Validity and Reliability of the Mongolian Version of Functional Assessment of Cancer Therapy-General (FACT-G)

Abstract

Background: The health-related quality of life (HRQOL) is an important indicator for determining the health outcomes of cancer treatment. The Functional Assessment of Cancer Therapy-General (FACT-G) scale, which was developed in the USA and validated in many countries, is widely used to measure the HRQOL in cancer patients. In Mongolia, there is no valid and reliable instrument to measure HRQOL for cancer patients. The purposes of this study are to empirically validate the FACT-G scale with Mongolian cancer patients.

Methods: This study is a methodological study. The English version of FACT-G was translated into the Mongolian language using the Functional Assessment of Chronic Illness Therapy (FACIT) translation and linguistic validation methodology. The translated Mongolian version of FACT-G was validated through content validity, item analysis, construct validity, convergent validity, and reliability using a convenience sample of 303 cancer patients recruited from four hospitals in Ulaanbaatar, Mongolia. Data were analyzed using descriptive statistics, an exploratory factor analysis with varimax rotation to determine the factor structure. Convergent validity was assessed by calculating the correlation between FACT-G and the Functional assessment instrument the COOP/WONCA charts. The reliability of the internal consistency for the total and its subscales was assessed by Cronbach’s alpha.

Results: A 4-factor, 20-item model demonstrated a satisfactory fit with significant factor loadings. The factor structure of the Mongolian version of the FACT-G scale was similar to that of the original version including the physical, social/family, emotional, and functional well-being subscales and these four factors were explained 65.5% of the variance. The convergent validity between the FACT-G Mongolian version and the COOP/WONCA charts was significant (r=.69, p <.001). Cronbach’s alpha for the total scale was .93 and that of subscales ranged from .72 to 89.

Conclusion: The Mongolian version of the FACT-G scale demonstrated satisfied validity and reliability. It is an appropriate instrument to use in research and clinical settings to assess the health-related quality of life of Mongolian cancer patients. For further validation of the Mongolian version of the FACT-G, it is necessary to conduct confirmatory factor analysis and replication studies with diverse samples.