Prevalence of overestimation or underestimation of the functional capacity using MRC score as compared to 6-minute walk test in patients with cardio-respiratory disorders.
OBJECTIVE
The first objective of our study was to assess whether patients diagnosed with cardio-respiratory disorders report overestimation or underestimation on recall (Medical Research Council (MRC) dyspnea scale) of their true functional capacity (walked distance during a 6-minute walk test (6MWT)). The second objective was to assess whether the measurement of breathlessness at the end of a 6MWT (Borg score) may help to identify dyspneic patients on recall.


METHODS
The 6MWTs of 746 patients aged from 40 to 80 years who were diagnosed with either chronic obstructive pulmonary disease (COPD, n = 355), diffuse parenchymal lung disease (n = 140), pulmonary vascular diseases (n = 188) or congestive heart failure (n = 63) were selected from a prospective Clinical Database Warehouse.


RESULTS
The percentage of patients who overestimated (MRC ≤ 2 with distance < lower limit of normal (LLN), 61/746, 8%; 95% confidence interval (CI): 6 to 10%) or underestimated (MRC > 2 with distance ≥LLN, 121/746, 16%; 95%CI: 14 to 19%) on recall their capacity was elevated. The overestimation seemed related to self-limitation, while the underestimation seemed related to patients who "work through" their breathing discomfort. These two latter groups of patients were mainly diagnosed with COPD. A Borg dyspnea score >3 (upper limit of normal) at the end of the 6MWT had 84% specificity for the prediction of a MRC score >1.


CONCLUSIONS
Almost one fourth of patients suffering from cardio-pulmonary disorders overestimate or underestimate on recall their true functional capacity. An elevated Borg dyspnea score at the end of the 6MWT has a good specificity to predict dyspnea on recall.
1AP-HP, Hôpital Européen Georges Pompidou, Service de Physiologie -Clinique de la Dyspnée, Paris , France.
Etienne
E
Callens
Sémia
S
Graba
Mohamed
M
Essalhi
Karine
K
Gillet-Juvin
Brigitte
B
Chevalier-Bidaud
Romain
R
Chenu
Bruno
B
Mahut
Christophe
C
Delclaux
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D016208:Databases, Factual; D004417:Dyspnea / Q000175:diagnosis* / Q000209:etiology; D005080:Exercise Test; D017079:Exercise Tolerance; D005260:Female; D006333:Heart Failure / Q000150:complications / Q000175:diagnosis*; D006801:Humans; D006976:Hypertension, Pulmonary / Q000150:complications / Q000175:diagnosis*; D017563:Lung Diseases, Interstitial / Q000150:complications / Q000175:diagnosis*; D008297:Male; D008875:Middle Aged; D015588:Observer Variation; D029424:Pulmonary Disease, Chronic Obstructive / Q000150:complications / Q000175:diagnosis*; D011655:Pulmonary Embolism / Q000150:complications / Q000175:diagnosis*; D057566:Self Report; D012680:Sensitivity and Specificity; D011795:Surveys and Questionnaires
activity-related dyspnea; chronic heart failure; chronic obstructive pulmonary disease; diffuse parenchymal lung disease; pulmonary vascular disease