Overview
After hip or knee replacement surgery, preventing blood clots is a major part of recovery. Patients are usually given an anticoagulant, or “blood thinner,” to reduce the risk of deep vein thrombosis and pulmonary embolism, two potentially serious complications after orthopedic surgery. However, not all blood thinners are the same, and patients may value the benefits and side effects of each option differently.
This study explored how patients who had recently undergone hip or knee replacement think about anticoagulation choices. The researchers wanted to know whether patients could be grouped into distinct preference patterns, sometimes called preference phenotypes, based on what matters most to them. These findings may help clinicians personalize postoperative prevention strategies in the future.
Why anticoagulation matters after joint replacement
Hip and knee replacement are common and highly effective operations that improve pain, mobility, and quality of life. Even so, surgery temporarily increases the risk of clot formation because of tissue injury, reduced mobility, and changes in blood flow. The most important clot-related complications include:
Bleeding: a side effect of anticoagulant therapy, which can range from minor bruising to more serious bleeding events.
Deep vein thrombosis: a clot that forms in a deep vein, usually in the leg.
Pulmonary embolism: a clot that travels to the lungs and can be life-threatening.
To lower these risks, surgeons often prescribe aspirin, warfarin, or a direct oral anticoagulant such as rivaroxaban. Each option has advantages and drawbacks. Aspirin is familiar, inexpensive, and simple to use, but may offer less potent clot prevention in some settings. Warfarin has long been used and is low cost, but requires regular blood testing and dose adjustments. Rivaroxaban is easier to take than warfarin and may provide stronger anticoagulation, but it is usually more expensive and may increase bleeding risk.
Study purpose and design
The study was connected to the Pulmonary Embolism Prevention after Hip and Knee Replacement, or PEPPER, trial, which is a large pragmatic clinical trial comparing aspirin, warfarin, and rivaroxaban after joint replacement surgery. In this companion survey study, the researchers examined how patients trade off benefits, risks, and costs when thinking about these treatments.
They created a multimedia conjoint analysis survey. Conjoint analysis is a method used to measure how people value different features of a choice. Instead of asking patients a single direct question, the survey presents multiple treatment scenarios with different combinations of outcomes, such as the chance of bleeding, the chance of clotting, and out-of-pocket cost. By analyzing the choices patients make, researchers can estimate which factors matter most.
The survey was given to 192 patients at the Medical University of South Carolina. All participants had undergone hip or knee replacement and were eligible for the PEPPER trial. They were surveyed 1 to 7 months after surgery, a time when many would still remember the details of their treatment and recovery.
What the researchers found
When the responses were analyzed across the whole group, patients generally considered the major adverse outcomes to be similarly important. On average, they cared about avoiding bleeding, venous thrombosis, and pulmonary embolism, with a somewhat stronger emphasis on preventing pulmonary embolism. This makes clinical sense because pulmonary embolism is often viewed as the most dangerous clot-related complication.
But the most striking finding was that the average did not represent most patients very well. Few individuals had preference patterns close to the population mean. Instead, the patients clustered into three distinct groups with minimal overlap:
1. Thrombosis-focused values
These patients placed the greatest weight on preventing clots, especially pulmonary embolism, even if that meant accepting higher bleeding risk or higher cost. Their preference pattern was most consistent with rivaroxaban, a stronger anticoagulant option.
2. Balanced values
These patients tried to balance bleeding risk and clot prevention. They did not strongly favor one outcome over the others and appeared comfortable with a middle-ground approach. Their pattern aligned most closely with aspirin-based treatment.
3. Out-of-pocket-cost-focused values
These patients were especially sensitive to what they would personally have to pay. For them, lower cost was a major deciding factor, and their preference pattern aligned with aspirin or warfarin, which are generally less expensive than rivaroxaban.
These three groups can be thought of as preference phenotypes: distinct ways that patients prioritize outcomes when choosing a preventive blood thinner after surgery.
Why these preference phenotypes matter
The study highlights an important point in postoperative care: one-size-fits-all prescribing may not match patient priorities. Two patients with the same operation and similar medical risk may choose differently if one is most worried about clots, another is most concerned about bleeding, and a third is mainly concerned about cost.
This has practical implications for shared decision-making. In shared decision-making, clinicians explain the options in plain language, discuss the expected benefits and risks, and incorporate the patient’s values into the final plan. A patient who strongly prioritizes avoiding pulmonary embolism may feel more comfortable with a more potent anticoagulant. Another patient who wants to minimize side effects or reduce expenses may prefer aspirin or warfarin.
The study also suggests that clinicians should not assume all postoperative patients weigh risks in the same way. Asking a few targeted questions about what matters most to the patient may help guide the choice of anticoagulant, improve satisfaction, and potentially improve adherence to treatment.
Strengths of the study
This work has several strengths. It focused on a real-world postoperative population rather than a hypothetical one, making the findings relevant to actual clinical care. The use of conjoint analysis allowed the researchers to estimate tradeoffs in a structured way instead of relying on simple yes-or-no answers. In addition, clustering analysis helped reveal meaningful subgroups that might otherwise have been hidden by averaging all patients together.
Because the study was aligned with the PEPPER trial, the treatment options and outcome probabilities were grounded in an important ongoing clinical question in orthopedic care.
Limitations to keep in mind
As with any survey study, there are important limitations. The patients came from a single medical center, so the results may not apply equally to all populations or health systems. The sample size was modest, and the survey was performed after surgery rather than before treatment decisions were made, which may influence how people think about risks.
Also, preference studies describe what patients value, not necessarily what is medically best in every case. The right anticoagulant still depends on individual factors such as prior clot history, bleeding risk, kidney function, mobility, cost coverage, and surgeon preference. A patient’s stated preference should inform but not replace medical judgment.
Clinical takeaway
This study shows that patients recovering from hip or knee replacement are not a single group with identical priorities. Instead, their views on anticoagulation fall into at least three meaningful preference patterns: clot prevention-focused, balanced, and cost-focused. Recognizing these patterns can help clinicians tailor discussions and choose postoperative anticoagulation more collaboratively.
For patients, the message is encouraging: there may be more than one reasonable option after joint replacement, and your own values matter. For clinicians, the message is equally important: taking a few minutes to ask what the patient fears most may lead to better, more personalized care.
Bottom line
After hip or knee replacement, blood clot prevention is essential, but patients differ in how they weigh the risks of bleeding, clotting, and cost. In this survey study, three clear preference phenotypes emerged. These findings support a more individualized approach to anticoagulation and reinforce the value of shared decision-making in orthopedic recovery.
