Bowel preparation for colonoscopy in very old patients: A randomized prospective trial comparing oral Sodium phosphate and polyethylene glycol electrolyte lavage solution

Colonoscopic preparations are defectively tolerated among many very old patients and the quality of preparation is often inadequate. Seventy-two patients aged 80 years or more were randomized to receive either NaP (37) or PEG (35) preparation. Patients' and endoscopists' opinions of the preparation and colonoscopy were ascertained, the adverse effects were recorded, clinical indicators of dehydration such as tongue dryness, upper body muscle weakness and confusion were assessed and laboratory tests were taken before and after the preparation. Patients' evaluations showed no significant difference regarding the tolerance of preparations. Only the frequency of nausea was higher in the NaP group (16%/9%, P = 0.01). Assessment of the indicators of dehydration showed a difference only in tongue dryness in the NaP group (P = 0.02). The quality of preparation was evaluated by endoscopists as good or excellent in 81% of cases in the NaP group and in 77% of cases in the PEG group. The median values of potassium decreased from 4.0 mmol/L to 3.7 mmol/L (P < 0.05) and of sodium increased from 142 mmol/L to 145 mmol/L (P < 0.05) after NaP preparation. Sodium phosphate and PEG preparations are almost equally tolerated and effective in very old inpatients. NaP preparations cause more changes in the levels of potassium and sodium. For those elderly patients who are vulnerable to complications caused by electrolyte disturbances we recommend PEG preparation.