Chronic Obstructive Pulmonary Disease (COPD)

November 18, 2020 14 min read


By Anne Wright, Registered Dietitian, reviewed by Clare-Thornton Wood, RD

This is an online CPD article. Once you’ve read the information below, click here to answer CPD questions and download a certificate for your professional portfolio.

 

 

Learning Objectives:

By the end of this article, you should:

  •    Understand the cause and impact of COPD.
  •    Be aware of the nutritional impact of COPD.
  •    Be able to describe the nutritional pathway of care in COPD.

 

Introduction

Chronic obstructive pulmonary disease (COPD) is a global public health concern and a major cause of morbidity and mortality (1). It is a common and treatable respiratory disease, characterised by persistent respiratory symptoms and airflow limitation; this is due to airway and/or alveolar abnormalities, usually caused by significant exposure to noxious (harmful) particles or gases (2). Common signs and symptoms of COPD include shortness of breath (particularly on exertion), ongoing/chronic cough, regular sputum production, frequent winter 'bronchitis'/lower respiratory tract infections and wheezing (3).

Malnutrition is common in patients with COPD, often leading to poor health outcomes/quality of life (4, 5). NHS treatment costs for COPD are approximately £1.9 billion per year (6). Identification and management of malnutrition in individuals with COPD can improve nutritional status, clinical outcomes, and reduce healthcare costs (7, 8). 

Figure 1: Key Statistics for COPD

  • COPD is the world’s third most common cause of death (9)

  •  >90% of COPD deaths occur in low­ and middle ­income countries (LMIC) (10)

  • The incidence/prevalence of COPD for men is 9.2% and for women 6.2%, but the gap between the two has been closing over time (11,12).

Aetiology and Diagnosis of COPD

COPD is a multifaceted disease, influenced by genetic and environmental factors (13). It develops when a genetically susceptible individual encounters sufficient inhaled environmental triggers. Cigarette smoke is the most common trigger in higher income countries (14). However, incidences of COPD also occur in non-smokers (15).

External risk factors associated with COPD in non-smokers include: 

  • Passive smoking (16)
  • Occupational exposure to dust (e.g. coal, silica, grain and flour dust) (17,18) 
  • Indoor air pollution from the burning of biomass fuels (14) 
  • Outdoor air pollution in urban areas (19).

Internal risk factors include genetic predisposition (20), damaged airways due to prenatal maternal smoke exposure (21) and childhood respiratory infection (21, 22).

A small percentage of patients with a genetically inherited disorder known as alpha-1 antitrypsin deficiency will develop COPD. This often affects younger individuals, and usually results in the development of emphysema in the lower lobes of the lungs. It can sometimes be associated with bronchiectasis, asthma and liver involvement (23).

The diagnosis of COPD is based on the presence of clinical symptoms (3), confirmed by spirometry tests. Spirometry is a standard procedure used to measure lung function (24); specifically, it measures the amount and/or speed of air inhaled and exhaled. 

A spirometer provides the following readings:

  • FEV1: Forced Expiratory Volume in One Second: volume of air exhaled in the first second
  • FVC: Forced Vital Capacity: amount of air that can be forcibly exhaled from the lungs after taking the deepest breath possible. 

The FEV1/FVC ratio is used in the diagnosis of COPD; a normal ratio is above 0.75-85, though this is age dependent. Values less than 0.70 are suggestive of airflow limitation with an obstructive pattern, and results in a diagnosis of COPD (2).

 

Impact of COPD

COPD impacts significantly both on an individual and at a population level. COPD is a progressively disabling condition associated with impaired health-related quality of life (QoL) (26), depression, anxiety (27), physical decline (25) and sleep problems (28). 

Depression in COPD patients is a predictor of poor QoL (29) and is associated with increased risk of hospital admissions (30, 31). NICE guidelines for depression in adults with a chronic physical health problem such as COPD recommend monitoring patients for anxiety and depression. Interventions such as structured group programmes or Cognitive Behavioural Therapy (CBT) may be useful (32).

