RSS Feeds
-
Underestimation of the risk of complications associated with colonoscopy
Submit responseTO THE EDITOR,
Similar to many other retrospective studies, the study by Warren et al. may underestimate the risk of complications associated with colonoscopy(1). When a colonoscopy is aborted due to a complication observed during the procedure, the procedure may be recorded as a flexible sigmoidoscopy (2) or incomplete colonoscopy. Such adverse events will not be counted as associated with colonoscopy, when only complete colonoscopies are evaluated, as in the study by Warren et. al. Conversely, this bias can lead to calculation of extremely high complication rates associated with flexible sigmoidoscopy, due to the inclusion of failed colonoscopies as flexible sigmoidoscopies(3).
In addition, the authors did not find any increased risk of cardiovascular events with colonoscopy. This may be due to evaluation of cardiovascular events within 30 days, rather than in the immediate peri- procedural time period, for e.g. within seven days of the index procedure. Most of the cardiac events directly related to a procedure do occur within the first few days of the index procedure(4). Larger number of events later in the month, when there maybe no difference between the colonoscopy and the control groups, could have overwhelmed any true difference in the rates of cardiovascular events in the first few days.
References
(1)Warren JL, Klabunde CN, Mariotto AB, Meekins A, Topor M, Brown ML, et al. Adverse events after outpatient colonoscopy in the Medicare population. Ann Intern Med 2009 Jun 16;150(12):849-57, W152.
(2) Singh H, Penfold RB, DeCoster C, Kaita L, Proulx C, Taylor G, et al. Colonoscopy and its complications across a Canadian regional health authority. Gastrointest Endosc 2009 Mar;69(3 Suppl):665-71.
(3) Schoen RE, Levin TR. Re: Risk of perforation after colonoscopy and sigmoidoscopy: a population-based study. J Natl Cancer Inst 2003 Jun 4;95(11):830-1.
(4) Gandhi R, Petruccelli D, Devereaux PJ, Adili A, Hubmann M, de BJ. Incidence and timing of myocardial infarction after total joint arthroplasty. J Arthroplasty 2006 Sep;21(6):874-7.
Conflict of Interest:
None declared
-
Is colonoscopy still safe in elderly people?
Submit responseWe have read with great interest the article by Dr. Warren et al. because it addresses the important issue of performing safety colonoscopy in the elderly. Age is an established factor associated with prolonged procedure (1) and with increased complications in colonoscopy with polypectomy, particularly in relation to various technical and organizational factors related to the endoscopy activity (2). However, as confirmed by our experience, the colonoscopy in the elderly remains a procedure burdened by low rates of complications and easy to perform (3). The population-based assessments, as noted by others (2), play a very important role in estimating the risk taken by the elderly who undergo a screening colonoscopy without symptomatic indications, as compared to the general population.
But two aspects of the article seem critical to us: 1) to compare the risk of adverse events (AE) for diagnostic and therapeutic colonoscopy using the general population as control; 2) to estimate the adjusted risk for AE by age and selected conditions using the pooled colonoscopy group (table 4). As it can be inferred from tables 3 and 4, the three samples considered (screening, diagnostic and polypectomy) have been, likely, drawn from populations statistically different with respect to the type of AE. In fact, only the screening procedure sample presents overlapping IC to those of the no colonoscopy sample, across all three types of AE. Only cardiovascular conditions have dissimilar behaviour across the four samples, as being independent factors to the identification of the patients’ risk, but not necessarily related to older age (i.e. ASA).
To verify this statement, we analyzed 617 colonoscopy we performed under deep sedation with propofol. Findings from the multivariate analysis showed that comorbidity as measured by ASA (but not age), sex, experience of the endoscopist and bowel preparation were significant factors explaining “difficult colonoscopy”, characterized as adverse anesthesiological events, specific complications or incompleteness of the colonoscopy. We considered prompt AE because it seems to us a more appropriate parameter for diagnostic practice than the 30 days AE, which is a common index used to investigate effects of interventional procedure.
One of the issues that the study by Warren could confirm, if the information on the diagnostic colonoscopy were available, it is that, probably, the old person often undergoes futile endoscopies (4); but the general conclusion of the article could infer wrong attitudes in diagnostic and therapeutic colonoscopy towards elderly, extending in endoscopy the ageism phenomenon, already present in cardiology and oncology.
References
1) Kim WH, Cho YJ, Park JY, Min PK, Kang JK, Park IS. Factors affecting insertion time and patient discomfort during colonoscopy. Gastrointest Endosc. 2000 Nov;52(5):600-5.
2) Janadomi JM. In search of quality colonoscopy. 1: Gastroenterology. 2008 Dec;135(6):1845-7. Epub 2008 Nov 8.
3) Cardin F., Barbato B., Terranova O. Outcomes of safe, simple colonoscopy in older adults. Age Ageing. 2005 Sep;34(5):513-5.
4) Mayor S. Seriously ill elderly patients are subjected to futile endoscopies. BMJ. 2004 Oct 16;329(7471):873.
Conflict of Interest:
None declared