To estimate the potential effect on cardiovascular event occurrence and treatment costs associated with increases in systolic blood pressure (SBP) among patients with osteoarthritis (OA) and rheumatoid arthritis (RA).
We used cardiovascular risk prediction models from the Framingham Heart Study and data on risk factors from the Third National Health and Nutrition Examination Survey (NHANES III) to estimate occurrences of ischemic heart disease and stroke over one year among US adults with OA/RA. Separate analyses were conducted for treated hypertensive patients, and untreated hypertensive and normotensive patients, respectively. Published estimates were used to assign costs to these events and to follow care. The effect of incremental increases in SBP on events and costs was then assessed. Monte Carlo simulation was undertaken to assess the range of event occurrence and costs associated with alternative assumptions regarding the distribution of increased SBP in the at-risk population.
Of the estimated 30 million adults in the US aged > or = 35 years with OA and RA, roughly 11.8 million (39%) receive pharmacologic treatment for hypertension. Increases in SBP of 1-5 mm Hg were associated with 7,100-35,700 additional ischemic heart disease and stroke events over one year, with corresponding costs (year 2000 USD) of 114-569 million year 2000 USD. A 20 mm Hg increase in SBP experienced by 15% of the at-risk population (equivalent to a population-average 3 mm Hg increase) is associated with about 21,700 additional events (95% CI 19,120, 24,221) and 346 million year 2000 USD (95% CI 305 year 2000 USD, 387 million) in associated costs.
Relatively small changes in SBP associated with use of common arthritis medications can have a significant effect on the cardiovascular risk profile. It is important that clinicians who treat patients with OA/RA accurately weigh the potential risks of these medications against their benefits.