Sabah local fruits are associated with number of INR out of range in patients with non-valvular atrial fibrillation receiving warfarin therapy: A retrospective cohort study

Drug-fruits interaction affects optimal anticoagulation, but little is known about this topic due to limited researches. This study aims to investigate the association between Sabah local fruits consumption among non-valvular atrial fibrillation patients receiving warfarin therapy and number of international normalised ratio (INR) out of range. A retrospective observational study was conducted on patients attending clinic from April 2016 to April 2017. Predictor variables measured were number of clinic visits with local fruits consumption, types of local fruits consumed and number of local fruits consumed within 1 week before clinic visit. Negative Binomial Regression Model was used to determine predictor associated with number of INR out of range. A total of 109 atrial fibrillation (AF) patients were evaluated, with an average age of 65.33 ± 9.59 years and predominantly male (n = 66, 60.5%). 946 of the 1,274 clinic visits recorded local fruits consumption during past one week. Increase in number of clinic visits with local fruits consumption was associated with 8% higher number of INR out of range, and it was significantly higher among patients who consumed Durian (incidence rate ratio [IRR] = 1.152, 95% confidence interval (CI) 1.004 – 1.322, p = 0.043), Tarap (IRR = 1.237, 95% CI 1.051–1.456, p = 0.010), Pineapple (IRR = 1.115, 95% CI 1.032 – 1.204, p = 0.005), Cempedak (IRR = 1.278, 95% CI 1.025–1.594, p = 0.029), Banana (IRR = 1.056, 95% CI 1.029–1.085, p < 0.001), and Papaya (IRR = 1.048, 95% CI 1.016–1.081, p = 0.002). Besides, taking either one or more types of local fruits significantly increased the number of INR out of range. In the final regression model, only number of clinic visits with local fruits consumption was retained (IRR = 1.08, 95% CI 1.05–1.10, p < 0.001). Local fruits consumption significantly affects quality of anticoagulation with warfarin; it should be considered when assessing possible cause of deranged INR.