Patient Characteristics Associated With Quality of Colonoscopy Preparation: A Systematic Review and Meta-analysis.

Background & Aims: Some features of patients are associated with inadequate bowel preparation, which reduces the effectiveness of colonoscopy examination. We performed a systematic review and meta-analysis of the association between patients' sociodemographic characteristics, health conditions, and medications with inadequate bowel preparation.

Methods: We searched the PubMed, Scopus, and Cochrane Review databases for randomized controlled trials cohort (prospective and retrospective), case-control, and cross-sectional studies published through March 2016. We collected information on study design, study population, and bowel preparation. For each factor, we obtained the odds ratio (OR) for inadequate bowel preparation. We conducted the meta-analyses using the random-effects approach and investigated any identified heterogeneity and publication bias via graphical methods, stratification, and meta-regression.

Results: We performed a meta-analysis of 67 studies, comprising 75,818 patients. The estimated pooled OR for inadequate bowel preparation was small for sociodemographic characteristics: 1.14 for age, and 1.23 for male sex (excluding studies in Asia, which had substantial heterogeneity and publication bias), and 1.49 for low education. The effect of high body mass index differed significantly in studies with mostly female patients (OR, 1.05) vs those with mostly male patients (OR, 1.30) (P = .013 for the difference). ORs for constipation and cirrhosis were heterogeneous; adjusted ORs were larger than unadjusted ORs (1.97 vs 1.29 for constipation and 3.41 vs 1.36 for cirrhosis). Diabetes (OR, 1.79), hypertension (OR, 1.25), stroke or dementia (OR, 2.09), and opioid use (OR, 1.70) were associated with inadequate bowel preparation. History of abdominal surgery (OR, 0.99) did not associate with inadequate bowel preparation. Use of tricyclic antidepressants had a larger effect on risk of inadequate bowel preparation in studies of mostly female patients (OR, 2.62) than studies of mostly male patients (OR, 1.42) (P = .085 for the difference).

Conclusions: In a systematic review and meta-analysis, we found no single patient-related factor to be solely associated with inadequate bowel preparation. Health conditions and use of some medications appear to be stronger predictors than sociodemographic characteristics.