LETTERS TO THE EDITOR
Errors, Omissions, and Publication Bias To the Editor–Although Drs Robb and Mariette1 in their review of adhesion prevention strategies infer funder independence and present findings conservatively, certain errors and omissions raise the issue of unacknowledged publication bias. Four studies, labeled as not funded by industry, were in fact funded by the sponsor of this review, Sanofi-Genzyme. Evidence for 3 of the studies (Oikonomakis 2002, Salum 2006, Dupre 2013) comes from the text of the studies themselves, and the fourth (Kusunoki 2005), from a Freedom of Information Act request2, which could have been revealed to the authors by Sanofi-Genzyme. Contrary to Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines, the authors did not report on seeking unpublished studies.3 This particularly refers to a 14-year Cleveland Clinic study,4 which found significant septic risk associated with sodium hyaluronate-carboxymethylcellulose (HA-CMC) use in primary restorative proctocolectomy. Given that Sanofi-Genzyme reported this study to the US Food and Drug Administration (FDA),5 one would expect them to have made the authors aware of it. The finding of reduction of adhesive small-bowel obstruction in the most influential study (Fazio, 2006)4 was disallowed by both a Cochrane Review6 and an FDA review (written communication from Dr Horbowyj, FDA clinical reviewer, e-mail to Dr Berkowitz, June 2005; Freedom of Information Act S027, https://drive. google.com/file/d/0B7mfGgLIOIyGNFY3ZTZiT2tyUEE/ view?usp=sharing. Accessed October 20, 2014) based on improper exclusion of patients postrandomization. This criticism is not acknowledged, even though the article by Kumar et al6 is referenced as supportive evidence. The use in repeat surgery is not addressed despite the underevaluated yet predominant use7 of HA-CMC in that setting. Errors and omissions can weaken a study’s reliability, especially where safety is the primary outcome. Recent studies have raised HA-CMC safety concerns, including unexplained fluid collections in abdominopelvic debulking surgery8 and increased risk of abscess after colectomy.9 Reporting to what extent information was made available from the funding source may protect against publication bias. Dis Colon Rectum 2015; 58: e53–e55 DOI: 10.1097/DCR.0000000000000343 © The ASCRS 2015 Diseases of the Colon & Rectum Volume 58: 4 (2015)
REFERENCES 1. Robb WB, Mariette C. Strategies in the prevention of the formation of postoperative adhesions in digestive surgery: a systematic review of the literature. Dis Colon Rectum. 2014;57:1228–1240. 2. Freedom of Information Act request #2008–6946, certified 12/17/2010. https://drive.google.com/file/d/0B7mfGgLIOIyGLU xnM2xOT2FxOWM/view?usp=sharing. Accessed October 20, 2014. 3. Liberati A, Altman DG, Tetzlaff J, et al. The PRISMA statement for reporting systematic reviews and meta-analyses of studies that evaluate health care interventions: explanation and elaboration. PLoS Med. 2009;6(7):e1000100. 4. Cornish JA, Tekkis PP, Kiran RP, et al. The effect of Seprafilm on septic complications and bowel obstruction following primary restorative proctocolectomy. Dis Colon Rectum. 2008;51[abstract]:647. 2008 Annual Meeting 2008 Podium Presentation video. http://www.dcprovidersonline.com/ascrs_cme/ee4e74 0e22b02d706b45fbb2f9ab16d3/814b.html. Accessed October 20, 2014. 5. FDA Adverse Event Database MAUDE. Report 1220423-201000003. https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfmaude/Detail.cfm?MDRFOI__ID=1591645. Accessed October 20, 2014. 6. Kumar S, Wong PF, Leaper DJ. Intra-peritoneal prophylactic agents for preventing adhesions and adhesive intestinal obstruction after non-gynaecological abdominal surgery. Cochrane Database of Systematic Reviews 2009, Issue 1. Art. No.: CD005080. DOI: 10.1002/14651858.CD005080.pub2. 7. Altuntas YE, Kement M, Oncel M, Sahip Y, Kaptanoglu L. The effectiveness of hyaluronan-carboxymethylcellulose membrane in different severity of adhesions observed at the time of relaparotomies: an experimental study on mice. Dis. Colon Rectum. 2008;51:1562. 8. Leitao MM Jr, Byrum GV 3rd, Abu-Rustum NR, et al. Postoperative intra-abdominal collections using a sodium hyaluronate-carboxymethylcellulose (HA-CMC) barrier at the time of laparotomy for uterine or cervical cancers. Gynecol Oncol. 2010;119:208–211. 9. Bashir S, Ananth CV, Lewin SN, et al. Utilization and safety of sodium hyaluronate-carboxymethylcellulose adhesion barrier. Dis Colon Rectum. 2013;56:1174–1184.
