Psychometric validation of the Afrikaans translation of two patient-reported outcomes instruments for reflux disease

Objectives : To verify the validity and reliability of two Afrikaans patient-reported outcomes instruments, a disease-specific and a health-related quality of life instrument in patients with reflux disease. Design : Psychometric validation study. Setting : South African, major referral gastroenterology clinic. Subjects : Consecutive patients with predominant symptoms of heartburn. Outcome measures : Patients completed the Afrikaans versions of the Gastrointestinal Symptom Rating Scale (GSRS), the Quality of Life in Reflux and Dyspepsia questionnaire (QOLRAD) and the Short Form Health-36 (SF-36). The frequency and severity of heartburn during the previous 7 days were recorded. Results : 125 patients (aged of 46.0 ±12.3 years, 74.4% female, 87% mixed race) completed the assessments. Most patients (62%) had severe symptoms and half (54%) had symptoms on more than 5 days in the previous week. Patients were most bothered by symptoms of reflux (mean GSRS score of 4.9), indigestion (4.0) and abdominal pain (4.0). These symptoms caused patients problems with food and drink (mean QOLRAD score of 3.5), emotional distress (3.6), impaired vitality (3.7) and sleep disturbance (3.8). The internal consistency of the GSRS symptom clusters was between 0.65 and 0.86 and, for QOLRAD dimensions, it was in the range 0.82 0.94. Test-retest reliability was 0.620.75 (GSRS) and 0.710.82 (QOLRAD). Relevant domains of GSRS and QOLRAD were significantly correlated. GSRS domains of abdominal pain and indigestion, and relevant QOLRAD domains, showed negative correlation with related SF-36 domains. Conclusions : The Afrikaans translations of GSRS and QOLRAD are valid and reliable instruments for use in clinical trials for the assessment of reflux symptoms and their impact on South African patients' healthrelated quality of life. South African Gastroenterology Review Vol. 4(1) 2006: 5-9