Table 1.

Characteristics of included studies

Study	Country	Study design	Bowel preparation	Mean age ± SD (range), in years †	Participants undergoing colonoscopy	Electrolyte prevalences or means (SD)/ range	Blood samples	Exclusion criteria
Ainley et al. 22	United Kingdom	Prospective cohort study	NaP 90 mL	61.6 (19–89)	100 outpatients	Prevalences	After bowel preparation	No exclusion criteria
Bae et al. 23	Korea	Randomized	PEG 4 L PEG 2 L plus NaP ‡	53.7 ± 14 53.4 ± 14	271 outpatients	Means plus SD	Before and after bowel preparation	Renal insufficiency Congestive heart failure Bowel obstruction/surgery
Beloosesky et al. 24	Israel	Prospective cohort study	NaP 90 mL or barium enema ‡	80.5 ± 6 (65–90)	36 inpatients	Means plus SD, prevalence of hypokalemia	Before and after bowel preparation	Renal or liver insufficiency Congestive heart failure Myocardial infarction ≤6 months CVA <3 months Active IBD or diverticulitis Bowel obstruction
Bitoun et al. 33	France	Prospective cohort study	PEG‐asc 2L NaP 90 mL	53.0	340 outpatients	Prevalences	Before and after bowel preparation	Age >75 years Renal insufficiency Congestive heart failure IBD Bowel obstruction/surgery
Clarkston et al. 25	United States of America	Randomized	PEG 4L NaP 90 mL	57.0 ± 2 (27–85)	98 outpatients	Means plus SD, prevalences	Before and after bowel preparation	Age >65 years Renal insufficiency Congestive heart failure Bowel surgery
Huppertz‐Hauss et al. 26	Norway	Randomized	PEG 4L PEG 2 L + bisacodyl NaP	58.0	231 outpatients	Means	Before and after bowel preparation	Renal or liver insufficiency Congestive heart failure Serum electrolyte abnormalities
Johanson et al. 34	United States of America	Randomized	PEG 2L + bisacodyl NaP tablets 90 mL	56.1 (20–83)	411 outpatients	Means plus SD	Before and after bowel preparation	Renal insufficiency Congestive heart failure Serum electrolyte abnormalities Use of digitalis preparations Myocardial infarction IBD Bowel obstruction/surgery
Klare et al. 27	Germany	Randomized	PEG 4L SPMC 300 mL	56.4 ± 16	200 out/inpatients	Means plus SD, prevalences	Before and after bowel preparation	Renal insufficiency Congestive heart failure ASA V or VI Urgent procedures
Lieberman et al. 28	United States of America	Prospective cohort study	NaP 90 mL	62.3 (29–77)	32 outpatients	Means plus range	Before and after bowel preparation	Non‐veterans Renal insufficiency
Marin Gabriel et al. 29	Spain	Randomized	PEG 4L NaP 90 mL	57.9 ± 16 46.9 ± 18	42 outpatients	Means plus SD, prevalences	Before, immediately after and 1 h after the end of colonoscopy	Renal or liver insufficiency Congestive heart failure Bowel obstruction/surgery Urgent procedures
Mathus‐Vliegen et al. 30	The Netherlands	Randomized	PEG 4L NaP 90 mL	48.8 ± 17 55.0 ± 17	94 outpatients	Means plus SD, prevalences	Before and after bowel preparation	Renal or liver insufficiency (NaP) Congestive heart failure Severe gastrointestinal ulcers (PEG) Electrolyte imbalances (NaP) Salt‐restricted diet (NaP) Use of calcium‐blockers, diuretics, digoxin, lithium (NaP)
Rex et al. 31	United States of America	Randomized	NaP 90 mL SPMC 10 mg	58 (21–83)	338 outpatients	Means plus SD	Before and after bowel preparation	Renal or liver insufficiency Congestive heart failure Serum electrolyte abnormalities Bowel obstruction/surgery IBD
Rostom et al. 32	Canada	Randomized	PEG 4L NaP 90 mL	55 52	193 outpatients	Prevalences	Before and after bowel preparation	Renal or liver insufficiency Congestive heart failure Bowel obstruction/surgery

^†Not in all studies available.

^‡Not implemented in the analysis.

ASA, American Association of Anesthesiologists; Asc, ascorbic acid; CVA, cerebrovascular accident; IBD, inflammatory bowel disease; NaP, sodium phosphate; OSS, oral sulfate solution; PEG, polyethylene glycol; SD, standard deviation; SPMC, sodium picosulfate plus magnesium citrate.