When to “CAP” Off Pneumonia Treatment

A 65-year-old woman is admitted to your inpatient service from the family health center. She is diagnosed with community-acquired pneumonia (CAP) based on a five-day history of cough and fever and a positive chest x-ray. She now requires oxygen at rest. She has a history of hypertension and diabetes, both of which have been controlled by oral medications. Antibiotic therapy is initiated—but what treatment duration is ideal?

The World Health Organization estimates that pneumonia is the third most common cause of mortality worldwide, causing 3.2 million deaths per year.² Appropriate prescribing of antibiotics is critical for successful treatment of CAP.

In 2007, the Infectious Diseases Society of America (IDSA) and the American Thoracic Society (ATS) created consensus guidelines for the treatment of CAP.³ These guidelines recommend a minimum five-day course of antibiotics if the patient is clinically stable (defined as afebrile for 48 h; heart rate ≤ 100 beats/min; respiratory rate ≤ 24 breaths/min^-1; systolic blood pressure ≥ 90 mm Hg; oxygen saturation ≥ 90%; normal mental status; and able to tolerate oral intake). Longer antibiotic treatment durations are recommended on an individualized basis (eg, if the isolated pathogen is not susceptible to the initial antibiotic or if the infection was caused by an extrapulmonary source).

However, these recommendations are not routinely followed. Practitioners often make it their custom to prescribe longer courses of antibiotics.⁴ Yet, we know that there are several reasons to consider shorter courses of antibiotics, including lower health care costs, fewer adverse effects, and lower rates of bacterial resistance.^5-7

Two meta-analyses were performed to compare the safety and efficacy of short- and long-course antibiotic therapy in CAP (≤ 7 d vs > 7 d, respectively).^8,9 Both meta-analyses found no difference in efficacy or safety between shorter and longer courses of antibiotics for CAP. Secondary outcomes noted a trend toward decreased antibiotic-associated adverse events with shorter courses of therapy.^8,9

However, there are limitations to broad implementation. Studies included in these analyses utilized a variety of antibiotic treatment regimens and longer courses (7 d vs 5 d) that are not recommended by the IDSA/ATS guidelines. Additionally, studies included both inpatient and outpatient treatment groups, so findings may not apply to an exclusively inpatient CAP population.^8,9

This study sought to validate the IDSA/ATS guidelines recommending a five-day course of antibiotics for hospitalized patients with CAP.¹

STUDY SUMMARY

No differences in clinical outcomes

This multicenter, double-blind, noninferiority randomized trial compared short-term antibiotic treatment duration (5 d) to physician-discretion antibiotic treatment duration among 312 patients (ages 18 and older) admitted for CAP to one of four teaching hospitals in Spain.¹ Pneumonia was diagnosed on chest radiograph with at least one symptom: cough, fever, dyspnea, or chest pain. Patients were excluded if, among other things, they had an immunocompromising condition, lived in a nursing home, had a recent hospital stay, used antibiotics within the previous 30 days, or had an uncommon pathogen, such as Pseudomonas aeruginosa or Staphylococcus aureus.¹

After receiving a minimum of five days of antibiotics, patients were randomly assigned to an intervention group (where, if clinically stable, no further antibiotics were given) or a control group (where physicians determined antibiotic duration).¹

Primary outcomes were clinical success rate at days 10 and 30 from admission (defined as resolution of signs and symptoms of CAP without further antibiotics) and improvement of CAP-related symptoms (as determined by an 18-item questionnaire scored 0-90, with higher scores indicative of greater severity). Secondary outcomes included duration of antibiotic use, time to clinical improvement, mortality, hospital readmission, hospital length of stay, and CAP recurrence.¹

Of the 312 participants, 162 were randomized to the intervention group and 150 to the control group. Mean age of patients in the intervention and control groups was 66.2 and 64.7, respectively. Other baseline demographics were similar between the groups. Nearly 80% of patients received quinolone treatment; < 10% received a ß-lactam plus a macrolide.¹

Clinical success rates were similar for the control and intervention groups at day 10 (49% vs 56%, respectively) and day 30 (89% vs 92%). Median antibiotic treatment duration was shorter in the intervention group than in the control group (5 d vs 10 d); the intervention group also had a lower rate of 30-day hospital readmissions (1.4% vs 6.6%). There were no differences for other secondary outcomes.¹