Risk-stratified thromboprophylaxis effects of aspirin versus low-molecular-weight heparin in orthopaedic trauma patients: a secondary analysis of the PREVENT CLOT trial.

BACKGROUND: The PREVENT CLOT trial concluded that thromboprophylaxis with aspirin was noninferior to low-molecular-weight heparin (LMWH) in preventing death after orthopaedic trauma. However, it was unclear if these results applied to patients at highest risk of thrombosis. Therefore, we assessed if the effect of aspirin versus LMWH differed based on patients' baseline risk of venous thromboembolism (VTE). METHODS: The PREVENT CLOT trial enrolled 12,211 adult patients with fractures. This secondary analysis stratified the study population into VTE risk quartiles: low (<1%) to high (>10%) using the Caprini Score. We assessed stratum-specific treatment effects using the win ratio method, in which each patient assigned to aspirin was paired with each assigned to LMWH. In each pair, we compared outcomes hierarchically, starting with death, then pulmonary embolism, deep vein thrombosis, and bleeding. The secondary outcome added patients' medication satisfaction as a fifth composite component. RESULTS: In the high risk quartile (n = 3052), 80% had femur fracture, pelvic, or acetabular fractures. Thoracic (47%) and head (37%) injuries were also common. In the low risk quartile (n = 3053), most patients had a tibia fracture (67%), 5% had a thoracic injury, and less than 1% had head or spinal injuries. Among high risk patients, thromboembolic events did not differ statistically between aspirin and LMWH (win ratio, 0.94; 95% CI, 0.82-1.08, p = 0.42). This result was consistent in the low (win ratio, 1.15; 95% CI, 0.90-1.47, p = 0.27), low-medium (win ratio, 1.05; 95% CI, 0.85-1.29, p = 0.68), and medium-high risk quartiles (win ratio, 0.94; 95% CI, 0.80-1.11, p = 0.48). When medication satisfaction was considered, favorable outcomes were 68% more likely with aspirin (win ratio, 1.68; 95% CI, 1.60-1.77; p < 0.001). CONCLUSION: Thromboembolic outcomes were similar with aspirin or LMWH, even among patients at highest risk of VTE. Aspirin was favored if medication satisfaction was also considered. LEVEL OF EVIDENCE: Level I, (therapeutic/care management).

Pragmatic design and inclusion of patient-partner representatives improves participant experience in clinical research.

Objectives: Patient engagement in the design and implementation of clinical trials is necessary to ensure that the research is relevant and responsive to patients. The PREP-IT trials, which include 2 pragmatic trials that evaluate different surgical preparation solutions in orthopaedic trauma patients, followed the patient-centered outcomes research (PCOR) methodology throughout the design, implementation, and conduct. We conducted a substudy within the PREP-IT trials to explore participants' experiences with trial participation. Methods: At the final follow-up visit (12 months after their fracture), patients participating in the PREP-IT trials were invited to participate in the substudy. After providing informed consent, participants completed a questionnaire that asked about their experience and satisfaction with participating in the PREP-IT trials. Descriptive statistics are used to report the findings. Results: Four hundred two participants participated in the substudy. Most participants (394 [98%]) reported a positive experience, and 376 (94%) participants felt their contributions were appreciated. The primary reasons for participation were helping future patients with fracture (279 [69%]) and to contribute to science (223 [56%]). Two hundred seventeen (46%) participants indicated that their decision to participate was influenced by the minimal time commitment. Conclusions: Most participants reported a positive experience with participating in the PREP-IT trials. Altruism was the largest motivator for participating in this research. Approximately half of the participants indicated that the pragmatic, low-participant burden design of the trial influenced their decision to participate. Meaningful patient engagement, a pragmatic, and low-burden protocol led to high levels of participant satisfaction.

Aspirin or Low-Molecular-Weight Heparin for Thromboprophylaxis after a Fracture.

