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.

[Development and validation of QPD 32, a specific questionnaire for measuring the quality of life of patients with peptic ulcer]. / Sviluppo e validazione di un questionario specifico per la misurazione della qualità della vita nei pazienti con malattia peptica: QPD 32.

Drugs need to be evaluated both in terms of efficacy, safety and regarding the patient's perception of his own health status. For these reasons, sensible, reliable and patient-oriented instruments are needed, besides the methodologies for evaluation of drug efficacy and safety. Such instruments substantially evaluate Health related Quality of Life (HrQoL). Concerning gastric acid hypersecretion few papers are available, based on HrQoL questionnaires, both general and specific. A research project led us to develop through patients and physicians involvement, a specific instrument to evaluate HrQoL as to the various aspects of the peptic disease. The project started in 1993 through a series of 4 focus groups with gastroenterologists and patients, followed by the preparation of a questionnaire named QPD48. Such instrument was psychometrically validated through a study named Herqules 1, involving 176 gastroenterologists and 1774 patients. The psychometric analysis on QPD48 led to the re-issue of a questionnaire named QPD32 with Chronbach's alfa equal to 0.91, based on 3 factor-referenced subscales evaluating pain, induced anxiety, constrained daily living and awareness of symptoms and agents. Concerning the concurrent validity a one-way analysis of variance showed highly significant differences associated with attack frequency with substantial effect sizes ranging from 0.46 to 1.27 of a standard deviation in the full scale. QPD 32 is patent protected and will be used in clinical trials.

Resolving mixtures of strategies in spatial visualization tasks.

The models of standard test theory, having evolved under a trait-oriented psychology, do not reflect the knowledge structures and the problem-solving strategies now seen as central to understanding performance and learning. In some applications, however, key qualitative distinctions among persons as to structures and strategies can be expressed through mixtures of test theory models, drawing on substantive theory to delineate the components of the mixture. This approach is illustrated with response latencies to spatial visualization tasks that can be solved by mental rotation or by a non-rotational rule-based strategy. It is assumed that a subject employs the same strategy on all tasks, but the possibility of extending the approach to strategy-switching is discussed.

A scale for assessing quality of life in adult asthma sufferers.

The Asthma Questionnaire is a 68-item quality of life scale designed to be sensitive to quality of life changes in clinical trials. The questionnaire covers 11 domains of life experience, the initial domain and item sets being derived from six qualitative focus groups of asthma patients. Psychometric analysis of responses of 101 asthma patients to the initial 101-item set showed the scale to be unidimensional despite being multi-domain, and the finding of unidimensionality was replicated during the further three stages of item refinement using 783 patients. The scale compensates for acquiescence bias as well as allowing a 'not applicable' response category. Validity of the scale was demonstrated by confirmation of expected group differences and the retest reliability was 0.948.