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.


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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