Validity and Reliability of Persian Translation of the Nepean Dyspepsia Index in Functional Dyspepsia in Iran

The aim of this study was to translate and evaluate the validity and reliability of the Nepean Dyspepsia Index (NDI)¡ as a disease-specific quality of life scale in patients with functional dyspepsia.
Forward-backward translation was done. 80 patients with dyspepsia from the outpatient department of Imam Reza Hospital were assessed. Data were analyzed using SPSS software version 20 and face validity¡ content validity (CVR)(pls spell out)¡ construct validity (Spearman''s rrho)¡ and reliability (test-retest and Cronbach''s Alpha) were evaluated.
CVR was between 0.80-1¡ which demonstrated good content validity. Test-retest reliability was good with correlation coefficient of 0.89 and intraclass correlation coefficient of 0.96. Internal consistency revealed α value of 0.93¡ which was well above the agreeable value of 0.70. These both indicate a good reliability. Spearman''s correlation coefficient was 0.48. between all NDI items and subscales which indicates moderate to good construct validity.(it seems that this sentence is not complete because in this format it is meaningless)
This study demonstrates that the Persian translation of SF-NDI (pls spell out the highlighted part) is a valid and reliable instrument to measure health related quality of life (HRQoL) in Iranian patients with dyspepsia. It also shows that HRQoL is significantly higher in patients with high school diploma or higher educational levels.