Researchers Imperial College London have developed a patient-reported outcome measure (PROM) for Crohn's perianal fistula - the Crohn’s Anal Fistula Quality of Life scale (CAF-QoL) - for use as a PROM in research and clinical practice by capturing impact of the condition on the patient. According to Dr Samuel O Adegbola, who helped develop the scale, this new PROM lends itself to utility in clinical trial design for Crohn’s perianal fistulas, enabling consistency in data sets collected in this condition. In addition, it also has the potential utility of assessment of disease impact in a clinic setting, to guide stratification of patients according to severity of disease impact and tailor appropriate management.
The researchers noted that there is currently no specific patient-derived quality of life tools to measure response to treatment for Crohn’s perianal fistula, therefore they decided to develop a new PROM for this complicated disease phenotype. The development of CAF-QoL was reported in the paper, ‘Development and initial psychometric validation of a patient-reported outcome measure for Crohn’s perianal fistula: the Crohn’s Anal Fistula Quality of Life (CAF-QoL) scale’, published in Gut.
The investigators developed a draft questionnaire using unstructured qualitative patient interviews on the experience of living with Crohn’s perianal fistula, a nationwide multidisciplinary consensus exercise, a systematic review of outcomes assessing medical/surgical/combined treatment and a patient and public involvement day. They assessed psychometric properties including construct validity (by comparison with the Hospital Anxiety and Depression Scale (HADS) and the UK Inflammatory Bowel Disease Questionnaire (UK-IBDQ)) and reliability and responsiveness was assessed by test–retest analysis.
In total, 211 patients contributed to development of a final 28-item questionnaire and they authors reported that the CAF-QoL demonstrated good internal consistency (Cronbach’s alpha 0.88), excellent stability (intraclass correlation 0.98) and good responsiveness and construct validity, with positive correlation with the UK-IBDQ and HADS.
In summary, the authors noted that:
- The CAF-QoL is the first disease-specific PROM in Crohn’s perianal fistula developed with a patient-centred methodology
- Completion takes about nine minutes on average and can be done with the clinician present or independently by the patient
- CAF-QoL can be utilised for assessing the benefit of interventions in clinical trials, both medical and surgical, as well as defining disease impact and severity in the clinical setting to aid decision-making; and
- CAF-QoL may also play a role in highlighting changing concerns and priorities that arise for patients between remission and relapse, which may guide individualised patient advice and support
“Ongoing refinement and validation of CAF-QoL will ultimately aid the utility of this PROM alongside an objective clinical outcome measure, both of which are necessary tools in the evaluation of perianal fistula,” they concluded. “The CAF-QoL scale will also need translation into different languages and cross-cultural validation to aid international dissemination.”
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