BACKGROUND: Clinical guidelines recommend low-molecular-weight heparin for thromboprophylaxis in patients with fractures, but trials of its effectiveness as compared with aspirin are lacking. METHODS: In this pragmatic, multicenter, randomized, noninferiority trial, we enrolled patients 18 years of age or older who had a fracture of an extremity (anywhere from hip to midfoot or shoulder to wrist) that had been treated operatively or who had any pelvic or acetabular fracture. Patients were randomly assigned to receive low-molecular-weight heparin (enoxaparin) at a dose of 30 mg twice daily or aspirin at a dose of 81 mg twice daily while they were in the hospital. After hospital discharge, the patients continued to receive thromboprophylaxis according to the clinical protocols of each hospital. The primary outcome was death from any cause at 90 days. Secondary outcomes were nonfatal pulmonary embolism, deep-vein thrombosis, and bleeding complications. RESULTS: A total of 12,211 patients were randomly assigned to receive aspirin (6101 patients) or low-molecular-weight heparin (6110 patients). Patients had a mean (±SD) age of 44.6±17.8 years, 0.7% had a history of venous thromboembolism, and 2.5% had a history of cancer. Patients received a mean of 8.8±10.6 in-hospital thromboprophylaxis doses and were prescribed a median 21-day supply of thromboprophylaxis at discharge. Death occurred in 47 patients (0.78%) in the aspirin group and in 45 patients (0.73%) in the low-molecular-weight-heparin group (difference, 0.05 percentage points; 96.2% confidence interval, -0.27 to 0.38; P<0.001 for a noninferiority margin of 0.75 percentage points). Deep-vein thrombosis occurred in 2.51% of patients in the aspirin group and 1.71% in the low-molecular-weight-heparin group (difference, 0.80 percentage points; 95% CI, 0.28 to 1.31). The incidence of pulmonary embolism (1.49% in each group), bleeding complications, and other serious adverse events were similar in the two groups. CONCLUSIONS: In patients with extremity fractures that had been treated operatively or with any pelvic or acetabular fracture, thromboprophylaxis with aspirin was noninferior to low-molecular-weight heparin in preventing death and was associated with low incidences of deep-vein thrombosis and pulmonary embolism and low 90-day mortality. (Funded by the Patient-Centered Outcomes Research Institute; PREVENT CLOT ClinicalTrials.gov number, NCT02984384.).

PREVENTion of CLots in Orthopaedic Trauma (PREVENT CLOT): a randomised pragmatic trial protocol comparing aspirin versus low-molecular-weight heparin for blood clot prevention in orthopaedic trauma patients.

INTRODUCTION: Patients who sustain orthopaedic trauma are at an increased risk of venous thromboembolism (VTE), including fatal pulmonary embolism (PE). Current guidelines recommend low-molecular-weight heparin (LMWH) for VTE prophylaxis in orthopaedic trauma patients. However, emerging literature in total joint arthroplasty patients suggests the potential clinical benefits of VTE prophylaxis with aspirin. The primary aim of this trial is to compare aspirin with LMWH as a thromboprophylaxis in fracture patients. METHODS AND ANALYSIS: PREVENT CLOT is a multicentre, randomised, pragmatic trial that aims to enrol 12 200 adult patients admitted to 1 of 21 participating centres with an operative extremity fracture, or any pelvis or acetabular fracture. The primary outcome is all-cause mortality. We will evaluate non-inferiority by testing whether the intention-to-treat difference in the probability of dying within 90 days of randomisation between aspirin and LMWH is less than our non-inferiority margin of 0.75%. Secondary efficacy outcomes include cause-specific mortality, non-fatal PE and deep vein thrombosis. Safety outcomes include bleeding complications, wound complications and deep surgical site infections. ETHICS AND DISSEMINATION: The PREVENT CLOT trial has been approved by the ethics board at the coordinating centre (Johns Hopkins Bloomberg School of Public Health) and all participating sites. Recruitment began in April 2017 and will continue through 2021. As both study medications are currently in clinical use for VTE prophylaxis for orthopaedic trauma patients, the findings of this trial can be easily adopted into clinical practice. The results of this large, patient-centred pragmatic trial will help guide treatment choices to prevent VTE in fracture patients. TRIAL REGISTRATION NUMBER: NCT02984384.

Effectiveness of Iodophor vs Chlorhexidine Solutions for Surgical Site Infections and Unplanned Reoperations for Patients Who Underwent Fracture Repair: The PREP-IT Master Protocol.

