At-Home Versus In-Clinic INR Monitoring: A Cost–Utility Analysis from The Home INR Study (THINRS)

Abstract

BACKGROUND: Effective management of patients using warfarin is resource-intensive, requiring frequent inclinic testing of the international normalized ratio (INR). Patient self-testing (PST) using portable at-home INR monitoring devices has emerged as a convenient alternative. As revealed by The Home INR Study (THINRS), event rates for PST were not significantly different from those for in-clinic high-quality anticoagulation management (HQACM), and a cumulative gain in quality of life was observed for patients undergoing PST. OBJECTIVE: To perform a cost-utility analysis of weekly PST versus monthly HQACM and to examine the sensitivity of these results to testing frequency. PATIENTS/INTERVENTIONS: In this study, 2922 patients taking warfarin for atrial fibrillation or mechanical heart valve, and who demonstrated PST competence, were randomized to either weekly PST (n = 1465) or monthly inclinic testing (n = 1457). In a sub-study, 234 additional patients were randomized to PST once every 4 weeks (n = 116) or PST twice weekly (n = 118). The endpoints were quality of life (measured by the Health Utilities Index), health care utilization, and costs over 2 years of follow-up. RESULTS: PST and HQACM participants were similar with regard to gender, age, and CHADS 2 score. The total cost per patient over 2 years of follow-up was $32,484 for HQACM and $33,460 for weekly PST, representing a difference of $976. The incremental cost per qualityadjusted life year gained with PST once weekly was $5566 (95 % CI, −$11,490 to $25,142). The incremental cost-effectiveness ratio (ICER) was sensitive to testing frequency: weekly PST dominated PST twice weekly and once every 4 weeks. Compared to HQACM, weekly PST was associated with statistically significant and clinically meaningful improvements in quality of life. The ICER for weekly PST versus HQACM was well within accepted standards for cost-effectiveness, and was preferred over more or less frequent PST. These results were robust to sensitivity analyses of key assumptions. CONCLUSION: Weekly PST is a cost-effective alternative to monthly HQACM and a preferred testing frequency compared to twice weekly or monthly PST.

Capsule Commentary on Phibbs et. al., At-Home versus In-Clinic INR Monitoring: A Cost-Utility Analysis from The Home INR Study (THINRS)

“…A recent meta-analysis of 22 studies found that self-testing improved outcomes, but could not judge its costeffectiveness. 2 The current study by Phibbs et al 3 addresses this gap in evidence.…”

“…4 The THINRS investigators found that self-monitoring had equivalent outcomes to traditional monthly monitoring and led to higher self-reported health-related quality of life as measured by the Health Utilities Index. Phibbs and colleagues 3 have followed these findings up with a cost-utility analysis to address the question: BIs this parity in outcomes but improvement in health-related quality of life worth paying for?^.…”

Efeito do acompanhamento telefônico na qualidade de vida relacionada à saúde de pacientes nos primeiros seis meses de uso da varfarina: ensaio clínico aleatorizado

“…A dose média semanal do ACO foi semelhante entre os grupos (µ=42,5 S=15,0 para o GI e µ=39,7 S=16 para o GC), corroborando com os resultados de outros estudos (VERRET et al, 2012;SILVA DE ASSIS et al, 2012;PELEGRINO, 2013;MATCHAR et al, 2015;PHIBBS et al, 2016).…”

“…Quanto às comorbidades consideradas como fatores de risco para a instabilidade do INR na faixa terapêutica adequada, a maioria dos participantes tinha diagnóstico de hipertensão arterial (61,5% para ambos os grupos). Os resultados se assemelharam aos de outros estudos, que apresentaram frequência entre 51% e 85,3%, para a mesma comorbidade (CORBI et al, 2011;BOLELA , 2013;DIER, 2010;STOUDENMIRE;DE REMER;ELEWA, 2014, PHIBBS et al, 2016. A dislipidemia foi a segunda comorbidade mais frequente entre os participantes (26,9% para o GI e 38,5% para o GC), seguida da Diabetes…”

“…Mellitus (26,9% para o GI e 30,8% para o GC). Outros estudos encontraram resultados similares em relação a essas comorbidades (BOLELA et al, 2013;SHAFFER et al, 2014;TURKER et al, 2015;BALCI et al, 2016;PHIBBS et al, 2016).…”