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A comparison of oral sulfate solution with sodium picosulfate and magnesium citrate in split doses as bowel preparation for colonoscopy
Letters to the editor
A comparison of oral sulfate solution with sodium picosulfate and magnesium citrate in split doses as bowel preparation for colonoscopy To the Editor: In the article, “A comparison of oral sulfate solution with sodium picosulfate/magnesium citrate in split doses as bowel preparation for colonoscopy,” Rex et al1 reported that oral sulfate solution (OSS) was more efficacious than sodium picosulfate and magnesium citrate (SPþMC) with responder rates for effective bowel cleansing of 94.6% versus 85.7%, respectively. Although overall responder rates for SPþMC were similar in both the present and SPþMC approval trials, an even greater SPþMC response would be anticipated using this study’s less-stringent, nonvalidated scale, compared with the validated Aronchick scale in the SPþMC approval trials. Prakash et al2 reported segmental OSS success rates of 84% ascending, 86.36% mid-colon, and 86.36% rectosigmoid, using the Ottawa scale. SPþMC approval trials obtained success rates of 90% ascending, 92% mid-colon, and 92% rectosigmoid, using the Ottawa scale.3,4 Despite inherent limitations in analyzing data from different trials, the above underscores that when compared using the same validated scale, SPþMC actually performs better than OSS. Furthermore, in stark comparison with this study and attesting to the efficacy of SPþMC, the cecum was reached in 596 of 598 SPþMC patients (99.7%).3,4 It is essential to adhere to the U.S. Food and Drug Administration–approved patient instructions and labeling for SPþMC. Following a clear liquid diet, consuming adequate fluid before and after the active ingredients, and proper reconstitution are all critical to ensure a successful preparation. In this trial, it appears that none of these recommendations were emphasized, resulting in the outcome disparity with results from the SPþMC approval trials. Additional confounding variables include indiscriminate assignment of constipated patients, with various degrees of severity to the 2 treatment groups5 and permitting SPþMC–treated patients to ingest iron products until the day of their procedure. Adenoma detection rate is the primary goal of screening colonoscopy, and SPþMC performed no differently from OSS. Adenoma detection rate, procedure times, and overall safety parameters were similar between the OSS and SPþMC treatment groups.
REFERENCES 1. Rex DK, Dipalma JA, McGowan J, et al. A comparison of oral sulfate solution with sodium picosulfate/magnesium citrate in split-doses as bowel preparation for colonoscopy. Gastrointest Endosc 2015;80:1113-23. 2. Prakash SR, Verma S, McGowan J, et al. Improving the quality of colonoscopy bowel preparation using an educational video. Can J Gastroenterol 2013;27:696-700. 3. Katz PO, Rex DK, Epstein M, et al. A dual-action, low-volume bowel cleanser administered the day before colonoscopy: results from the SEE CLEAR II study. Am J Gastroenterol 2013;108:401-9. 4. Rex DK, Katz PO, Bertiger G, et al. Split-dose administration of a dual-action, low-volume bowel cleanser for colonoscopy: the SEE CLEAR I study. Gastrointest Endosc 2013;78:132-41. 5. Rex DK. Bowel preparation for colonoscopy: entering an era of increased expectations for efficacy [Editorial]. Clin Gastroenterol Hepatol 2014;12:458-62. http://dx.doi.org/10.1016/j.gie.2014.09.063
Response:
Gerald Bertiger, MD Hillmont GI Flourtown, Pennsylvania, USA James Bugni, PhD Morris Barocas, MD Ferring Pharmaceuticals, Inc Parsippany, New Jersey, USA
I agree that the bowel cleansing scale used in the trial1 comparing oral sulfate solution (OSS) with sodium picosulfate plus magnesium citrate (SPþMC) is not validated. However, the scale definitions have substantial similarities to the Aronchick scale, and the scale has been accepted by the U.S. Food and Drug Administration (FDA) in pivotal trials.2,3 The key element in a bowel cleansing trial is blinding of the colonoscopists, which in this study was effective and complete. The blinded evaluations found that OSS produced superior cleansing compared with SPþMC. The trials cited by Barcas et al are not head-to-head comparisons of OSS with SPþMC. The study by Prakash et al4 had no control group. Although I agree that comparing studies is fraught with error, in the trial of OSS versus SPþMC, the rate of excellent or good preparation achieved with OSS (94.7%) is comparable with the 97.2% rate described in the pivotal trials of OSS.3 Similarly, the rate of excellent or good preparation with SPþMC (85.7%) is comparable with the 84.2% rate of excellent or good preparation on the Aronchick scale with split dose SPþMC in a pivotal trial of split-dose SPþMC.5 The rates of excellent or good preparation in the SPþMC studies were below 85%, despite the exclusion of constipated patients in those studies.5,6 In the trial comparing OSS with SPþMC, there were 11 constipated patients in the SPþMC arm and 12 in the OSS arm.1 In the OSS versus SPþMC trial, SPþMC was provided to the study participants in FDA-approved commercial packaging, which includes the stirring step (and the associated diagram on the outside of the box) and full prescribing information inside each kit. A few patients early in the trial ingested a light breakfast with SPþMC. As noted in the report, a sensitivity analysis restricted to those patients who had only clear liquids on the morning before colonoscopy had no effect on the results relative to an analysis including all patients.
