Conflict of interest in the assessment of thromboprophylaxis after total joint arthroplasty: a systematic review

Venous thromboembolism rates after hip and knee arthroplasty and hip fractures

BACKGROUND

The ideal thromboprophylaxis regime following lower limb arthroplasty and proximal femur fractures remains controversial. Guidelines disagree on the type of chemical prophylaxis, its dose or duration. This article describes a method of monitoring venous thromboembolism (VTE) rates following Total Hip (THA), Total Knee Arthroplasty (TKA) and surgery for hip fractures (NOF#).

METHODS

Over 3 years, all patients investigated for VTE were analysed using Picture Archiving Communications System (PACS). All positive scans were then cross-referenced using PACS and local registry data to see if they had undergone THA, TKA or NOF# in the preceding 90 days. Mortality data were obtained from the national administrative database, Hospital Episode Statistics.

RESULTS

Five thousand seven hundred eighty-eight patients underwent investigation for VTE and there were 29 diagnoses of PE and 24 of DVT. There was a 0.77% rate of symptomatic DVT after THA, 0.05% after TKA and 0.55% after NOF #. The rate of confirmed symptomatic PE for THA was 0.46, 0.27% for TKA and 0.96% for NOF #. Mortality at one-year post-THA was 0.6, 0.6% for TKA and 25.9% after NOF#. All patients contacted either remained within the catchment area for the minimum 90 postoperative days or died within the catchment area.

CONCLUSIONS

The 90 day post-operative prevalence of symptomatic VTE of 1.2, 0.3 and 1.5% in THA, TKA and NOF # respectively are similar to other studies using symptomatic and imaging positive VTE as their endpoint. The study uses a method of collecting data which can be utilised in centres where PACS is available.

Evidencia sobre conflictos de intereses en medicina

Introducción. La principal responsabilidad de los médicos es la de actuar en beneficio de los pacientes; sin embargo, existen situaciones en las cuales surgen intereses secundarios que pueden afectar este compromiso y generar conflictos de intereses.Objetivo. Analizar las revisiones sistemáticas y los metaanálisis actualmente disponibles en la literatura sobre el conflicto de intereses en medicina para sintetizar la información al respecto.Materiales y métodos. Se realizó una búsqueda en las bases de datos MEDLINE y LILACS mediante la siguiente estrategia de búsqueda: revisiones sistemáticas y metaanálisis sobre conflictos de intereses en medicina publicados en revistas científicas seriadas; no se aplicaron restricciones de idioma o año de publicación. Los estudios que cumplieron con los criterios de inclusión fueron agrupados según la actividad médica evaluada; además, de cada uno de ellos se extrajo la cantidad y el tipo de estudios y las conclusiones.Resultados. Se seleccionaron 29 publicaciones que se agruparon en estudios basados en artículos de investigación, en guías de práctica clínica, en la práctica clínica, y en publicaciones orientadas a los pacientes.Conclusiones. Los estudios originales incluidos en las revisiones sistemáticas y los metaanálisis analizados en el presente estudio no siempre reportan los conflictos de intereses; sin embargo, cuando estos se mencionan, hay una tendencia a presentar resultados que favorecen el medicamento o la tecnología del patrocinador.

Association of Aspirin With Prevention of Venous Thromboembolism in Patients After Total Knee Arthroplasty Compared With Other Anticoagulants: A Noninferiority Analysis

Importance

There has been significant debate in the surgical and medical communities regarding the appropriateness of using aspirin alone for venous thromboembolism (VTE) prophylaxis following total knee arthroplasty (TKA).

Objective

To determine the acceptability of aspirin alone vs anticoagulant prophylaxis for reducing the risk of postoperative VTE in patients undergoing TKA.

Design, Setting, and Participants

Noninferiority study of a retrospective cohort of TKA cases submitted to the Michigan Arthroplasty Registry Collaborative Quality Initiative at 29 member hospitals, ranging from small community hospitals to large academic and nonacademic medical centers in Michigan. The study included 41 537 patients who underwent primary TKA between April 1, 2013, and October 31, 2015. Clinical events were monitored for 90 days after surgery. Data were analyzed between September and October 2016.

