Ruling out pulmonary embolism across different subgroups of patients and healthcare settings: protocol for a systematic review and individual patient data meta-analysis (IPDMA)

BACKGROUND

Diagnosing pulmonary embolism in suspected patients is notoriously difficult as signs and symptoms are non-specific. Different diagnostic strategies have been developed, usually combining clinical probability assessment with D-dimer testing. However, their predictive performance differs across different healthcare settings, patient subgroups, and clinical presentation, which are currently not accounted for in the available diagnostic approaches.

METHODS

This is a protocol for a large diagnostic individual patient data meta-analysis (IPDMA) of currently available diagnostic studies in the field of pulmonary embolism. We searched MEDLINE (search date January 1, 1995, till August 25, 2016) to retrieve all primary diagnostic studies that had evaluated diagnostic strategies for pulmonary embolism. Two authors independently screened titles, abstracts, and subsequently full-text articles for eligibility from 3145 individual studies. A total of 40 studies were deemed eligible for inclusion into our IPDMA set, and principal investigators from these studies were invited to participate in a meeting at the 2017 conference from the International Society on Thrombosis and Haemostasis. All authors agreed on data sharing and participation into this project. The process of data collection of available datasets as well as potential identification of additional new datasets based upon personal contacts and an updated search will be finalized early 2018. The aim is to evaluate diagnostic strategies across three research domains: (i) the optimal diagnostic approach for different healthcare settings, (ii) influence of comorbidity on the predictive performance of each diagnostic strategy, and (iii) optimize and tailor the efficiency and safety of ruling out PE across a broad spectrum of patients with a new, patient-tailored clinical decision model that combines clinical items with quantitative D-dimer testing.

DISCUSSION

This pre-planned individual patient data meta-analysis aims to contribute in resolving remaining diagnostic challenges of time-efficient diagnosis of pulmonary embolism by tailoring available diagnostic strategies for different healthcare settings and comorbidity.

SYSTEMATIC REVIEW REGISTRATION

Prospero trial registration: ID 89366.

Continuation of low-molecular-weight heparin treatment for cancer-related venous thromboembolism: a prospective cohort study in daily clinical practice

Essentials Low-molecular-weight heparin (LMWH) injections for venous thromboembolism (VTE) may be burdensome. Patients with active cancer and confirmed VTE were included to evaluate LMWH continuation. The cumulative incidence of discontinuation was 21% after a median period of 90 days. One out of five patients discontinued LMWH injections because of side effects.

SUMMARY

Background Current guidelines recommend low-molecular-weight heparin (LMWH) monotherapy for 3-6 months as the first-line treatment for cancer-associated venous thromboembolism (VTE). However, although daily administration of LMWH injections over a course of several months may be burdensome, the number of patients who stop treatment because of LMWH side-effects is unknown. Objectives To evaluate the continuation rate and complications of daily LMWH injections in patients with cancer-associated VTE. Methods Consecutive patients with active cancer and objectively confirmed symptomatic proximal deep vein thrombosis and/or pulmonary embolism, treated at three Dutch hospitals and one Spanish hospital, were included to evaluate continuation LMWH therapy during LMWH treatment. Patients were excluded when they received other anticoagulants, were lost to follow-up, or experienced a venous catheter-associated thrombosis. Results A total of 372 patients were analyzed during LMWH treatment for a maximum of 180 days. The cumulative incidence of discontinuation was 21% (95% confidence interval [CI] 17-25) after a median period of 90 days (interquartile range 60-120 days). Only female sex was found to be significantly associated with premature LMWH discontinuation (odds ratio 1.6; 95% CI 1.03-2.5). Thirty patients (8.1%) developed recurrent VTE, 30 patients (8.3%) suffered a major bleed, and 106 patients (28%) died. Conclusion Our study reveals that one of five patients with cancer-associated VTE stopped LMWH injections because of side-effects. This finding provides relevant background information for current clinical trials investigating the efficacy and safety of direct oral anticoagulants as compared with LMWH.