Physical inactivity and non-steroidal anti-inflammatory drug (NSAID) use are established risks for serious cardiovascular events.  Osteoarthritis can contribute to these risk factors by reducing patient mobility and NSAID use for symptom relief.  Using data from a registry of patients with moderate-severe osteoarthritis, Ravi and colleagues evaluated the relationship between total joint arthroplasty of the hip and knee and subsequent risk for serious cardiovascular events.

Using a propensity score matched landmark analysis design with a median follow-up of seven years, the authors compared outcomes among patients that underwent total joint arthroplasty with those who did not.  The primary outcome of serious cardiovascular event included acute myocardial infarction, stroke or transient ischemic attack, congestive heart failure, coronary revascularization, or in-hospital cardiac death.  The authors found patients that underwent total joint arthroplasty were at a significantly reduced risk for serious cardiovascular events (hazard ratio 0.56; 95% CI 0.43 to 0.74; P < 0.001).  This corresponded to an absolute risk reduction of 12.4% (95% CI 1.7% to 23.1%) and a number needed to treat of 8 (95% CI 4 to 57).  Given the observational nature of the study, the investigators evaluated the potential impact of unmeasured confounders on the findings.  This analysis demonstrated the primary results are robust as an unmeasured confounder would need a very high prevalence (75%) and strong association with the outcome (relative risk of 66%) to negate the observed findings.

Conclusions: This study strongly suggests that joint replacement has a significant effect on future cardiovascular events in patients with osteoarthritis.  However, it is unclear if this benefit is predominantly related to improved physical activity, reduced use of NSAIDs after surgery, or other factors.  Understanding the predominant mediator of these findings would further guide the optimal approach to all patients with osteoarthritis to reduce cardiovascular risk.

• Ravi B, Croxford R, Austin PC, et al. The relation between total joint arthroplasty and risk for serious cardiovascular events in patients with moderate-severe osteoarthritis: propensity score matched landmark analysis. BMJ 2013;347.