{Reference Type}: Journal Article
{Title}: Psychometric Evaluation of the Diary for Irritable Bowel Syndrome Symptoms-Constipation in a Prospective Observational Study.
{Author}: McLeod L;Ervin C;Fehnel SE;Eremenco S;Carson RT;Hanlon J;Coons SJ; ;
{Journal}: Value Health
{Volume}: 27
{Issue}: 5
{Year}: 2024 May 2
{Factor}: 5.101
{DOI}: 10.1016/j.jval.2024.01.013
{Abstract}: <B>OBJECTIVE: </B>To evaluate the psychometric properties of the Diary for Irritable Bowel Syndrome Symptoms-Constipation (DIBSS-C), which was developed to support primary and secondary endpoints in irritable bowel syndrome (IBS) with predominant constipation (IBS-C) clinical trials.<BR><B>METHODS: </B>Observational data were collected from 108 adults with IBS-C using a smartphone-type device for 17 days. DIBSS-C data regarding bowel movements (BMs) were collected for each event (along with the Bristol Stool Form Scale); abdominal symptoms were rated each evening. Global status items and the Gastrointestinal Symptom Rating Scale-IBS were completed on day 10 and day 17 and the IBS-Symptom Severity Scale on day 17. Item-level performance, internal consistency reliability, test-retest reliability, and construct validity were evaluated.<BR><B>RESULTS: </B>The Abdominal Symptoms Domain score demonstrated high internal consistency reliability (Cronbach's alpha week 1 = 0.98; week 2 = 0.96) and test-retest reliability (intraclass correlation coefficient [ICC] = 0.93). Test-retest reliability was stronger for abdominal symptoms (ICC = 0.91-0.94) than for the frequency-based BM-related outcomes (ICC = 0.54-0.66). Key construct validity hypotheses were supported by moderate to strong correlations with the corresponding Gastrointestinal Symptom Rating Scale-IBS, IBS-Symptom Severity Scale, and Bristol Stool Form Scale items. All known-groups comparisons were statistically significant for the abdominal symptom items and domain score; evidence for known-groups validity of BM-related outcomes was supportive when based on constipation severity.<BR><B>CONCLUSIONS: </B>The results of this study provided key psychometric evidence for the DIBSS-C, ultimately contributing to its qualification by the US Food and Drug Administration for use in IBS-C clinical trials.