Validation of a disease‐specific quality‐of‐life questionnaire in a large sample of Dutch achalasia patients

SUMMARY. The aim of this study was to validate a translated version of an achalasia‐specific quality‐of‐life questionnaire (achalasia‐DSQoL) by examining its psychometric properties in a Dutch cohort of achalasia patients. The achalasia‐DSQoL was administered to 171 treated achalasia patients together with a clinical symptom score and the RAND‐36. Validation methods included factor analysis, known‐group techniques, Cronbach's alpha and Spearman rank correlation with other questionnaires and feasibility. About 72.5% of the achalasia patients completed the questionnaires. The achalasia‐DSQoL showed evidence of an underlying construct and seems reliable with a Cronbach's alpha of 0.77. The question concerning heartburn did not correlate with the other items on the questionnaire. Known‐group techniques demonstrated that the achalasia‐DSQoL discriminates between achalasia patients in clinical remission and patients who are not. There was a moderate correlation between the achalasia‐DSQoL and the RAND‐36 subscales. The questionnaire was easy in use. The translated version of the achalasia‐DSQoL is a valid and reliable instrument to compare groups of achalasia patients although the question concerning heartburn should be excluded.