Exposures

The method of pharmacologic prophylaxis: neither aspirin nor anticoagulants for 668 patients (1.6%), aspirin only for 12 831 patients (30.9%), anticoagulant only (eg, low-molecular-weight heparin, warfarin, and Xa inhibitors) for 22 620 patients (54.5%), and both aspirin/anticoagulant for 5418 patients (13.0%). Most patients were also using intermittent pneumatic compression stockings.

Main Outcome and Measures

The primary composite outcome was the first occurrence of VTE or death. The noninferiority margin was specified as 0.3. The secondary outcome was bleeding events.

Results

Of the 41 537 patients, 14 966 were men (36%), and the mean age was 65.8 years. A VTE event occurred in 573 of 41 537 patients (1.38%); 32 of 668 (4.79%) who received no pharmacologic prophylaxis, 149 of 12 831 (1.16%) treated with aspirin alone, 321 of 22 620 (1.42%) with anticoagulation alone, and 71 of 5418 (1.31%) prescribed both aspirin and anticoagulation. Aspirin only was noninferior for the composite VTE outcome compared with those receiving other chemoprophylaxis (adjusted odds ratio, 0.85; 95% CI, 0.68-1.07, P for inferiority = .007). Bleeding occurred in 457 of 41 537 patients (1.10%), 10 of 668 (1.50%) without prophylaxis, 116 of 12 831 (0.90%) in the aspirin group, 258 of 22 620 (1.14%) with anticoagulation, and 73 of 5418 (1.35%) of those receiving both. Aspirin alone was also noninferior for bleeding complications (adjusted odds ratio, 0.80; 95% CI, 0.63-1.00, P for inferiority <.001).

Conclusions and Relevance

In this study of patients undergoing TKA, aspirin was not inferior to other anticoagulants in the postoperative rate of VTE or death. Aspirin alone may provide similar protection from postoperative VTE compared with other anticoagulation treatments.

Differences in Reported Outcomes in Industry-Funded vs Nonfunded Studies Assessing Thromboprophylaxis After Total Joint Arthroplasty

BACKGROUND

There are numerous studies discussing thromboprophylaxis after total joint arthroplasty (TJA), with varying conclusions. Patient inclusion criteria may be different for each study, which may lead to selection bias and misrepresentation of data. This study aimed to investigate if industry funding impacted patient demographics and overall reported outcomes of studies analyzing venous thromboembolism (VTE) prevention after TJA.

METHODS

Electronic searches were completed using Ovid, PubMed, and Embase databases. Studies were included if (1) they are published in the English language between 2000 and 2016; (2) they included patients undergoing total hip arthroplasty (THA) or total knee arthroplasty (TKA); and (3) they evaluated prevention and control of postoperative VTE with at least one of the following thromboprophylactic agents: aspirin, enoxaparin, dalteparin, dabigatran, apixaban, rivaroxaban, dabigatran, ximelagatran, fondaparinux, or coumadin. Data were extracted and analyzed via mixed-effect logistic regression.

RESULTS

Fifty-seven studies were included; 29 were industry funded, and 28, nonfunded. There were no significant differences between patient's age, body mass index, or revision exclusions between funded and nonfunded studies. Funded studies reported less pulmonary embolisms, fewer events of major bleeding, and significantly less 90-day mortality compared with nonfunded studies.

CONCLUSION

Industry-funded studies reported less pulmonary embolisms, major bleeding, and mortality compared with nonfunded studies. Detailed demographic data were missing from the literature, and we were unable to demonstrate the cause of different reported outcomes between industry-funded and nonfunded studies. Further investigations should be aimed toward understanding how funded studies report less adverse outcomes in analyzing VTE after TJA.

Wound Discharge After Pharmacological Thromboprophylaxis in Lower Limb Arthroplasty

BACKGROUND

The benefits vs risk of pharmacological prophylaxis for thromboembolic disease in orthopedic patients remain controversial. Pharmacological thromboprophylaxis regimes are commonly used in this patient group. Few studies specifically examine wound complications attributable to this therapy. In this prospective trial, we investigated the effect of various regimens on postoperative wounds.

