Alternative diagnosis other than pulmonary embolism as a subjective variable in the Wells clinical decision rule: not so bad after all

Accuracy of physicians' intuitive risk estimation in the diagnostic management of pulmonary embolism: an individual patient data meta-analysis

BACKGROUND

In patients clinically suspected of having pulmonary embolism (PE), physicians often rely on intuitive estimation ("gestalt") of PE presence. Although shown to be predictive, gestalt is criticized for its assumed variation across physicians and lack of standardization.

OBJECTIVES

To assess the diagnostic accuracy of gestalt in the diagnosis of PE and gain insight into its possible variation.

METHODS

We performed an individual patient data meta-analysis including patients suspected of having PE. The primary outcome was diagnostic accuracy of gestalt for the diagnosis of PE, quantified as risk ratio (RR) between gestalt and PE based on 2-stage random-effect log-binomial meta-analysis regression as well as gestalts' sensitivity and specificity. The variability of these measures was explored across different health care settings, publication period, PE prevalence, patient subgroups (sex, heart failure, chronic lung disease, and items of the Wells score other than gestalt), and age.

RESULTS

We analyzed 20 770 patients suspected of having PE from 16 original studies. The prevalence of PE in patients with and without a positive gestalt was 28.8% vs 9.1%, respectively. The overall RR was 3.02 (95% CI, 2.35-3.87), and the overall sensitivity and specificity were 74% (95% CI, 68%-79%) and 61% (95% CI, 53%-68%), respectively. Although variation was observed across individual studies (I2, 90.63%), the diagnostic accuracy was consistent across all subgroups and health care settings.

CONCLUSION

A positive gestalt was associated with a 3-fold increased risk of PE in suspected patients. Although variation was observed across studies, the RR of gestalt was similar across prespecified subgroups and health care settings, exemplifying its diagnostic value for all patients suspected of having PE.

Comparison of the Wells score and the revised Geneva score as a tool to predict pulmonary embolism in outpatients over age 65

TITLE

Comparison of the Wells score and the revised Geneva score as a tool to predict pulmonary embolism in outpatients over 65 years of age.

INTRODUCTION

The incidence and mortality of pulmonary embolism (PE) is high in the elderly. The Wells score (SW) and the revised Geneva score (RGS) have been validated in patient populations with a large age range. The aim of this study was to compare the predictive accuracy of these two scores in diagnosis of PE in patients over 65 years of age.

METHOD

A prospective multicentre study (nine French and three Belgian centres) was conducted at the same time as the PERCEPIC study. A total of 1757 patients admitted with suspected PE were included and divided into two groups according to age (≥65 years or <65 years). The pre-test probability of PE was assessed prospectively for the RGS. The SW was calculated retrospectively. The predictive accuracy of the two scores was compared by the area under the curve (AUC) of the ROC curves.

RESULTS

The overall prevalence of PE was 11.3%. The prevalence among patients aged ≥65 in the low, moderate and high pre-test probability groups, evaluated using the WS and was respectively 13.5% (CI 95%: CI 9.9-17.3), 28.2% (CI 22.1-34.3), 50% (CI 26-74) and 8.1% (CI 3.2-12.9), 22.3% (CI 18.2-26.3), 43.7% (CI 25.6-61.9) using the RGS. The AUC for the WS and RGS for patients aged ≥65 was 0.632 (CI 0.574-0.691) and 0.610 (CI 0.555-0.666). The difference between the AUCs was not statistically significant (p = .441).

CONCLUSION

In the population for this study, the WS and RGS have the same PE diagnostic accuracy in patients over age 65. This result should be validated in a prospective study that directly compares these scores.

Ruling Out Pulmonary Embolism in Primary Care: Comparison of the Diagnostic Performance of "Gestalt" and the Wells Rule

PURPOSE

Diagnostic prediction models such as the Wells rule can be used for safely ruling out pulmonary embolism (PE) when it is suspected. A physician's own probability estimate ("gestalt"), however, is commonly used instead. We evaluated the diagnostic performance of both approaches in primary care.

METHODS

Family physicians estimated the probability of PE on a scale of 0% to 100% (gestalt) and calculated the Wells rule score in 598 patients with suspected PE who were thereafter referred to secondary care for definitive testing. We compared the discriminative ability (c statistic) of both approaches. Next, we stratified patients into PE risk categories. For gestalt, a probability of less than 20% plus a negative point-of-care d-dimer test indicated low risk; for the Wells rule, we used a score of 4 or lower plus a negative d-dimer test. We compared sensitivity, specificity, efficiency (percentage of low-risk patients in total cohort), and failure rate (percentage of patients having PE within the low-risk category).

