This study evaluated the psychometric properties of the Turkish version of the European Organization for Research and Treatment of Cancer EORTC QLQ-ELD14, a health-related quality-of-life module developed for older patients with cancer. The stated aim was to assess whether the translated instrument demonstrates acceptable validity and reliability for research and clinical use in older Turkish-speaking oncology patients.
A total of 113 older patients with cancer were included in the validation study. The authors assessed construct validity using both exploratory factor analysis and confirmatory factor analysis. Convergent validity was examined via correlation analyses with the EORTC QLQ-C30, the core cancer quality-of-life questionnaire. Known-group validity was tested by comparing instrument scores across patient groups defined by cancer stage, Karnofsky Performance Status, and the Charlson Comorbidity Index. Reliability assessment included calculation of Cronbach's alpha for internal consistency, test–retest reliability, and intraclass correlation coefficients (ICC) for subscale agreement.
Factor analysis of the Turkish EORTC QLQ-ELD14 supported a seven-factor structure, which the authors report as indicating that the instrument is a sufficient measurement tool in this population. Both exploratory and confirmatory factor analyses were used to examine dimensionality and model fit. The abstract reports that these analyses demonstrated the translated questionnaire’s factor structure was appropriate for older patients with cancer in the Turkish context.
Convergent validity testing found moderate to high correlations between the EORTC QLQ-ELD14 and the EORTC QLQ-C30, with correlation coefficients ranging from r = -0.40 to -0.83 and p < 0.05. These negative correlation values likely reflect differing scoring directions between some subscales (for example, higher symptom scores versus higher functioning scores) and indicate that the ELD14 relates meaningfully to the established core questionnaire.
The Turkish EORTC QLQ-ELD14 demonstrated clinical validity by discriminating between groups of patients with different clinical profiles. Known-group comparisons were performed according to cancer stage, Karnofsky Performance Status, and Charlson Comorbidity Index, and results showed the instrument could distinguish between these predefined groups, supporting its usefulness for identifying differences in health-related quality of life tied to disease severity, functional status, and comorbidity burden.
Internal consistency for the scale was reported with a Cronbach’s α coefficient of 0.719, which meets commonly used thresholds for acceptable reliability in multi-item measures. The intraclass correlation coefficients for all subscales were above 0.80, indicating high agreement across repeated measurements. Test–retest assessment showed excellent reliability, further supporting score stability over time in the conditions evaluated.
Based on the presented analyses, the authors conclude that the Turkish version of the EORTC QLQ-ELD14 is a valid and reliable instrument for assessing health-related quality of life in older patients with cancer and is suitable for use by researchers and clinicians. Its seven-factor structure, demonstrated convergent validity with the QLQ-C30, ability to discriminate clinically relevant groups, acceptable internal consistency (Cronbach’s α = 0.719), and high intraclass correlation coefficients (all > 0.80) support its psychometric adequacy.
The abstract reports primary psychometric outcomes but does not provide detailed procedural information in this summary, including recruitment setting, the time interval used for test–retest, item-level statistics, or full model-fit indices from confirmatory factor analysis. Those details were not reported in the abstract and would require review of the full text for complete appraisal.
Clinicians and investigators working with older Turkish-speaking oncology patients can consider the Turkish EORTC QLQ-ELD14 as an appropriate module to supplement the QLQ-C30 when assessing age-specific quality-of-life domains. The instrument’s demonstrated ability to reflect differences by disease stage, functional status, and comorbidity supports its potential utility in both clinical assessment and outcome research.