Therapeutic drug monitoring in older adults treated with beta-lactams or daptomycin in a French tertiary hospital: A retrospective study (TEldBet).

INTRODUCTION

Predispositions such as immunosenescence expose older adults to infections. Aging and sepsis lead to pharmacokinetic modifications, especially in antibiotic treatments. For severe infections such as infective endocarditis or bacteraemia, high doses of antibiotics are needed, frequently beta-lactams. Due to pharmacokinetic changes, older adults are at risk of overexposure or underexposure. The first can lead to adverse events and the second to longer length of stay or treatment failure, both of which lead to functional decline.

METHODS

A retrospective single-centre study. Aged ≥ 75 years, the included patients suffered from a bacterial infection requiring high-dose intravenous beta-lactams or daptomycin. The primary endpoint was the proportion of patients having undergone serum concentration measurement. Secondary endpoints included the clinical and biological characteristics associated with serum concentration monitoring, the clinical and biological factors associated with the likelihood of monitoring, and outcomes related to whether or not serum concentration measurement was performed.

RESULTS

One hundred and fifty-two (152) patients were included. The proportion of patients having undergone serum concentration measurement was 40.1% (61). The median age was 80 ± 9 years. The median Charlson Comorbidity Index score was 8 ± 4. Patients having undergone serum concentration monitoring had significantly higher rates of bacteraemia and endocarditis. Patients with Therapeutic Drug Monitoring (TDM) were found to experience fewer adverse events (39.3%, 95% CI: 27.1-52.7 vs. 45.1%, 95% CI: 34.6-55.8; p = 0.414) and lower in-hospital mortality (13.1%, 95% CI: 5.8-24.2 vs. 17.6%, 95% CI: 10.4-27.0; p = 0.459).

CONCLUSION

While TDM could help to optimize treatment of older adults with infections, it remains underused. Further studies are needed to confirm its usefulness in the management of severe infections.