Assessing the quality of life of adults with chronic respiratory diseases in routine primary care:: Construction and. rst validation of the 10-Item Respiratory Illness Questionnaire-monitoring 10 (RIQ-MON10)

Background: As doctors' judgements about the burden of a disease often differ from patients' own assessments a manageable method to incorporate the latter into routine care might support patient-centered decision-making. For this purpose we shortened the 55-Item Quality of Life for Respiratory Illness Questionnaire (QoL-RIQ). Methods: Secondary analyses of the data of 3 controlled studies (n = 328, 502 and 555). Procedures: inter-item correlations, scale distributions, Cronbach's alpha and factor analysis. Dyspnoea, forced expiratory volume in 1 s (FEV1), COOP/WONCA charts, the Medical Research Council-ECCS symptoms questionnaire and the MOS-SF 36 served as criteria to test validity and responsiveness. Results: Item-reduction resulted in a 10-item short form (alpha's 0.87-0.90), consisting of 2 5-item factors: ( 1) physical and emotional complaints and ( 2) physical and social limitations. The correlations of the short form with dyspnoea (r from 0.57 to 0.60), the generic health status instruments (r from 0.39 to 0.59) and lung function (r from 0.10 to 0.15) fulfilled the criteria. Further results: a clinical relevant score difference (> 0.5) between upper and lower quartiles of the convergent instruments, an intraclass correlation between repeated scores in a stable group of 0.82 and a standardised response mean of 0.86 in an improved group of patients. Conclusions: The short form (RIQ-MON10) maintained the psychometric properties of the original instrument and is promising for assessing quality of life (QoL) during routine primary care visits.