title: Correlation between Colon Transit Time Test Value and Initial Maintenance Dose of Laxative in Children with Chronic Functional Constipation.
abstract: OBJECTIVE
  To evaluate the correlation between colon transit time (CTT) test value and initial maintenance dose of polyethylene glycol (PEG) 4000 or lactulose.
  
  
  METHODS
  Of 415 children with chronic functional constipation, 190 were enrolled based on exclusion criteria using the CTT test, defecation diary, and clinical chart. The CTT test was performed with prior disimpaction. The laxative dose for maintenance was determined on the basis of the defecation diary and clinical chart. The Shapiro-Wilk test and Pearson's and Spearman's correlations were used for statistical analysis.
  
  
  RESULTS
  The overall group median value and interquartile range of the CTT test was 43.8 (31.8) hours. The average PEG 4000 dose for maintenance in the overall group was 0.68±0.18 g/kg/d; according to age, the dose was 0.73±0.16 g/kg/d (<8 years), 0.53±0.12 g/kg/d (8 to <12 years), and 0.36±0.05 g/kg/d (12 to 15 years). The dose of lactulose was 1.99±0.43 mL/kg/d (<8 years) or 1.26±0.25 mL/kg/d (8 to <12 years). There was no significant correlation between CTT test value and initial dose of laxative, irrespective of the subgroup (encopresis, abnormal CTT test subtype) for either laxative. Even in the largest group (overall, n=109, younger than 8 years and on PEG 4000), the correlation was weak (Pearson's correlation coefficient [R]=0.268,p=0.005). Within the abnormal transit group, subgroup (n=73, younger than 8 years and on PEG 4000) correlation was weak (R=0.267,p=0.022).
  
  
  CONCLUSIONS
  CTT test value cannot predict the initial maintenance dose of PEG 4000 or lactulose with linear correlation.
authors.affiliation: Department of Pediatrics, Konkuk University School of Medicine, Seoul, Korea.
authors.forename: Mock Ryeon
authors.initials: MR
authors.lastname: Kim
authors.affiliation: Department of Pediatrics, Konkuk University School of Medicine, Seoul, Korea.
authors.forename: Hye Won
authors.initials: HW
authors.lastname: Park
authors.affiliation: Department of Pediatrics, Konkuk University School of Medicine, Seoul, Korea.
authors.forename: Jae Sung
authors.initials: JS
authors.lastname: Son
authors.affiliation: Department of Pediatrics, Konkuk University School of Medicine, Seoul, Korea.
authors.forename: Ran
authors.initials: R
authors.lastname: Lee
authors.affiliation: Department of Pediatrics, Konkuk University School of Medicine, Seoul, Korea.
authors.forename: Sun Hwan
authors.initials: SH
authors.lastname: Bae
keywords: Child; Constipation; Correlation; Intestinal transit; Laxatives