RESULTS

With 3 months of follow-up, 73 patients (12%) were confirmed to have venous thromboembolism (a surrogate for PE at baseline). The c statistic was 0.77 (95% CI, 0.70-0.83) for gestalt and 0.80 (95% CI, 0.75-0.86) for the Wells rule. Gestalt missed 2 out of 152 low-risk patients (failure rate = 1.3%; 95% CI, 0.2%-4.7%) with an efficiency of 25% (95% CI, 22%-29%); the Wells rule missed 4 out of 272 low-risk patients (failure rate = 1.5%; 95% CI, 0.4%-3.7%) with an efficiency of 45% (95% CI, 41%-50%).

CONCLUSIONS

Combined with d-dimer testing, both gestalt using a cutoff of less than 20% and the Wells rule using a score of 4 or lower are safe for ruling out PE in primary care. The Wells rule is more efficient, however, and PE can be ruled out in a larger proportion of suspected cases.

Values of the Wells and revised Geneva scores combined with D-dimer in diagnosing elderly pulmonary embolism patients

BACKGROUND

Pulmonary embolism (PE) can be difficult to diagnose in elderly patients because of the coexistent diseases and the combination of drugs that they have taken. We aimed to compare the clinical diagnostic values of the Wells score, the revised Geneva score and each of them combined with D-dimer for suspected PE in elderly patients.

METHODS

Three hundred and thirty-six patients who were admitted for suspected PE were enrolled retrospectively and divided into two groups based on age (≥65 or <65 years old). The Wells and revised Geneva scores were applied to evaluate the clinical probability of PE, and the positive predictive values of both scores were calculated using computed tomography pulmonary arteriography as a gold standard; overall accuracy was evaluated by the area under the curve (AUC) of receiver operator characteristic curve; the negative predictive values of D-dimer, the Wells score combined with D-dimer, and the revised Geneva score combined with D-dimer were calculated.

RESULTS

Ninety-six cases (28.6%) were definitely diagnosed as PE among 336 cases, among them 56 cases (58.3%) were ≥65 years old. The positive predictive values of Wells and revised Geneva scores were 65.8% and 32.4%, respectively (P < 0.05) in the elderly patients; the AUC for the Wells score and the revised Geneva score in elderly was 0.682 (95% confidence interval [CI]: 0.612-0.746) and 0.655 (95% CI: 0.584-0.722), respectively (P = 0.389). The negative predictive values of D-dimer, the Wells score combined with D-dimer, and the revised Geneva score combined with D-dimer were 93.7%, 100%, and 100% in the elderly, respectively.

CONCLUSIONS

The diagnostic value of the Wells score was higher than the revised Geneva score for the elderly cases with suspected PE. The combination of either the Wells score or the revised Geneva score with a normal D-dimer concentration is a safe strategy to rule out PE.

Alternative diagnoses in patients in whom the GP considered the diagnosis of pulmonary embolism

INTRODUCTION

Pulmonary embolism (PE) often presents with nonspecific symptoms and may be an easily missed diagnosis. When the differential diagnosis includes PE, an empirical list of frequently occurring alternative diagnoses could support the GP in diagnostic decision making.

OBJECTIVES

To identify common alternative diagnoses in patients in whom the GP suspected PE but in whom PE could be ruled out. To investigate how the Wells clinical decision rule for PE combined with a point-of-care d-dimer test is associated with these alternative diagnoses.

METHODS

Secondary analysis of the Amsterdam Maastricht Utrecht Study on thrombo-Embolism (Amuse-2) study, which validated the Wells PE rule combined with point-of-care d-dimer testing in primary care. All 598 patients had been referred to and diagnosed in secondary care. All diagnostic information was retrieved from the GPs' medical records.

RESULTS

In 516 patients without PE, the most frequent alternative diagnoses were nonspecific thoracic pain/dyspnoea (42.6%), pneumonia (13.0%), myalgia (11.8%), asthma/chronic obstructive pulmonary disease (4.8%), panic disorder/hyperventilation (4.1%) and respiratory tract infection (2.3%). Pneumonia occurred almost as frequent as PE. Patients without PE with either a positive Wells rule (>4) or a positive d-dimer test, were more often (odds ratio = 2.1) diagnosed with a clinically relevant disease than patients with a negative Wells rule and negative d-dimer test.

