Dried Plums (Prunes) vs. Polyethylene Glycol 4000 for Treatment of Functional Constipation in Children - Randomised Controlled Trial

We will conduct a randomized open-label trial at the Department of Paediatrics of the Medical University of Warsaw. The trial will be initiated by the investigators and conducted independently of any commercial entities. The aim will be to assess the effectiveness of dried prunes in the management of functional constipation in children in comparison to PEG 4000. Patients will be included into our study when functional constipation will be diagnosed according to ROME IV criteria. Those patients which will meet inclusion criteria will be assigned randomly to receive prunes at dose 3,5 g/kg/d in three portions a day, for 4 weeks (amount of prescribed prunes will be calibrated with the weight that child ought to have on WHO growth charts at 50th percentile) or PEG 4000 at dose 0,5 g/kg/d once daily orally, for 4 weeks. Parents of the children allocated to the prunes group will receive written information from dietician how to introduce prunes into child's diet (i.e. prunes should be introduced every day in three meals; prunes can be chopped or grinded before eating them; prunes can be eaten alone or child may eat them as a part of bigger meal (which is prefered version); prunes can be introduced with yoghurt, cereals, nuts and seeds as a morning meal). All patients will be asked to discontinue any laxatives if they used them previously. In case of rectal impaction noted on physical examination, PEG 4000 at dose of 1.5 g/kg for 3-5 consecutive days will be recommended. All subjects parents will receive a stool diary to record the frequency of bowel movements; stool consistency according to Bristol Stool Form Scale (which refers to 7 pictures of different forms of stool; 1 for hard lumps to 7 for watery stools); frequency of episodes of fecal soiling, pain during defecation, or abdominal pain or flatulence; use of additional laxative treatment; and adverse effects during the 4 weeks of the intervention. All patients or their parents (if child is too young) will be asked to write down selfreported 3 day food diaries on non-consecutive days, 2 d during the week and 1 d during the weekend to assess fiber intake during the study period .. All patients will be informed of rescue therapy -when there will be no defecation for 3 consecutive days during ongoing trail, PEG 4000 will be allowed at the dose of 1.5 g/kg/d until the child will pass a stool.

During the study period, every week investigator will call the patients parents to assess compliance with the study protocol.

Second visit will take place at the end of the trial (4th week). During this visit, investigators will collect stool diaries. Prunes used in the study will be purchased by parents of the children. It will be advised for parents to buy prunes under the trade mark of "Makar" in order to avoid product composition variability bias. Choice of the trade mark was taken considering the price of a product.

This study is designed as a randomized, open label controlled trial with 1:1 allocation. In order to obtain comparable groups, block randomisation will be performed (each block will contain four patients: two in the intervention group and two in the control group). The randomisation list will be generated using the statistical program StatsDirect by an independent person and will be kept by a staff member not involved in the trial.

Based on available data in the literature, we assume that a clinically significant difference in the effectiveness is 15%. To detect such a difference between the study groups with a power of 80% and alpha of 5%, a sample of 100 children is needed. Assuming approximately 10% loss to follow-up, we aim to recruit a total of 110 children for this study.