Sodium Phosphate Does Not Increase Risk for Acute Kidney Injury After Routine Colonoscopy, Compared With Polyethylene Glycol

Published:January 31, 2014DOI:

      Background & Aims

      Oral sodium phosphate (OSP) is a common bowel purgative administered before colonoscopy; the Food and Drug Administration has warned against its use because of concerns about acute kidney injury (AKI) from the absorbed phosphate and dystrophic calcification. However, it is not clear if OSP is associated with AKI in the general population or in high-risk subgroups undergoing colonoscopy. We estimated the risk of AKI among patients undergoing a screening colonoscopy using OSP vs polyethylene glycol (PEG) for bowel cleansing in a large, US-based claims database.


      We used an insurance database to identify a cohort of patients ages 50 to 75 years who underwent screening colonoscopies as outpatients from January 2000 through November 2008 (before the Food and Drug Administration warning), receiving OSP (n = 121,266) or PEG (n = 429,430) within 30 days beforehand, without prior use of either drug. We collected data from patients for 6 months afterward to identify those who developed AKI or renal failure, or received dialysis. Adjusted and propensity score-matched hazard ratios (HR) and 95% confidence intervals (CI) were estimated using Cox proportional hazards models. We investigated the effects in subgroups with higher AKI risk (patients with chronic kidney disease, kidney stones, hypertension, or diabetes, or using antihypertensive or nonsteroidal anti-inflammatory drugs).


      AKI occurred in 0.2% of OSP users and in 0.3% of PEG users (adjusted HR, 0.86; 95% CI, 0.75–0.99). OSP users matched well with PEG users, producing similar estimates (HR, 0.85; 95% CI, 0.72–1.01). We did not observe a consistent increase in the risk of AKI or other outcomes in any subgroups analyzed.


      In a large database analysis, we did not associate administration of OSP before colonoscopy with increased risk of postprocedure AKI, even in high-risk clinical subgroups.


      Abbreviations used in this paper:

      AKI (acute kidney injury), CI (confidence interval), CKD (chronic kidney disease), FDA (Food and Drug Administration), HR (hazard ratio), OSP (oral sodium phosphate), PEG (polyethylene glycol), PS (propensity score)
      To read this article in full you will need to make a payment
      AGA Member Login
      Login with your AGA username and password.
      One-time access price info
      • For academic or personal research use, select 'Academic and Personal'
      • For corporate R&D use, select 'Corporate R&D Professionals'

      Purchase one-time access:

      Already a print subscriber? Claim online access
      Already an online subscriber? Sign in
      Institutional Access: Sign in to ScienceDirect


