Empiric Antipseudomonal Antibiotics Are Overused in Patients With COPD and CAP

A new, simple scoring system has the potential to drastically reduce the overuse of empiric antipseudomonal antibiotics in patients with chronic obstructive pulmonary disease (COPD) and community-acquired pneumonia (CAP), according to study findings published in Archivos de Bronconeumología, an international journal of the Spanish Respiratory Society of Pulmonology and Thoracic Surgery. 

Researchers sought to evaluate the microbiologic patterns associated with risk factors for using empiric antibiotic therapy in patients with COPD who are hospitalized for CAP. The investigators conducted a secondary analysis of the Global Initiative for Methicillin-resistant Staphylococcus aureus Pneumonia (GLIMP), an international, multicenter, observational, point-prevalence study of hospitalized patients with COPD and CAP, conducted between March 2015 and June 2015. GLIMP included immunocompetent patients with COPD who were hospitalized with CAP from 37 countries in all continents.

The secondary analysis of GLIMP involved 689 patients with COPD hospitalized for CAP (mean [SD] age, 72 (11) years; 67% male). Of those patients, 11% had very severe airflow limitation (forced expiratory volume in 1 second [FEV₁] ≤30%), 10% had bronchiectasis, and 5% had experienced a previous Pseudomonas aeruginosa infection.

Researchers first identified risk factors associated with various microorganisms and then developed a scoring system to help guide decision-making regarding empiric antipseudomonal antibiotic treatment. The most frequently isolated microorganisms identified included Streptococcus pneumoniae (8%) and Gram-negative bacteria (8%), P aeruginosa (7%), and Haemophilus influenzae (3%).

The investigators further found that P aeruginosa was the microorganism associated with a higher number of risk factors in patients with COPD hospitalized with CAP. Using this risk factor data, the researchers designed a 5-point scoring system to define the prevalence of P aeruginosa (with a score of 5 indicating the highest likelihood of prevalence). The scoring system used 3 independent variables that were each given different scoring weights: prior P aeruginosa infection or isolation, weighted as 3 points; hospitalization in the previous 12 months, weighted as 1 point; and bronchiectasis, weighted as 1 point.

Data analysis showed the prevalence of P aeruginosa in patients with COPD with scores of 0 and 1 point was 2% and 5%, respectively, whereas the prevalence was 20% in those with scores of 2 points and 50% in those with scores of 3 points or more. Further analysis showed that more than half of those with scores of 0 or 1 received unnecessary antipseudomonal treatment. Moreover, researchers projected that using the scoring system to avoid the unnecessary use of antipseudomonal agents in patients with scores of 1 or less reduced the likelihood of overtreatment from 54.1% to 6.2% and increased the likelihood of appropriate nonuse from 39.3% to 87.2%.

Study limitations include the different local standards of care used at the multiple centers involved in the study; the lack of information on patient outcomes; and the subsequent inability to define causal relationships.

The researchers concluded that “The new scoring system has the potential to reduce empiric anti-pseudomonal antibiotic use from 54.1% to 6.2%.” However, they noted,

“Future validation and implementation studies will help us determine the impact of these findings in the routine clinical practice.”

Disclosure: Some of the study authors have declared affiliations with biotech, pharmaceutical, and/or device companies. Please see the original reference for a full list of authors’ disclosures.