Table 3.

Independent risk factors for inadequate bowel preparations in multivariate analyses.

Author	N	Split Prep used?	Variable	OR (95% CI)
Dik et al. 2015	1331	yes	tricyclic antidepressants	5.3 (2.3–12.5)
			opiates	1.9 (1.0–3.6)
			diabetes	2.1 (1.3–3.4)
			chronic constipation	2.7 (1.7–4.3)
			prior abdominal/pelvic surgery	1.8 (1.3–2.6)
			prior inadequate prep	1.8 (1.1–3.0)
			current hospitalization	1.8 (1.0–3.1)
Fayad et al. 2013	2163	yes	BMI ≥ 30 kg/m2	1.46 (1.21–1.75)
			tobacco	1.28 (1.07–1.54)
			narcotics	1.28 (1.04–1.57)
			hypertension	1.30 (1.07–1.57)
			diabetes	1.38 (1.12–1.69)
			dementia	3.02 (1.22–7.49)
Hassan et al. 2012	2811	Only for 12%	male	1.2 (1.02–1.5)
			high BMI	1.1 (1.03–1.1)
			older age	1.01 (1.004–1.02)
			prior colorectal surgery	1.6 (1.2–2.2)
			cirrhosis	5.0 (2.6–10.4)
			Parkinson disease	3.2 (1.2–9.3)
			diabetes	1.8 (1.3–2.5)
			positive FOBT	0.6 (0.5–0.8)
Borg et al. 2009	1588	no	BMI ≥25	1.28 (1.01–161)
Chan et al. 2011	501	3 day prep w/bisacodyl and low-residue diet followed by 2L PEG	Lower education level	2.35 (1.54 – 3.60)
			appt waiting time > 16 wks	1.86 (1.04 – 3.37)
			non-adherence to prep instructions	4.76 (3.00 – 7.55)
Chung et al. 2009	362	no (4L morning of)	age > 60 years old	2.8 (1.04–7.4)
			diabetes	8.6 (6.3–19.4)
			appendectomy	4.6 (2.0–10.5)
			colorectal resection	7.5 (3.4–17.6)
			hysterectomy	3.4 (1.1–10.4)
Lebwohl et al. 2010	12,430	no	on Medcaid	1.84 (1.61–2.11)
			later time of day appt	1.89 (1.71–2.09)
			marital status	0.89 (0.80–0.98)
			increased age	1.09 (1.05–1.14)
			male	1.44 (1.31–1.59)
			inpatient status	1.51 (1.26–1.80)
Ness at al. 2001	649	approximately half	Procedure time	1.15 (1.05, 1.25)
			non-adherence to prep instructions	2.68 (1.52, 4.75)
			cirrhosis	3.71 (1.17, 11.75)
			inpatient status	3.13 (1.15, 8.50)
			constipation	2.81 (1.10, 7.20)
			tricyclic antidepressant	2.99 (1.10, 8.15)
			hx of polyps	0.55 (0.31, 0.98)
			male	1.54 (1.03, 2.30)
			stroke or dementia	2.23 (1.00, 4.97)