(ChemotherapyAdvisor) – A study of patients enrolled in supportive care/palliative oncology clinical trials found a high attrition rate “associated with various patient characteristics and a high baseline symptom burden,” according to an article published in Cancer.
Few studies have documented why patients commonly drop out of supportive care/palliative oncology clinical trials, both before reaching the primary end point and at the end of the study. David Hui MD, MSc, of the Department of Palliative Care and Rehabilitation Medicine, The University of Texas MD Anderson Cancer Center, Houston, TX, and colleagues reviewed all prospective interventional supportive care/palliative oncology trials conducted at the institution between 1999 and 2011 and extracted patient and study characteristics and attrition data.
Of 1,214 patients included in 18 clinical trials, median age was 60 years; 41% had an Eastern Cooperative Oncology Group performance status of ≥3, a median Edmonton Symptom Assessment Scale (ESAS) for fatigue of 7 of 10, and a median ESAS for dyspnea of 2 of 10.
Attrition rate was 26% (95% CI 23%–28%) for the primary end point and 44% (95% CI 41%–47%) for the end of the study, Dr. Hui noted.
For the primary end point dropout, common reasons included symptom burden (21%), patient preference (15%), hospitalization (10%), and death (6%). Primary end point attrition was associated with a higher baseline intensity of fatigue (OR, 1.10 per point; P=0.01) and a longer study duration (P=0.04).
Attrition at the end of the study was associated with higher baseline levels of dyspnea (OR 1.06; P=0.01), fatigue (OR, 1.08; P=0.01), Hispanic race (OR, 1.87; P=0.002), higher level of education (P=0.02), longer study duration (P=0.01), and outpatient studies (P=0.05).
“These findings have implications for future clinical trial design including eligibility criteria and sample size calculation,” the authors concluded.