A new study shows that about one in four adults who prescribe an antibiotic in an outpatient setting for pneumonia does not respond to the treatment. The study also shows that antibiotic is also ineffective with other diseases like cancer and diabetes.

In an article published in Eureka Alert, there are 22.1 percent of adults observed that were not responsive to the antibiotics that were prescribed to them. "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," lead author Dr. James McKinnel said in this year's American Thoracic Society International Conference.

The additional antibiotic therapy noted in Dr. McKinnell's study increases the risk of having antibiotic resistance and complications like C. difficile infection. He said that it is difficult in treating pneumonia and could be life-threatening for the older adults.

His colleagues conducted the study about the dynamism of antibiotic and pneumonia because of the current community-acquired pneumonia guidelines from the Infectious Diseases Society of America and American Thoracic Society and their provided direction. However, large-scale and real-world data are needed in order to better understand and optimize these antibiotic choices to better define clinical risk factors that could be associated with treatment failure.

"Our findings suggest that the community-acquired pneumonia treatment guidelines should be updated with more robust data on risk factors for clinical failure," Dr. McKinnel said. In an article published in Healio, he added that the data provide numerous insights into characteristics of patients who are at the high risk of complications and clinical failure because of the antibiotic therapy.

"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," he said. Dr. McKinnel added that elderly patients are also more vulnerable and should be treated more carefully and potentially with more aggressive antibiotic therapy.

The study showed that there are thousand of patients who actually suffered from other conditions that were not treated with combination antibiotic therapy or respiratory fluoroquinolone even if it was recommended by the guidelines. These other conditions include chronic obstructive pulmonary disease, cancer, and diabetes.