Comparative effectiveness of adjunctive rifampicin versus gentamicin for prosthetic valve endocarditis due to...

Although adjunctive rifampicin and/or gentamicin have been recommended for Staphylococcus aureus prosthetic valve endocarditis, evidence regarding the evaluation of their clinical effectiveness is limited.

To compare the clinical impact of adjunctive rifampicin without gentamicin, and adjunctive gentamicin without rifampicin therapies for S. aureus prosthetic valve endocarditis.

This retrospective study used TriNetX to evaluate multicentre electronic medical records of patients aged 18 years or older in the USA between 2016 and 2024. After propensity score matching, HRs were estimated with 95% CIs. Covariates included age, sex, ethnicity and medical comorbidities.

A total of 353 and 369 patients were identified in the rifampicin and gentamicin groups, respectively. One-year all-cause mortality was observed in 87 (31.3%) and 111 (39.9%) patients in the rifampicin and gentamicin groups after propensity score matching, respectively, leading to an HR of 0.71 (95% CI, 0.54-0.94; P = 0.016). The HRs were not statistically significant for ICU admission (HR 0.93; 95% CI, 0.74-1.18; P = 0.540), recurrent endocarditis (HR 0.76; 95% CI, 0.42-1.40; P = 0.381), kidney failure (HR 0.93; 95% CI, 0.74-1.18; P = 0.540) or hepatic failure (HR 0.96; 95% CI, 0.66-1.39; P = 0.822).

The rifampicin-containing regimen without gentamicin was associated with reduced 1 year mortality compared with the gentamicin-containing regimen without rifampicin. Although the results should be interpreted with caution because of potential residual unmeasured confounders, including duration of antimicrobial treatment and biases, our findings provide further evidence that adjunctive gentamicin may not be routinely needed for S. aureus prosthetic valve endocarditis.