Challenges in management of warfarin anti-coagulation in advanced HIV/aids patients with venous thrombotic events – a case series from a research clinic in rural Kericho, Kenya

Background: Venous thrombotic events (VTE) occur at high rates in HIV/AIDS patients and are likely under-diagnosed in rural sub-Saharan Africa. Objective: To describe clinical presentations and challenges in the management of VTE in patients with advanced HIV/AIDS. Design: Case series from patients enrolled in a prospective observational cohort study. Settings: A clinical research centre in rural Kericho, Kenya. Subjects: Two hundred patients with median age 38 (30-47) years, BMI 16.9 (12.4-20.3) kg/m2, haemoglobin 9.3 (6.8-13.4) g/dL, CD4+ T-cell count 27 (4-77) cells/mm3 and plasma HIV RNA 5.23 (3.70-5.88) log10copies/mL. Interventions: VTE cases were diagnosed by clinical presentation and Doppler/ radiographic confirmation. Anti-coagulation therapy was managed by a multidisciplinary team; patients were initiated on enoxaparin or heparin followed by warfarin. Results: Over two years, 11 patients (5.5%) experienced VTE. All but one (10/11, 90.9%) case occurred within six months of starting ART. Nine patients had peripheral VTE (five popliteal, four femoral) and two had cerebral sinus thromboses. VTE was diagnosed 52 (1-469) days after ART initiation, and 81.8% of cases were outpatients at presentation. All patients received at least one concomitant medication that could significantly interact with warfarin (efavirenz, nevirapine, lopinavir/ritonavir, rifampicin, trimethoprim-sulfamethoxazole, and fluconazole). A median of 39 (10-180) days and eight (4-22) additional clinic visits were required to achieve/maintain a therapeutic INR of 2-3. Two minor bleeding complications occurred. No recurrent VTE cases were observed. Conclusion: Consideration of VTE and preparedness for management in patients with advanced HIV/AIDS starting ART is critical in sub-Saharan Africa. Overcoming challenges in anti-coagulation is possible in rural settings using a multidisciplinary team approach.