439:Hemodynamics; D006801:Humans; D008297:Male; D008603:Mental Health; D008875:Middle Aged; D011594:Psychometrics; D012129:Respiratory Function Tests; D012720:Severity of Illness Index