External validation of the Khorana score for the prediction of venous thromboembolism in cancer patients: A systematic review and meta-analysis.

in International journal of nursing studies by Xuan Huang, Hongxiu Chen, Sha Meng, Lihui Pu, Xueqiong Xu, Ping Xu, Shengyuan He, Xiuying Hu, Yong Li, Guan Wang

TLDR

  • The Khorana score is a tool that helps doctors identify cancer patients who are at high risk of getting a blood clot during chemotherapy. However, the score's accuracy in predicting this risk is not always clear. This study uses a review of many studies to see how well the Khorana score works in different types of cancer patients. The study found that the score is not very good at predicting the risk of blood clots in most types of cancer patients, either in the hospital or at home. The study suggests that doctors should use the score with caution and consider other factors when deciding whether a patient needs to take steps to prevent blood clots.

Abstract

Venous thromboembolism is the leading cause of death in cancer patients, second only to tumor progression. The Khorana score is recommended by clinical guidelines for identifying ambulatory cancer patients at high risk of venous thromboembolism during chemotherapy. However, its predictive performance is debated among cancer patients. To map the applicability of the Khorana score in cancer patients and to assess its predictive performance across various cancer types, providing guidance for clinicians and nurses to use it more appropriately. Systematic review and meta-analysis. A comprehensive literature search of the electronic database was first conducted on August 30, 2023, and updated on May 20, 2024. Studies examining the Khorana score's predictive performance (including but not limited to the areas under the curve, C-index, and calibration plot) in cancer patients were included. The Prediction Model Risk of Bias Assessment Tool (PROBAST) was applied to evaluate the methodological quality of the included studies. Data synthesis was achieved via random-effects meta-analysis using the R studio software. The subgroup analysis was performed according to the study design, clinical setting, cancer type, anti-cancer treatment stage, and country. The review incorporated 67 studies, including 58 observational studies and nine randomized controlled trials. All included studies assessed the Khorana score's discrimination, with the C-index ranging from 0.40 to 0.84. The pooled C-index for randomized controlled trials was 0.61 (95 % CI 0.51-0.70), while observational studies showed a pooled C-index of 0.59 (95 % CI 0.57-0.60). Subgroup analyses revealed the pooled C-index for lung cancer, lymphoma, gastrointestinal cancer, and mixed cancer patients as 0.60 (95 % CI 0.53-0.67), 0.56 (95 % CI 0.51-0.61), 0.59 (95 % CI 0.39-0.76), and 0.60 (95 % CI 0.58-0.61), respectively. Inpatient and outpatient settings had the pooled C-index of 0.60 (95 % CI 0.58-0.63) and 0.58 (95 % CI 0.55-0.61), respectively. Calibration was assessed in only four studies. All included studies were identified to have a high risk of bias according to PROBAST. The Khorana score has been widely validated in various types of cancer patients; however, it exhibited poor capability (pooled C-index<0.7) in accurately discriminating VTE risk among most types of cancer patients either in inpatient or outpatient settings. The Khorana score should be used with caution, and high-quality studies are needed to further validate its predictive performance. The protocol for this study is registered with PROSPERO (registration number: CRD42023470320).

Overview

  • The study aims to map the applicability of the Khorana score in cancer patients and assess its predictive performance across various cancer types. The Khorana score is a widely validated tool for identifying ambulatory cancer patients at high risk of venous thromboembolism during chemotherapy. However, its predictive performance is debated among cancer patients. The study uses a systematic review and meta-analysis to evaluate the Khorana score's discrimination in cancer patients, including but not limited to the areas under the curve, C-index, and calibration plot. The study includes 67 studies, including 58 observational studies and nine randomized controlled trials. The review incorporates subgroup analyses according to study design, clinical setting, cancer type, anti-cancer treatment stage, and country. The study's primary objective is to provide guidance for clinicians and nurses to use the Khorana score more appropriately.

Comparative Analysis & Findings

  • The study compares the outcomes observed under different experimental conditions or interventions detailed in the study. The study identifies the Khorana score's predictive performance in cancer patients, including but not limited to the areas under the curve, C-index, and calibration plot. The study finds that the Khorana score exhibits poor capability (pooled C-index<0.7) in accurately discriminating VTE risk among most types of cancer patients either in inpatient or outpatient settings. The study also identifies that the Khorana score should be used with caution, and high-quality studies are needed to further validate its predictive performance.

Implications and Future Directions

  • The study's findings suggest that the Khorana score has limited predictive performance in cancer patients, and its use should be cautioned. The study identifies the need for high-quality studies to further validate the Khorana score's predictive performance. The study also suggests that future research should focus on developing more accurate and personalized predictive models for venous thromboembolism risk in cancer patients. The study's findings have significant implications for clinical practice, as they highlight the importance of using the Khorana score with caution and considering other risk factors when assessing venous thromboembolism risk in cancer patients.
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