Introduction To determine the impact of Crohn's Disease (CD) and its treatment from the patient's perspective a high quality CD-specific PROM is required. This must have; a meaningful theoretical basis, relevant, well-targeted content derived from CD patients and unidimensional, reliable and valid scales.

Aims/Background This study describes the development of the CLIQ that is shown to meet these criteria. The CLIQ adopted the needs-based model of Quality of Life (QoL) and the World Health Organisation classification of functioning.

Method The 3 key development stages were; item generation from qualitative patient interviews, assessment of face and content validity in further patient interviews and item reduction and evaluation in a postal survey. Respondents also completed the Nottingham Health Profile (NHP), Unidimensional Fatigue Impact Scale (UFIS) and a demographic questionnaire. Approximately a third of the sample completed the CLIQ again, two weeks later, to determine test-retest reliability (reproducibility).

Results Thirty qualitative interviews identified 3,000 statements concerning CD and its treatment. Draft scales were assessed by 15 CD patients who found them easy to complete, comprehensive and relevant. The CLIQ was then administered to 273 patients (34.4% male; aged 16–79 (SD 15.1) years. Rasch analyses identified unidimensional scales of QoL and Activity Limitations. Psychometric analyses showed these scales to be reproducible and to have construct validity.

Conclusion The CLIQ is the first PROM specific to CD. The scientifically rigorous methodology employed ensures that it patient-based outcome accurately and that it will prove valuable in clinical practice, trials and audit.