November 1st, 2013

Hip and Knee Replacements Associated with Lower CV Risk

Total joint arthroplasty was associated with reduced cardiovascular risk among patients with knee or hip osteoarthritis in a BMJ study.

Researchers in Canada matched roughly 150 people aged 55 or older with moderate-to-severe knee or hip osteoarthritis who underwent total joint replacement to people with osteoarthritis who did not have surgery.

People who underwent arthroplasty were less likely to have a serious cardiovascular event during 7 years’ follow-up, compared with those who did not have surgery (hazard ratio, 0.56). The authors estimate that the number needed to treat to prevent one cardiovascular event was 8.

The authors offer several potential explanations for the surgery’s observed cardiovascular benefit, including improvements in exercise capability

6 Responses to “Hip and Knee Replacements Associated with Lower CV Risk”

  1. This is an example of a study that made me wonder why it is in a top journal. Only 150 people? Without more insight into the mechanism I am not sure it is more than of minor interest. Is it selection? Is it that people with surgery then have more activity? What is the value of this information?? Seems that it would take a lot for me to refer people with osteoarthritis to surgery to reduce their CV risk.

  2. to my way of thinking this is a pretty thorough study. A total of 2200 adults with hip or knee osteoarthritis aged 55 or more at recruitment (1996-98) were followed prospectively until death or 2011. Use of a propensity score reduced the cohort to 153 matched pairs (i.e. 306 patients) but helped to mitigate bias due to confounding by indication, as well as to balance some cardiovascular risk factors between the 2 groups, such as pre-existing CV disease, diabetes, hypertension, smoking status, body mass index etc. No question that “these findings require confirmation in larger studies” as the authors conclude and Dr. Krumholz hints at in his remarks. However, this findings are exceedingly provocative and highly unlikely to exert a detrimental effect on BMJ’s outstanding impact factor!

  3. Really appreciate the perspective of Dr. Messerli. It is interesting to think about what you gain – and what you lose – with the match. And how it might affect the generalizability of the findings. I certainly agree that it is worth having in the literature – I just wondered about whether it was worthy of real estate in a top journal. But I have great respect for Dr. Messerli – and value his opinion.

  4. Francis Kempf, MD says:

    Difficult to evaluate the data – common sense suggests that this finding could be true. One of the “endpoints” for a cardiac event is an emergency room visit. How many ER visits vs. documented ischemic events occurred? To me, an ER visit is a not a valid marker for a cardiac event.

  5. Saurav Chatterjee, MD says:

    But Dr Messerli, wouldnt the fact that for trying to find matched pairs (153 only)led to almost 90% of the dataset having been excluded?And also would it not indicate that the used dataset was probably not an optimal one to study the research question?

  6. Karen Politis, MD says:

    Perhaps people with established cardiovascular disease or other factors that increase their cardiovascular risk would be less likely to decide to have major elective orthopaedic surgery. Although a total joint replacement seems routine, it is not an easy decision for the patient and his/her relatives. It requires an optimistic outlook on life, hope for improved activity, and a functioning social safety network.