Validity of a Work Productivity and Activity Impairment questionnaire for patients with symptoms of gastro-esophageal reflux disease (WPAI-GERD)--results from a cross-sectional study

Abstract

Objectives: To validate a Work Productivity and Activity Impairment questionnaire (WPAI-GERD) developed to measure lost productivity due to symptoms of gastro-esophageal reflux disease (GERD).

Methods and data: The WPAI-GERD was administered along with two quality-of-life questionnaires, Quality of Life in Reflux and Dyspepsia (QOLRAD) and Short Form 36 (SF-36), to a Swedish working population (N = 136) visiting a general practitioner for symptoms attributed to GERD. Correlation coefficients were calculated between each productivity variable derived from the WPAI-GERD and symptom severity, symptom frequency, quality of life dimensions, age, and gender. Statistical tests were carried out to determine the relationship between each productivity variable and the severity of heartburn.

Results: High correlations (range: 0.30-0.75) were found between productivity and symptom severity as well as between productivity and quality-of-life dimensions related to work and daily activities. The results demonstrated the ability of the questionnaire to discriminate between different grades of heartburn severity. On average, patients with heartburn reported 2.5 hours absence from work, 23% reduced productivity while at work, and 30% reduced productivity while doing regular daily activities during the week preceding the consultation. The SF-36 scores implied that patients, especially those with moderate-to-severe heartburn, had a poor quality of life compared with a normal population.

Conclusion: The results indicate a high convergent and discriminant validity of the WPAI-GERD questionnaire and also show that patients consulting a physician because of symptoms attributed to GERD report substantial impairment in both productivity and health-related quality of life.