Stroke risk may be higher up to 12 weeks after hip replacement, study finds

Risk for stroke is elevated up to 12 weeks after total hip replacement, according to a new study.

Researchers in Denmark performed a nationwide cohort study to determine the timing of stroke after total hip replacement surgery. Patients who had had a primary total hip replacement were matched by age, sex and region with three controls who had not had total hip or knee replacement surgery. The effects of comorbid conditions and medications on the timing of stroke were also assessed. The study results were published early online Nov. 6 by Stroke.

A total of 66,583 patients and 199,995 controls were included in the study. Mean age in both groups was 71.9 years, and most of the study population (63.1%) was female. Previous use of cardiovascular drugs was slightly more likely and prevalence of previous cerebrovascular disease was modestly higher in total hip replacement patients than controls, while use of pain relievers was substantially higher. Compared with matched controls, patients who had total hip replacement had a 4.7-fold increased risk for ischemic stroke and a 4.4-fold increased risk of hemorrhagic stroke in the first two weeks after surgery. This elevated risk persisted for a total of six weeks and 12 weeks, respectively. Risk for ischemic stroke was 70% lower in patients who took antiplatelet agents after hospital discharge. Statistical power was too low to detect significant effect modification for hemorrhagic stroke.

The authors noted that they did not have data available on body mass index, which may affect stroke risk, or on use of antithrombotic agents during hospitalization, among other limitations. However, they concluded that risk for ischemic and hemorrhagic stroke appeared to be elevated for at least six and at least 12 weeks, respectively, after total hip replacement and that risk assessment for stroke in individual patients undergoing this procedure should be considered during this time period. Although use of antiplatelet therapy appeared to substantially lower postoperative risk for ischemic stroke, the authors wrote that “this seemingly protective effect should be interpreted with caution, given the observational design and the lack of information on inpatient antithrombotic use.”