Antifungal therapeutic drug monitoring adherence high, though room for improvement exists
Click Here to Manage Email Alerts
Key takeaways:
- Providers treating patients with antifungals reported a moderate-to-high percentage of any therapeutic drug monitoring.
- Barriers included long turnaround times and uncertainty around TDM recommendations.
A recent survey showed moderate to high adherence for antifungal therapeutic drug monitoring adherence, though there was room for improvement, specifically when using certain antifungals as prophylaxis.
“We recently conducted an analysis looking at the utilization of antifungal therapeutic drug monitoring (TDM) among people in hospitals receiving itraconazole, posaconazole, and voriconazole. TDM is testing that checks the amount of a drug that is in a patient’s blood,” Dallas J. Smith, PharmD, epidemiologist in CDC’s Mycotic Diseases Branch, told Healio. “We found less than 16% of TDM-eligible patients received TDM.”
Smith explained that having medication levels that are too low could lead to treatment failure and potential resistance, whereas having levels that are too high can lead to drug toxicity, like liver toxicity.
“We wanted to identify what barriers health care providers have for using antifungal TDM to better understand appropriate interventions and improve how health care providers use and prescribe antifungal TDM,” he said.
Through the Emerging Infections Network, researchers emailed a link to an online survey three times in March 2023 to 1,903 network members who work as infectious disease physicians and health care professionals in North America — specifically at five clinics in the United States and one in Canada.
Survey questions assessed the use of systemic azole antifungals — itraconazole, posaconazole, voriconazole, isavuconazole and fluconazole — for the treatment and prophylaxis of invasive fungal infections, the estimated proportion of patients for whom TDM was used by drug and indication, perceived utility of hydroxyitraconazole testing and barriers to TDM use. The researchers then evaluated practice-related factors associated with any TDM use by drug and indication.
Of the 523 respondents who completed the survey, 91% were infectious disease physicians and 73% practiced at a university or teaching hospital. Among the 364 (70%) respondents who routinely care for patients receiving antifungal prophylaxis, most cared for five or more patients per drug within the last year, and among those who treated patients receiving each antifungal, 90% reported any TDM use during treatment with voriconazole, 72% for posaconazole, 72% for itraconazole, 40% for isavuconazole and 10% for fluconazole.
When asked whether hydroxyitraconazole testing is helpful in a patient’s clinical care, 32% said “always” or “often,” 20% said “sometimes” or “rarely” and 47% said “never” or “do not use” hydroxyitraconazole testing.
The survey also revealed that respondents with less than 15 years of experience more frequently reported any TDM use during treatment using itraconazole (66% vs. 77%), posaconazole (63 vs. 78%) and voriconazole (83% vs. 95%) compared with respondents with 15 years or more of experience.
Compared with other practice settings, respondents at university or nonuniversity teaching hospitals were also more likely to report TDM use during posaconazole (79% vs. 46%), voriconazole (92% vs. 83%) and isavuconazole treatment (46% vs. 21%), whereas those caring for pediatric patients were more likely to report TDM use during posaconazole (87% vs. 66%) and isavuconazole treatment (55% vs. 35%) than those caring for adult patients.
Among respondents who routinely care for patients on antifungal prophylaxis, 65% reported any TDM use during prophylaxis with voriconazole, 55% for posaconazole, 32% for itraconazole, 27% for isavuconazole and 4% for fluconazole.
Through the survey, the researchers determined that barriers to performing TDM included long turnaround times for send-out tests (74%), difficulty coordinating testing logistics (48%), uncertainty around TDM recommendations (39%), difficulty interpreting results (28%), uncertainty about TDM benefits (18%), cost (14%) and challenges with insurance coverage (11%), although 10% reported having no barriers.
“Antifungal therapeutic drug monitoring is a critical tool for antifungal stewardship to help make sure the limited antifungal treatment options remain effective. Antifungal stewardship includes giving the right drug, at the right time, at the right dose, for the right duration; another critical aspect of antifungal stewardship is to make sure the right amount of drug is in the patient’s blood,” Smith said. “Developing onsite TDM technology, incorporating pharmacists into antifungal TDM protocols, and furthering research to inform optimal TDM practices can improve how and when health care providers use antifungal TDM.”
Collapse
Click Here to Manage Email Alerts