Up to 90% of patients referred for ultrasonography with suspected deep venous thrombosis (DVT) of the leg do not have the disease.
To evaluate the safety and efficiency of using a clinical decision ...rule that includes a point-of-care d-dimer assay at initial presentation in primary care to exclude DVT.
A prospective management study.
Approximately 300 primary care practices in 3 regions of the Netherlands (Amsterdam, Maastricht, and Utrecht).
1028 consecutive patients with clinically suspected DVT.
Patients were managed on the basis of the result of the clinical decision rule, which included a d-dimer result. Patients with a score of 3 or less were not referred for ultrasonography and received no anticoagulant treatment; patients with a score of 4 or more were referred for ultrasonography.
The primary outcome was symptomatic, objectively confirmed, venous thromboembolism during 3-month follow-up.
The mean age of the 1028 study patients was 58 years, and 37% of patients were men. A valid score was obtained in 1002 patients (98%). In 500 patients (49%), with a score of 3 or less, 7 developed venous thromboembolism within 3 months (incidence, 1.4% 95% CI, 0.6% to 2.9%). A total of 502 patients (49%) had a score of 4 or more; 3 did not have ultrasonography. Ultrasonography showed DVT in 125 patients (25%), for an overall prevalence in evaluable patients of 13% (125 of 1002). Of the 374 patients who had normal ultrasonography results, 4 developed venous thromboembolism within 3 months (1.1% CI, 0.3% to 2.7%).
The study lacked a randomized design and relied on clinical follow-up to detect missed thrombotic disease.
A diagnostic management strategy in primary care by using a simple clinical decision rule and a point-of-care d-dimer assay reduces the need for referral to secondary care of patients with clinically suspected DVT by almost 50% and is associated with a low risk for subsequent venous thromboembolic events.
The Netherlands Organization for Scientific Research.
Abstract Purpose The Wells rule is widely used for clinical assessment of patients with suspected deep vein thrombosis (DVT), especially in the secondary care setting. Recently a new clinical ...decision rule for primary care patients (the primary care rule) has been proposed, because the Wells rule is not sufficient to rule out DVT in this setting. The objective was to compare the ability of both rules to safely rule out DVT and to efficiently reduce the number of referrals for leg ultrasound investigation that would result in a negative finding. Methods Family physicians collected data on 1,086 patients to calculate the scores for both decision rules before leg ultrasonography was performed. In all patients D-dimer (dimerized plasmin fragment D) testing was performed using a rapid point-of-care assay. Patients were stratified into risk categories defined by each rule and the D-dimer result. Outcomes were DVT (diagnosed by ultrasonography) and venous thromboembolic complications or death caused by a possible thromboembolic event during a 90-day follow-up period. We calculated the differences between the 2 rules in the number of missed diagnoses and the proportions of patients that needed ultrasound testing. Results Data from 1,002 eligible patients were used for this analysis. A venous thromboembolic event occurred during follow-up in 7 patients with a low score and negative D-dimer finding, both with the Wells rule (7 of 447; 1.6%; 95% confidence interval CI, 0.7%-3.3%) and the primary care rule (7 of 495; 1.4%; 95% CI, 0.6%-3.0%). Using the Wells rule, 447 patients (45%) would not need referral for further testing compared with 495 patients (49%) when using the primary care rule (McNemar P <.001). Conclusions In primary care, suspected DVT can safely be ruled out using either of the 2 rules in combination with a point-of-care D-dimer test. Both rules can reduce unnecessary referrals for compression ultrasonography by about 50%, though the primary care rule reduces it slightly more.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, UILJ, UKNU, UL, UM, UPUK
Point-of-care D-dimer tests have recently been introduced to enable rapid exclusion of deep venous thrombosis (DVT) without the need to refer a patient for conventional laboratory-based D-dimer ...testing. Before implementation in practice, however, the diagnostic accuracy of each test should be validated.
We analyzed data of 577 prospectively identified consecutive primary care patients suspected to have DVT, who underwent 5 point-of-care D-dimer tests-4 quantitative (Vidas®, Pathfast™, Cardiac®, and Triage®) and 1 qualitative (Clearview Simplify®)-and ultrasonography as the reference method. We evaluated the tests for the accuracy of their measurements and submitted a questionnaire to 20 users to assess the user-friendliness of each test.
All D-dimer tests showed negative predictive values higher than 98%. Sensitivity was high for all point-of-care tests, with a range of 0.91 (Clearview Simplify) to 0.99 (Vidas). Specificity varied between 0.39 (Pathfast) and 0.64 (Clearview Simplify). The quantitative point-of-care tests showed similar and high discriminative power for DVT, according to calculated areas under the ROC curves (range 0.88-0.89). The quantitative Vidas and Pathfast devices showed limited user-friendliness for primary care, owing to a laborious calibration process and long analyzer warm-up time compared to the Cardiac and Triage. For the qualitative Clearview Simplify assay, no analyzer or calibration was needed, but interpretation of a test result was sometimes difficult because of poor color contrast.
Point-of-care D-dimer assays show good and similar diagnostic accuracy. The quantitative Cardiac and Triage and the qualitative Clearview Simplify D-dimer seem most user-friendly for excluding DVT in the doctor's office.
