Oral beta-lactams provide noninferior postdischarge pyelonephritis treatment



– Patients hospitalized for pyelonephritis and discharged after receiving intravenous antibiotic treatment who then received step-down treatment with an oral beta-lactam had 30-day outcomes that were noninferior to patients who received an oral fluoroquinolone or trimethoprim-sulfamethoxazole as their discharge regimen, in a retrospective study of 211 patients managed at either of two U.S. hospitals.

This was the largest comparison reported on oral beta-lactam drugs for postdischarge treatment of pyelonephritis relative to the standard oral agents, fluoroquinolones and trimethoprim-sulfamethoxazole (Bactrim), Athena Hobbs, PharmD, said at an annual scientific meeting on infectious diseases. The superiority of an oral fluoroquinolone or trimethoprim-sulfamethoxazole and inferiority of oral beta-lactam drugs were cited in 2010 guidelines for managing pyelonephritis from the Infectious Diseases Society of America (Clin Infect Dis. 2011 March 1;52 [5]: e103-20).

Although limited as a nonrandomized, retrospective comparison, the finding of at least similar efficacy by beta-lactam agents “opens new treatment options” that avoid issues with drug resistance and adverse effects from treatment with fluoroquinolones or trimethoprim-sulfamethoxazole, Dr. Hobbs said in a video interview. Beta-lactams have already been embraced for this indication by some hospitalists, demonstrated by their use of beta-lactam antibiotics for 122 (58%) of the 211 patients included in the study. Among the 89 patients discharged on a non–beta-lactam, 69 (78%) had fluoroquinolone treatment and the remaining 20 patients went home taking trimethoprim-sulfamethoxazole. The new finding “confirms that we are not doing harm to patients,” with this existing practice of mostly prescribing an oral beta-lactam drug, noted Dr. Hobbs, an infectious diseases pharmacy specialist at Baptist Memorial Hospital in Memphis.

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The study included patients aged 18-89 years hospitalized during 2014-2017 for a primary diagnosis of pyelonephritis at Baptist or at a second Hospital in Austin, Tex. The study excluded patients in intensive care, with a urologic abnormality, pregnant women, and patients treated with an intravenous antibiotic other than a beta-lactam for more than 24 hours. The most commonly used intravenous drugs were cefazolin and ceftriaxone. The enrolled patients averaged just over 40 years old, and more than 90% were women.

The study’s primary outcome was the 30-day rate of either hospital readmission or an ED visit for pyelonephritis or a urinary tract infection. This occurred in 4.9% of the patients discharged on an oral course of a beta-lactam drug, and in 5.6% of those discharged on either a fluoroquinolone or trimethoprim-sulfamethoxazole, a difference that was not statistically significant and that met the prespecified criteria for noninferiority, Dr. Hobbs reported. The most commonly prescribed oral beta-lactam was cefuroxime in about half the patients, followed by cephalexin or cefadroxil in about a quarter of patients, and amoxicillin with clavulanate in 19%. The two arms of the study also showed no significant difference in infection recurrences during 90-day follow-up.

The study received no commercial funding. Dr. Hobbs had no relevant disclosures.

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