Antibiotics often prescribed for pneumonia despite normal clinical signs

At least one-third of antibiotic prescriptions for suspected pneumonia in hospitalized patients may be unnecessary, highlighting the importance of antibiotic stewardship strategies, a US study showed.

The researchers of this observational study used records of non-ventilated adult patients admitted to one of four hospitals in Massachusetts, US, between May 1, 2017 and July 1, 2018 (194,521 admissions). Of these, 6.3 percent received antibiotic therapy, 9,540 patients for possible community-acquired pneumonia (CAP; treatment initiated on day 1 or 2; mean age 67.6 years, 48 percent female) and 2,733 for possible hospital-acquired pneumonia (HAP; treatment initiated on day 3 onwards; mean age 66.7 years, 44.3 percent female).

All clinical signs – temperature, oxygen saturation, respiratory rate, and white blood cell (WBC) count – were within reference ranges on the first day of antibiotic treatment in 18.7 and 13.5 percent of patients with CAP and HAP, respectively. These included normal temperature (78.6 and 70.8 percent, respectively), oxygen saturation ≥95 percent (39.0 and 34.9 percent, respectively), median daily respiratory rate <22 breaths/minute (81.5 and 79.8 percent, respectively), and daily maximum WBC count >4,000 and <12,000/μL (55.1 and 48.5 percent, respectively). [JAMA Network Open 2020;3:e2010700]

A total of 7,268 and 2,200 patients who were treated for possible CAP and HAP, respectively, had ≥1 abnormal clinical sign on day 1 of antibiotic therapy. All clinical signs normalized within a median 3 days for CAP and 4 days for HAP. 

Of those with all clinical signs within reference range on day 1 of antibiotic therapy, treatment was continued for a median 4 and 5 days in patients with possible CAP and HAP, respectively. Among those with clinical signs outside reference range on day 1 of antibiotic therapy, treatment was continued for a median 0 days after normalization of all signs in possible CAP and HAP.

Patients with suspected CAP or HAP received antibiotics for a median 5 days. However, antibiotic treatment lasted ≥7 days for 30.9 percent of patients with CAP and ≥10 days for 17.4 percent of patients with HAP.

After normalization of all clinical signs, antibiotic therapy was continued for ≥3 days in 34.8 and 38.4 percent of patients with possible CAP and HAP, respectively, and for ≥5 days in 19.8 and 25.9 percent, respectively.

Including inpatient and discharge days, 71,706 days of antibiotics were prescribed for possible pneumonia. Of these, 10,254 antibiotic-days were prescribed for patients in whom all clinical signs were within reference ranges on day 1 of antibiotic administration, while 14,724 antibiotic-days were prescribed from day 3 after all clinical signs had normalized among patients who initially had abnormal signs.

“These two figures suggest that as many as 24,978 of 71,706 antibiotic-days (34.8 percent) of treatment prescribed for possible pneumonia may have been unnecessary,” said the researchers.

“Guidelines recommend treating CAP for 5 days and HAP for 7 days, but adherence to these guidelines is poor,” they said.

“[In this study,] many patients were given courses of antibiotic therapy that exceed current guideline recommendations [with] more than a third of antibiotic-days prescribed for pneumonia … potentially unnecessary,” they added.

To counter this overprescribing, the researchers suggested two potential antibiotic stewardship strategies. “[D]ecrease initiation of antibiotic therapy for patients with clinical signs within reference ranges and tailor antibiotic courses to patients’ clinical trajectories,” they said.

The former would require clinicians to “weigh patients’ objective clinical data more heavily before prescribing antibiotics for possible pneumonia.” As for the latter, “clinicians should customize treatment durations to patients’ clinical trajectories rather than prospectively specifying fixed courses for all patients,” they said. “Clinical sign monitoring could potentially be the basis for a new antibiotic stewardship measurement,” they added.