Background: Dyspnea in obesity is common and dyspnea questionnaires are mostly validated for chronic respiratory diseases. The study aims to assess how modified Medical Research Council (mMRC) dyspnea scale correlates with post exercise dyspnea Borg scale in 6-minute walk test of the obese population. Methods: We performed a retrospective observational study on 342 obese patients with 6 MWT tests from February 2008 to November 2014 at a single tertiary hospital. Linear regression analysis was used to assess the relationship between mMRC and Borg dyspnea score. Fractional polynomial regression was used to analyze the relationship of mMRC and Borg scores with BMI. Results: MMRC dyspnea score was a strong predictor of post exercise dyspnea Borg score in the obese population in a univariate regression model (coefficient = 0.764, p ≤ 0.001). When adjusted to age, BMI, 6 MWT distance and PFT parameters in a multivariate regression model, the relationship remained statistically significant (coefficient = 0.587, p ≤ 0.001). The relationship was stronger in obese group with no airflow obstruction. Conclusion: In obese population, pre-exercise mMRC dyspnea score correlates significantly with post exercise dyspnea Borg score regardless of airflow obstruction. This is the first validity study regarding mMRC scale in assessing dyspnea in the obese population.
References
[1]
Ogden, C.L., Carroll, M.D., Kit, B.K. and Flegal, K.M. (2014) Prevalence of Childhood and Adult Obesity in the United States, 2011-2012. JAMA, 311, 806-814.
https://doi.org/10.1001/jama.2014.732
[2]
Salome, C.M., King, G.G. and Berend, N. (2010) Physiology of Obesity and Effects on Lung Function. Journal of Applied Physiology, 108, 206-211.
https://doi.org/10.1152/japplphysiol.00694.2009
[3]
Sin, D.D., Jones, R.L. and Man, S.F.P. (2002) Obesity Is a Risk Factor for Dyspnea but Not for Airflow Obstruction. Archives of Internal Medicine, 162, 1477.
https://doi.org/10.1001/archinte.162.13.1477
[4]
Collet, F., Mallart, A., Bervar, J.F., Bautin, N., Matran, R., Pattou, F., et al. (2007) Physiologic Correlates of Dyspnea in Patients with Morbid Obesity. International Journal of Obesity (London), 31, 700-706. https://doi.org/10.1038/sj.ijo.0803460
[5]
O’Donnell, D.E., O’Donnell, C.D.J., Webb, K.A. and Guenette, J.A. (2012) Respiratory Consequences of Mild-to-Moderate Obesity: Impact on Exercise Performance in Health and in Chronic Obstructive Pulmonary Disease. Pulmonary Medicine, 2012, Artilce ID: 818925. https://doi.org/10.1155/2012/818925
[6]
Zutler, M., Singer, J.P., Omachi, T.A., Eisner, M., Iribarren, C., Katz, P., et al. (2012) Relationship of Obesity with Respiratory Symptoms and Decreased Functional Capacity in Adults without Established COPD. Primary Care Respiratory Journal, 21, 194-201. https://doi.org/10.4104/pcrj.2012.00028
[7]
Lin, C.-K. and Lin, C.-C. (2012) Work of Breathing and Respiratory Drive in Obesity. Respirology, 17, 402-411. https://doi.org/10.1111/j.1440-1843.2011.02124.x
[8]
Mahler, D.A. and Wells C.K. (1988) Evaluation of Clinical Methods for Rating Dyspnea. Chest, 93, 580-586. https://doi.org/10.1378/chest.93.3.580
[9]
Launois, C., Barbe, C., Bertin, E., Nardi, J., Perotin, J.-M., Dury, S., et al. (2012) The Modified Medical Research Council Scale for the Assessment of Dyspnea in Daily Living in Obesity: A Pilot Study. BMC Pulmonary Medicine, 12, 61.
https://doi.org/10.1186/1471-2466-12-61
[10]
Stenton, C. (2008) The MRC Breathlessness Scale. Occupational Medicine (London), 58, 226-227. https://doi.org/10.1093/occmed/kqm162
[11]
Beriault, K., Carpentier, A.C., Gagnon, C., Ménard, J., Baillargeon, J.-P., Ardilouze, J.-L., et al. (2009) Reproducibility of the 6-Minute Walk Test in Obese Adults. International Journal of Sports Medicine, 30, 725-727.
https://doi.org/10.1055/s-0029-1231043
[12]
Larsson, U.E. and Reynisdottir, S. (2008) The Six-Minute Walk Test in Outpatients with Obesity: Reproducibility and Known Group Validity. Physiotherapy Research International, 13, 84-93. https://doi.org/10.1002/pri.398
[13]
Hsu, K.-Y., Lin, J.-R., Lin, M.-S., Chen, W., Chen, Y.-J. and Yan, Y.-H. (2013) The Modified Medical Research Council Dyspnoea Scale Is a Good Indicator of Health-Related Quality of Life in Patients with Chronic Obstructive Pulmonary Disease. Singapore Medical Journal, 54, 321-327.
https://doi.org/10.11622/smedj.2013125
[14]
Hajiro, T., Nishimura, K., Tsukino, M., Ikeda, A., Koyama, H. and Izumi, T. (1998) Analysis of Clinical Methods Used to Evaluate Dyspnea in Patients with Chronic Obstructive Pulmonary Disease. American Journal of Respiratory and Critical Care Medicine, 158, 1185-1189. https://doi.org/10.1164/ajrccm.158.4.9802091
[15]
ATS (2002) Statement: Guidelines for the Six-Minute Walk Test. American Journal of Respiratory and Critical Care Medicine, 166, 111-117.
https://doi.org/10.1164/ajrccm.166.1.at1102
[16]
Mahler, D.A. and Horowitz, M.B. (1994) Perception of Breathlessness during Exercise in Patients with Respiratory Disease. Medicine and Science in Sports and Exercise, 26, 1078-1081. https://doi.org/10.1249/00005768-199409000-00002
[17]
Miller, M.R., Quanjer, P.H., Swanney, M.P., Ruppel, G. and Enright, P.L. (2011) Interpreting Lung Function Data using 80% Predicted and Fixed Thresholds Misclassifies More than 20% of Patients. Chest, 139, 52-59.
https://doi.org/10.1378/chest.10-0189
[18]
Pellegrino, R., Viegi, G., Brusasco, V., Crapo, R.O., Burgos, F., Casaburi, R., et al. (2005) Interpretative Strategies for Lung Function Tests. The European Respiratory Journal, 26, 948-968. https://doi.org/10.1183/09031936.05.00035205
