title: Polar vectors as a method for evaluating the effectiveness of irritable bowel syndrome treatments: an analysis with pinaverium bromide 100mg plus simethicone 300mg po bid.
abstract: BACKGROUND
  Irritable Bowel Syndrome (IBS) is a disorder characterized by abdominal pain or discomfort associated with changes in bowel habit. Currently there are no objective outcome measures for evaluating the effectiveness of treatments for this disorder.
  
  
  OBJECTIVE
  To determine the usefulness of a method of analysis that employs polar vectors to evaluate the effectiveness of IBS treatments.
  
  
  METHODS
  Data from a Phase IV clinical study with 1677 active IBS-Rome III patients who received 100mg of pinaverium bromide+300mg of simethicone (PB+S) po bid for a period of four weeks were used for the analysis. Using the Bristol Stool Scale as a reference, the consistency and frequency of each type of bowel movement were recorded weekly in a Bristol Matrix (BM) and the data were expressed as polar vectors.
  
  
  RESULTS
  The analysis showed a differential response to the PB+S treatment among the IBS subtypes: in reference to the IBS with constipation subtype, the magnitude of the vector increased from 10.2 to 12.5, reaching maximum improvement at two weeks of treatment (p<0.05, Scheffé). In the IBS with diarrhea and mixed IBS subtypes, the magnitude of the vector decreased from 19 to 14 (p<0.05) and from 16.5 to 13 (p<0.05), respectively, with continuous improvement for a period of four weeks. There was no definable vectorial pattern in the unsubtyped IBS group.
  
  
  CONCLUSIONS
  Analysis with polar vectors enables treatment response to be measured in different IBS subtypes. All the groups showed improvement with PB+S, but each one had its own characteristic response in relation to vector magnitude and direction. The proposed method can be implemented in clinical studies to evaluate the efficacy of IBS treatments.
authors: Research Office, Hospital General de México O.D., Mexico City, Mexico. jclalvar@yahoo.com
authors: J C
authors: JC
authors: López-Alvarenga
authors: S
authors: S
authors: Sobrino-Cossío
authors: J M
authors: JM
authors: Remes-Troche
authors: J
authors: J
authors: Chiu-Ugalde
authors: J A
authors: JA
authors: Vargas-Romero
authors: M
authors: M
authors: Schmulson
mesh_terms: D000293:Adolescent; D000328:Adult; D000465:Algorithms; D002121:Calcium Channel Blockers / Q000627:therapeutic use*; D003248:Constipation / Q000209:etiology / Q000628:therapy; D004338:Drug Combinations; D005260:Female; D005765:Gastrointestinal Agents / Q000627:therapeutic use*; D006801:Humans; D043183:Irritable Bowel Syndrome / Q000175:diagnosis / Q000628:therapy*; D008297:Male; D008875:Middle Aged; D009025:Morpholines / Q000627:therapeutic use*; D012841:Simethicone / Q000627:therapeutic use*; D012959:Socioeconomic Factors; D055815:Young Adult
chemical_list: D002121:Calcium Channel Blockers; D004338:Drug Combinations; D005765:Gastrointestinal Agents; D009025:Morpholines; D012841:Simethicone; C013199:pinaverium