In addition to respiratory symptoms, and mental health problems, COPD patients often have comorbidities such as: 

  •     Lung cancer (33) 
  •     Asthma (34) 
  •     Hypertension (35) 
  •     Cardiovascular disease (36)
  •     Diabetes (37) 
  •     Metabolic syndrome (38)
  •     Osteoporosis (35).

Comorbidity in COPD has also been associated with more frequent hospital admissions (after exacerbation) and higher mortality (39, 40). 

 

Nutritional Impact

Unintentional weight loss and disease-related malnutrition are common problems in patients with COPD (41). Inadequate dietary intake contributes to malnutrition in COPD patients (42, 43). This may be due to factors such as loss of appetite, depression and anxiety and/or physical limitations such as difficulty breathing while eating, problems chewing, taste alterations and coughing (44). 

Additionally, malnutrition in COPD may be due to:

  • Imbalance between energy intake and expenditure; it has been demonstrated that resting energy expenditure (REE) is increased by 27.9±0.7 kcal/kg FFM/day in COPD patients (45) 
  • Systemic inflammation (46) 
  • Hypoxia (when the blood does not deliver enough oxygen to the air sacs in the lungs) (47)
  • Effect of medications (47) 
  • Changes in body composition (48, 49)   

Malnutrition is a significant and independent predictor of mortality in COPD patients (50). Associated negative outcomes of malnutrition in COPD include decreased muscle strength, rapid lung deterioration, reduced exercise capacity, increased length of hospital stay and worsening QoL indices (51).

Interestingly, an obesity paradox has been described in chronic obstructive pulmonary disease (COPD), with overweight and mild obesity (BMI 25-30 kg/m2) being associated with improved survival rate and a slower decline in lung function (52). The question of the obesity paradox is still, however, being examined (53).

 

Nutritional Care in COPD

Routine nutritional risk screening is recommended for individuals with COPD across all settings using a validated screening tool such as the Malnutrition Universal Screening Tool (MUST) (54, 55). Screening can be embedded in existing COPD care pathways such asThe Managing Malnutrition in COPD Pathway (55); it should take place on first contact with a patient and after  changes in condition (e.g. recent exacerbations or change in social or psychological status). 

Repeat screening should take place at least annually and more frequently if risk of malnutrition is identified (56). NICE guidelines recommend BMI is calculated in all patients, with particular attention to unintentional weight loss (>3Kg) in older people (57).

Nutritional requirements for COPD patients should be assessed individually, considering clinical state (stable or exacerbation) and disease severity as well as likely activity levels (58). For patients who have lost weight, a weight gain of 2kg should be used as a therapeutic target, as this amount has been associated with a number of functional improvements in (stable) COPD patients (58, 59). 

For acute exacerbations, minimising weight loss and muscle mass may be an appropriate goal (55). Management options for treatment of malnutrition in COPD can include dietary advice;  assistance with eating;  texture modified diets and oral nutritional supplements (ONS), where indicated (55, 2).

Based on clinical consensus, it has been suggested that energy requirements for patients with COPD requiring nutritional support are approximately 30kcal/kg/day (for weight maintenance) or 45 kcal/kg/day when weight gain is required. Protein recommendations suggest a daily intake of  1.0–1.2 g protein/kg/day and up to 1.5g/kg/day for those who are malnourished/unwell (58). However, nutritional requirements should always be assessed on an individual basis. 

 

Managing Malnutrition in COPD Pathway

TheManaging Malnutrition in COPD Pathway is a practical guide to support healthcare professionals in nutritional management of COPD, including identification and management of malnutrition. It is based on clinical evidence, clinical experience and accepted best practice; and includes guidance to assist in appropriate use of ONS. (55) 

The pathway (see figure 2) recommends a treatment algorithm for COPD patients based on MUST screening tool scores. It is accompanied by a series of colour-coded information booklets for use with patients. These  include dietary advice for the three malnutrition risk categories (low, medium, high).

Figure 2: Brief Summary: Identifying Malnutrition According to Risk Category Using ‘MUST’ - First Line Management Pathway (55)

MUST score of 0 indicates low risk (routine clinical care).

