In addition, women older than 65 had a 17% increase (RR 1.17, 95% CI 1.07-1.26) and those younger than 65 had a 26% increase (RR 1.26, 95% CI 1.13-1.42), the researchers reported in the December Arthritis Care & Research.
It's been widely acknowledged 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.
However, despite the fact that osteoarthritis is far more common (rheumatoid arthritis affects only about 1% of the population) little is known about its relation to cardiovascular disease.
And while osteoarthritis typically has been considered a disease of "wear and tear," it's now recognized that inflammation plays a part, at least in early disease.
Other reasons why patients with osteoarthritis might be at risk for cardiovascular disease include immobility because of their 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% 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 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% CI 1.11-1.62) for older men, 1.45 (95% CI 1.22-1.72) for older women, and 1.45 (95% CI 1.22-1.72) for younger women.
For congestive heart failure, the corresponding relative risks were 1.25 (95% CI 1.02-1.54) for older men, 1.20 (95% CI 1.03-1.39) for older women, and 1.29 (95% 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% CI 1.26-2.58). However, women with joint replacement had relative risks of 1.31 (95% CI 1.12-1.54) for cardiovascular disease, 1.73 (95% CI 1.28-2.35) for ischemic heart disease, and 1.36 (95% 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 colleagues concluded.