Michael Waldron, B.A. New York, New York
The Authors Reply To the Editor–We read with interest Mr Waldron’s1 interpretation of our recently published systematic review on strategies to prevent adhesion formation after digestive tract surgery.2 The correspondence correctly points out e53
Errors, Omissions, and Publication Bias To the Editor–Although Drs Robb and Mariette1 in their review of adhesion prevention strategies infer funder independence and present findings conservatively, certain errors and omissions raise the issue of unacknowledged publication bias. Four studies, labeled as not funded by industry, were in fact funded by the sponsor of this review, Sanofi-Genzyme. Evidence for 3 of the studies (Oikonomakis 2002, Salum 2006, Dupre 2013) comes from the text of the studies themselves, and the fourth (Kusunoki 2005), from a Freedom of Information Act request2, which could have been revealed to the authors by Sanofi-Genzyme. Contrary to Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines, the authors did not report on seeking unpublished studies.3 This particularly refers to a 14-year Cleveland Clinic study,4 which found significant septic risk associated with sodium hyaluronate-carboxymethylcellulose (HA-CMC) use in primary restorative proctocolectomy. Given that Sanofi-Genzyme reported this study to the US Food and Drug Administration (FDA),5 one would expect them to have made the authors aware of it. The finding of reduction of adhesive small-bowel obstruction in the most influential study (Fazio, 2006)4 was disallowed by both a Cochrane Review6 and an FDA review (written communication from Dr Horbowyj, FDA clinical reviewer, e-mail to Dr Berkowitz, June 2005; Freedom of Information Act S027, https://drive. google.com/file/d/0B7mfGgLIOIyGNFY3ZTZiT2tyUEE/ view?usp=sharing. Accessed October 20, 2014) based on improper exclusion of patients postrandomization. This criticism is not acknowledged, even though the article by Kumar et al6 is referenced as supportive evidence. The use in repeat surgery is not addressed despite the underevaluated yet predominant use7 of HA-CMC in that setting. Errors and omissions can weaken a study’s reliability, especially where safety is the primary outcome. Recent studies have raised HA-CMC safety concerns, including unexplained fluid collections in abdominopelvic debulking surgery8 and increased risk of abscess after colectomy.9 Reporting to what extent information was made available from the funding source may protect against publication bias. Dis Colon Rectum 2015; 58: e53–e55 DOI: 10.1097/DCR.0000000000000343 © The ASCRS 2015 Diseases of the Colon & Rectum Volume 58: 4 (2015)
REFERENCES 1. Robb WB, Mariette C. Strategies in the prevention of the formation of postoperative adhesions in digestive surgery: a systematic review of the literature. Dis Colon Rectum. 2014;57:1228–1240. 2. Freedom of Information Act request #2008–6946, certified 12/17/2010. https://drive.google.com/file/d/0B7mfGgLIOIyGLU xnM2xOT2FxOWM/view?usp=sharing. Accessed October 20, 2014. 3. Liberati A, Altman DG, Tetzlaff J, et al. The PRISMA statement for reporting systematic reviews and meta-analyses of studies that evaluate health care interventions: explanation and elaboration. PLoS Med. 2009;6(7):e1000100. 4. Cornish JA, Tekkis PP, Kiran RP, et al. The effect of Seprafilm on septic complications and bowel obstruction following primary restorative proctocolectomy. Dis Colon Rectum. 2008;51[abstract]:647. 2008 Annual Meeting 2008 Podium Presentation video. http://www.dcprovidersonline.com/ascrs_cme/ee4e74 0e22b02d706b45fbb2f9ab16d3/814b.html. Accessed October 20, 2014. 5. FDA Adverse Event Database MAUDE. Report 1220423-201000003. https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfmaude/Detail.cfm?MDRFOI__ID=1591645. Accessed October 20, 2014. 6. Kumar S, Wong PF, Leaper DJ. Intra-peritoneal prophylactic agents for preventing adhesions and adhesive intestinal obstruction after non-gynaecological abdominal surgery. Cochrane Database of Systematic Reviews 2009, Issue 1. Art. No.: CD005080. DOI: 10.1002/14651858.CD005080.pub2. 7. Altuntas YE, Kement M, Oncel M, Sahip Y, Kaptanoglu L. The effectiveness of hyaluronan-carboxymethylcellulose membrane in different severity of adhesions observed at the time of relaparotomies: an experimental study on mice. Dis. Colon Rectum. 2008;51:1562. 8. Leitao MM Jr, Byrum GV 3rd, Abu-Rustum NR, et al. Postoperative intra-abdominal collections using a sodium hyaluronate-carboxymethylcellulose (HA-CMC) barrier at the time of laparotomy for uterine or cervical cancers. Gynecol Oncol. 2010;119:208–211. 9. Bashir S, Ananth CV, Lewin SN, et al. Utilization and safety of sodium hyaluronate-carboxymethylcellulose adhesion barrier. Dis Colon Rectum. 2013;56:1174–1184.
Michael Waldron, B.A. New York, New York
The Authors Reply To the Editor–We read with interest Mr Waldron’s1 interpretation of our recently published systematic review on strategies to prevent adhesion formation after digestive tract surgery.2 The correspondence correctly points out e53
