Comparing outcomes among outpatients treated for pyelonephritis with oral cephalosporins versus first-line agents.

Fluoroquinolones and trimethoprim/sulfamethoxazole (TMP-SMX) are first-line agents for acute pyelonephritis. Oral β-lactams are second-line agents owing to reported lower efficacy rates, primarily seen with aminopenicillins rather than cephalosporins. The increase in resistance rates and adverse effects associated with first-line agents provides justification to reconsider oral cephalosporins for pyelonephritis. Therefore, the objective of this study was to determine whether there is a difference in urinary tract infection (UTI) recurrence rates between oral cephalosporins and first-line agents in the treatment of acute pyelonephritis. This was a retrospective, single-centre, observational cohort study from 1 December 2018 to 31 May 2020. The study population was adult TRICARE beneficiaries with a diagnosis of acute pyelonephritis who were treated with oral antibiotics. The two cohorts compared were first-line antibiotics (ciprofloxacin, levofloxacin and TMP-SMX) and oral cephalosporins. The primary outcome was UTI recurrence rate at 30 days, which was defined as a repeat clinic visit, emergency department visit or hospital admission for a UTI (cystitis or pyelonephritis). The secondary outcome was to determine independent risk factors for UTI recurrence. A total of 268 cephalosporin and 211 first-line cases were included. The primary composite outcome of UTI recurrence within 30 days occurred in 44 (16%) cephalosporin and 36 (17%) first-line cases (P = 0.851). Independent risk factors for UTI recurrence were chronic kidney disease and Klebsiella spp. isolation. In conclusion, there was no significant difference in UTI recurrence rates between oral cephalosporins and first-line agents in the treatment of acute pyelonephritis in the outpatient setting.