Date of Award

7-2025

Degree Type

Dissertation

Degree Name

Master of Medicine (MMed)

First Advisor

Dr. Nancy Okinda

Second Advisor

Prof. Marcus Lance

Third Advisor

Dr. Laura Kirui

Department

Pathology (East Africa)

Abstract

Background 

Patients admitted to the hospital have been reported to have coagulation abnormalities due to various factors including immobilisation, preexisting disease, and current illness. The overall incidence of venous thromboembolism (VTE) in critically ill patients varies from 15% to well over 50%, even with the use of prophylactic measures in most patients. Low molecular weight heparin (LMWH) and unfractionated heparin (UFH) are the recommended drugs for VTE prophylaxis in inpatient care. Although not standardly recommended, the laboratory can offer monitoring of anti-Factor Xa using the gold standard method of chromogenic anti-Factor X assay. The anti-Factor Xa levels are notably affected by morbid obesity and disturbed creatinine clearance.

This study investigated the proportion of admitted patients on prophylactic standard-dose low molecular weight heparin (LMWH) and the respective levels of anti-Factor Xa.

In addition associated factors affecting the anti-Factor Xa levels in critically ill patients on LMWH prophylaxis were assessed.

Methods 

Single centre, prospective, cross-sectional study based in Aga Khan University Hospital, Nairobi Kenya. Ninety-two participants were enrolled from inpatient units and blood was collected in 3.2% citrated vacutainers for anti-Factor Xa level which was then spun to form platelet poor plasma that was stored at -80oC before analysis using chromogenic assay. Baseline details for participants were sourced from the hospital Electronic Medical Record System. Data analysis was done using descriptive analysis for continuous variables, and we used one-way ANOVA, Kruskal-Wallis tests, and multinomial logistic regression for comparative analysis.

Results 

Of the 92 participants, 87.8% (n=79) had subprophylactic anti-Factor Xa levels, 7.8% (n=7) had prophylactic, and 4.4% (n=4) had supra-prophylactic levels. Creatinine clearance differed significantly across these categories (p = 0.022), with higher values associated with subprophylactic levels. Multinomial logistic regression confirmed this association (OR = 1.03; 95% CI: 1.00–1.06; p = 0.033). Other variables, including BMI and vasopressor use, were not significantly associated with anti-Factor Xa level.

Conclusion 

This study highlights a high prevalence of subprophylactic anti-Factor Xa levels among hospitalized patients receiving standard LMWH prophylaxis, particularly those with higher creatinine clearance. These findings suggest that standard dosing may not achieve optimal anticoagulation in all patients, emphasising the need for individualised dosing strategies.

First Page

1

Last Page

80

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