Trends of anticoagulation control among adult outpatients on long-term Warfarin therapy in a Tertiary Teaching and Referral Hospital in Kenya

Abstract

Background: Anticoagulation control using warfarin therapy has several challenges especially in resource constrained settings.

Objective: To describe the trends of anticoagulation control among adult outpatients on warfarin therapy at Kenyatta National Hospital.

Design: Cross-sectional study.

Setting: Anticoagulation clinics in the hospital. Participants: 180 outpatients aged ≥18 years.

Main outcome measures: Level of anticoagulation and adverse drug reactions (ADRs).

Methods: Participants’ sociodemographic characteristics and details of ADRs were acquired through face-to-face interviews. The level of anticoagulation was determined through assessment of international normalized ratios (INRs) for the six clinic attendances with INR of 2-3 being considered therapeutic. Data analysis was conducted onto IBM Statistical Package for Social Sciences version 23. Pearson’s Chi square was used to determine the strength of associations between outcome measures and  sociodemographics, with statistical significance set at p≤0.05.

Results: Females were majority (76.7%) and the mean age of participants was 43.4 (±13.2) years. Therapeutic anticoagulation was maintained by 35.2-48.4% patients across six follow-ups and was better among the males (p=0.0398) especially those suffering from heart diseases. ADRs were experienced by almost 50% of the patients where bleeding (27.8%) mainly occurred at INR>3(80.0%). ADRs were significantly more common among the participants without spouses, who were primarily suffering from heart diseases (p=0.0081).

Conclusions: Anticoagulation control is poor though patients with cardioembolic disorders have better INRs but more ADRs. Clinical and laboratory monitoring of warfarin therapy should be intensified among females. Future studies should correlate warfarin anticoagulation control with patient, clinician or hospital related factors.