CONCLUSION

In primary care patients suspected of PE, the most common clinically relevant diagnosis other than PE was pneumonia. A positive Wells rule or a positive d-dimer test are not only positively associated with PE, but also with a high probability of other clinically relevant disease.

Comparison of the Wells and Revised Geneva Scores for the diagnosis of pulmonary embolism: an Australian experience

BACKGROUND/AIMS

Clinical prediction rules form an integral component of guidelines on the diagnostic approach to pulmonary embolism (PE). The Wells Score is commonly used but is subjective, while the newer Revised Geneva Score is based entirely on objective variables. The aim of this study was to compare the diagnostic accuracy of the Wells and Revised Geneva Scores for the diagnosis of PE.

METHODS

Patients presenting to the emergency department with clinically suspected PE and referred for CT pulmonary angiogram or ventilation/perfusion scintigraphy were evaluated. The Wells and Revised Geneva Scores were calculated on the same cohort of patients and dichotomized into low and intermediate/high probability groups. The sensitivities and specificities were compared using McNemar's test. Overall accuracy was determined using receiver operator characteristic curve analysis.

RESULTS

A total of 98 consecutive patients was included. The overall prevalence of PE was 15.3%. The frequency of PE in the low, intermediate and high probability groups was similar for both clinical prediction rules. Compared with the Revised Geneva Score, the Wells Score showed a lower sensitivity with borderline significance (46.7% vs 80.0%, P= 0.06) and a significantly higher specificity (67.5% vs 47.0%, P= 0.002). The overall accuracy of both rules was similar (P= 0.617).

CONCLUSION

Using the accepted guidelines in which a high pretest probability leads to further imaging and a low probability leads to a D-dimer blood test, use of the more specific Wells Score could safely reduce the number of unnecessary scans. This would need to be confirmed with larger, prospective trials.

[Diagnosis of pulmonary embolism]

Nowadays the diagnosis of pulmonary embolism (PE) is based on a "diagnostic strategy" rather than a single test. The first step, after identifying patients with suspicion of PE, is to establish the pre-test clinical probability. Several scores are available to make a standardised and reproducible assessment of the clinical probability and these, therefore, represent valuable diagnostic tools. Indeed, it is the clinical probability that guides further investigation. In patients with low or intermediate clinical probability, PE can be safely ruled out by a negative D-dimer in approximately one-third of patients without additional imaging. In the case of a positive D-dimer or high clinical probability, CT pulmonary angiography is now the recommended imaging technique. However, lower limb venous compression ultrasound and ventilation/perfusion scans remain useful in patients with contraindications to CT; mainly those with renal insufficiency. In the presence of readily available and strongly validated diagnostic strategies, the challenge for the future will probably be better identification of patients in whom PE should be suspected.

Comparison of the Wells score with the simplified revised Geneva score for assessing pretest probability of pulmonary embolism

INTRODUCTION

The Wells score is widely used in the assessment of pretest probability of pulmonary embolism (PE). The revised Geneva score is a fully standardized clinical decision rule that was recently validated and further simplified. We compared the predictive accuracy of these two scores.

METHODS

Data from 339 patients clinically suspected of PE from two prospective management studies were used and combined. Pretest probability of PE was assessed prospectively by the Wells score. The simplified revised (SR) Geneva score was calculated retrospectively. The predictive accuracy of both scores was compared by area under the curve (AUC) of receiver operating characteristic (ROC) curves.

RESULTS

The overall prevalence of PE was 19%. Prevalence of PE in the low, moderate and high pretest probability groups assessed by the Wells score and by the simplified revised Geneva score was respectively 2%(95% CI (CI) 1-6) and 4% (CI 2-10), 28% (CI 22-35) and 25% (CI 20-32), 93% (CI 70-99) and 56% (CI 27-81). The Wells score performed better than the simplified revised Geneva score in patients with a high suspicion of PE (p<0.05). The AUC for the Wells score and the simplified revised Geneva score was 0.85 (CI: 0.81 to 0.89) and 0.76 (CI: 0.71 to 0.80) respectively. The difference between the AUCs was statistically significant (p=0.005).

CONCLUSIONS

In our population the Wells score appeared to be more accurate than the simplified revised Geneva score. The impact of this finding in terms of patient outcomes should be investigated in a prospective study.