METHODS

A prospective, observational, multicenter study involving patients undergoing elective hip or knee arthroplasty was undertaken. Patients were divided into 3 groups depending on thromboprophylaxis: no anticoagulation, aspirin, or low molecular weight heparin (LMWH) (enoxaparin). Surgical wounds were evaluated for each regime using the Southampton Wound Assessment Score.

RESULTS

Over a 12-month period, 327 patients were enrolled with a mean age of 68.1 years (±11.2 years). There were 105 patients in the no anticoagulation group (32.1%), 97 patients in the aspirin group (29.7%), and 125 patients in the LMWH group (38.2%). Wound scores were evaluated for evidence and amount of discharge. The use of LMWH conferred a 4.92 times greater risk and aspirin a 3.64 times greater risk of wound discharge than no pharmacological thromboprophylaxis (P < .0001). There were no significant differences in the incidence of deep vein thrombosis or pulmonary embolus between groups either as an inpatient or postdischarge.

CONCLUSION

There is a significant increase in the risk of wound discharge when aspirin or LMWH is used in arthroplasty patients. As potential complications of wound problems are significant, a more balanced view of risk vs benefit needs to be taken when prescribing thromboprophylaxis for this patient group.

Aspirin and the prevention of venous thromboembolism following total joint arthroplasty: commonly asked questions

The number of arthroplasties being performed increases each year. Patients undergoing an arthroplasty are at risk of venous thromboembolism (VTE) and appropriate prophylaxis has been recommended. However, the optimal protocol and the best agent to minimise VTE under these circumstances are not known. Although many agents may be used, there is a difference in their efficacy and the risk of bleeding. Thus, the selection of a particular agent relies on the balance between the desire to minimise VTE and the attempt to reduce the risk of bleeding, with its undesirable, and occasionally fatal, consequences.

Acetylsalicylic acid (aspirin) is an agent for VTE prophylaxis following arthroplasty. Many studies have shown its efficacy in minimising VTE under these circumstances. It is inexpensive and well-tolerated, and its use does not require routine blood tests. It is also a ‘milder’ agent and unlikely to result in haematoma formation, which may increase both the risk of infection and the need for further surgery. Aspirin is also unlikely to result in persistent wound drainage, which has been shown to be associated with the use of agents such as low-molecular-weight heparin (LMWH) and other more aggressive agents.

The main objective of this review was to summarise the current evidence relating to the efficacy of aspirin as a VTE prophylaxis following arthroplasty, and to address some of the common questions about its use.

There is convincing evidence that, taking all factors into account, aspirin is an effective, inexpensive, and safe form of VTE following arthroplasty in patients without a major risk factor for VTE, such as previous VTE.

Cite this article: Bone Joint J 2017;99-B:1420–30.

Industry sponsorship and research outcome

BACKGROUND

Clinical research affecting how doctors practice medicine is increasingly sponsored by companies that make drugs and medical devices. Previous systematic reviews have found that pharmaceutical-industry sponsored studies are more often favorable to the sponsor's product compared with studies with other sources of sponsorship. A similar association between sponsorship and outcomes have been found for device studies, but the body of evidence is not as strong as for sponsorship of drug studies. This review is an update of a previous Cochrane review and includes empirical studies on the association between sponsorship and research outcome.

OBJECTIVES

To investigate whether industry sponsored drug and device studies have more favorable outcomes and differ in risk of bias, compared with studies having other sources of sponsorship.

SEARCH METHODS

In this update we searched MEDLINE (2010 to February 2015), Embase (2010 to February 2015), the Cochrane Methodology Register (2015, Issue 2) and Web of Science (June 2015). In addition, we searched reference lists of included papers, previous systematic reviews and author files.

SELECTION CRITERIA

Cross-sectional studies, cohort studies, systematic reviews and meta-analyses that quantitatively compared primary research studies of drugs or medical devices sponsored by industry with studies with other sources of sponsorship. We had no language restrictions.