778 GASTROINTESTINAL ENDOSCOPY Volume 81, No. 3 : 2015
www.giejournal.org
A comparison of oral sulfate solution with sodium picosulfate and magnesium citrate in split doses as bowel preparation for colonoscopy To the Editor: In the article, “A comparison of oral sulfate solution with sodium picosulfate/magnesium citrate in split doses as bowel preparation for colonoscopy,” Rex et al1 reported that oral sulfate solution (OSS) was more efficacious than sodium picosulfate and magnesium citrate (SPþMC) with responder rates for effective bowel cleansing of 94.6% versus 85.7%, respectively. Although overall responder rates for SPþMC were similar in both the present and SPþMC approval trials, an even greater SPþMC response would be anticipated using this study’s less-stringent, nonvalidated scale, compared with the validated Aronchick scale in the SPþMC approval trials. Prakash et al2 reported segmental OSS success rates of 84% ascending, 86.36% mid-colon, and 86.36% rectosigmoid, using the Ottawa scale. SPþMC approval trials obtained success rates of 90% ascending, 92% mid-colon, and 92% rectosigmoid, using the Ottawa scale.3,4 Despite inherent limitations in analyzing data from different trials, the above underscores that when compared using the same validated scale, SPþMC actually performs better than OSS. Furthermore, in stark comparison with this study and attesting to the efficacy of SPþMC, the cecum was reached in 596 of 598 SPþMC patients (99.7%).3,4 It is essential to adhere to the U.S. Food and Drug Administration–approved patient instructions and labeling for SPþMC. Following a clear liquid diet, consuming adequate fluid before and after the active ingredients, and proper reconstitution are all critical to ensure a successful preparation. In this trial, it appears that none of these recommendations were emphasized, resulting in the outcome disparity with results from the SPþMC approval trials. Additional confounding variables include indiscriminate assignment of constipated patients, with various degrees of severity to the 2 treatment groups5 and permitting SPþMC–treated patients to ingest iron products until the day of their procedure. Adenoma detection rate is the primary goal of screening colonoscopy, and SPþMC performed no differently from OSS. Adenoma detection rate, procedure times, and overall safety parameters were similar between the OSS and SPþMC treatment groups.
REFERENCES 1. Rex DK, Dipalma JA, McGowan J, et al. A comparison of oral sulfate solution with sodium picosulfate/magnesium citrate in split-doses as bowel preparation for colonoscopy. Gastrointest Endosc 2015;80:1113-23. 2. Prakash SR, Verma S, McGowan J, et al. Improving the quality of colonoscopy bowel preparation using an educational video. Can J Gastroenterol 2013;27:696-700. 3. Katz PO, Rex DK, Epstein M, et al. A dual-action, low-volume bowel cleanser administered the day before colonoscopy: results from the SEE CLEAR II study. Am J Gastroenterol 2013;108:401-9. 4. Rex DK, Katz PO, Bertiger G, et al. Split-dose administration of a dual-action, low-volume bowel cleanser for colonoscopy: the SEE CLEAR I study. Gastrointest Endosc 2013;78:132-41. 5. Rex DK. Bowel preparation for colonoscopy: entering an era of increased expectations for efficacy [Editorial]. Clin Gastroenterol Hepatol 2014;12:458-62. http://dx.doi.org/10.1016/j.gie.2014.09.063
Response:
Gerald Bertiger, MD Hillmont GI Flourtown, Pennsylvania, USA James Bugni, PhD Morris Barocas, MD Ferring Pharmaceuticals, Inc Parsippany, New Jersey, USA
I agree that the bowel cleansing scale used in the trial1 comparing oral sulfate solution (OSS) with sodium picosulfate plus magnesium citrate (SPþMC) is not validated. However, the scale definitions have substantial similarities to the Aronchick scale, and the scale has been accepted by the U.S. Food and Drug Administration (FDA) in pivotal trials.2,3 The key element in a bowel cleansing trial is blinding of the colonoscopists, which in this study was effective and complete. The blinded evaluations found that OSS produced superior cleansing compared with SPþMC. The trials cited by Barcas et al are not head-to-head comparisons of OSS with SPþMC. The study by Prakash et al4 had no control group. Although I agree that comparing studies is fraught with error, in the trial of OSS versus SPþMC, the rate of excellent or good preparation achieved with OSS (94.7%) is comparable with the 97.2% rate described in the pivotal trials of OSS.3 Similarly, the rate of excellent or good preparation with SPþMC (85.7%) is comparable with the 84.2% rate of excellent or good preparation on the Aronchick scale with split dose SPþMC in a pivotal trial of split-dose SPþMC.5 The rates of excellent or good preparation in the SPþMC studies were below 85%, despite the exclusion of constipated patients in those studies.5,6 In the trial comparing OSS with SPþMC, there were 11 constipated patients in the SPþMC arm and 12 in the OSS arm.1 In the OSS versus SPþMC trial, SPþMC was provided to the study participants in FDA-approved commercial packaging, which includes the stirring step (and the associated diagram on the outside of the box) and full prescribing information inside each kit. A few patients early in the trial ingested a light breakfast with SPþMC. As noted in the report, a sensitivity analysis restricted to those patients who had only clear liquids on the morning before colonoscopy had no effect on the results relative to an analysis including all patients.
778 GASTROINTESTINAL ENDOSCOPY Volume 81, No. 3 : 2015
www.giejournal.org