In older adults with community-acquired pneumonia (CAP), treatment with β-lactam plus doxycycline was associated with a decreased risk for 30 and 90-day all-cause mortality, supporting current guideline recommendations for CAP treatment. These findings, from a retrospective observational cohort study, were published in Clinical Infectious Diseases.

Data for this study were sourced from the Department of Veterans Affairs (VA) Health Care System. Researchers sought to assess the effect of doxycycline among patients aged 65 years and older who were discharged from a VA hospital with a diagnosis of CAP between 2001 and 2012 were. Patients who did not receive antibiotic therapy concordant with the American Thoracic Society/Infectious Diseases Society of America (ATS/IDSA) clinical practice guidelines were excluded from the study. The primary outcomes were all-cause mortality within 30 and 90 days of hospital admission. To balance cohort differences, the researchers used a propensity matching approach.

Among a total of 70,533 patients included in the study, the mean age was 77.9 (SD, 7.4) years and 98.2% were men. Of these patients, 7.4% received a treatment regimen that contained doxycycline and 92.5% received an alternative guideline-concordant treatment regimen.


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After stratification by treatment regimen, the researchers noted that patient groups differed significantly in terms of sex (P =.001), ethnicity (P <.0001), number of outpatient visits within the past year (P =.005), receipt of noninvasive ventilation during hospitalization (P =.002); and rates of dementia (P =.0001), stroke (P =.002), metastatic solid tumor (P =.005), diabetes (P =.007), or any prior malignancy (P =.04).

Among all patients included in the study, the unadjusted 30-day mortality rate was 6.4% for those who received β-lactam plus doxycycline and 9.1% for those who received an alternative treatment regimen (P <.0001). In addition, the mean hospital stay was 5.5 (SD, 6.8) and 5.84 (SD, 9.50) days among patients who received β-lactam plus doxycycline and those who received an alternative treatment regimen, respectively (P =.01).

Among a propensity match cohort of 5278 patients from each treatment group, 30-day (odds ratio [OR], 0.72; 95% CI, 0.63-0.84) and 90-day (OR, 0.83; 95% CI, 0.74-0.92) mortality were significantly decreased among those who received β-lactam plus doxycycline (P <.001).

This study was limited by the lack of information about patients’ medication allergies and its predominantly male population.

These data indicated that β-lactam plus doxycycline for the treatment of older adults with CAP was superior to alternative guideline-concordant treatment regimens. The researchers concluded that “randomized [controlled] trials are needed to confirm this finding and to identify the best therapies for patients hospitalized with CAP.”

Disclosure: One author declared affiliations with industry. Please see the original reference for a full list of disclosures.

Reference

Uddin M, Mohammed T, Metersky M, Anzueto A, Alvarez CA, Mortensen EM. Effectiveness of beta-lactam plus doxycycline for patients hospitalized with community-acquired pneumonia. Clin Infect Dis. 2021;ciab863. doi:10.1093/cid/ciab863