Patient-reported barriers for adherence to prophylactic enoxaparin after orthopedic trauma surgery

Venous thromboembolism following orthopedic trauma surgery remains prevalent despite prophylaxis being a standard of care. Enoxaparin injection is a commonly utilized prophylaxis regimen among high-risk patients. Patient-reported rates of nonadherence and barriers to enoxaparin use are not described in the literature. A better understanding of these barriers and their impact on adherence to post-discharge prophylaxis regimens may shed light on persistent outcomes gaps.

Semi-structured interviews were administered to adult patients prescribed prophylactic enoxaparin and presenting to orthopedic surgery outpatient clinic at an urban level 1 trauma center for a post-operative appointment following traumatic injury from April to July 2023. Patients self-reported their age, gender, race, and mobility. Inductive thematic analysis with three-reviewer consensus identified common barriers among responses. Adherence rates were calculated by dividing patients' estimated number of missed doses over total prescribed doses at the point of inquiry.

We identified 154 eligible patients through chart review, and 50 enrolled and interviewed. Participants had a mean age of 37 years. Of 50 participants, 20 identified as female; 25 identified as Black or African American, 16 as White, 5 as Hispanic, 2 as Asian, and 2 as multiracial. Twenty-one participants were non-ambulatory at time of interview. Mean and median patient-reported adherence were 64.5 % (SD 35.5) and 70.5 % (IQR 33-100) respectively. Five patients reported complete nonadherence, while 17 patients reported perfect adherence. Every participant reporting complete nonadherence identified as Black or African American, as compared to 8 out of 17 reporting perfect adherence. Despite acknowledging a twice-daily prescription, 17 patients reported once-daily rather than twice-daily use. Inductive thematic analysis revealed the following six barriers to prophylaxis adherence (number of participants reporting): Inconvenience (18 patients), Pain (16), Fear (12), Acquisition (7), Bruising (7), and Mechanism (7). Altogether, 40 patients endorsed at least one barrier to adherence.

Most patients face barriers to adherence with post-discharge prophylactic enoxaparin, and the resultant rates of adherence are low. This may contribute to persistent outcomes gaps in the orthopedic trauma population despite prophylaxis standards. Changes in prescribing patterns and patient engagement techniques may improve post-operative thromboembolic outcomes.