Efficacy of Mesalamine in Diarrhea-predominant Irritable Bowel Syndrome (dIBS)

Patients rated the severity of their GI symptoms. The GIS scale goes from 1 to 7 with 1 being the worse and 7 as the best score showing improvement in symptoms. The GIS was performed at week one and at week 12 during each of the interventions. The comparisons below list the mean difference for each intervention from baseline (BL) with standard deviations then we list the p-value for the differences of baseline to intervention are reported using the Mann-Whitney test with a two-tailed p value provided.

Colonoscopy/flexible sigmoidoscopy will be performed and mucosal biopsies will be obtained. Each biopsy was stained for activated t lymphocytes, mast cells and eosinophils .

CD117 staining was done for Mast cells. H and E staining was used to identify lymphocytes and eosinophils. Each path specimen was then noted to have increased versus normal number of these inflammatory cells.

Subjects rate pain on a standardized scale. This is a standardized test used to evaluate patients with IBS. Baseline values are compared to 12 weeks after mesalamine and 12 weeks after placebo treatments. The FBDSI is score is interpreted as such: Severity of IBS is rated as none (0 points), mild (1-36 points), moderate as 37-110 points and severe as >110 points. Therefore patients can have a score higher than 110.

A questionnaire is given to each patient and was completed at baseline then after 12 weeks of intervention with mesalamine and then placebo in the cross-over study. The IBS-QOL comprises 34 items with 5-point response scales (0 to 4) that cover eight dimensions of HRQL: dysphoria (8 items), interference with activity (7 items), body image (4 items), health worry (3 items),food avoidance (3 items), social reaction (4 items), sexual concerns (2 items) and relationships (3 items). Higher values indicate better HRQL after converting the raw score on the IBS-QOL into 0 to 100 points.

A questionnaire is given to each patient with scoring done on a Likert scale ranking from 0-42 which combines anxiety and depression scales. Each of these are scored from 0-21 depending on anxiety versus the depression parameters. Comparison of change in HADs after 12 weeks of intervention with either mesalamine or placebo is provided here with only the total value provided-range is from 0-42.

Each item on the questionnaire is scored from 0-3 and this means that a person can score between 0 and 3 with zero being none at all or occasional and 3 as most of the time. The scale used is a Likert scale and therefore the data returned from the HADS is ordinal.

The best score for the HADS therefore is a 0 with the worst score a 42 for combined anxiety and depression scores.

For the subscales of depression and anxiety, the best score is a 0 and the worst is a 21. This data is not provided here.

Data below includes the change from baseline in the HADS scores.

Ability of test substances to permeate the intestinal mucosa. The Lactulose/Mannitol test (Genova Diagnostics®, Ashville, NC) directly measures the ability of mannitol and lactulose to permeate the intestinal mucosa. Patient ingests 5 grams of lactulose and 2 grams of mannitol dissolved in a 100 ml of water. Urine is then collected for 24 hours and the ratio of the urinary excretion of lactulose to mannitol is measured. This testing is performed only after completion of each treatment period , after 12 weeks of mesalamine and after 12 weeks of placebo.

Normal ratio of lactulose/mannitol is any value <0.7. An abnormal ratio is defined as >0.7 ratio. The lactulose is measured in the urine as g/kg and the urinary excretion of mannitol is also measures as g/kg.