COPD: Assessment of Body Weight 2019
Click here to see the explanation of recommendation ratings (Strong, Fair, Weak, Consensus, Insufficient Evidence) and labels (Imperative or Conditional). To see more detail on the evidence from which the following recommendations were drawn, use the hyperlinks in the Supporting Evidence Section below.
COPD: Assessment of Body Weight Status
The RDN should assess body mass index (BMI) or other measures of body weight in adults with COPD. Strong evidence suggests an association between body weight status and mortality in adults with COPD. The lowest BMI groups had higher mortality rates when compared to higher BMI groups. Furthermore, a BMI classification of approximately 25.0kg/m2 to 29.99kg/m2 appeared to lower the risk of mortality when compared to both higher and lower BMI classifications. In primarily unadjusted results, there was fair evidence of a positive association between BMI and FEV1 percentage predicted and FEV1/forced vital capacity (FVC). An increasing BMI was also shown to reduce longitudinal declines in these measures over time.
Risks/Harms of Implementing This Recommendation
There are no potential risks or harms associated with the application of this recommendation.
Conditions of Application
There are no conditions which may limit the application of the recommendation.
Potential Costs Associated with Application
Costs may include expenses related to medical nutrition therapy (MNT) visits from an RDN.
A total of 22 studies were included in the evidence analysis supporting the recommendation:
- Eleven prospective cohort studies: Three positive quality (Hallin et al, 2007; Schols et al, 2005; Tsimogianni et al, 2009) and eight neutral quality (Abston et al, 2017; Baccioglu et al, 2014; Galesanu et al, 2014; Koul et al, 2017; Piquet et al, 2013; Pothirat et al, 2007; Qiu et al, 2009; Rutten et al, 2013)
- Ten neutral quality retrospective cohort studies (Jiang et al, 2017; Lainscak et al, 2011; Lim et al, 2017; Marti et al, 2006; O'Donnell et al, 2011; Ranieri et al, 2008; Slinde et al, 2005; Uh et al, 2011; Yamauchi et al, 2014; Zapatero et al, 2013)
- One negative quality case-control study (Dimov et al, 2013).
Body Weight and Lung Function Outcomes
All studies using FEV1 % predicted and FEV1/FVC as an outcome found a positive association with BMI or BMI category. In addition, one longitudinal study showing increasing BMI reduced declines in these measures over time. While these studies appear to indicate that increasing BMI is associated with improvements in FEV1 % predicted and FEV1/FVC, most results did not include adjustment for relevant confounders and should be interpreted with caution. Results for other lung function measures (FEV1, FVC, FVC % predicted) were either mixed or not significant.
- FEV1 stratified into quintiles and BMI (one study): One study (Abston et al, 2017) found BMI was not associated with FEV1 in the overall group or in any of the FEV1 quintiles. In each of the FEV1 quintiles, FVC % predicted showed inverse associations with BMI, while FEV1/FVC showed a positive association with BMI.
- BMI stratified into quartiles and FEV1 (one study): One study (Lainscak et al, 2011) found a positive association between FEV1 (ml/s) and BMI divided into quartiles in subjects hospitalized for an acute exacerbation of COPD (AECOPD), with FEV1 increasing as BMI category increased.
- BMI and Lung Function (non-adjusted) (six studies): Six studies (Dimov et al, 2013; Galesanu et al, 2014; Hallin et al, 2007; Lim et al, 2017; O'Donnell et al, 2011; Qiu et al, 2009) found BMI was positively associated with FEV1 % predicted in analyses that were unadjusted for confounding variables. BMI was positively correlated with FEV1/FVC in two studies (O’Donnell et al; Qiu et al). In addition, Qiu et al found a higher BMI was also associated with a lower decline in FEV1/FVC and FEV1 % predicted over time. Two studies (Galesanu et al and O’Donnell et al) found that BMI was not associated with FVC and FVC % predicted. O’Donnell et al found BMI was not associated with FVC % predicted. Galesanu et al found NS association between FEV1 and BMI, while Lim et al found FEV1 to be highest in subjects classified as OB by either the WHO or Asian-Pacific methods of BMI. FEV1 was not reported in four studies (Dimov et al; Hallin et al; O’Donnell et al; Qiu et al).
Body Weight and Mortality Outcomes
The majority of studies comparing BMI (kg/m2) between survivors and non-survivors with COPD found survivors had a significantly higher BMI. Among studies comparing mortality rates between BMI categories, a lower risk of mortality was found as BMI classification increased. Likewise, those in the lowest BMI groups had higher mortality rates when compared to those in higher BMI groups. In studies evaluating BMI as a predictor of mortality, those in the lowest BMI categories consistently showed higher mortality risk when compared to those in higher BMI classifications. While increasing body weight appeared to be protective when BMI was evaluated as a continuous variable, studies evaluating BMI as a categorical variable found that a BMI of approximately 25.0-29.99 had a lower risk of mortality, when compared to both higher and lower BMI classifications.
