Psychometric properties of the Perform Questionnaire: a brief scale for assessing patient perceptions of fatigue in cancer

Fatigue is a symptom with a relevant impact on the daily lives of cancer patients and is gaining importance as an outcome measure. The Perform Questionnaire (PQ) is a new scale originally developed among Spanish-speaking patients for the assessment of perception and beliefs about fatigue in cancer patients. An observational longitudinal multicenter study was carried out on cancer patients with fatigue. Fatigue-specific measures (FACT-F), generic health-related quality-of-life measures (NHP), and PQ were gathered at baseline and 3 months later. Feasibility, reliability (internal consistency and test-retest), validity, sensitivity to change, and minimally important differences were analysed. Four hundred thirty-seven patients were included in the study: 60.5% were women, the mean age was 59.1 years, the mean time from diagnosis was 2.2 years, 33.6% of patients had breast cancer, and 29.1% had anaemia (haemoglobin (Hb) < 11 g/dL). Low levels of missing items and ceiling/floor effects (< 10%) were found. The overall Cronbach's alpha and intraclass correlation coefficient were 0.94 and 0.83, respectively. The PQ score was associated with fatigue intensity, the need for a caregiver, and the Hb level. Its association was stronger with the FACT-F than with non-specific health measures (NHP). The PQ showed good sensitivity to change for improved and worsening health status. A minimally important difference of 3.5 was estimated in patients whose Hb level had improved by at least 1 g/dL. The PQ measured the attitudes and beliefs about fatigue among cancer patients in clinical practice and showed good psychometric properties among Spanish-speaking patients.