Soy Polysaccharide Fiber for the Treatment of Chronic Constipation in Children: a Randomized, Double-blind Trial

The study was performed out at outpatient clinic of Pediatric Gastroenterology at the Federal University of São Paulo (São Paulo, Brazil), located in the southeastern region of Brazil. It is a public referral hospital for pediatric gastroenterology attendance in the Metropolitan area of the São Paulo and in Brazil. In general, the patients go to consultation after a referral from a primary care center.

Study design and sample size The design was a randomized double-blind trial, placebo-controlled study. Sample size was calculated by the formula of comparison of two proportions, using clinical improvement as a primary outcome. It had been previously calculated that a minimum of 14 patients in each group will give a power of 80% to detect a effect size of 50% with significance at the level of 5% (one-sided).

Inclusion criteria

• Patients over two years of age at first consultation and chronic functional constipation were included. Chronic constipation was defined by the occurrence of any of the following, for at least 2 weeks, independently of stool frequency: passage of hard, scybalous, pebble-like or cylindrical cracked stools, straining or painful defecation, passage of large stools that may clog the toilet, or stool frequency less than 3 per week.

Exclusion criteria

• The exclusion criteria applied were organic constipation, regular use of dietary fiber in the preceding 30 days or drugs causing constipation.