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Is Medicine based on evidences or merely on opinion? An example: cardiotoxicity of COX-2 inhibitors.
Submit responseThe cardiotoxicity of COX-2 inhibitors is becoming a topic of great interest, and cardiotoxicity as class effect or not is the question raised. The paper of Kimmel et al. (1) deals with this topic by examining whether the risk for cardiotoxicity differs among the COX-2 inhibitors celecoxib and rofexocib and nonselective nonaspirin NSAIDs. Seemingly, it is a work academically perfect with a large sample size. Moreover, I appreciated cautions on biases the editors expressed, but I believe all that is not enough. I previously remembered dangers of both misuse of statistics and study design biases before jumping to biologically implausible conclusions (2). In this case, there are no evident matters on plausibility, but this could be itself a confounding factor able to lower attention to important issues. Indeed, all patients and clinicians want to know whether cardiotoxicity is a class effect, and thereby applicable to any COX-2 inhibitor, or whether cardiotoxicity is limited to certain drugs in the class. Moreover, the editorial of Finckh et at (3) just affirmed that “the work of Kimmel and colleagues shed some light on this question”. Another time, the danger of strongly biased conclusions looms up to the horizon, and the possibility to mold physician opinion likewise. This study was a case-control one based on a telephone interview, and all we know limitations of this kind of design. Nevertheless, there are almost other two main methodological problems that invalidate results of Kimmel et al work. Firstly, control-patients and case-ones did not match for principal characteristics: control-patients were younger, leaner, with different race and gender distribution etc.. But a heavy selection bias gets over matching failure: only about 50% of eligible participants completed interviews. We do not know anything about the second half of the selected sample, and so results could be totally reversed. Secondly, patients taking COX-2 inhibitors were scantly represented, particularly in the case-patient group (18 and 27 respectively for Celcoxib and Rofecoxib), and multivariable logistic regression assumptions were not entirely satisfied (4). In conclusion, the actual question I want to raise is: what is the role of relevant journals to oversee true methodological quality of papers? The question is not of little importance since strongly biased studies alike of sound ones published on relevant journals can influence physician opinion and prescription behaviour. Is there the danger of a clinical practice increasingly based on opinion dressed up as evidence?
1) Kimmel SE, Berlin JA, Reilly M, Jaskowiak J, Kishel L, hittams J, Strom BL. Patients exposed to rofecoxib and celecoxib have different odds of nonfatal myocardial infarction. Ann Intern Med. 2005 Feb 1;142(3):157- 64.
2) Corrao S. Protective effect of smoking: misleading use of statistics. Radiology. 2004 Dec;233(3):934
3) Finckh A, Aronson MD. Cardiovascular risks of cyclooxygenase-2 inhibitors: where we stand now. Ann Intern Med. 2005 Feb 1;142(3):212-4.
4) Ottenbacher KJ, Ottenbacher HR, Tooth L, Ostir GV. A review of two journals found that articles using multivariable logistic regression frequently did not report commonly recommended assumptions. J Clin Epidemiol. 2004 Nov;57(11):1147-52.
Salvatore Corrao, MD, Director
Clinical Methodology, Epidemiology and Statistics Department
“Civico e Benfratelli” National Relevance Hospital Trust Piazza Nicola Leotta, 2
90127 Palermo – Italy
s.corrao@tiscali.it
Conflict of Interest:
None declared
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COX-2 and Perceptions of Conflict of Interest
Submit responseDavid A. Nardone 6714 NE Copper Beech Drive Hillsboro, Oregon danardone@verizon.net 503-648-6565
To the Editor:
As I read the recently published information regarding cyclooxygenase-2 inhibitors in the Annals I was heartened (1-2). Since the latter part of 2004 there has been a dearth of reliable information for physicians to offer objective recommendations to patients and for patients to make informed decisions. However, when I reviewed the sections for grant support and conflicts of interest, I became dismayed. Four of the seven authors of the original article, one of the two editorial authors, and both lead authors offered at least one potential affiliation with a drug company. I think it odd that the Annals felt compelled to rely, to this extent, on these experts for addressing such an important clinical issue. Surely there are consultants, who do not possess these potentially negative characteristics and who are qualified to perform critical appraisals of the pharmaceutical literature. At this point I am conflicted. The analyses and advice rendered appear relevant and reliable, but I must wonder if the majority of these authors could be biased. Publishing these potential conflicts is an excellent idea, but I am not certain it is sufficient to allay the concerns of physicians and patients, who desire and deserve an unbiased opinion. Perceptions sometimes speak volumes.
REFERENCES
1. Kimmel SE, Berlin JA, Reilly M, Jaskowiak J, Kishel L, Chittams J, Strom BL. Patients Exposed to Rofecoxib and Celecoxib Have Different Odds of Nonfatal Myocardial Infarction. Ann Intern Med 2005: 142: 157- 164
2. Finckh A, Aronson MD. Cardiovascular Risks of Cyclooxygenase-2 Inhibitors: Where Do We Stand Now? Ann Intern Med 2005;142: 212-214.
Sincerely, David A. Nardone, MD (Retired) Clinical Director Primary Care Staff Physician VHA Medical Center Professor Emeritus Oregon Health & Sciences University
Conflict of Interest:
None declared