When cyclooxygenase-2 (Cox-2)
inhibitors burst on the scene a decade ago amidst much
fanfare, Betty Chung, a 78-year-old retired legal secretary,
was among the first to clamour for the new drug to help
treat her osteoarthritis. Her physician gave in to her
demands and prescribed one of the legion Cox-2 inhibitors
out there. After all, one's pretty much the same as the
other -- or is it? A Canadian study that reviewed the
histories of 140,000 patients suggests that some Cox-2
inhibitors carry the same risks of congestive heart failure
(CHF) as traditional non-steroidal anti-inflammatory drugs
(NSAIDs), while others emphatically do not.
The study, published in the
May 29 issue of The Lancet, was prompted by current
concerns about Cox-2 inhibitors cardiovascular safety
in general and CHF in particular. Therese Stukel, PhD,
of the Institute for Clinical Evaluative Sciences in
Toronto and her team set out to test this proposition,
looking at two of the most popular Cox-2 inhibitors:
celecoxib and rofecoxib.
The researchers looked at the records of NSAID-naive
Ontario patients aged 66 years or older, of which 14,583
were started on rofecoxib, 18,908 on celecoxib and 5,391
on older non-selective NSAIDs. These patients were compared
to 100,000 randomly selected non-NSAID users who served
as controls. The primary endpoint was admission to hospital
for CHF. This 11-year-long retrospective study totalled
55,000 person-years of followup, and recorded 654 admissions
for CHF -- so statistical power was certainly not lacking.
The results are likely to bring cheer to Pfizer marketers.
After adjustment for other risk factors, the celecoxib-,
rofecoxcib-, and non-selective NSAID-treated patients
were 0.9, 1.8 and 1.4 times more likely to have CHF
than the control group. These findings are consistent
with those of previous randomized trials of osteoarthritis
patients with longstanding hypertension showing significantly
greater increases in systolic blood pressure in those
receiving rofecoxib than those on celecoxib.
Another interesting find was that non-selective NSAIDs
increased the risk of readmission in patients previously
admitted for CHF, but did not increase the risk of new
disease. Rofecoxib, by contrast, also increased the
risk of first-time CHF.
The authors note that patients in all three treatment
groups were more likely to need antihypertensive drugs
after starting their treatment. They suggest that when
all forms of cardiac disease are taken into account,
the gap between celecoxib and rofecoxib might not be
so wide, and that "celecoxib might not be entirely
devoid of clinically important cardiovascular effects."
"Although the estimated absolute risks of admission
were small in those without a recent previous history
of congestive heart failure," say the authors,
"the low estimated number needed to treat to harm
in those with a recent history makes these findings
clinically relevant."
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