Influence of Interprofessional Care on Vancomycin Therapy Management in Hematology: A Retrospective Quality Improvement Analysis

Background: Vancomycin therapy is challenging in hematology patients due to their complex therapies, frequent infections, variable renal function, and nephrotoxic co-medications, resulting in high pharmacokinetic variability. Methods: Vancomycin therapy was retrospectively analyzed over three consecutive periods using routine clinical data from a German tertiary academic hematology ward, focusing on recommended loading dose administration, therapeutic trough concentration attainment (15–20 mg/L), and a potential acute kidney injury (AKI): (I) baseline cohort (BC)—usual care; (IIa) infectious diseases support cohort (IDSC)—following collaboration with infectiologists; and (IIb) infectious diseases and pharmacy support cohort (IDPSC)—following additional clinical pharmacist involvement. Results: Overall, 155 patients receiving 164 vancomycin cycles were included. Recommended loading dose adherence increased from 3.3% (n = 3/90) in the BC to 32.6% (n = 15/46) in the IDSC and 53.6% (n = 15/28) in the IDPSC. The difference was statistically significant for both IDSC and IDPSC vs. BC (χ2 test, p < 0.001). Across cohorts, therapeutic trough concentrations were attained faster with the recommended than with an inadequate loading dose (median 4 vs. 8 days; log-rank test, p = 0.001). Subtherapeutic trough levels decreased (BC 78.6% vs. IDSC 65.5% vs. IDPSC 46.4%), while supratherapeutic levels increased (BC 7.6% vs. IDSC 10.8% vs. IDPSC 23.2%), accompanied by a higher AKI incidence (BC 20.0% vs. IDSC 17.4% vs. IDPSC 39.3%). The difference in AKI was statistically significant for IDPSC vs. BC (χ2 test, p = 0.038) and IDSC (χ2 test, p = 0.037). Conclusions: A recommended vancomycin loading dose within the interprofessional care cohort achieves therapeutic trough concentrations faster but requires close monitoring for nephrotoxicity.