Importance: The risk of developing a surgical site infection after extremity fracture repair is nearly 5 times greater than in most elective orthopedic surgical procedures. For all surgical procedures, it is standard practice to prepare the operative site with an antiseptic solution; however, there is limited evidence to guide the choice of solution used for orthopedic fracture repair. Objective: To compare the effectiveness of iodophor vs chlorhexidine solutions to reduce surgical site infections and unplanned fracture-related reoperations for patients who underwent fracture repair. Design, Setting, and Participants: The PREP-IT (Program of Randomized Trials to Evaluate Pre-operative Antiseptic Skin Solutions in Orthopaedic Trauma) master protocol will be followed to conduct 2 multicenter pragmatic cluster randomized crossover trials, Aqueous-PREP (Pragmatic Randomized Trial Evaluating Pre-Operative Aqueous Antiseptic Skin Solution in Open Fractures) and PREPARE (Pragmatic Randomized Trial Evaluating Pre-Operative Alcohol Skin Solutions in Fractured Extremities). The Aqueous-PREP trial will compare 4% aqueous chlorhexidine vs 10% povidone-iodine for patients with open extremity fractures. The PREPARE trial will compare 2% chlorhexidine in 70% isopropyl alcohol vs 0.7% iodine povacrylex in 74% isopropyl alcohol for patients with open extremity fractures and patients with closed lower extremity or pelvic fractures. Both trials will share key aspects of study design and trial infrastructure. The studies will follow a pragmatic cluster randomized crossover design with alternating treatment periods of approximately 2 months. The primary outcome will be surgical site infection and the secondary outcome will be unplanned fracture-related reoperations within 12 months. The Aqueous-PREP trial will enroll a minimum of 1540 patients with open extremity fractures from at least 12 hospitals; PREPARE will enroll a minimum of 1540 patients with open extremity fractures and 6280 patients with closed lower extremity and pelvic fractures from at least 18 hospitals. The primary analyses will adhere to the intention-to-treat principle and account for potential between-cluster and between-period variability. The patient-centered design, implementation, and dissemination of results are guided by a multidisciplinary team that includes 3 patients and other relevant stakeholders. Discussion: The PREP-IT master protocol increases efficiency through shared trial infrastructure and study design components. Because prophylactic skin antisepsis is used prior to all surgical procedures and the application, cost, and availability of all study solutions are similar, the results of the PREP-IT trials are poised to inform clinical guidelines and bring about an immediate change in clinical practice. Trial Registration: ClinicalTrials.gov Identifiers: NCT03385304 and NCT03523962.

Which orthopaedic trauma patients are likely to refuse to participate in a clinical trial? A latent class analysis.

OBJECTIVE: The study aimed to assess systematic differences in the characteristics of patients that consented for the trial compared with the broader pool of eligible patients in a large, pragmatic orthopaedic trauma trial. DESIGN: A retrospective observational study performed from April 2017 to March 2018. SETTING: Academic trauma centre in Baltimore, USA. PARTICIPANTS: There were 642 eligible adult trial participants with an operative fracture to the appendicular skeleton and were indicated for blood clot prophylaxis. The median age of the sample was 50 years (IQR: 31-63), and 60% were male. PRIMARY OUTCOME MEASURE: The primary outcome was the refusal to enrol in the trial. Demographic and injury covariates were included in iterations of latent class models. The final model was selected based on a minimum Bayesian information criterion. RESULTS: The final model identified three clusters with five covariates predictive of cluster membership (age, neighbourhood-based socioeconomic status, alcohol use, multiple fractures, multiple surgeries). The three clusters were associated with 22% (Cluster 1), 38% (Cluster 2) and 62% (Cluster 3) refusal rates, respectively. Members of Cluster 3 (n=84) were most commonly between 66 and 80 years of age (49% vs 6% (Cluster 1) and 21% (Cluster 2)), of high neighbourhood-based socioeconomic status (85% vs 63% (Cluster 1) and 8% (Cluster 2)), with isolated fractures (100% vs 80% (Cluster 1) and 92% (Cluster 2)), and were less likely to have multiple surgeries compared with the other clusters (28% vs 47% (Cluster 1) and 35% (Cluster 2)). CONCLUSION: In this study, the likelihood of refusing to participate in the trial ranged from 22% to 62% in the three identified clusters. Elderly age, high socioeconomic status, and less severe injuries defined the cluster that was most likely to refuse trial participation. TRIAL REGISTRATION NUMBER: NCT02984384.