Diagnosis and Treatment of Acute Exacerbations of COPD and Chronic Bronchitis
Abstract & Commentary
By Allan J. Wilke, MD, MA, Chair, Department of Integrative Medicine, Ross University School of Medicine, Commonwealth of Dominica. Dr. Wilke reports no financial relationship to this field of study.
Synopsis: Although there are few studies that specifically look at the elderly, this review provides useful information on the diagnosis and treatment of acute exacerbation of COPD and chronic bronchitis.
Source: Albertson TE, et al. The diagnosis and treatment of elderly patients with acute exacerbation of chronic obstructive pulmonary disease and chronic bronchitis. J Am Geriatr Soc 2010;58:570-579.
Chronic obstructive pulmonary disease (COPD) is a syndrome of chronic bronchial inflammation, bronchiectasis, reversible (although not fully) small-airway obstruction, and emphysema. Chronic bronchitis (CB) is a disease of large airways with cough productive of sputum on most days for ≥ 3 months/year for ≥ 2 consecutive years, not necessarily airway obstruction. COPD incidence increases with age, but its incidence is decreasing over time. In Canada, it was 4.4/1000 in the 35-49 years age group, but 17.9/1000 in the ≥ 65 years age group in 2007.1 In 1996, it was 5.0/1000 and 28.5/1000 in those age groups, respectively. This decrease probably represents public health efforts to prevent adolescents and young adults from starting smoking and physicians addressing smoking cessation with their patients, and should manifest in a decrease in COPD many years hence. In contrast, the prevalence in the ≥ 65 years group was 17.9% in 1996 and 22.2% in 2007. The increase probably represents the aging of the cohort who began smoking a half century ago and our success in keeping them alive. In 1996, it was 2.9% in the 35-49 years age group; in 2007, it was 2.7%. This is good news, at least for Canadians. However, in 2008, COPD was fourth on the list of worldwide causes of death, and by 2020, it will have risen to third as the rest of the world experiences the consequences of its smoking habit.2
In this review, Albertson and colleagues examined the diagnosis and treatment of acute exacerbation of COPD (AECOPD) and chronic bronchitis (AECB) in the elderly. Their first observation is that AECOPD and AECB are not the same entity. The interaction of COPD, CB, and aging is complex and involves increased risk of aspiration, weaker respiratory muscles, and decrease in cell-mediated and humoral immunity, among other age-related changes.
Syllogistically, AECOPD represents an acute, sustained worsening of a patient's previously stable COPD. It is usually (70% of the time) precipitated by a lung infection (bacterial, viral, or both), but pollutant exposure, congestive heart failure, and pulmonary embolism should be in the differential diagnosis. The usual bacteria involved are non-encapsulated Haemophilus influenzae, Moraxella catarrhalis, Streptococcus pneumoniae, and Pseudomonas aeruginosa. Interestingly, when pre- and post-exacerbation cultures and molecular typing have been performed, the organisms were the same, but different strains emerged.
AECB is CB with increased sputum production, sputum purulence, and worsening dyspnea. There are several triggers for AECB, including tobacco smoke, poor compliance with COPD therapies, and exacerbation of CHF, but the overwhelming cause is infection. The causative organisms comprise influenza, parainfluenza, rhinovirus, coronavirus, adenovirus, respiratory syncytial virus, S. pneumoniae, H. influenzae, H. parainfluenzae, M. catarrhalis, Staphylococcus aureus, P. aeruginosa, and Enterobacteriaceae. The last two are more common in patients with the worst FEV1. Frequently, the bacteria are resistant to beta-lactams, macrolides, and trimethoprim/sulfamethoxazole (TMP/SMX). Elderly patients have drug-resistant bacteria more frequently than younger ones. The elderly are also more like to harbor H. influenzae and P. aeruginosa.
