Correct Application of Clinical Prediction Rules for VTE Associated With High Efficiency, Low Failure Rate

Applying clinical prediction rules (CPRs) correctly when treating patients with venous thromboembolism (VTE) in primary care was found to be associated with low failure rate, according to a study published in BMJ Open.

In this cross-sectional diagnostic cohort study, patients (N=1477) suspected of having deep venous thromboembolism (DVT; n=993; median age, 64 years; range, 15-96 years; 42.6% men) or pulmonary embolism (PE; n=484; median age, 49 years; range, 13-94 years; 32.0% men) were recruited from primary care centers in the Netherlands between 2013 and 2017 . All patients were evaluated by their clinician following the 7-item CPR to assess risk for DVT and PE (scores: 0-8 for DVT; 0-12.5 for PE).

In the DVT and PE groups, 42.5% and 23.3% of patients, respectively had D-dimer levels >500 ng/mL, 17.2% and 10.1% had high-risk CPR scores, respectively, with median CRP scores of 2 (range, 0-7) and 1.5 (range, 0-7) points, respectively.

A total of 23.2% of participants were diagnosed with DVT, and 7.9% with PE.

In the cohort, the failure rate of the CPR was 1.8% (95% CI, 1.02%-3.06%) and efficiency was 53% (95% CI, 50.4%-55.5%). In cases in which the CPR was used correctly vs incorrectly, the failure (1.51%; 95% CI, 0.77%-2.86% vs 3.31%; 95% CI, 1.07%-8.76%, respectively) and efficiency (58.1%; 95% CI, 55.2%-61.0% vs 35.7%; 95% CI, 30.6%-41.1%, respectively) rates were more favorable.

Of 787 patients with suspected DVT in whom CPR was correctly applied, (408 patients not referred (51.8% efficiency), and 8 patients had VTE (failure rate, 1.96%). Of 206 patients in whom CPR was incorrectly applied, efficiency was 27.7% and failure rate, 7.02%.

Of 351 patients with suspected PE and correct application of the CPR 72.1% were not referred, of whom 2 had VTE (failure rate, 0.79%).

Incorrect applications of CPR were due to use of wrong CPR, inappropriate D-dimer testing use, use in inappropriate patient populations (eg, patients treated with anticoagulants, pregnant women, or children).

Determinants of incorrect CPR use among patients with suspected VTE were: previous VTE (odds ratio [OR], 4.45; 95% CI, 2.73-7.25), heart failure (OR, 3.26; 95% CI, 1.47-7.21), recent surgery or immobilization (OR, 1.57; 95% CI, 1.00-2.47), asthma or chronic obstructive pulmonary disease (OR, 1.38; 95% CI, 0.95-2.01), and active malignancy (OR, 1.11; 95% CI, 0.67-1.86).

Study limitations include the fact that the point-of-care D-dimer test used was later removed from the market due to quality-related concerns.

“Correct application of CPRs for VTE in primary care is associated with a high efficiency and an acceptable low failure rate,” concluded the study authors. “Importantly, in nearly a quarter of patients, the CPRs were incorrectly applied that resulted in a lower efficiency and a higher failure rate. Such incorrect application of CPRs was more common in the presence of concurrent heart failure.”

Reference

Van Maanen R, Kingma A E C, Oudega R, et al. Real-life impact of clinical prediction rules for venous thromboembolism in primary care: a cross-sectional cohort study. BMJ Open. 2020;10(12):e039913. doi:10.1136/bmjopen-2020-039913