Association between transportation barriers and anticoagulation control among an inner‐city, low‐income population: A prospective observational cohort study

Abstract Background Anticoagulation with warfarin represents a transportation‐sensitive treatment state. Transportation barrier is a common reason for not using health care services. Objective To assess the association between transportation barriers to anticoagulation clinic and anticoagulation control (AC) among an inner‐city, low‐income population. Patients/Methods Adults expected to be on chronic warfarin therapy were recruited from an ambulatory anticoagulation clinic. Participants completed a validated questionnaire that assessed transportation barriers to clinic, defined as self‐reported trouble getting transportation to a clinic and a composite score of the presence of transportation barriers. Suboptimal AC was defined as time in therapeutic range (TTR) <60% over 6 months. Prevalence ratios with 95% confidence intervals (CIs), adjusted for age, sex, and annual household income, described the association of transportation trouble and barriers with AC. Results Of 133 participants, 42.9% had suboptimal AC. Mean age was 60.4 (SD, 13.6) years, and the majority of participants were women (62.2%). Participants with transportation trouble were more likely to report being disabled/unable to work (63.6%) and annual household income <$15 000 (45.5%). Mean TTR was significantly lower for participants with transportation trouble compared to those without (53.8% [SD, 24.7%] vs 64.7% [SD, 25.0%]; P = .03). Participants reporting transportation trouble or at least one transportation barrier were 1.60 (95% CI, 1.07‐2.39) and 1.68 (95% CI, 1.01‐2.80) times more likely, respectively, to have suboptimal AC compared to those without. Conclusion Inner‐city, low‐income individuals with transportation barriers were more likely to have suboptimal AC. Further research is warranted to evaluate the impact of alleviating patient‐specific transportation barriers on anticoagulation outcomes.