Predictors of warfarin non-adherence in younger adults after valve replacement surgery in the South Pacific

Abstract

Objectives Globally, mechanical valves are predominant as replacements for adolescents and younger adults with rheumatic heart disease (RHD). Mechanical valve implantation necessitates lifelong antithrombotic management (warfarin) and associated lifestyle modification, with event-free survival largely dependent on international normalised therapeutic ratios (INRs) remaining within the target therapeutic range. There is limited information on factors that may influence warfarin adherence among younger people or those in resource-limited settings. This study sought to identify predictors of warfarin adherence after valve replacement surgery for RHD in Fiji (n=127). Methods A cross-sectional study design was used.Results The sample had a mean age of 31.23 years (SD 13.34) and a mean time-since-surgery of 3.72 years (SD 3.95). Just over half were women (n=71, 56%) and almost two-thirds were indigenous (I-taukei, n=78, 61%). Most had an isolated valve procedure (n=94, 74%) and at the time of survey, they were in New York Heart Association Class I (n=97, 76%). A quarter (n=33, 26%) reported poor adherence with anticoagulation therapy and 13.38% (n=17) reported complete warfarin cessation. While younger age was significantly associated with non-adherence to warfarin therapy ( p=0.008), the independent predictors of people who discontinue warfarin completely were those not understanding why warfarin was needed (OR=9.97, p=0.006); a history of forgetting to take warfarin (OR=8.64, p=0.0013) and travel time to heart clinic >1 hour (OR=5.80, p=0.039). Conclusions While medication adherence is complex and multifactorial, the consequences of warfarin nonadherence are potentially catastrophic. These results provide an important first step towards the development of country-specific and disease-specific strategies to improve warfarin adherence.

Relationship Between Family Caregiver Burden and Medication Adherence in Patients with Mechanical Valve Replacement: A Structural Equation Model

“…Non-adherence to medication in post-operative MVR patients can lead to poor clinical outcomes, higher disease mortality, and unnecessary health care expenditures, 48 so it is essential to enhance long-term survival by improving medication adherence in this patient population. The mean medication adherence score was 5.72 ± 1.79, with 43.7% of participants in low adherence, which was higher than the 13.2% to 33.26% in studies conducted in China and other countries, 49,50 this difference may be related to the study region, design and sample size. However, it still indicated that medication adherence was suboptimal and improving medication adherence in patients after MVR was a significant problem to be solved urgently.…”

Relationship Between Family Functioning and Medication Adherence in Chinese Patients With Mechanical Heart Valve Replacement: A Moderated Mediation Model

“…However, according to the World Health Organization, the average adherence rate for long-term medications is only 50% and even lower in low-and middle-income countries. ( Thomson Mangnall et al, 2016 ).…”

Non-Vitamin K Oral Anticoagulants in Adults with Congenital Heart Disease: A Systematic Review

“…Most importantly, NOACs do not require laboratory monitoring, making them more acceptable for younger active patients [ 38 ]. A recent cross-sectional study demonstrated high non-adherence rates or discontinuation of warfarin (26% and 17% respectively) in 127 young patients (mean age 31.2 years) after valve replacement surgery for rheumatic heart disease with a mean time since surgery of 3.7 years [ 39 ]. In general, adherence to NOACs is superior to VKAs [ 40 ], with one out of three patients who start warfarin for atrial fibrillation discontinuing treatment after one year of therapy [ 41 , 42 , 43 , 44 ].…”