Assessment of Fatigue in Patients with Chronic Myeloid Leukemia Receiving Targeted Therapy: A Cross-Sectional Study

Background: Fatigue is a common side effect of tyrosine kinase inhibitor (TKI) therapy in patients with chronic myeloid leukemia (CML), leading to reduced health-related quality of life (HRQoL) and decreased treatment adherence. Aim: To evaluate the severity of fatigue and the factors influencing it, including vitamin D deficiency, in CML patients undergoing TKI therapy. Methods: This cross-sectional observational study included 60 CML patients on TKI therapy. Fatigue severity was assessed using the 13-item Functional Assessment of Chronic Illness Therapy-Fatigue (FACIT-Fatigue) scale, with severe fatigue defined as a score of ≤30. HRQoL was evaluated using the Functional Assessment of Cancer Therapy-General (FACT-G). Vitamin D levels were measured, and sociodemographic, clinical, and laboratory data were collected from patient records. Results: The mean age of participants was 44.6 years, with 34 (57%) being female. The median duration of treatment was 82.3 months. Severe fatigue was reported by 29 (48%) participants. Univariate analysis showed significant associations between severe fatigue and factors such as TKI dose, adherence to treatment, time to first complete cytogenetic response, and vitamin D deficiency (p = 0.009, 0.006, 0.021 and <0.001; respectively). Multivariate analysis confirmed a significant association between severe fatigue and vitamin D deficiency. Additionally, severe fatigue and vitamin D deficiency were both significantly linked to poorer overall HRQoL. Conclusion: Healthcare providers should address factors influencing fatigue, particularly vitamin D deficiency, in the management of CML patients receiving TKI therapy.