- BMI (mean ±SD) between survivors and non-survivors (five studies): Five studies evaluated the difference in BMI between survivors and non-survivors with COPD. Four studies (Hallin et al, 2007; Marti et al, 2006; Ranieri et al, 2008; Tsimogianni et al, 2009) found significantly higher BMI in survivors vs. non-survivors. One study (Galesanu et al, 2014) found no differences in BMI between the groups.
- Differences in Mortality Rates between BMI Categories (six studies): Two studies (Abston et al, 2017, Lainscak et al, 2011) classified the BMIs of participants into quintiles or quartiles (respectively) and found a lower risk of mortality as BMI categorization increased. In three studies that were unadjusted for confounding variables (Koul et al, 2017; Pothirat, et al, 2007; Uh et al 2011), two studies found higher mortality in the lowest BMI groups (Koul, Pothirat). Koul found higher mortality 2 years after AECOPD in the lowest BMI group compared to the 23-24.9 group. Pothirat found higher mortality in the lowest BMI group compared to the next higher group (both with severe COPD). Uhl found NS differences in cumulative survival rate between all BMI groups. Zapatero found that the OB group (using ICD-9 codes) had a 51% reduction in risk of mortality, compared to NW group after adjusting for possible confounders in patients hospitalized for AECOPD.
- BMI and weight status as a predictor of mortality (11 studies):
- Five studies evaluated BMI (or % reference weight) as a continuous variable as a predictor of mortality in subjects with COPD. Three studies (Galesanau et al, 2014; Ranieri et al, 2008; Schols et al, 2005) found BMI was a predictor of mortality in univariate analyses. Two studies (Jiang et al, 2017; Ranieri et al, 2008) reported BMI was a predictor of mortality in adjusted multivariate analysis. A fourth study (Galesanu et al, 2014) found NS association between BMI and mortality in adjusted multivariate analysis. The fifth study (Slinde et al, 2005) that used % reference weight did not find an association with mortality.
- Seven studies evaluated BMI as a categorical variable as a predictor of mortality and adjusting for confounding variables (Hallin et al, 2007; Jiang et al, 2017; Marti et al, 2006; Piquet et al, 2013; Rutten et al, 2013, Tsimogianni et al, 2009; Yamauchi et al, 2014). Mortality risk was higher for subjects in the lowest BMI group (ranging from <18.5 to <25) when compared to higher BMI groups. Yamauchi found higher all-cause in-hospital mortality in the lowest BMI group and lower mortality in the higher BMI categories compared to the 18.5-22.9 group in an Asian population. Hallin found higher risk for 2-year mortality after AECOPD in all BMI categories compared to the 25-30 group. Marti found higher risk for both all-cause and respiratory mortality in the lower BMI groups compared to the 25-29.9 group and higher risk for all-cause mortality in the 20-24.9 group compared to the 25-29.9 groups. Piquet found no difference in risk for mortality between the lowest and 20-25 group, but a lower risk for mortality 48 months after AECOPD in the higher BMI categories. Rutten found the highest 2 and 3-year survival in subjects in BMI categories 25-29.99 compared to lower groups as well as those above 30. Jiang found a higher risk of mortality as BMI group classification decreased. Tsimogianni found that a BMI group of <25 had a higher risk of 3-year mortality.
Recommendation Strength Rationale
Conclusion statements supporting the recommendation are Grade I, Good/Strong and Grade II, Fair.
- Risks/Harms of Implementing This Recommendation
The recommendations were created from the evidence analysis on the following questions. To see detail of the evidence analysis, click the blue hyperlinks below (recommendations rated consensus will not have supporting evidence linked).
Abston E, Comellas A, Reed R, Kim V, Wise R, Brower R, Fortis S, Beichel R, Bhatt S, Zabner J ,Newell J ,Hoffman E, Eberlein M. Higher BMI is associated with higher expiratory airflow normalised for lung volume (FEF25-75/FVC) in COPD. BMJ Open Respiratory Research 2017; 4:e000231
Galesanu R, Bernard S, Marquis K, Lacasse Y, Poirier P, Bourbeau J, Maltais F. Obesity in chronic obstructive pulmonary disease: is fatter really better?. Canadian Respiratory Journal. 2014; 21:297-301
Hallin R, Gudmundsson G, Suppli Ulrik C, Nieminen M, Gislason T, Lindberg E, Brøndum E, Aine T, Bakke P, Janson C. Nutritional status and long-term mortality in hospitalised patients with chronic obstructive pulmonary disease (COPD). Respiratory Medicine. 2007; 101:1,954-1,960.
Jiang J, Zhao J, Yuan Y, Di S. Risk factors associated with acute exacerbation of chronic obstructive pulmonary disease: A retrospective analysis in 4,624 patients. Biomedical Research. 2017; 28:3,855-3,859.
