Comparison of various clinical scoring systems in assessing the probability of pulmonary thromboembolism in adults in a Tertiary Care Hospital in South India

Ramalingam Gogulakrishnan; Gayathri Anur Ramakrishnan

doi:10.4103/japt.japt_18_23

ORIGINAL ARTICLE

Year : 2023 | Volume : 6 | Issue : 2 | Page : 39-44

Comparison of various clinical scoring systems in assessing the probability of pulmonary thromboembolism in adults in a Tertiary Care Hospital in South India

Ramalingam Gogulakrishnan¹, Gayathri Anur Ramakrishnan²
¹ Department of Respiratory Medicine, Tiruvarur Medical Center, Tiruvarur, Tamil Nadu, India
² Department of Respiratory Medicine, Apollo Hospital, Chennai, Tamil Nadu, India

Date of Submission	10-May-2023
Date of Decision	19-May-2023
Date of Acceptance	22-May-2023
Date of Web Publication	13-Jul-2023

Correspondence Address:
Dr. Ramalingam Gogulakrishnan
C-3, Ramalingam Memorial Flats, Javulikara Street, Tiruvarur - 610 001, Tamil Nadu
India

Source of Support: None, Conflict of Interest: None

DOI: 10.4103/japt.japt_18_23

Abstract

Aim: The aim of the study was to compare various clinical scoring systems used in detecting pulmonary embolism (PE) in adults in Tertiary Care Hospital in South India. Materials and Methods: Prospective study was done in Apollo Hospital, Greams Road, Chennai, from January 2016 to December 2017. Sixty-five patients with suspected PE were included in the study. Details such as age, sex, pulse rate, and blood pressure were collected. Probability of PE was calculated with all four clinical scoring systems (Wells score, simplified Wells score, revised Geneva score, and simplified revised Geneva score) and compared with computed tomography–pulmonary angiography which was considered the gold standard. Results: This study included 65 patients with suspected PE. Among 65 patients, 39 (60%) were male and 26 (40%) were female. PE was present in 23 (35.4%) patients, of which 14 (60.9%) were male and 9 (39.1%) were female, but the difference was not statistically significant (P = 0.916). Wells score had a sensitivity of 87%, specificity of 67%, positive predictive value (PPV) of 59%, and negative predictive value of 90%. Simplified Wells score had a sensitivity of 91%, specificity of 50%, PPV of 50%, and negative predictive value of 91%. The revised Geneva score had a sensitivity of 70%, specificity of 52%, PPV of 44%, and negative predictive value of 76%. Simplified revised Geneva score had a sensitivity of 65%, specificity of 57%, PPV of 45%, and negative predictive value of 75%. Conclusion: From this study, we were able to infer that the simplified Wells score had high sensitivity and Wells score had high specificity in the diagnosis of PE. Simplified revised Geneva score had the least negative predictive value. It is very important to have a high index of suspicion for the diagnosis of PE and the clinical predictability scores are valuable tools in this regard.

Keywords: Geneva score, pulmonary embolism, Wells score

How to cite this article:
Gogulakrishnan R, Ramakrishnan GA. Comparison of various clinical scoring systems in assessing the probability of pulmonary thromboembolism in adults in a Tertiary Care Hospital in South India. J Assoc Pulmonologist Tamilnadu 2023;6:39-44

How to cite this URL:
Gogulakrishnan R, Ramakrishnan GA. Comparison of various clinical scoring systems in assessing the probability of pulmonary thromboembolism in adults in a Tertiary Care Hospital in South India. J Assoc Pulmonologist Tamilnadu [serial online] 2023 [cited 2023 Sep 30];6:39-44. Available from: https://www.japt.in//text.asp?2023/6/2/39/381415

Introduction

Pulmonary embolism (PE) and deep-vein thrombosis (DVT) are together called as venous thromboembolism (VTE). The annual incidence of VTE is found to be 117/100,000 persons (PE, 69/100,000; DVT, 48/100,000) in the European population.^[1] The prevalence of VTE had been initially considered rare among the Asian population.^[2],[3] However, recent studies suggest that the prevalence of VTE is similar in the Asian population as in the Caucasian population.^[4]

PE has high morbidity and mortality. Among the deaths due to PE, 34% were due to sudden fatal PE.^[5] Hence, the early diagnosis of PE is essential. PE has a wide range of clinical presentation ranging from incidental diagnosis to fatal PE on presentation. Not one symptom is pathognomonic of PE.^[6] Although clinical judgment is necessary for diagnosing PE, it is not standardized. Hence, clinical scoring systems have been used for predicting the pretest probability of PE.s

Various scoring systems have been introduced and validated over the years. Wells score and revised Geneva score are more commonly used for assessing the pretest probability of PE.^[7],[8] Both scoring systems have been simplified further and validated [Table 1] and [Table 2].^[9],[10] Clinical scoring systems help in deciding the next investigation in a case of suspected PE. This study aims to analyze the efficacy of clinical scoring systems in detecting pulmonary thromboembolism among suspected patients in a Tertiary Care Hospital in South India.

