Measuring quality of life in dyspeptic patients: development and validation of a new specific health status questionnaire: final report from the Italian QPD project involving 4000 patients.

Objective: Despite the fact that gastrointestinal disorders represent one of the most common reasons for medical consultations, formal assessment of patients' health-related quality of life (HRQOL) has been carried out only in a few studies, and in most cases generic questionnaires have been adopted. Because the specific issue of living with dyspeptic problems has been addressed in very few cases and no questionnaire has been shown to be appropriate for the Italian setting, a prospective project was launched to develop a specific HRQOL questionnaire for dyspepsia sufferers tailored to Italian patients but also appropriate in other cultural settings.

Methods: The project consisted in a 3-yr, three-phase survey, in which different versions of the quality of life in peptic disease questionnaire (QPD) were developed through expert and patient focus groups and empiric field studies and then administered to patients recruited in five multicenter studies. Standard psychometric techniques were used to evaluate the validity, reliability, responsiveness, and patient acceptability of the QPD.

Results: Three different versions of the QPD questionnaire were self-administered to more than 4000 patients. The final 30-item version, measuring three health concepts related to dyspeptic disease (anxiety induced by pain, social restriction, symptom perception), fulfilled the recommended psychometric criteria in terms of reliability and validity, correlated with health concepts measured with a well-known independent generic HRQOL instrument (the SF-36 Health Survey questionnaire) and was relatively invariant to diagnosis and sociodemographic variables; it also correlated with a measure of gastric pain frequency and was able to detect meaningful differences over time.

Conclusions: Although further validation studies in different cultural and linguistic settings are mandatory before any firm conclusions can be drawn regarding the cross-cultural validity of the QPD, the data obtained provide evidence of the psychometric validity and robustness of the questionnaire when used in a fairly large, well-characterized population of Italian dyspeptic patients.