Psychometric properties of the EORTC QLQ-C30 in Uganda

Abstract

Background Self-reported measures play a crucial role in research, clinical practice and health assessment. Instruments used to assess self-reported health-related quality of life (HRQoL) need validation to ensure that they measure what they are intended to, detect true changes over time and differentiate between subjects. A generic instrument measuring HRQoL adapted for use among people living with cancer in Uganda is lacking; therefore, this study aimed to evaluate the psychometric properties of the European Organisation for Research and Treatment of Cancer (EORTC) QLQ-C30 in patients with cancer in Uganda. Methods Adult patients with various types of cancer (n = 385) cared for at the Uganda Cancer Institute answered the EORTC QLQ-C30 in Luganda or English language, the two most spoken languages in the country. The two language versions were evaluated with regard to data quality (floor and ceiling effects and missing responses), reliability (internal consistency) and validity (construct, known-group and criterion). Construct validity was examined through confirmatory factor analysis (CFA). Mean scores were compared between groups differing in disease stage to assess known-group validity. Criterion validity was examined according to associations between two QLQ-C30 subscales (Global quality of life and Physical function) and the Karnofsky Performance Scale (KPS). Results Floor and ceiling effects were observed for several scales in the Luganda and English versions. All EORTC scales with the exception of Cognitive function (Luganda α = 0.66, English α = 0.50) had acceptable Cronbach’s alpha values (0.79–0.96). The CFA yielded good fit indices for both versions (RMSEA = 0.08, SRMR = 0.05 and CFI = 0.93). Known-group validity was demonstrated with statistically significant better HRQoL reported by patients with disease stages I–II compared to those in stages III–IV. Criterion validity was supported by positive correlations between KPS and the subscales Physical function (Luganda r = 0.75, English r = 0.76) and Global quality of life (Luganda r = 0.59, English r = 0.72). Conclusion The Luganda and English versions of the EORTC QLQ-C30 appear to be valid and reliable measures and can be recommended for use in clinical research to assess HRQoL in adult Ugandans with cancer. However, the cognitive scale did not reach acceptable internal consistency and needs further evaluation.

Psychometric properties of the Spanish version of the European Organization for Research and Treatment of Cancer Quality of Life Questionnaire (EORTC QLQ-C30)

“…The aim of this study was to appraise the psychometric properties of the Spanish version of the EORTC QLQ-C30 in a sample of patients with varying diagnoses. The results support the use of the EORTC scale to gauge quality of life in patients with cancer and confirm the stability of its construct in different types of tumor, which has also been corroborated by other studies [4,32,33] As previously mentioned, the factorial structure found in this study is organized around two factors: Quality of life and Physical health. The first factor includes all the items on the scale, reflecting a plausible unidimensional structure, in which all the items exhibit suitable factor loadings and proper goodness-of-fit indicators and could reflect physical well-being in cancer patients.…”

“…The reliability estimates of the sum scores evaluated by means of McDonal's omega (ω) was excellent, with values of 0.94 for quality of life and 0.86 for the physical health dimension. Other studies have yielded similar results in which the values ranged from 0.74 to 0.95 [4,32,33].…”

“…The first factor includes all the items on the scale, reflecting a plausible unidimensional structure, in which all the items exhibit suitable factor loadings and proper goodness-of-fit indicators and could reflect physical well-being in cancer patients. This unidimensional HRQL structure was similarly encountered by [18,34] in which all the items are assumed to be latent variables of a single dimension and are a good indicator of HRQL [4,32,33]. In our series, items 29 and 30 that originally pertains to the overall health scale would be included in the general factor of our quality-of-life rating scale.…”

Health-related Quality of Life Among Adult Patients With Cancer in Uganda

“…For purposes of this study, we translated the EORTC QLQ-C30 (version 3.0) into Luganda language and culturally adapted the instrument in accordance with the procedure developed by EORTC [16]. This was followed by an evaluation of the psychometric properties of the Luganda and English versions, the two most spoken languages in the country [17]. The results provided evidence for the validity and reliability of the Luganda and English versions of the EORTC QLQ-C30 for assessment of HRQoL in adult Ugandans with cancer.…”

“…However, the cognitive scale did not reach acceptable internal consistency and needs further evaluation. The present study is based on the same sample that was used in the psychometric evaluation [17] and will now in detail describe the HRQoL of adult patients with cancer in Uganda.…”