Recently, a diagnostic score was developed to safely exclude deep-vein thrombosis (DVT) in primary care. A large prospective study, in which general practitioners used this diagnostic score to decide ...which patients needed referral, revealed that the number of referrals for ultrasound measurements was reduced by almost 50%, at the cost of an acceptably low risk (1.4%, 95% confidence interval CI 0.6% to 2.9%) of venous thromboembolic events in non-referred patients. However, simple adjustments to the diagnostic score (so-called updating) might further improve the accuracy; i.e. reduce the proportion of missed diagnoses (safety) or increase the proportion of patients who do not need to be referred (efficiency). We applied two updating methods to determine whether adjusting the weights of the predictors or adding new predictors could further improve the accuracy of the diagnostic score. The weights of the predictors did not need to be adjusted, but inclusion of ‘history of DVT’ and ‘prolonged travelling’ significantly added predictive value (p-values 0.014 and 0.023, respectively). However, adding these predictors to the diagnostic score did not improve the safety and efficiency: at equal safety (1.4% missed diagnoses among the non-referred patients), the efficiency was lower (43.5%, 95% CI 40.4% to 46.6% compared to 49.4%, 95% CI 46.3% to 52.5%). The diagnostic score for excluding DVT in primary care has good accuracy in its original form and could not be improved by including additional predictors. This suggests that the original diagnostic score can be used to safely exclude clinically suspected DVT in primary care.
In primary care, the physician has to decide which patients with a suspicion of deep vein thrombosis (DVT) have to be referred for further diagnostic work-up. Accurate referral is of utmost ...importance because unrecognized and therefore untreated DVT may cause pulmonary embolism. The classic clinical findings are not sufficiently accurate for the diagnosis of DVT. The majority of the referred patients, 70 to 80%, do not have DVT and this puts a burden on both patients and health care budgets. Diagnosis in primary care is different from that in secondary care caused by the referral mechanism or spectrum difference. Diagnostic tests derived in secondary care, therefore, cannot simply be generalized to primary-care patients. The well-known diagnostic rule for DVT, the Wells rule, does not adequately rule out DVT in primary-care patients. A proper diagnostic rule for use in primary care is lacking; therefore, we investigated the data of 1,295 patients in primary care suspected of having DVT. We developed and validated a simple diagnostic decision rule to exclude the presence of DVT safely in primary care. Independent diagnostic indicators of the presence of DVT were male gender, oral contraceptive use, presence of malignancy, recent surgery, absence of leg trauma, vein distension, calf circumference difference, and D-dimer test result. Application of this rule could reduce the number of referrals by at least 23%, whereas only 0.7% of the patients with a DVT would not be referred. A diagnosis strategy is given, together with a practical flow diagram.
Background. Recently, a new, simple diagnostic rule was introduced to enable GPs to safely refrain from referring a considerable proportion of the patients suspected of having deep vein thrombosis ...(DVT). The rule (which includes seven patient history and physical examination items plus the result of a D-dimer test) discriminates ‘very low’ risk patients (not to be referred) from patients with an increased risk of DVT (to be referred). However, the rule's ‘efficiency’ (proportion of patients designated by the rule as very low risk) and safety (DVT prevalence among these very low risk patients) may change according to patient characteristics. Objective. To test the rule's safety and efficiency in clinically relevant subgroups; i.e. across three age groups, in men and women, and in patients with and without a history of DVT, separately. Methods. We retrospectively analysed data of 2086 primary care patients suspected of DVT, in whom all rule items and the result of the reference (‘gold’) standard (compression ultrasonography) were collected. Results. The rule's efficiency decreased with age from 38.1% in the relatively young (<50 years) compared to 9.8% in patients aged ≥70 years. The percentage of DVT among the very low risk patients was <1.5% in all subgroups. The low efficiency in the elderly could be improved without compromising the safety by increasing the D-dimer threshold. Conclusion. The rule can safely exclude DVT in primary care patients suspected of DVT, irrespective of age, gender and history of DVT.
In secondary care the Wells clinical decision rule (CDR) combined with a quantitative D-dimer test can exclude pulmonary embolism (PE) safely. The introduction of point-of-care (POC) D-dimer tests ...facilitates a similar diagnostic strategy in primary care.We estimated failure-rate and efficiency of a diagnostic strategy using the Wells-CDR combined with a POC-D-dimer test for excluding PE in primary care.We considered ruling out PE safe if the failure rate was <2% with a maximum upper confidence limit of 2.7%.
We performed a scenario-analysis on data of 2701 outpatients suspected of PE. We used test characteristics of two qualitative POC-D-dimer tests, as derived from a meta-analysis and combined these with the Wells-CDR-score.
In scenario 1 (SimpliRed-D-dimer sensitivity 85%, specificity 74%) PE was excluded safely in 23.8% of patients but only by lowering the cut-off value of the Wells rule to <2. (failure rate: 1.4%, 95% CI 0.6-2.6%)In scenario 2 (Simplify-D-dimer sensitivity 87%, specificity 62%) PE was excluded safely in 12.4% of patients provided that the Wells-cut-off value was set at 0. (failure rate: 0.9%, 95% CI 0.2-2.6%)
Theoretically a diagnostic strategy using the Wells-CDR combined with a qualitative POC-D-dimer test can be used safely to exclude PE in primary care albeit with only moderate efficiency.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Our validated primary care rule safely excludes deep vein thrombosis in one-quarter of patients suspected of having the disease. We recommend the use of this rule by family practitioners.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
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