Koul P, Dar H, Jan R, Shah S, Khan U. Two-year mortality in survivors of acute exacerbations of chronic obstructive pulmonary disease: A North Indian study. Lung India : Official Organ of Indian Chest Society 2017; 34:511-516
Lainscak M, von Haehling S, Doehner W, Sarc I, Jeric T, Ziherl K, Kosnik M, Anker S, Suskovic S. Body mass index and prognosis in patients hospitalized with acute exacerbation of chronic obstructive pulmonary disease. Journal of Cachexia, Sarcopenia and Muscle. 2011; 2:81-86.
Marti S, Muñoz X, Rios J, Morell F, Ferrer J. Body weight and comorbidity predict mortality in COPD patients treated with oxygen therapy. The European Respiratory Journal. 2006; 27:689-696.
Piquet J, Chavaillon J, David P, Martin F, Blanchon F, Roche N. High-risk patients following hospitalisation for an acute exacerbation of COPD. The European Respiratory Journal 2013; 42:946-55
Pothirat C, Phetsuk N, Deesomchok A, Theerakittikul T, Bumroongkit C, Liwsrisakun C, Inchai J. Clinical characteristics, management in real world practice and long-term survival among COPD patients of Northern Thailand COPD club members. Journal of the Medical Association of Thailand = Chotmaihet thangphaet. 2007; 90:653-662.
Ranieri P, Bianchetti A, Margiotta A, Virgillo A, Clini E, Trabucchi M. Predictors of 6-month mortality in elderly patients with mild chronic obstructive pulmonary disease discharged from a medical ward after acute nonacidotic exacerbation. Journal of the American Geriatrics Society. 2008; 56:909-913.
Rutten E, Calverley P, Casaburi R, Agusti A, Bakke P, Celli B, Coxson H, Crim C, Lomas D, Macnee W, Miller B, Rennard S, Scanlon P, Silverman E, Tal-Singer R, Vestbo J, Watkins M, Wouters E. Changes in body composition in patients with chronic obstructive pulmonary disease: do they influence patient-related outcomes?. Annals of Nutrition & Metabolism. 2013; 63:239-247.
Schols A, Broekhuizen R, Weling-Scheepers C, Wouters E. Body composition and mortality in chronic obstructive pulmonary disease. The American Journal of Clinical Nutrition. 2005; 82:53-59.
Slinde F, Grönberg A, Engström C, Rossander-Hulthén L, Larsson S. Body composition by bioelectrical impedance predicts mortality in chronic obstructive pulmonary disease patients. Respiratory Medicine. 2005; 99:1,004-1,009.
Tsimogianni A, Papiris S, Stathopoulos G, Manali E, Roussos C, Kotanidou A. Predictors of outcome after exacerbation of chronic obstructive pulmonary disease. Journal of General Internal Medicine. 2009; 24:1,043-1,048.
Uh S-T, Lee JY, Koo SM, Kim YK, Kim KU, Park JS, Park SW, Jang AS, Kim DJ, Choi JS, Na JO, Suh KH, Kim YH, Park C-S,. The Survival Rate of Korean Patients with COPD with or without Acute Exacerbations. Tuberculosis and Respiratory Diseases. 2011; 70:474-481
Yamauchi Y, Hasegawa W, Yasunaga H, Sunohara M, Jo T, Takami K, Matsui H, Fushimi K, Nagase T. Paradoxical association between body mass index and in-hospital mortality in elderly patients with chronic obstructive pulmonary disease in Japan. International Journal of Chronic Obstructive Pulmonary Disease. 2014; 9:1,337-1,346.
Zapatero A, Barba R, Ruiz J, Losa J, Plaza S, Canora J, Marco J. Malnutrition and obesity: influence in mortality and readmissions in chronic obstructive pulmonary disease patients. Journal of Human Nutrition and Dietetics : the Official Journal of the British Dietetic Association 2013; 26:16-22.
Dimov D, Tacheva T, Koychev A, Ilieva V, Prakova G, Vlaykova T.. Obesity in Bulgarian patients with chronic obstructive pulmonary disease. Chronic Respiratory Disease. 2013; 10:215-222.
Lim J, Lee J, Kim J, Hwang Y, Kim T, Lim S, Yoo K, Jung K, Kim Y, Rhee C. Comparison of World Health Organization and Asia-Pacific body mass index classifications in COPD patients. International Journal of Chronic Obstructive Pulmonary Disease. 2017; 12:2,465-2,475.
O'Donnell D, Deesomchok A, Lam Y, Guenette J, Amornputtisathaporn N, Forkert L, Webb K.. Effects of BMI on static lung volumes in patients with airway obstruction. Chest. 2011; 140:461-468.
Qiu T, Tang Y, Xu Z, Xu D, Xiao J, Zhang M, Feng Y, Wang K. Association between body mass index and pulmonary function of patients with chronic obstructive pulmonary disease. Chinese Medical Journal. 2009; 122:1,110-1,111
References not graded in Academy of Nutrition and Dietetics Evidence Analysis Process