A psyllium-supplemented gastrointestinal diet is effective for the management of chronic constipation in cats: a 6-month controlled clinical trial.

ObjectivesThis study evaluated the efficacy of a psyllium-enriched diet for the management of chronic constipation in cats.MethodsA multicentre, controlled, blinded, 6-month trial randomly assigned client-owned cats to a gastrointestinal test diet containing 6% psyllium or similar control diet containing 0.5% psyllium (as-fed values). Inclusion criteria included two or more constipation episodes in the previous 6 months and two or more constipation signs for 14 days or longer. Constipation severity (stool consistency and frequency, and defecation pain/difficulty) was scored on days 7, 30, 60, 90 and 180. Cats could switch diets if constipation signs did not improve or the diet was not tolerated. Diet failure was defined as study withdrawal due to lack of improvement in constipation, new gastrointestinal signs or diet switch. Cats switching diets were considered as new cases in the group into which they moved, and statistical analyses (linear and linear mixed models) included them in both diet groups.ResultsOf 49 cats enrolled, two were removed for non-compliance, leaving 26 in the test group (18 assigned, eight switched from control) and 30 in the control group (29 assigned, one switched from test). Of the remaining cats, 19/26 and 11/30 completed 6 months of the test and control diets, respectively. The rate of diet failure for gastrointestinal reasons was significantly higher in the control group than in the test group (22/30 [73.3%] vs 7/26 [26.9%];