The authors argue that there is enough overlap between AECOPD and AECB that they can be considered the same entity for treatment purposes. They recommend empiric therapy in the elderly, based on a risk-stratification approach that factors in comorbidity and recent exposure to antibiotics, with the caveat that no prospective studies have been performed to validate this approach. The first step is to evaluate the patient to determine which of the three cardinal CB symptoms (increased sputum, increased purulence, and increased dyspnea) are present. The next consideration is the presence of comorbidities (e.g., FEV1 < 50% predicted, ischemic heart disease, home oxygen use, chronic oral corticosteroid use). A patient with only increased sputum and no risk factors is considered a "simple" exacerbation and can be started on amoxicillin, a second- or third-generation cephalosporin, doxycycline, an extended spectrum macrolide, or TMP/SMX. A patient with risk factors is automatically a "complicated" exacerbation and should be started on a respiratory flouroquinolone or a beta-lactam/beta-lactamase combination. Studies have shown that treatment failure and in-hospital mortality is reduced with antibiotic use, and a short course (< 5 days) is as effective as a standard 10-14 day course. The earlier the antibiotics are started, the better. Patients receiving their first dose before they entered the hospital have lower short-term mortality. It is important to avoid administering an antibiotic that has been prescribed in the last 3 months as there is greater chance of drug resistance. It's also important to remember that the elderly are subject to altered pharmacokinetics (decreased hepatic function, decreased renal function, changes in volume of distribution, etc.) and to consider that when prescribing.
Non-antibiotic therapy starts with short-acting inhaled b2-agonists. Inhaled ipratropium can be considered as an add-on therapy, because the combination has not been proven conclusively to improve outcomes in AECOPD. There is no difference in efficacy between administration by nebulizer and by metered-dose inhaler with a spacer. No consistent benefits have been shown for IV aminophylline. Hydration is important, as is supplemental oxygen. Systemic corticosteroids and non-invasive positive pressure ventilation are helpful. Preventive measures include advising and assisting smoking cessation, immunization against pneumonia and influenza, and initiation of home oxygen therapy in qualifying individuals.
Commentary
This review is not an easy read. It is chock-full of information, but densely written and redundant at times. That said, if you need a refresher in COPD, this is a good place to start.
We will be dealing with patients with COPD for many years to come, if not forever, unless everyone suddenly stops smoking, and we will have to unlearn some of our previous teaching. For instance, we were taught that b-blockers were to be strictly avoided in patients with COPD. Now we learn that b-blockers may reduce the risk of exacerbations and improve survival.3 The GOLD was launched in 1997. It relies heavily on use of spirometry to confirm diagnosis of COPD. However, we are not referring our patients for spirometry, because we fail to recognize their risk factors for COPD.4 The issue of early antibiotic therapy for COPD was the subject of an article published after this review (see the June 29 issue of Internal Medicine Alert).5 This study confirmed improved outcomes when hospitalized patients are treated with antibiotics. It also noted that these patients had a higher rate of readmission for Clostridium difficile infections. Another study from the same group published after this review looked at low-dose oral vs high-dose IV corticosteroids in AECOPD.6 Turns out they are equivalent in terms of outcomes, and length of stay and cost favored the oral route. Unfortunately, these are retrospective cohort studies, not the prospective studies that Albertson and colleagues were hoping for.
References
1. Gershon AS, et al. Trends in chronic obstructive pulmonary disease prevalence, incidence, and mortality in Ontario, Canada, 1996 to 2007: A population-based study. Arch Intern Med 2010;170:560-565.
2. World Health Organization. Available at: www.who.int/mediacentre/factsheets/fs310_2008.pdf. Accessed May 21, 2010.
3. Rutten FH, et al. Beta-blockers may reduce mortality and risk of exacerbations in patients with chronic obstructive pulmonary disease. Arch Intern Med 2010;170:880-887.
4. Hill K, et al. Prevalence and underdiagnosis of chronic obstructive pulmonary disease among patients at risk in primary care. CMAJ 2010;182:673-678.
5. Rothberg MB, et al. Antibiotic therapy and treatment failure in patients hospitalized for acute exacerbations of chronic obstructive pulmonary disease. JAMA 2010;303:2035-2042.
6. Lindenauer PK, et al. Association of corticosteroid dose and route of administration with risk of treatment failure in acute exacerbation of chronic obstructive pulmonary disease. JAMA 2010;303:2359-2367.
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