Osteoarthritis Heightens Risk of Cardiovascular Disease

Patients with osteoarthritis of the hip or knee — about 10 percent to 12 percent of the world’s population — are at heightened risk for cardiovascular disease, a prospective longitudinal study suggests.

After adjustment for risk factors, men older than 65 with osteoarthritis had a 15 percent increased risk of hospitalization for cardiovascular disease (RR 1.15, 95 percent CI 1.04-1.27), according to M. Mushfiqur Rahman, and his colleagues at the University of British Columbia in Vancouver, Canada, (Rahman is a Ph.D. candidate there).

In addition, women older than 65 had a 17 percent increase (RR 1.17, 95 percent CI 1.07-1.26) and those younger than 65 had a 26 percent increase (RR 1.26, 95 percent CI 1.13-1.42), the researchers reported in Arthritis Care & Research.

Researchers have long established that patients with rheumatic and autoimmune diseases associated with chronic inflammation such as rheumatoid arthritis, systemic sclerosis, and systemic lupus erythematosus have a high risk for cardiovascular disease and related mortality. But little is known about the influence osteoarthritis has on cardiovascular illness despite its prevalence among the planet’s inhabitants (rheumatoid arthritis affects only about 1 percent of the population).

And while osteoarthritis typically has been considered a disease of “wear and tear,” it now is recognized that inflammation plays a part, at least in early stages of the disease.

Other reasons osteoarthritis might affect cardiovascular disease include immobility (due to chronic pain) and the use of nonsteroidal anti-inflammatory drugs.

To explore a possible link, Rahman and colleagues selected a sample population from individuals enrolled in an administrative database in British Columbia between April 1991 and March 2009.

Among the 12,745 patients with osteoarthritis and 36,886 matched controls that comprised the sample, mean age was 58 and 60 percent were women.

During a mean 13 years of follow-up, there were 7,995 hospitalizations for cardiovascular disease.

A total of 2,023 were for myocardial infarction (MI), 2,335 were non-MI ischemic heart disease, 1,917 were for stroke, and 1,720 were congestive heart failure.

In the multivariate analyses, the researchers adjusted for age, sex, socioeconomic status, body mass index, and coexisting conditions that could influence cardiovascular risk such as hypertension, chronic obstructive pulmonary disease, and diabetes.

When the researchers analyzed the data according to specific diagnoses, they found relative risks for ischemic heart disease of 1.33 (95 percent CI 1.11-1.62) for older men, 1.45 (95 percent CI 1.22-1.72) for older women, and 1.45 (95 percent CI 1.22-1.72) for younger women.

For congestive heart failure, the corresponding relative risks were 1.25 (95 percent CI 1.02-1.54) for older men, 1.20 (95 percent CI 1.03-1.39) for older women, and 1.29 (95 percent CI 1-1.68) for younger women, respectively.

No increased risk was seen in these multivariate analyses for MI or stroke or for men younger than 65.

The researchers then considered whether the severity of osteoarthritis was a factor by examining risks for patients who had required total joint replacement.

They found that men who had undergone joint replacement only had significantly higher risk for congestive heart failure (RR 1.80, 95 percent CI 1.26-2.58). However, women with joint replacement had relative risks of 1.31 (95 percent CI 1.12-1.54) for cardiovascular disease, 1.73 (95 percent CI 1.28-2.35) for ischemic heart disease, and 1.36 (95 percent CI 1.02-1.81) for congestive heart failure.

Strengths of the study included its representative sample, long follow-up, and adjustment for multiple relevant risk factors.

Limitations were the lack of information in the database on diet and smoking and the possibility of misdiagnoses.

Despite these limitations, “this large, longitudinal study has allowed us to identify statistically significant and biologically plausible relationships that provide a rationale for further biologic, physiologic, and epidemiologic studies of cardiovascular outcomes in persons with [osteoarthritis],” Rahman and his colleagues concluded.