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

Recurrent constipation is common in cats. Long-term management should include dietary modifications. Objective This study evaluated the efficacy of a psyllium-enriched diet for the management of chronic constipation in cats. Methods A multi-centre, 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 ≥2 constipation episodes in the previous 6 months and ≥2 constipation signs for ≥14 days. 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 new cases in the group into which they moved, and statistical analyses (linear and linear mixed models) included them in both diet groups. Results Of 49 cats enrolled, 2 were removed for non-compliance, leaving 26 in the test group (18 assigned, 8 switched from control), and 30 in the control group (29 assigned, 1 switched from test). 19/26 and 11/30 cats completed 6 months of the test and control diet, respectively. The rate of diet failure for gastrointestinal reasons was significantly higher in the control (22/30 [73.3%]) versus test group (7/26 [26.9%]; P = 0.0005). Constipation signs improved significantly from baseline in both groups at each visit after Day 7. For stool consistency, improvement was significantly greater in the test versus control group except at Day 30. Conclusions and relevance In cats with chronic constipation, a 6% psyllium-supplemented gastrointestinal diet resulted in sustained improvement of clinical signs, a significantly lower probability of diet failure and greater improvements in stool consistency than a control gastrointestinal diet.