DATA COLLECTION AND ANALYSIS

Two assessors screened abstracts and identified and included relevant papers. Two assessors extracted data, and we contacted authors of included papers for additional unpublished data. Outcomes included favorable results, favorable conclusions, effect size, risk of bias and whether the conclusions agreed with the study results. Two assessors assessed risk of bias of included papers. We calculated pooled risk ratios (RR) for dichotomous data (with 95% confidence intervals (CIs)).

MAIN RESULTS

Twenty-seven new papers were included in this update and in total the review contains 75 included papers. Industry sponsored studies more often had favorable efficacy results, RR: 1.27 (95% CI: 1.17 to 1.37) (25 papers) (moderate quality evidence), similar harms results RR: 1.37 (95% CI: 0.64 to 2.93) (four papers) (very low quality evidence) and more often favorable conclusions RR: 1.34 (95% CI: 1.19 to 1.51) (29 papers) (low quality evidence) compared with non-industry sponsored studies. Nineteen papers reported on sponsorship and efficacy effect size, but could not be pooled due to differences in their reporting of data and the results were heterogeneous. We did not find a difference between drug and device studies in the association between sponsorship and conclusions (test for interaction, P = 0.98) (four papers). Comparing industry and non-industry sponsored studies, we did not find a difference in risk of bias from sequence generation, allocation concealment, follow-up and selective outcome reporting. However, industry sponsored studies more often had low risk of bias from blinding, RR: 1.25 (95% CI: 1.05 to 1.50) (13 papers), compared with non-industry sponsored studies. In industry sponsored studies, there was less agreement between the results and the conclusions than in non-industry sponsored studies, RR: 0.83 (95% CI: 0.70 to 0.98) (six papers).

AUTHORS' CONCLUSIONS

Sponsorship of drug and device studies by the manufacturing company leads to more favorable efficacy results and conclusions than sponsorship by other sources. Our analyses suggest the existence of an industry bias that cannot be explained by standard 'Risk of bias' assessments.

Does Extended-Release Liposomal Bupivacaine Better Control Pain Than Bupivacaine After Total Knee Arthroplasty (TKA)? A Prospective, Randomized Clinical Trial

Liposomal bupivacaine periarticular injection (PAI) offers sustained bupivacaine release after TKA, but few prospective independent studies exist. In this prospective, blinded study, liposomal bupivacaine was randomized against bupivacaine and incorporated into a comprehensive multimodal pain management protocol. 111 primary TKAs were randomized to receive PAI: 58 patients received 266 mg (20cc) liposomal bupivacaine mixed with 75 mg (30cc) 0.25% bupivacaine, and 53 patients received 150 mg (60cc) 0.25% bupivacaine. Visual analog pain scores and narcotic use were determined. No pain score differences occurred between study and control patients: Day 1: 4.5/4.6 (P=0.73); Day 2: 4.4/4.8 (P=0.27); or Day 3: 3.5/3.7 (P=0.58). Narcotic use was similar during hospitalization, 51.8/54.2 (P=0.34). The study medication costs $285, and the control medication costs $2.80. This finding does not justify the routine use of liposomal bupivacaine.

How do you know it is true? Integrity in research and publications: AOA critical issues

High-quality medical care is the result of clinical decisions based upon scientific principles garnered from basic, translational, and clinical research. Information regarding the natural history of diseases and their responses to various treatments is introduced into the medical literature through the approximately one million PubMed journal articles published each year. Pharmaceutical and device companies, universities, departments, and researchers all stand to gain from research publication. Basic and translational research is highly competitive. Success in obtaining research funding and career advancement requires scientific publication in the medical literature. Clinical research findings can lead to changes in the pattern of orthopaedic practice and have implications for the utilization of pharmaceuticals and orthopaedic devices. Research findings can be biased by ownership of patents and materials, funding sources, and consulting arrangements. The current high-stakes research environment has been characterized by an increase in plagiarism, falsification or manipulation of data, selected presentation of results, research bias, and inappropriate statistical analyses. It is the responsibility of the orthopaedic community to work collaboratively with industry, universities, departments, and medical researchers and educators to ensure the integrity of the content of the orthopaedic literature and to enable the incorporation of best practices in the care of orthopaedic patients.

