long term maintenance Comparison: osmotic laxative versus placebo (PEG versus placebo)

OutcomeMeta- analysis detailsSummary Statisticsp (hetero) and I2Comments:Study qualityDirectnessImprecisionInconsistencyReporting BiasGRADE CommentsGRADE Evidence Rating
Global improvement of IBS symptoms (no. patients)No evidence for this outcome----------------------
No of patients not using rescue medication1 trial; 48 patients; from RCT; (long term maintenance design)RR=1.61 (95%CI 1.05, 2.47)Statistically significant, favours PEG; NNT 4 for control group risk of 52%GoodIndirect setting- minor, secondary care OPDPreciseconsistent---Laxatives as rescue medication. Probably some IBS patients, but secondary care. Corazziari 1996Moderate
rescue medication use1 trial; 48 patients; from RCT; (long term maintenance design)RR=0.33 (95%CI 0.12, 0.9)statistically significant at 8 weeks, favours PEG. NNT 4GoodIndirect setting- minor, secondary care OPDWide CIconsistent---Laxatives as rescue medication. Probably some IBS patients, but secondary care. Corazziari 1996Low
rescue medication use1 trial; 65 patients; from RCT; (long term maintenance design)MD=−1.5 (95%CI −2.96, − 0.04)statistically significant; in favour of PEG at 8 weeks. Placebo group 2.2 per 4 weeks.GoodIndirect setting- minor, secondary care OPDFairly wide CIconsistent---Number of laxatives used/4 weeks (rescue). Probably some IBS patients, but secondary care. Corazziari 2000. Withdrawal of laxative after 4 weeks in respondersLow
pain number of patients1 trial; 48 patients; from RCT; (long term maintenance design)RR=0.69 (95%CI 0.28, 1.69)not statistically significant at 8 weeks; placebo group rate 35%GoodIndirect setting- minor, secondary care OPDFairly wide CIconsistent---Probably includes some IBS patients, but secondary care.Low
No of patients with bloating1 trial; 48 patients; from RCT; (long term maintenance design)RR=0.69 (95%CI 0.42, 1.13)no statistically significant difference at 8 weeks; control group rate 70%GoodIndirect setting- minor, secondary care OPDPreciseconsistent---Probably includes some IBS patients, but secondary care.Moderate
Bloating score1 trial; 65 patients; from RCT; (long term maintenance design)Statistically significant difference at 8 weeks in severity of bloating (p<0.001)GoodIndirect setting- minor, secondary care OPD-----------Reported by authors. Probably some IBS patients, but secondary care. Corazziari 2000. Withdrawal of laxative after 4 weeks in responders----
No of patients with improved bowel habit1 trial; 65 patients; from RCT; (long term maintenance design)RR=3.95 (95%CI 1.86, 8.42)Large statistically significant effect at 8 weeks, favours PEG. NNT 2. Placebo group rate 18%GoodIndirect setting- minor, secondary care OPDFairly wide CIconsistent---Probably some IBS patients, but secondary care. Corazziari 2000. Withdrawal of laxative after 4 weeks in respondersModerate
Stool freq1 trial; 48 patients; from RCT; (long term maintenance design)MD=2 (95%CI 0.89, 3.11)Statistically significant increase in stool frequency per week for patients given PEG at 8 weeks. Placebo group 2.8/weekGoodIndirect setting- minor, secondary care OPDPreciseconsistent---Probably some IBS patients, but secondary care. Corazziari 1996.Moderate
Stool freq1 trial; 65 patients; from RCT; (long term maintenance design)MD=3.13 (95%CI 1.35, 4.91)Large statistically significant increase in stool frequency in PEG group at 8 weeks. Control group 4.39/weekGoodIndirect setting- minor, secondary care OPDPreciseconsistent---Probably some IBS patients, but secondary care. Corazziari 2000. Withdrawal of laxative after 4 weeks in respondersModerate
Use of laxatives1 trial; 65 patients; from RCT; (long term maintenance design)MD=−10 (95%CI −16.09, − 3.91)Statistically significant at 8 weeks. Favours PEG. Placebo group 43 sachets/4 weeks.GoodIndirect setting- minor, secondary care OPDPreciseconsistent---Number of intervention laxatives used/4 weeks. Probably some IBS patients, but secondary care. Corazziari 2000. Withdrawal of laxative after 4 weeks in respondersModerate
Number of withdrawals1 trial; 65 patients; from RCT; (long term maintenance design)RR=0.13 (95%CI 0.03, 0.53)Statistically significant at 20 weeks; favours PEG. NNT 3 for placebo group rate of 46%GoodIndirect setting- minor, secondary care OPDWide CIconsistent---Probably some IBS patients, but secondary care. Corazziari 2000. Withdrawal of laxative after 4 weeks in respondersLow

From: Appendix F, Grading the evidence

Cover of Irritable Bowel Syndrome in Adults
Irritable Bowel Syndrome in Adults: Diagnosis and Management of Irritable Bowel Syndrome in Primary Care [Internet].
NICE Clinical Guidelines, No. 61.
National Collaborating Centre for Nursing and Supportive Care (UK).
Copyright © 2008, Royal College of Nursing.

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