Study: Antibiotic Therapy Doesn’t Work for Nearly One in Four Adults With Pneumonia

Specialist calls for guideline changes

Approximately one in four (22%) adults prescribed an antibiotic in an outpatient setting for community-acquired pneumonia (CAP) does not respond to treatment, according to a new study presented at the 2017 American Thoracic Society International Conference.

“Pneumonia is the leading cause of death from infectious disease in the United States, so it is concerning that we found nearly one in four patients with community-acquired pneumonia required additional antibiotic therapy, subsequent hospitalization, or emergency room evaluation,” said lead author James A. McKinnell, MD, an infectious disease specialist in Los Angeles. “The additional antibiotic therapy noted in the study increases the risk of antibiotic resistance and complications like C. difficile (‘C diff’) infection, which is difficult to treat and may be life-threatening, especially for older adults.”

Although current CAP guidelines from the American Thoracic Society and the Infectious Diseases Society of America, published in 2007, provide some direction, large-scale, real-world data are needed to better understand and optimize antibiotic choices and to better define clinical risk factors that may be associated with treatment failure, the researchers said.

McKinnell and his colleagues examined databases containing records for 251,947 adult patients who were treated between 2011 and 2015 with a single class of antibiotics (beta-lactam, macrolide, tetracycline, or fluoroquinolone) after a visit to their physician for treatment for CAP. The scientists defined treatment failure as the need to refill antibiotic prescriptions, switching to another antibiotic, or an ER visit or hospitalization within 30 days after receiving the initial antibiotic prescription. Overall, the total antibiotic failure rate was 22%, but patients with certain characteristics––such as older age or having certain other diseases in addition to pneumonia––had higher rates of drug failure. After adjusting for patient characteristics, the failure rates by class of antibiotic were 26% for beta-lactams; 23% for macrolides and tetracycline; and 21% for fluoroquinolones.

“Our findings suggest that the community-acquired pneumonia treatment guidelines should be updated with more-robust data on risk factors for clinical failure,” McKinnell said. “Our data provide numerous insights into characteristics of patients who are at higher risk of complications and clinical failure. Perhaps the most striking example is the association between age and hospitalization: patients over the age of 65 were nearly twice as likely to be hospitalized compared to younger patients when our analysis was risk adjusted, and nearly three times more likely in unadjusted analysis. Elderly patients are more vulnerable and should be treated more carefully, potentially with more-aggressive antibiotic therapy.”

McKinnell also said that his study found substantial regional variations in treatment outcomes, which are not specifically addressed in CAP guidelines. In addition, the study showed that thousands of patients with other conditions––such as chronic obstructive pulmonary disease, cancer, or diabetes––were not treated with combination antibiotic therapy or respiratory fluoroquinolones, as the guidelines recommend.

“While certain aspects of the guidelines need to be updated, some prescribers also have room for improvement and should implement the current guidelines,” McKinnell concluded.

Source: EurekAlert; May 21, 2017.