Venous Thromboembolism (VTE) Prophylaxis for Hip and Knee Arthroplasty: Changing Trends

Venous thromboembolism (VTE) has been identified as an immediate threat to patients undergoing major orthopedic procedures such as total hip arthroplasty (THA) and total knee arthroplasty (TKA). Given the known dangers of VTE, arthroplasty surgeons are sensitive to the need for VTE thromboprophylaxis. However, the modalities of thromboprophylaxis used to minimize the risks to patients have been variable. Clinical practice guidelines have been published by several professional organizations, while some hospitals have established their own protocols. The 2 most popular guidelines are those published by the Academy of Orthopaedic Surgeons (AAOS) and American College of Chest Physicians (ACCP), both from North America. Prior to 2012, these recommendations varied depending on underlying definitions, methodology, and goals of the 2 groups. For the first time, both groups have similar recommendations that focus on minimizing symptomatic VTE and bleeding complications. The key to determining the appropriate chemoprophylaxis for patients is to balance efficacy of a prophylactic agent, while being safe in regards to bleeding complications. However, a multimodal approach that focuses on early postoperative mobilization and the use of mechanical prophylaxis, in addition to chemoprophylaxis, is essential.

DVT prophylaxis after TKA: routine anticoagulation vs risk screening approach - a randomized study

The American College of Chest Physicians (ACCP) recommended routine anticoagulation for thromboprophylaxis in patients undergoing lower limb arthroplasty. We compared results of routine anticoagulation Vs risk stratified approach for Deep Venous Thrombosis (DVT) prophylaxis after TKA in terms of symptomatic DVT and wound complications. Nine hundred TKAs done in 673 patients were randomized after DVT risk screening to routine anticoagulation (n = 450) or to risk stratification (n = 450) and selective anticoagulation. 194 patients in the risk screening group received only Aspirin. Primary outcome was symptomatic DVT and wound complication. This randomized study showed that the symptomatic DVT rates after TKA were similar whether patients were routinely anticoagulated or selectively anticoagulated after risk screening. However there was a significantly higher incidence of wound complications (P < 0.014) after routine anticoagulation.

Conflict of interest in the assessment of hyaluronic acid injections for osteoarthritis of the knee: an updated systematic review

The search results of a recent systematic review of prospective, randomized, placebo-controlled trials on hyaluronic acid injections for knee arthritis were updated and reviewed for funding source and qualitative conclusions. Forty-eight studies were identified; 30 (62.5%) were industry funded, and 3 (6.25%) were not. Fifteen (31.3%) studies did not identify a funding source. An association was observed between a reported potential financial conflict of interest of the author and the qualitative conclusion (P=0.018). None of the studies with a reported financial conflict of interest of at least one author had an unfavorable conclusion; 11 (35%) of the 31 studies with no industry-affiliated authors indicated that hyaluronic acid injection for knee osteoarthritis was no more effective than a placebo injection.

Spine surgery research: on and beyond current strategies

BACKGROUND CONTEXT

Systematic reviews of the literature are powerful tools in evidence-based medicine. However, the design and report of systematic reviews in spinal surgery contain many aspects amenable to improvement.

PURPOSE

To discuss the issues especially relevant for systematic reviews in spinal surgery.

METHODS

From our experience of systematic reviews and meta-analyses of clinical trials in spinal surgery, we infer guidance for the design and execution of systematic literature reviews.

RESULTS

There are many difficulties associated with the design as well as conduct of clinical trials and consequently appraising evidence in spinal surgery. New treatments should be compared with the gold standard before other comparisons are investigated. Studies should present data as thoroughly as possible regarding all subgroups and follow-up moments, possibly in supplementary material. To provide the highest level of evidence, systematic reviews should be as rigorously designed as possible.

CONCLUSIONS

Gathering information on clinical effectiveness in spinal surgery can be improved both at the clinical study level and at the systematic review level. Alternatives to randomized controlled trials such as comparative studies can be valuable tools on the clinical effectiveness of treatments in spinal surgery. The experience reflected in this article can support the scientific efforts in this field.