(215) Prevalence, Attributes, and Risk-Factors of QT-Interval Extending Drugs & Drug-Drug Interactions in Cancer Patients: A Prospective Study in a Tertiary Care Hospital

Sunday, August 28, 2022

8:00 AM – 1:45 PM CEST

Location: Hall C

Publication Number: 1260

Presenting Author(s)

Biswadeep Das, MTech(Bioengineering), MD(Pharmacology), PG Dip(Medical Education)
– Additional Professor, Department of Pharmacology, All India Institute of Medical Sciences(AIIMS) Rishikesh, All India Institute of Medical Sciences(AIIMS) Rishikesh, Rishikesh, Uttarakhand, India

Co-Author(s)

Aakash Agnihotri
– AIIMS Rishikesh, Rishikesh, Uttarakhand, India
Manjunath Bidarolli
– AIIMS Rishikesh, Rishikesh, Uttarakhand, India
CHAYNA SARKAR
– NEIGRIHMS, SHILLONG,MEGHALAYA 793018,INDIA, Shillong, Meghalaya, India

Background: Cardiomyopathy and other forms of cardiac toxicity are significant adverse effect of cancer treatment. Many anticancer drugs are known to cause significant QT-prolongation.

Objectives: To explore the extent of use of QT interval prolonging drugs and QT-prolonging drug-drug interactions(QT-DDIs) in cancer patients, and
To identify the prevalence of as well as characterize risk factors for possible QTc prolongation and TdP in cancer patients attending OPD
in a tertiary care hospital.

Methods: This study was a prospective, hospital-based, cross-sectional study for a one-year period(September 2020-September 2021), at the medical-oncology and radiation-oncology departments of AIIMS Rishikesh, India. All types of cancer patients, irrespective of their age or sex were included in the study over a period of one year. Risk-stratification of QT-prolonging drugs were executed in accordance with AzCERT/CredibleMeds list of QT-prolongation and QT-prolonging drug-drug interactions(DDIs) identified by using four online drug interactions checker softwares. Descriptive statistics with percentage was used for appropriate variables. Univariate & Multivariate Regression models were used to establish relationship between risk factors proposed to be responsible for QT-prolongation. QT-DDI outcome was used as an independent variable. Microsoft Excel and Strata(version 12) were used for statistical analysis.

Results: 1331 cancer patients were enrolled in the study. The overall prevalence of QT-prolonging drugs was 97.3%. Prevalence of QT-prolonging drugs was observed to be higher in females(50.1%) as compared to males(47.1%). Ondansetron, pantoprazole, domperidone, olanzapine and tramadol were the most frequent QT-prolonging drugs used in the cancer patients. QT-DDIs were found in 466(35.0%) cancer patients. Drug combination most frequently involved in QT-DDIs was ondansetron with domperidone(10.1%). Most of the QT-DDIs could be attributed to pharmacodynamic mechanisms(63%). Univariate regression analysis showed significant results for various risk factors, viz., 6-7 prescribed drugs(p < 0.001), 8-9 prescribed drugs(p < 0.001), ≥10 prescribed drugs(p < 0.001), Breast cancer(p < 0.001), GI cancer(p < 0.001) , CML(p < 0.001), Genitourinary cancer (p=0.001), ovarian cancer(p < 0.001), and NHL(p=0.024).

Conclusions: This study revealed a high prevalence of QT-prolonging drugs and QT-DDIs among cancer patients who are treated with anticancer and non-anticancer drugs. Hence, it's crucial to institute precautions, stay vigilant, and proactively avoid QT prolongation in clinical situations. Evidence-based pragmatic QTc interval prolongation risk assessment tools and standard operating protocols are imperative for cancer patients.