 

  • Provide green information leaflet: Eating Well For Your Lungs to raise awareness of the importance of a healthy diet, review/re-screen annually and treat according to local guidelines if BMI >30 (obese).


 MUST score of 1 indicates  medium risk (observe).


  • Provide yellow leaflet:  Improving Your Nutrition In COPD to support dietary advice (tailored to maximise nutritional intake). NICE recommends COPD patients with a BMI <20kg/m2 should be prescribed ONS. Review progress after 1-3 months.  If improving, continue until ‘low risk’;  if deteriorating, consider treating as ‘high risk’.


 MUST score of 2 or over indicates high risk (treat).

 

  • Provide red leaflet: Nutrition Support In COPD  to support dietary advice (tailored to maximise nutritional intake). Prescribe ONS and monitor progress. On improvement, consider managing as ‘medium risk’. Refer to dietitian if no improvement or more specialist support is required. 

Oral Nutritional Supplements and COPD

A growing number of studies supports the use of ONS in malnourished patients with COPD. A Cochrane Review of 17 studies  (60) assessing the impact of nutritional support on weight gain, respiratory function, muscle strength, exercise capacity, and QoL, and found that ONS promoted weight gain, with an increase in fat-free mass, fat mass, improved 6-minute walk distance, and skinfold thickness in malnourished COPD patients.

A further systematic review and meta-analyses of nutritional support found that in 12 randomized controlled trials, ONS significantly improved respiratory muscle strength, handgrip strength, weight gain (≥2 kg), exercise performance, and QoL (59). 

The use of ONS in COPD patients whilst in hospital has also been associated with a 22% decreased length of hospital stay, a 13% reduction in hospitalisation costs, and a decrease in  probability of readmission within 30 days (61). NICE COPD guidelines [NG115]  (57) recommend ONS are provided for those with a low BMI (<20kg/m2). 

 

Appropriate Usage of ONS

TheManaging Malnutrition in COPD Pathway recommends the following for the appropriate use of ONS for patients with a low BMI (< 20Kg/m2) or at risk of malnutrition (MUST score 2 or above) (55):

  • Prescribe: average 2 ONS bottles/sachets/day in addition to oral intake. Clinical benefits of ONS are often seen with 300-900kcal/day, typically within 2-3 months of supplementation.
  • Patients may benefit from a low volume, high energy, high protein ONS in addition to dietary advice 
  • If following a pulmonary rehabilitation programme, consider increased energy and protein requirements.
  • Review for compliance and adjust for type/ flavour, if needed, after 4 weeks.
  • Continue ONS for a 12-week duration according to clinical condition/nutritional needs.
  • Monitor progress and review goals after 12 weeks (and thereafter every 3 months or sooner if clinical concern).
  • If nutrition goals have been met/good progress, consider reducing to 1 ONS per day for 2 weeks before stopping. Encourage maximising dietary intake, consider powdered nutritional supplements/self-purchase.
  • If nutrition goals have not been met/limited progress, check ONS compliance and amend prescription as necessary, reassess for more intensive nutrition support. If not compliant refer to a specialist dietitian. Review every 3-6 months or upon change in clinical condition.
  • If goals of intervention have been met and the individual is no longer at risk of malnutrition: stop ONS prescription.

 

Summary

COPD is a progressively disabling condition which has significant implications on a patient and public health level. Malnutrition is common in patients with COPD, and is associated with negative outcomes such as decreased muscle strength, rapid lung deterioration, reduced exercise capacity, increased length of hospital stay and worsening QoL indices.

Nutritional screening, using a validated tool such as the MUST, and prompt intervention is recommended for COPD patients. Screening can be embedded into care pathways such as theManaging Malnutrition in COPD Pathway. Management options for the treatment of malnutrition in COPD can include food-first nutrition support advice, assistance with eating, texture modified diets and ONS, where indicated. Patients requiring nutrition support should be regularly monitored by Registered Dietitians until goals of intervention have been met and the individual is no longer at risk of malnutrition. 

 

Further Resources on COPD


To complete CPD questions on this resource

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