title: 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: OBJECTIVE
  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
  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.
  
  
  CONCLUSIONS
  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.
authors.affiliation: Health Economics AstraZeneca R&D, Mölndal, Sweden. Peter.Wahlqvist@Astrazeneca.com
authors.forename: Peter
authors.initials: P
authors.lastname: Wahlqvist
authors.forename: Jonas
authors.initials: J
authors.lastname: Carlsson
authors.forename: Nils-Olov
authors.initials: NO
authors.lastname: Stålhammar
authors.forename: Ingela
authors.initials: I
authors.lastname: Wiklund
mesh_terms: D000041:Absenteeism; D000203:Activities of Daily Living; D000328:Adult; D001294:Attitude to Health; D003430:Cross-Sectional Studies; D005260:Female; D005764:Gastroesophageal Reflux / Q000503:physiopathology / Q000523:psychology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D011788:Quality of Life; D012720:Severity of Illness Index; D011795:Surveys and Questionnaires; D013548:Sweden