Real-life impact of clinical prediction rules for venous thromboembolism in primary care: a cross-sectional cohort study

YEARS clinical decision rule for diagnosing pulmonary embolism: a prospective diagnostic cohort follow-up study in primary care

OBJECTIVES

The Wells rule is often used in primary care to rule out pulmonary embolism (PE), but its efficiency is low as many referred patients do not have PE. In this study, we evaluated in primary care an alternative and potentially more efficient diagnostic strategy-the YEARS algorithm; a simplified three-item version of the Wells rule combined with a pretest probability adjusted D-dimer interpretation.

DESIGN

In this comprehensive prospective diagnostic validation study, primary care patients suspected of PE were enrolled by their general practitioner. All three YEARS items were collected in addition to D-dimer results, and patients were followed for 3 months to establish the final diagnosis.

SETTING

Primary care in the Netherlands.

PARTICIPANTS

753 patients with suspected acute PE were included. Five patients (0.7%) were lost to follow-up.

MAIN OUTCOME MEASURES

Failure rate (number of PE cases among patients classified by the algorithm as 'PE ruled-out') and efficiency (fraction of patients classified as 'PE probable/further imaging needed').

RESULTS

Prevalence of PE was 5.5% (41/748 patients). In total, 603 patients were classified as 'PE ruled-out' by the YEARS algorithm (532 with zero YEARS items and a D-dimer<1000 ng/mL and 71 with≥1 positive YEARS item and a D-dimer<500 ng/mL), resulting in an efficiency of 80.6% (603/748 patients, 95% CI 77.6% to 83.4%). Of these patients, three patients had a diagnosis of non-fatal PE during 3 months follow-up, all three with zero YEARS items and D-dimer between 500 and 1000 ng/mL, resulting in an overall diagnostic failure rate of 0.50% (3/603 patients, 95% CI 0.13% to 1.57%). In the patients categorised as 'imaging needed' (n=145), a total of 38 (26.2%) were indeed diagnosed with PE.

CONCLUSIONS

Our study suggests that acute PE can be safely ruled out in 80% of patients by the YEARS algorithm in a primary care setting, while only 20% of patients required referral to hospital care for imaging tests. In those classified as 'imaging needed', PE was present in about one in every four patients, demonstrating a high detection proportion.

Clinical decision rules in primary care: necessary investments for sustainable healthcare

Clinical judgement in primary care is more often decisive than in the hospital. Clinical decision rules (CDRs) can help general practitioners facilitating the work-through of differentials that follows an initial suspicion, resulting in a concrete 'course of action': a 'rule-out' without further testing, a need for further testing, or a specific treatment. However, in daily primary care, the use of CDRs is limited to only a few isolated rules. In this paper, we aimed to provide insight into the laborious path required to implement a viable CDR. At the same time, we noted that the limited use of CDRs in primary care cannot be explained by implementation barriers alone. Through the case study of the Oudega rule for the exclusion of deep vein thrombosis, we concluded that primary care CDRs come out best if they are tailor-made, taking into consideration the specific context of primary health care. Current CDRs should be evaluated frequently, and future decision rules should anticipate the latest developments such as the use of point-of-care (POC) tests. Hence, such new powerful diagnostic CDRs could improve and expand the possibilities for patient-oriented primary care.

Two point-of-care test-based approaches for the exclusion of deep vein thrombosis in general practice: a cost-effectiveness analysis

BACKGROUND

In the diagnostic work-up of deep vein thrombosis (DVT), the use of point-of-care-test (POCT) D-dimer assays is emerging as a promising patient-friendly alternative to regular D-dimer assays, but their cost-effectiveness is unknown. We compared the cost-effectiveness of two POCT-based approaches to the most common, laboratory-based, situation.

METHODS

A patient-level simulation model was developed to simulate the diagnostic trajectory of patients presenting with symptoms of DVT at the general practitioner (GP). Three strategies were defined for further diagnostic work-up: one based on current guidelines ('regular strategy') and two alternative approaches where a POCT for D-dimer is implemented at the 1) phlebotomy service ('DVT care pathway') and 2) GP practice ('fast-POCT strategy'). Probabilities, costs and health outcomes were obtained from the literature. Costs and effects were determined from a societal perspective over a time horizon of 6 months. Uncertainty in model outcomes was assessed with a one-way sensitivity analysis.

RESULTS

The Quality-Adjusted Life Years (QALYs) scores for the three DVT diagnostic work-up strategies were all around 0.43 across a 6 month-time horizon. Cost-savings of the two POCT-based strategies compared to the regular strategy were €103/patient for the DVT care pathway (95% CI: -€117-89), and €87/patient for the fast-POCT strategy (95% CI: -€113-67).

CONCLUSIONS

Point-of-care-based approaches result in similar health outcomes compared with regular strategy. Given their expected cost-savings and patient-friendly nature, we recommend implementing a D-dimer POCT device in the diagnostic DVT work-up.