A pharmacist-driven antimicrobial stewardship intervention targeting cytomegalovirus viremia in ambulatory solid organ transplant recipients.

Background: There is a growing need for robust antimicrobial stewardship interventions in both ambulatory and solid organ transplant (SOT) populations.

Methods: A retrospective quasi-experiment was conducted to evaluate the impact of a pharmacist-driven antimicrobial stewardship intervention targeting cytomegalovirus (CMV) viremia in ambulatory SOT recipients. The intervention consisted of (a) real-time CMV DNA surveillance and result notification conducted by the pharmacist and (b) recommendations for the optimization of drug therapy provided at the time of result notification. The intervention period was compared to a pre-intervention period of usual care. Of 431 adult SOT recipients who had an initial quantifiable CMV viral load in the ambulatory setting, 185 received antiviral induction therapy and were included for analysis.

Results: Significantly fewer patients in the intervention period reached a CMV viral load >10 000 IU/mL immediately prior to treatment (10.6% vs 27.3%; P = 0.004), and a significantly greater proportion of patients in the intervention period achieved CMV eradication at 21 days (84.5% vs 71.7%; P = 0.038). Additional differences favoring the intervention period were antiviral initiation within 5 days of the first quantifiable CMV DNA (62.4% vs 55.0%; P = 0.02) and time-to-CMV eradication (25.5 vs 28.9 days; P = 0.003). Although not significant, there were also numerical reductions in CMV-related hospital admissions (11.9% vs 19.0%; P = 0.188) and CMV disease (5.9% vs 12.0%; P = 0.151) during the intervention period, as well as fewer episodes of CMV resistance at 1-year (2.3% vs 4.0%; P = 0.689).

Conclusion: Together, these findings suggest a potential role for pharmacist involvement in CMV surveillance and treatment optimization in ambulatory SOT recipients.