Validation of the Malay Brief Pain Inventory questionnaire to measure cancer pain.

The original version of the Brief Pain Inventory (BPI) was translated into a Malay version by the standard procedure and was then evaluated for its psychometric properties. Of 119 eligible patients, a total of 113 (95%) agreed to participate in this study. Ages ranged from 18 to 76 years and interviews were conducted between August, 2004 and November, 2004. The pain intensity items demonstrated high loading with one factor, whereas the pain interference items were loaded on another factor. Two factors explained 62% of the variance. Compared to the Karnofsky Performance Scale, the pain intensity scales had a moderate negative (Pearson's) correlation (-0.520, P < 0.001) and the pain interference scales had a high negative correlation (-0.732, P < 0.001), showing good concurrent validity. The coefficient alpha of both subscales demonstrated good internal consistency of the items. The intraclass correlation coefficient for the test-retest stability was 0.61 for the pain intensity scale and 0.88 for the pain interference scale. The Malay version of the BPI is a reliable and valid instrument for cancer pain assessment and is comparable with the original version of the BPI in terms of structure and psychometric properties.