Assessment of Responsiveness to Treatment by Experience Sampling Method

The primary objective of this study is to assess the internal and external responsiveness of the ESM-PROM in examining changes in symptom scores between baseline and post-treatment. Secondary objectives are to identify differences in characteristics between responders and non-responders to linaclotide and to assess for side effects of linaclotide treatment, using the ESM-PROM. This is a prospective, observational, single-group, open-label study, initiated and performed in Maastricht University Medical Center (MUMC+). The study population will conclude 30 IBS-C subjects that are newly prescribed with linaclotide by their treating physician at the outpatient department of gastroenterology and hepatology in the Maastricht UMC+. Primary study outcomes are the weekly average of the mean and maximum abdominal pain scores per day on the ESM-PROM per period (i.e. baseline, after 4 weeks and after 12 weeks). The ESM-PROM is completed during 7 consecutive days at each period and therefore, the measurements start one week before linaclotide treatment (baseline) and end one week after finishing linaclotide treatment (after 12 weeks). Further endpoints are the change scores of abdominal pain between pre- and post-treatment, measured using the ESM-PROM. Additionally, the proportion of overall responders to linaclotide treatment after 4 and 12 weeks assessed using the conventional end-of-day diary will be used to evaluate external responsiveness. Further endpoints are symptom scores as reported using the ESM-PROM, concerning abdominal pain, bloating, abdominal fullness, fecal urgency, stool consistency, straining, CSBM frequency and SBM frequency. Secondary outcomes are other factors measured using the ESM-PROM, i.e. non-GI physical symptoms, psychological status at the moment of symptom assessment, contextual information regarding the moment of symptom assessment as well as information on food and substance intake.