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Association of Medication Adherence With Health Outcomes in the ISCHEMIA Trial
R Angel Garcia1, John A Spertus1, Mary C Benton1
1Cardiovascular Research, Saint Luke's Mid America Heart Institute, Kansas City, Missouri, USA; Department of Biomedical and Health Informatics, University of Missouri-Kansas City, Kansas City, Missouri, USA.
Insights
Medication nonadherence in chronic coronary disease (CCD) is linked to poorer health status, irrespective of treatment strategy. Improving adherence is crucial for better outcomes in patients with CCD.
Area of Science:
- Cardiology
- Clinical Research
- Health Outcomes
Background:
- The ISCHEMIA trial investigated medical vs. invasive approaches for chronic coronary disease (CCD).
- This analysis focused on the impact of medication nonadherence on patient health status outcomes within the trial.
- Nonadherence was assessed using the Morisky-Green-Levine Adherence Scale.
Purpose of the Study:
- To compare 12-month health status in adherent versus nonadherent CCD patients.
- To test the hypothesis that nonadherent patients might have better outcomes with invasive management.
- To evaluate the association of adherence with health status across different treatment strategies.
Main Methods:
- Randomized controlled trial (ISCHEMIA) with 4,480 participants.
- Medication adherence assessed at baseline; patients categorized as adherent or nonadherent.
- 12-month health status measured by Seattle Angina Questionnaire (SAQ-7) summary score; analyzed using Bayesian proportional odds models.
Main Results:
- Over 27% of participants (1,245) were nonadherent at baseline.
- Nonadherent patients reported worse baseline health status in both conservative and invasive arms.
- Adherence was associated with significantly better 12-month health status (higher SAQ-7 SS) in both treatment groups, with no interaction.
Conclusions:
- Medication nonadherence is prevalent in CCD and associated with worse health status at baseline and 12 months.
- Health status outcomes in CCD patients are negatively impacted by nonadherence, regardless of treatment strategy.
- Interventions to enhance medication adherence are essential for improving patient outcomes in CCD.
Background:
The ISCHEMIA (International Study of Comparative Health Effectiveness With Medical and Invasive Approaches) trial randomized participants with chronic coronary disease (CCD) to guideline-directed medical therapy with or without angiography and revascularization. The study examined the association of nonadherence with health status outcomes.
Objectives:
The study sought to compare 12-month health status outcomes of adherent and nonadherent participants with CCD with an a priori hypothesis that nonadherent patients would have better health status if randomized to invasive management.
Methods:
Self-reported medication-taking behavior was assessed at randomization with a modified 4-item Morisky-Green-Levine Adherence Scale, and participants were classified as adherent or nonadherent. Twelve-month health status was assessed with the 7-item Seattle Angina Questionnaire (SAQ-7) summary score (SS), which ranges from 0 to 100 (higher score = better). The association of adherence with outcomes was evaluated using Bayesian proportional odds models, including an interaction by study arm (conservative vs invasive).
Results:
Among 4,480 randomized participants, 1,245 (27.8%) were nonadherent at baseline. Nonadherent participants had worse baseline SAQ-7 SS in both conservative (72.9 ± 19.3 vs 75.6 ± 18.4) and invasive (71.0 ± 19.8 vs 74.2 ± 18.7) arms. In adjusted analyses, adherence was associated with higher 12-month SAQ-7 SS in both treatment groups (mean difference in SAQ-7 SS with conservative treatment = 1.6 [95% credible interval: 0.3-2.9] vs with invasive management = 1.9 [95% credible interval: 0.8-3.1]), with no interaction by treatment.
Conclusions:
More than 1 in 4 participants reported medication nonadherence, which was associated with worse health status in both conservative and invasive treatment strategies at baseline and 12 months. Strategies to improve medication adherence are needed to improve health status outcomes in CCD, regardless of treatment strategy. (International Study of Comparative Health Effectiveness With Medical and Invasive Approaches [ISCHEMIA]; NCT01471522).
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