Among patients undergoing joint surgery, those with rheumatoid arthritis (RA) have almost double the risk of death at 6 weeks compared with those without RA, as well as an increased risk of death and myocardial infarction (MI) at 1 year, an Australian study found.

The risks are elevated not just for surgeries like hip joint replacement, but also for relatively minor procedures such as shoulder surgery.

"Understanding the risks of postoperative MI and mortality can help patients with RA make informed decisions about undergoing joint surgery procedures," wrote Sharon Van Doornum, MD, and colleagues from the Royal Melbourne Hospital and University of Melbourne, Australia.The study was published in Arthritis Research & Therapy.

In an earlier study, the researchers found that RA patients had an increased risk for mortality post MI, and were more likely than other patients to have had a preceding medical illness or surgical event. This led them to surmise that RA patients may have an increased burden of silent cardiovascular (CV) disease that is uncovered by physiological stress.

For this new study, researchers used the Victorian Admitted Episodes Dataset, which contains demographic and clinical information on hospital admissions in the Australian state of Victoria. They analyzed joint surgeries performed between July 1, 2000 and June 30, 2007, and used a 2-year retrospective period to detect RA cases.

The investigators looked at MI and all-cause death as well as CV death at 6 weeks and 1 year. CV deaths included MI, angina pectoris, ischemic heart disease, congestive heart failure, cardiomyopathy, arrhythmia, pulmonary edema, stroke, thromboembolism, and cardiac arrest.

During the study period, a total of 240,571 patients underwent 308,589 joint surgeries. Of these, 3,654 (1.2%) were performed on 2,219 patients (0.92%) with RA.



Among the RA patients, hip and knee joint arthroplasty were the most common surgeries (55.5%).Unadjusted models showed that RA patients had greater odds of experiencing MI or death at both time points compared with non-RA patients. After adjusting for age, sex, comorbidities, and other potential confounders (including socioeconomic status and types of admission, patients, and joint surgeries), the odds ratio for MI at 6 weeks in RA patients remained elevated but was no longer statistically significant.

However, adjusted odds ratios for all other outcomes remained significantly higher in the RA group, at 1.85 (95% CI 1.09-3.13) at 6 weeks and 2.18 (95% CI 1.66-2.86) at 12 months for all-cause death. In addition, the odds ratios for CV death were 1.90 (95% CI 1.07-3.37) at 6 weeks and 2.30 (95% CI 1.65-3.22) at 12 months, and the odds ratio for MI at 12 months was 1.70 (95% CI 1.27-2.28).

The researchers also looked at patients undergoing total knee joint replacement or total hip joint replacement, and found that the adjusted odds ratios for CV death at 6 weeks and 12 months, and all-cause mortality at 12 months, were significantly higher for those with RA in the hip replacement group. There was no between-group difference in the adjusted odds ratio for MI and death at either time point following knee replacement surgery.

The risk for MI at 6 weeks among RA patients was elevated even for knee arthroscopy and shoulder surgery. Such procedures, said the authors, might represent a less significant hemodynamic insult.

A limitation of the study was that the researchers didn't have information on RA severity, activity, treatment, or use of cardiovascular medicines.

Asked to comment, Ziv Paz, MD, of the Division of Rheumatology & Lupus Center, Beth Israel Deaconess Medical Center in Boston, noted that the cause of cardiovascular death was not well defined. For example, he said, ischemic heart disease, congestive heart failure, or angina pectoris could have been a chronic diagnosis that had no direct relation to the death. He called information the study used, which was from 2000 to 2007, "old data," pointing out that "several recent studies actually suggest an overall decrease in cardiovascular mortality in the RA population."

Also, the regression analysis model used in the study did not account for such potential confounders as rates of post-surgery complications, including septic arthritis or the need of redo surgeries.

"Patients with very active disease are at independent increased risk for cardiovascular disease. In addition, the treatment for RA can impair healing and suppress the patient's immune system, which by itself will make them more prone to an undesired outcome."

In any case, it is recommended that doctors screen all patients for modifiable cardiovascular risk factors before major surgery, regardless of their RA status.

"It's also recommended that clinicians consult the surgical team about the management of steroids and immune-suppression around the surgery," Paz said. "And ideally, the patients should be in clinical remission prior to surgery."

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