Guideline-Based Antibiotic Therapy Reduces Mortality in Older Patients With CAP

Risk of cardiovascular death at 1-year post-infection is significantly reduced in patients over 65 years of age hospitalized with community acquired pneumonia (CAP) and treated with guideline-concordant antibiotic therapy, according to study findings published in Chest.

In North America, infection severity determines which guideline-recommended empiric antibiotic therapy is recommended for those hospitalized with CAP. In the absence of severe disease, recommended therapies are a combination of a beta-lactam and a macrolide (clarithromycin or azithromycin) or monotherapy with a respiratory fluoroquinolone; in severe cases requiring intensive care unit (ICU) admission, a broad spectrum beta-lactam with either a macrolide or a fluoroquinolone is recommended.

Investigators explored how initial use of guideline-concordant antibiotic therapy in older patients hospitalized with CAP affected 1-year all-cause and cardiovascular mortality rates.

The researchers conducted a retrospective cohort study of 1909 patients (>65 years of age) who survived hospitalization for CAP between 2004 and 2015 at the Ottawa Hospital in Ontario, Canada. Investigators reviewed patient information from provincial and hospital databases to determine: (1) if the selection of initial antibiotic therapy for CAP was concordant with current clinical practice guidelines; and (2) if there was an association between guideline-concordance and 1-year cardiovascular and all-cause mortality following the patients’ index CAP hospitalization. The analysis adjusted for CAP severity; 1-year overall expected risk of death; and history of heart failure, myocardial infarction, pneumonia, or cerebrovascular disease.

Need for ICU care was used as surrogate for severe CAP. Among patients without intensive care within 24 hours of admission, therapy that included the combination of a guideline-preferred beta-lactam agent plus clarithromycin or azithromycin or monotherapy with a respiratory fluoroquinolone was considered guideline-concordant. Among patients requiring intensive care within 24 hours of admission, the combination of a guideline-preferred beta-lactam plus a macrolide or a respiratory fluoroquinolone was guideline-concordant.

More than half of patients (mean age 81 years) visited an emergency room in the year prior to their index CAP admission, and almost a third of patients had been admitted. About one-fifth of patients were institutionalized and another one-fifth required at-home assistance.

The combination of a beta-lactam and macrolide was the most common antibiotic therapy (37.4%) and fluoroquinolones the most frequent solo therapy (33.3%). There were 10.3% receiving all 3 antibiotic classes and 1.3% received none of them. Overall, antibiotic therapy was guideline-concordant in 89.7% of patients.

Over 31% of patients died within 1 year of CAP hospitalization. Of those who did not survive, more were older, male, and dependent at baseline, with a higher Charlson Comorbidity Index score; those who did not survive also had more previous emergency department visits or hospitalizations by ambulance and were more likely to have been previously been admitted for pneumonia.

Patients who did not receive guideline-concordant initial antibiotic therapy tended to be male, residents of chronic care facilities, and in need of home oxygen; they also had more previous emergency department visits or hospitalizations by ambulance, and had higher pneumonia severity scores.

The investigators noted 145 patients (7.7%) had cardiovascular death within 1 year of admission. This occurrence was more likely in individuals with history of heart failure, cerebrovascular disease, or myocardial infarction.

A significant (almost 50%) reduction in cardiovascular risk of death 1 year after CAP admission was associated with the use of guideline-concordant antibiotic therapy (HR, 0.53; 95% CI, 0.34-0.80; P =.003). Additionally, the researchers found use of guideline-concordant antibiotic therapy was associated with a nonsignificant lower all-cause mortality trend at 1-year post-CAP (hazard ratio [HR], 0.82; 95% CI, 0.65-1.04; P =.099).

Study limitations include the study’s retrospective design; reliance on administrative data; unaccounted-for CAP admissions; unaccounted-for patients treated according to previously used pneumonia guidelines; unaccounted-for health factors prior to the index CAP admissions that may have influenced long-term outcomes; and inability to determine if pneumococcus or viral pathogens affected findings.

Investigators concluded “Use of guideline-concordant antibiotic therapy for CAP treatment in elderly hospitalized patients is associated with a significant reduction in the risk of cardiovascular death at 1-year post-CAP.” They wrote “This finding further supports current clinical practice guideline recommendations for CAP treatment.”