Table 1: Original and simplified wells score

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Table 2: Original and simplified revised Geneva score

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Aims and objectives

The study aimed to compare various clinical scoring systems and find the sensitivity and specificity of the Wells score, simplified Wells score, revised Geneva score, and simplified revised Geneva score in assessing the probability of pulmonary thromboembolism.

Materials and Methods

This prospective observational study was conducted at Apollo Hospitals, Greams Road, Chennai, India, from January 2016 to December 2017. All hospitalized patients with suspected PE were included in the study. Patient's vital parameters, including heart rate and blood pressure and epidemiological data such as age and sex, were collected. Pretest probability for PE was calculated with all four clinical scoring systems and compared with the computed pulmonary angiogram.

Inclusion criteria

All hospitalized patients with suspected PE (sudden-onset dyspnea, worsening of existing dyspnea, or sudden-onset pleuritic chest pain) with age of more than 18 years were included in the study.

Exclusion criteria

Patients who did not undergo computed tomographic (CT) pulmonary angiography (contrast allergy, renal insufficiency, and pregnancy) were excluded from the study.

Statistical analysis

All the categorical variables were expressed as percentage (%). All continuous variables were expressed as mean ± standard deviation. Comparison of categorical variables such as gender and systolic blood pressure with PE presence or absence was done by either the Chi-square test or Fisher's exact test based on the number of observations. Comparison of continuous variables was analyzed by independent sample “t” test. Receiver operating characteristic (ROC) curve was drawn to find out the cutoff values in each scoring system to predict pulmonary thromboembolism.

Based on the cutoff values derived sensitivity, specificity, positive predictive value (PPV), and negative predictive value were computed by taking the standard of reference as CT pulmonary angiography. Data entry was done on Microsoft Excel spreadsheet. Data analysis was carried out using IBM SPSS Statistics for Windows version 25.0, Armonk, NY:IBM Corp. All P < 0.05 were considered statistically significant.

Results

A total of 65 patients were included in the study. Among 65 patients, 39 (60%) were male and 26 (40%) were female [Graph 1]. PE was present in 23 (35.4%) of 65 suspected patients diagnosed by CT–pulmonary angiography [Graph 2]. Of the 23 patients detected to have PE, 14 (60.9%) were male and 9 (39.1%) were female, but the difference was not statistically significant [P = 0.916, [Table 3]]. The mean heart rate of patients with PE was 105.91 ± 15.15/min. The mean systolic blood pressure among patients with PE was 114.52 ± 23.94 mmHg [Table 4]. Among patients with PE, 21.7% had hypotension. The difference in vital signs was not statistically significant (P = 0.87), among the patients with the presence or absence of PE.

Table 3: Gender distribution of pulmonary embolism

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Table 4: Mean heart rate and blood pressure of the study population

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Wells score

Wells score classified 31 (47.7%) patients as PE-unlikely. PE was present in 3 (9.7%) patients among the PE-unlikely category [Table 5].

Table 5: Wells score probability and computed tomography–pulmonary angiography results

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Simplified wells score

Simplified Wells score classified 23 patients as PE-unlikely. Among 23 patients, two had PE. Hence, it had a prevalence of 8.7% in the PE-unlikely group [Table 6].

Table 6: Simplified wells score probability and computed tomography–pulmonary angiography results

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Revised Geneva score

Twenty-nine patients were classified as PE-unlikely according to the revised Geneva score. PE was present in seven patients of the PE-unlikely category. The prevalence of PE in the PE-unlikely category was 24.1% [Table 7].

Table 7: Revised Geneva score probability and computed tomography–pulmonary angiography results

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Simplified revised Geneva score

Thirty-two patients were classified to PE-unlikely category by simplified revised Geneva score. Among 32 patients, eight had PE. The prevalence of PE in PE-unlikely category was 25% [Table 8].

Table 8: Simplified revised Geneva score probability and computed tomography–pulmonary angiography results

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Sensitivity and specificity of four scoring systems

Among the four scoring systems, the simplified Wells score had the maximum sensitivity (0.91), and the simplified revised Geneva score had the least sensitivity (0.65). Specificity was maximum for the Wells score (0.67) and least for the simplified Wells score (0.5).

The Wells score had the maximum PPV (0.59) and the revised Geneva score had the least PPV (0.44). Negative predictive value was maximum for the simplified Wells score (0.90) and least for the simplified revised Geneva score (0.75) [Table 9].

