Validation of the Japanese version of the Quality of Life-Assessment of Growth Hormone Deficiency in Adults (QoL-AGHDA)

Objective: To evaluate validity and reliability of the Japanese version of the Quality of Life-Assessment of Growth Hormone Deficiency in Adults (QoL-AGHDA). Design: Observational study; cross-sectional, longitudinal. Methods: Seventy-five adults with growth hormone deficiency completed the SF-36 (a generic health-related QOL scale) and the QoL-AGHDA before growth hormone replacement therapy and approximately 3 weeks later (when the therapy began). A sample (n = 1000) of controls from the general population was also studied. We computed rates of missing data, measured reproducibility and internal consistency reliability, and tested for known-groups validity, concurrent validity, unidimensionality (by principle component analysis), and content validity. Results: Rates of missing data were low (0-1.4%). The mean of QoL-AGHDA scores in the patients was 8.2 (SD, 6.4). The scores were reproducible (k = 0.41-0.78), and internally consistent (alpha = 0.91) and the scale was unidimensional. QoL-AGHDA scores were associated with SF-36 scores as hypothesized. Scores were significantly higher in the patients than in controls (8.1 ± 0.7, and 5.6 ± 0.2, P < 0.001). Discrimination between patients and controls was slightly better using scores on the "General Health" and "Role Physical" subscale of the SF-36 as explanatory variables than using QoL-AGHDA scores. Conclusions: The QoL-AGHDA's reliability, validity, and rates of missing data were satisfactory, and the scale was confirmed to be unidimensional. However, because some subscales of the SF-36 were better for discriminating patients from controls, the content validity of the QoL-AGHDA may need to be re-evaluated.