Diagnostic applicability of modified wells score with compression duplex ultrasound in predicting deep vein thrombosis among suspected cases at Muhimbili National Hospital
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Date
2025
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Kairuki University
Abstract
Background: Diagnosing DVT poses a challenge for clinicians due to its nonspecific symptoms and the limited sensitivity and specificity of physical examination findings. Various diagnostic methods have been employed, yet uncertainty regarding their accuracy challenges the establishment of cost-effective protocols. This is especially problematic in resource-limited settings, where excessive reliance on Compressed Duplex ultrasound can strain financial resources and delay care, while exclusive use of the Modified Wells Score may lead to under diagnosis.
Objective: To assess the diagnostic applicability of the Modified Wells Score for deep vein thrombosis using compression duplex ultrasound as the reference standard.
Methods: The study was conducted at Muhimbili National Hospital (MNH) from April to June 2025. Data regarding socio-demographic, clinical, type of diagnostic tool for DVT used, and operator factors were collected using a questionnaire. Data analysis was done using Statistical Package for Social Sciences (SPSS) version 23. The Receiver Operating Characteristic (ROC) curve was used to assess the validity of the Modified Wells Score and Compression Duplex Ultrasound in distinguishing between positive and negative DVT cases, along with calculating the area under the curve (AUC). The McNemar test was used to compare the two diagnostic modalities. A p-value of less than 0.05 will be considered statistically significant when appropriate.
Results: A total of 227 Patients were included, with 125 (55.1%) females and 207 (91.2%) having secondary education or higher.5 pt (2.2%) had a previous history of DVT (5, 2.2%). Hypertension was present in 139 (61.2%), Diabetes in 92 (40.5%), and Obesity in 33 (14.5%). According to the Modified Wells’ score, 100 (44.1%) were classified as unlikely and 127 (55.9%) as likely to have DVT. Compression duplex ultrasound confirmed DVT in 80 (88.9%) of the likely group in MWS versus10 (11.1%) in the unlikely group (p = 0.001). The Modified Wells Score showed fair accuracy (AUC = 0.775) at a cut-off >1, with sensitivity 88.9%, specificity 65.7%, overall accuracy 74.9%, NPV 90%, and PPV 63%, supporting its use as a screening tool rather than a confirmatory test.
Conclusion: The Modified Wells’ score is a reliable screening and stratifying tool for deep vein thrombosis, especially effective in ruling out DVT in low-risk patients due to high sensitivity and negative predictive value. While its moderate specificity and lower positive predictive value require confirmatory imaging as an added diagnostic tool. Combining the score with D-dimer testing improves accuracy and cost-effectiveness, consistent with clinical guidelines. Given variability across populations and settings, local validation and cut-off adjustments are recommended to optimize its use. Overall, the Modified Wells’ score supports efficient risk stratification and better resource allocation.
Recommendations: Clinicians may use the Modified Wells’ score MWS to screen suspected DVT, especially to exclude low-risk cases and reduce unnecessary imaging. Positive scores require confirmatory imaging. Combining the Modified Wells’ score with D-dimer testing improves accuracy and cost-effectiveness. Health-care institutions should validate and adjust cut-offs locally to optimize performance. Future research should assess diagnostic accuracy across diverse populations and settings.
Description
A dissertation report presented in partial fulfillment of the prerequisites for the award of the Master of Medicine in general surgery degree at Kairuki university
Keywords
Deep Vein Thrombosis, duplex ultrasound, Muhimbili National Hospital
Citation
Mabusi, Briella N.S., 2025. Diagnostic applicability of modified wells score with compression duplex ultrasound in predicting deep vein thrombosis among suspected cases at Muhimbili national hospital. Dissertation. Kairuki University