Table 9: Sensitivity, specificity, positive predictive values, and negative predictive values of four scoring systems

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Discussion

PE is a diagnostic challenge due to its nonspecific symptoms and signs. Timely diagnosis of PE is required, as both underdiagnosis and overdiagnosis are associated with significant morbidity and mortality. PE can be fatal if untreated and overtreatment can have increased risk of major bleeding. Clinical prediction rules help in deciding the next investigation of choice for the patient.

In our study, the prevalence of PE was 35.4%. Wide range of prevalence has been reported in literature ranging from 15.33% to 29.6%.^{[11],[12],[13],[14],[15]}

Proportion of patients classified as PE-unlikely was 47.7% for the Wells score, 35.4% for the simplified Wells score, 44.6% for the revised Geneva score, and 49.2% for the simplified revised Geneva score. Douma et al.^[16] found more than half of the patients in the PE-unlikely category (72% for the Wells score, 62% for the simplified Wells score, 69% for the revised Geneva score, and 71% for the simplified revised Geneva score).

The prevalence of PE was more in males than females, but this difference was not statistically significant (P = 0.916). Silverstein et al.^[1] also had similar observations of PE being more common in males.

Tachycardia was found in 55% of patients with PE and 45% of patients without PE. Hypotension was found in 21.7% of patients with PE and 7.1% of patients without PE and the difference is not statistically significant (P = 0.87). Miniati et al.^[17] also had similar observations and found hypotension was present in only 3% of patients with PE.

The prevalence of PE in the PE-unlikely category was 9.7% for the Wells score, 8.7% for the simplified Wells score, 24.1% for the revised Geneva score, and 25% for the simplified revised Geneva score. The simplified Wells score had the least and simplified revised Geneva score had the maximum prevalence of PE in the PE-unlikely category. Other studies also have reported similar observations.^{[7],[16],[18]}

Sensitivity was maximum for the simplified Wells score (0.91), followed by the Wells score (0.87), revised Geneva score (0.70), and simplified revised Geneva score (0.65). El Wahsh and Agha^[19] and Douma et al.^[16] also found that simplified Wells score had maximum sensitivity. Wong et al.,^[11] Klok et al.,^[12] and Ceriani et al.^[20] concluded both the Wells score and the revised Geneva score were equally sensitive. In our study, we found the Wells score was more sensitive than the revised Geneva score as observed in other studies.^{[13],[14],[21],[22],[23]}

Specificity was maximum for the Wells score (0.66), followed by the simplified revised Geneva score (0.57), revised Geneva score (0.52), and simplified Wells score (0.50). Douma et al.^[16] also had a similar observation. On the contrary, El Wahsh and Agha^[19] found the simplified revised Geneva score had maximum specificity and Wells score had the least specificity.

The negative predictive value was the maximum for the simplified Wells score (0.91), followed by the Wells score (0.90), revised Geneva score (0.75), and simplified revised Geneva score (0.75). Douma et al.^[16] also had similar findings. El Wahsh and Agha^[19] found the Wells score had maximum negative predictive value.

PPV was maximum for the Wells score (0.58) and least for the revised Geneva score (0.44). Christopher et al.^[24] also found simplified Wells score performs better over the simplified revised Geneva score, but both had higher PPV's compared to our study.

On ROC curve analysis of our data, the optimal cutoff value for the Wells score and simplified Wells score was similar, as derived in earlier studies.^[16] The Wells score had maximum area under curve and the least for the simplified revised Geneva score in ROC curve analysis [Graph 3]. Douma et al.^[16] also had a similar observation.

Limitations

The sample size of the study was small, so large-scale studies are required to confirm the findings. This study had not characterized the patients as high-risk and low-risk PE. D-dimer data were not collected, as it was not a part of objective of the study.

Conclusion

PE is not uncommon among the Indian population and the diagnosis is frequently missed. All individuals with suspected PE must undergo clinical pretest probability to decide on the next investigation of choice. From this study, we were able to infer that the simplified Wells score had high sensitivity and the Wells score had high specificity in the diagnosis of PE. The revised Geneva score had the least negative predictive value. It is very important to have a high index of suspicion for the diagnosis of PE and the clinical predictability scores are valuable tools in this regard.

Recommendations

A clinical prediction rule must be applied for all patients with suspected PE, to decide on further investigations. Wells score performs better as compared to the revised Geneva score. Simplified Wells score can be used, over the original Wells score due to ease of application and prevention of miscalculations. All PE-likely patients must undergo CT with pulmonary angiography for confirmation of the presence or absence of PE.

Acknowledgment

I would like to thank my guide Dr. A. R. Gayathri, for her constant support and all other consultants in the Department of Respiratory Medicine, with special mention to Dr. L. Sundarajan and Dr. R. P. Ilangho for their inputs in the dissertation review meeting. I also thank my colleagues for their support during my study.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.

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