Systematic review of risk prediction scores for venous thromboembolism following joint replacement

Background: Venous thromboembolism (VTE) is an important cause of morbidity and a preventable cause of deaths following lower limb joint replacement. Risk prediction scores that help to predict individual VTE risk following lower limb joint replacement may inform the development of preventive strategies and guide treatment decisions. We aimed to systematically review the evidence on the development and/or validation of risk prediction scores for VTE following lower limb joint replacement. Methods: Population-based studies that have developed and/or validated a risk prediction score for VTE following hip or knee replacement and randomised controlled trials (RCTs) that have evaluated the clinical impact of a score were searched for in MEDLINE, Embase, Web of Science, and The Cochrane Library to April 2018. Results: Five observational cohort studies describing five risk scores were included. No RCTs were identified. The number of component variables in a single risk score ranged from 5 to 26. Three risk scores comprised 5-8 component variables. None of the studies reported calibration or discrimination statistics. Two risk scores were externally validated in single-institution cohorts and were reported to perform well. One study evaluated the general surgery Caprini risk score in primary hip and knee replacement patients and did not find it useful for VTE risk stratification. Conclusions: Few VTE risk prediction scores in lower limb joint replacement exist and these have methodological issues, have been inadequately reported, not been sufficiently validated, and their impact on patient outcomes and decision making is unknown. Research is urgently warranted in the field. Systematic review registration: PROSPERO 2018: CRD42018088712.