        • Patel V.
        • Emmett M.
        • Santa Ana C.A.
        • et al.
        Pathogenesis of nephrocalcinosis after sodium phosphate catharsis to prepare for colonoscopy: intestinal phosphate absorption and its effect on urine mineral and electrolyte excretion.
        Hum Pathol. 2007; 38 (author reply 194–195): 193-194
        • Biberstein M.
        • Parker B.A.
        Enema-induced hyperphosphatemia.
        Am J Med. 1985; 79: 645-646
        • Korzets A.
        • Dicker D.
        • Chaimoff C.
        • et al.
        Life-threatening hyperphosphatemia and hypocalcemic tetany following the use of fleet enemas.
        J Am Geriatr Soc. 1992; 40: 620-621
        • Vukasin P.
        • Weston L.A.
        • Beart R.W.
        Oral Fleet Phospho-Soda laxative-induced hyperphosphatemia and hypocalcemic tetany in an adult: report of a case.
        Dis Colon Rectum. 1997; 40: 497-499
        • Desmeules S.
        • Bergeron M.J.
        • Isenring P.
        Acute phosphate nephropathy and renal failure.
        N Engl J Med. 2003; 349: 1006-1007
        • Markowitz G.S.
        • Nasr S.H.
        • Klein P.
        • et al.
        Renal failure due to acute nephrocalcinosis following oral sodium phosphate bowel cleansing.
        Hum Pathol. 2004; 35: 675-684
        • Markowitz G.S.
        • Stokes M.B.
        • Radhakrishnan J.
        • et al.
        Acute phosphate nephropathy following oral sodium phosphate bowel purgative: an underrecognized cause of chronic renal failure.
        J Am Soc Nephrol. 2005; 16: 3389-3396
        • Connor A.
        • Sykes L.
        • Roberts I.S.
        • et al.
        Acute phosphate nephropathy after sodium phosphate preparations.
        BMJ. 2008; 337: a182
        • Ori Y.
        • Herman M.
        • Tobar A.
        • et al.
        Acute phosphate nephropathy-an emerging threat.
        Am J Med Sci. 2008; 336: 309-314
        • Brunelli S.M.
        Association between oral sodium phosphate bowel preparations and kidney injury: a systematic review and meta-analysis.
        Am J Kidney Dis. 2009; 53: 448-456
        • Hurst F.P.
        • Bohen E.M.
        • Osgard E.M.
        • et al.
        Association of oral sodium phosphate purgative use with acute kidney injury.
        J Am Soc Nephrol. 2007; 18: 3192-3198
        • Russmann S.
        • Lamerato L.
        • Motsko S.P.
        • et al.
        Risk of further decline in renal function after the use of oral sodium phosphate or polyethylene glycol in patients with a preexisting glomerular filtration rate below 60 ml/min.
        Am J Gastroenterol. 2008; 103: 2707-2716
        • Khurana A.
        • McLean L.
        • Atkinson S.
        • et al.
        The effect of oral sodium phosphate drug products on renal function in adults undergoing bowel endoscopy.
        Arch Intern Med. 2008; 168: 593-597
        • Ehrenpreis E.D.
        • Parakkal D.
        • Semer R.
        • et al.
        Renal risks of sodium phosphate tablets for colonoscopy preparation: a review of adverse drug reactions reported to the US Food and Drug Administration.
        Colorectal Dis. 2011; 13: e270-e275
        • Russmann S.
        • Lamerato L.
        • Marfatia A.
        • et al.
        Risk of impaired renal function after colonoscopy: a cohort study in patients receiving either oral sodium phosphate or polyethylene glycol.
        Am J Gastroenterol. 2007; 102: 2655-2663
        • Singal A.K.
        • Rosman A.S.
        • Post J.B.
        • et al.
        The renal safety of bowel preparations for colonoscopy: a comparative study of oral sodium phosphate solution and polyethylene glycol.
        Aliment Pharmacol Ther. 2008; 27: 41-47
        • Abaskharoun R.
        • Depew W.
        • Vanner S.
        Changes in renal function following administration of oral sodium phosphate or polyethylene glycol for colon cleansing before colonoscopy.
        Can J Gastroenterol. 2007; 21: 227-231
        • Brunelli S.M.
        • Lewis J.D.
        • Gupta M.
        • et al.
        Risk of kidney injury following oral phosphosoda bowel preparations.
        J Am Soc Nephrol. 2007; 18: 3199-3205
        • Seol D.C.
        • Hong S.N.
        • Kim J.H.
        • et al.
