Measuring patients’ satisfaction with their anti-TNF treatment in severe Crohn’s disease: scoring and psychometric validation of the Satisfaction for PAtients in Crohn’s diseasE Questionnaire (SPACE-Q(©))

BACKGROUND: Severe Crohn’s disease management includes anti-tumor necrosis factor (anti-TNF) drugs that differ from early-stage treatments regarding efficacy, safety, and convenience. This study aimed to finalize and psychometrically validate the Satisfaction for PAtients in Crohn’s diseasE Questionnaire (SPACE-Q(©)), developed to measure satisfaction with anti-TNF treatment in patients with severe Crohn’s disease. METHODS: A total of 279 patients with severe Crohn’s disease receiving anti-TNF therapy completed the SPACE-Q 62-item pilot version at inclusion and 12 and 13 weeks after first anti-TNF injection. The final SPACE-Q scoring was defined using multitrait and regression analyses and clinical relevance considerations. Psychometric validation included clinical validity against Harvey–Bradshaw score, concurrent validity against Treatment Satisfaction Questionnaire for Medication (TSQM), internal consistency reliability, test–retest reliability, and responsiveness against the patient global impression of change (PGIC). RESULTS: Quality of completion was good (55%–67% of patients completed all items). Four items were removed from the questionnaire. Eleven scores were defined within the final 58-item SPACE-Q: disease control; symptoms, anal symptoms, and quality of life transition scales; tolerability; convenience; expectation confirmation toward efficacy, side effects, and convenience; satisfaction with treatment; and motivation. Scores met standards for concurrent validity (correlation between SPACE-Q satisfaction with treatment and TSQM satisfaction scores =0.59), internal consistency reliability (Cronbach’s α=0.67–0.93), test–retest reliability (intraclass correlations =0.62–0.91), and responsiveness (improvement in treatment experience assessed by the SPACE-Q for patients reporting improvement on the PGIC). Significantly different mean scores were observed between groups of patients with different Harvey–Bradshaw disease severity scores. CONCLUSION: The SPACE-Q is a valid, reliable, and responsive instrument to measure satisfaction with anti-TNF treatment in patients with severe Crohn’s disease and for use in future studies.