Sutton, D., Dumbleton, S., & Allaway, C. (2007). Can increased dietary fiber reduce laxative requirement in peritoneal dialysis patients? Journal of Renal Care, 33, 177–178.

To explore the extent to which peritoneal dialysis (PD) patients are affected by constipation, how many laxatives they use on a regular basis, and barriers to managing constipation when their dietary fiber is increased.

In stage 1, the investigators established current bowel habits and laxative use. In stage 2 (N = 23), fiber intake was increased by 6 to 12 g per day using a dietary fiber supplement, partially hydrolyzed guar gum (PHGG). Finally, in stage 3 (N = 17), patients' daily diet was modified to include foods naturally high in fiber, aiming for 6 to 12 g per day more than their current intake, and bowel habits and laxative use were monitored.

A stool-and-laxative recording diary was sent to 126 PD patients. Forty-six reported using laxatives. All respondents using laxatives were invited to use a soluble dietary fiber supplement for four weeks, followed by dietary advice to see whether they could achieve the same effect using high-fiber foods.

• The study reported on a sample of 23 PD patients using laxatives.
• Patients were included in the study if they had received PD at home for at least three months.

United Kingdom

This was a descriptive study with a three-stage audit and intervention project.

A stool-and-laxative diary was used to measure number of bowel movements per day.

• In stage 1, a recording diary was sent to 126 patients with PD. Seventy patients returned the diary, and 46 reported using laxatives.
• In stage 2, 23 of 46 patients entered the intervention stage. Seventeen succeeded in replacing prescribed laxatives with the fiber supplement. All 23 patients successfully increased fiber and reduced laxative use within a four-week period.
• In stage 3, 17 patients were asked to increase dietary fiber by modifying their daily food intake. Sixteen tried to increase their intake of high-fiber foods; of them, 8 succeeded. However, only two patients were able to reduce their fiber supplement intake.

Fiber supplementation may be as effective as laxative treatment in preventing constipation. In addition, fiber supplementation was preferred by patients in this study, as many felt it improved bowel habits without the side effects of stimulant laxatives.

Fiber supplements cost much more than standard laxatives.

• The sample size was small.
• Only eight patients tried to increase their dietary fiber intake, limiting the value of the study. 
• The fiber supplement was used as a thickening and stabilizing agent. It helped renal patients on fluid restriction because psyllium and methyl cellulose require a lot of fluids to be effective. In addition, PHGG has negligible potassium and phosphate. This is not transferable to patients with cancer unless they are in renal compromise.
• The research design had flaws.
• The study did not compare the use of bulk-forming fiber or dietary with soluble fiber.
• A subjective patient-preferred questionnaire was administered. No tool was presented for patient outcomes assessed, which can be subjective for the clinicians evaluating the study.