        Change in renal function after sodium phosphate preparation for screening colonoscopy.
        World J Gastroenterol. 2010; 16: 2010-2016
        • Johanson J.F.
        • Popp Jr., J.W.
        • Cohen L.B.
        • et al.
        A randomized, multicenter study comparing the safety and efficacy of sodium phosphate tablets with 2L polyethylene glycol solution plus bisacodyl tablets for colon cleansing.
        Am J Gastroenterol. 2007; 102: 2238-2246
      1. FDA requires new safety measures for oral sodium phosphate products to reduce risk of acute kidney injury risk associated with both prescription and over-the-counter (OTC) products. Volume 2013. US Food and Drug Administration, Silver Spring, MD2008
        • Brunelli S.M.
        • Feldman H.I.
        • Latif S.M.
        • et al.
        A comparison of sodium phosphosoda purgative to polyethylene glycol bowel preparations prior to colonoscopy.
        Fam Med. 2009; 41: 39-45
        • Juluri R.
        • Eckert G.
        • Imperiale T.F.
        Polyethylene glycol vs. sodium phosphate for bowel preparation: a treatment arm meta-analysis of randomized controlled trials.
        BMC Gastroenterol. 2011; 11: 38
        • Juluri R.
        • Eckert G.
        • Imperiale T.F.
        Meta-analysis: randomized controlled trials of 4-L polyethylene glycol and sodium phosphate solution as bowel preparation for colonoscopy.
        Aliment Pharmacol Ther. 2010; 32: 171-181
        • Belsey J.
        • Crosta C.
        • Epstein O.
        • et al.
        Meta-analysis: the relative efficacy of oral bowel preparations for colonoscopy 1985-2010.
        Aliment Pharmacol Ther. 2012; 35: 222-237
        • Lawrance I.C.
        • Willert R.P.
        • Murray K.
        Bowel cleansing for colonoscopy: prospective randomized assessment of efficacy and of induced mucosal abnormality with three preparation agents.
        Endoscopy. 2011; 43: 412-418
        • Parsons L.S.
        Reducing bias in a propensity score matched-pair sample using greedy matching techniques. Twenty-Sixth Annual SAS® Users Group International Conference.
        SAS Institute, Inc, Cary, NC2001
        • Nordin B.E.C.
        Urinary excretion. Calcium, phosphate, and magnesium metabolism: clinical physiology and diagnostic procedures.
        Longman Group Limited, New York1976
        • Patel V.
        • Nicar M.
        • Emmett M.
        • et al.
        Intestinal and renal effects of low-volume phosphate and sulfate cathartic solutions designed for cleansing the colon: pathophysiological studies in five normal subjects.
        Am J Gastroenterol. 2009; 104: 953-965
        • Winkelmayer W.C.
        • Schneeweiss S.
        • Mogun H.
        • et al.
        Identification of individuals with CKD from Medicare claims data: a validation study.
        Am J Kidney Dis. 2005; 46: 225-232
        • Vlasschaert M.E.
        • Bejaimal S.A.
        • Hackam D.G.
        • et al.
        Validity of administrative database coding for kidney disease: a systematic review.
        Am J Kidney Dis. 2011; 57: 29-43
        • Kaufman J.
        • Dhakal M.
        • Patel B.
        • et al.
        Community-acquired acute renal failure.
        Am J Kidney Dis. 1991; 17: 191-198
        • Feest T.G.
        • Round A.
        • Hamad S.
        Incidence of severe acute renal failure in adults: results of a community based study.
        BMJ. 1993; 306: 481-483
        • Liano F.
        • Pascual J.
        Epidemiology of acute renal failure: a prospective, multicenter, community-based study. Madrid Acute Renal Failure Study Group.
        Kidney Int. 1996; 50: 811-818
        • Obialo C.I.
        • Okonofua E.C.
        • Tayade A.S.
        • et al.
        Epidemiology of de novo acute renal failure in hospitalized African Americans: comparing community-acquired vs hospital-acquired disease.
        Arch Intern Med. 2000; 160: 1309-1313
        • Greenland S.
        • Lash T.L.
        Bias analysis.
        in: Rothman K.J. Greenland S. Lash T.L. Modern epidemiology. 3rd ed. Lippincott Williams & Wilkins, Philadelphia, PA2008
        • Chubak J.
        • Pocobelli G.
        • Weiss N.S.
        Tradeoffs between accuracy measures for electronic health care data algorithms.
        J Clin Epidemiol. 2012; 65: 343-349.e2