Definition of immobility in studies of thromboprophylaxis in hospitalized medical patients: A systematic review
A portion of this manuscript was previously presented as a poster at the American Society of Hematology Annual Meeting in 2007, and the abstract was published in Blood (ASH Annual Meeting Abstracts), Nov 2007; 110: 968.
Background
Venous thromboembolism (VTE) is a common, serious and preventable complication in hospitalized patients. Thromboprophylaxis in medical patients is safe, effective, and cost saving, but remains underutilized. Although immobility plays an important role in determining VTE risk in medical patients, no clear criteria exist to guide clinicians in assessing immobility when making decisions about thromboprophylaxis.
Objectives
A systematic review was conducted to determine how immobility is defined and operationalized in randomized controlled trials (RCTs) of thromboprophylaxis in medical inpatients.
Methods
PubMed database was searched until September 2008 for RCTs of thromboprophylaxis in medical patients. Articles retrieved were further hand-searched to identify additional RCTs. Definitions of “immobility” were assessed.
Results
Twenty-one RCTs were retrieved, 18 were retained and 17 of these defined, to varying degrees, “immobility.” Studies used several definition criteria, including the patient's degree of activity (14 studies), time spent immobile or mobile (13 studies), distance walked (4 studies) and underlying reason for immobility (4 studies); 14 studies used a combination of criteria. Definitions were clearly operationalized in 15 studies. The concept of “immobility” was utilized in study introductions (4 studies), inclusion/exclusion criteria (16 studies), as a stratification variable before randomization (1 study), in ongoing patient assessment (1 study), in treatment decisions (5 studies), as part of the study intervention (2 studies), as standard of care (2 studies), and in the results, discussion or conclusions (12 studies).
Conclusions
There is a marked lack of consistency in how the concept of immobility is defined and utilized in RCTs of thromboprophylaxis in medical inpatients. This circumstance may contribute to the underutilization of thromboprophylaxis in clinical practice with medical inpatients.
Department of Nursing, Sir Mortimer B. Davis Jewish General Hospital, Montreal, Canada; School of Nursing, McGill University, Montreal, Canada; Centre for Clinical Epidemiology and Community Studies, Sir Mortimer B. Davis Jewish General Hospital, Montreal, Canada; Division of General Internal Medicine, Faculty of Medicine, McGill University, Montreal, Canada
Corresponding author: Jessica D. Emed, RN, MSc, Department of Nursing, Sir Mortimer B. Davis Jewish General Hospital, 3755 Cote Ste. Catherine Road, Rm. B-109, Montreal, QC H3T 1E2.
ABSTRACT