Cost-effectiveness of strategies for diagnosing pulmonary embolism among emergency department patients presenting with undifferentiated symptoms

STUDY OBJECTIVE

Symptoms associated with pulmonary embolism can be nonspecific and similar to many competing diagnoses, leading to excessive costly testing and treatment, as well as missed diagnoses. Objective studies are essential for diagnosis. This study evaluates the cost-effectiveness of different diagnostic strategies in an emergency department (ED) for patients presenting with undifferentiated symptoms suggestive of pulmonary embolism.

METHODS

Using a probabilistic decision model, we evaluated the incremental costs and effectiveness (quality-adjusted life-years gained) of 60 testing strategies for 5 patient pretest categories (distinguished by Wells score [high, moderate, or low] and whether deep venous thrombosis is clinically suspected). We performed deterministic and probabilistic sensitivity analyses.

RESULTS

In the base case, for all patient pretest categories, the most cost-effective diagnostic strategy is to use an initial enzyme-linked immunosorbent assay D-dimer test, followed by compression ultrasonography of the lower extremities if the D-dimer is above a specified cutoff. The level of the preferred cutoff varies with the Wells pretest category and whether a deep venous thrombosis is clinically suspected. D-dimer cutoffs higher than the current recommended cutoff were often preferred for patients with even moderate and high Wells categories. Compression ultrasonography accuracy had to decrease below commonly cited levels in the literature before it was not part of a preferred strategy.

CONCLUSION

When pulmonary embolism is suspected in the ED, use of an enzyme-linked immunosorbent assay D-dimer assay, often at cutoffs higher than those currently in use (for patients in whom deep venous thrombosis is not clinically suspected), followed by compression ultrasonography as appropriate, can reduce costs and improve outcomes.

Diagnostic management of clinically suspected acute pulmonary embolism

Current diagnostic management of hemodynamically stable patients with clinically suspected acute pulmonary embolism (PE) consists of the accurate and rapid distinction between the approximate 20-25% of patients who have acute PE and require anticoagulant treatment, and the overall majority of patients who do not have the disease in question. Clinical outcome studies have demonstrated that, using algorithms with sequential diagnostic tests, PE can be safely ruled out in patients with a clinical probability indicating PE to be unlikely and a normal D-dimer test result. This obviates the need for additional radiological imaging tests in 20-40% of patients. CT pulmonary angiography (CTPA) has become the first line tool to confirm or exclude the diagnosis of PE in patients with a likely probability of PE or an elevated D-dimer blood concentration. While single-row-detector technology CTPA has a low sensitivity for PE and bilateral compression ultrasound (CUS) of the lower limbs is considered necessary to rule out PE, multi-row-detector CTPA is safe to exclude PE without the confirmatory use of CUS.

Comparison of the revised Geneva score with the Wells rule for assessing clinical probability of pulmonary embolism

BACKGROUND

The revised Geneva score, a standardized clinical decision rule in the diagnosis of pulmonary embolism (PE), was recently developed. The Wells clinical decision is widely used but lacks full standardization, as it includes subjective clinician's judgement. We have compared the performance of the revised Geneva score with the Wells rule, and their usefulness for ruling out PE in combination with D-dimer measurement.

METHODS

In 300 consecutive patients, the clinical probability of PE was assessed prospectively by the Wells rule and retrospectively using the revised Geneva score. Patients comprised a random sample from a single center, participating in a large prospective multicenter diagnostic study. The predictive accuracy of both scores was compared by area under the curve (AUC) of receiver operating characteristic (ROC) curves.

RESULTS

The overall prevalence of PE was 16%. The prevalence of PE in the low-probability, intermediate-probability and high-probability categories as classified by the revised Geneva score was similar to that of the original derivation set. The performance of the revised Geneva score as measured by the AUC in a ROC analysis did not differ statistically from the Wells rule. After 3 months of follow-up, no patient classified into the low or intermediate clinical probability category by the revised Geneva score and a normal D-dimer result was subsequently diagnosed with acute venous thromboembolism.

CONCLUSIONS

This study suggests that the performance of the revised Geneva score is equivalent to that of the Wells rule. In addition, it seems safe to exclude PE in patients by the combination of a low or intermediate clinical probability by the revised Geneva score and a normal D-dimer level. Prospective clinical outcome studies are needed to confirm this latter finding.