Assessment of chemotherapy-related adverse drug reactions among multiple myeloma patients at Kenyatta national hospital.

Background: Despite treatment modalities for multiple myeloma can cause adverse drug reactions (ADRs), data are scarce about the types, severity and preventability of chemotherapy-related ADRs in Kenya. This study aimed to assess the chemotherapy-related ADRs among multiple myeloma patients at Kenyatta National Hospital (KNH).

Methods: A one-arm retrospective cohort study was carried out among all eligible adult patients with a documented diagnosis of multiple myeloma between 1^st January 2017 to 31^st December 2023. A data abstraction tool was used to assess sociodemographics, clinical characteristics and chemotherapy-related ADRs. The Schumock and Thornton scale and the modified Hartwig and Siegel severity scale were employed to evaluate the preventability and severity of ADRs, respectively. Data analysis was performed using the Statistical Package for Social Sciences (SPSS) version 29.0 software. The results were presented using mean, frequency and percentage. Binary logistic regression was employed to assess factors influencing ADRs. A p-value of less than 0.05 was considered statistically significant.

Results: The prevalence of ADRs in this study was 81.5% with a total of 230 ADRs identified. The primary ADRs identified were peripheral neuropathy (21.7%), nausea and vomiting (14.8%), neutropenia (12.2%) and anemia (11.3%). The majority of the ADRs (51.7%) were moderate in severity, and 29.8% were of mild severity. Preventability assessments of the ADRs showed that most of them (68.2%) were definitely preventable and 13.2% were probably preventable. VRD (Bortezomib/Lenalidomide/Dexamethasone) and VCD (Bortezomib/Cyclophosphamide/Dexamethasone) treatment regimens were responsible for most of the ADRs. VRD (AOR = 11.1, 95% CI = 3.7-32.8, p < 0.001) and VCD treatment regimens (AOR = 4.8, 95% CI = 1.1-20.0, p = 0.033) were the significant factors affecting the occurrence of ADRs.

Conclusion: Overall, the incidence of chemotherapy-related ADRs in multiple myeloma patients at KNH was notably high (81.5%). Despite the moderate severity of the ADRs, their preventable nature highlights the potential for improved patient outcomes through careful regimen selection and monitoring.