• Registry Data: Low Socioeconomic Status Associated with Increased Risk of Bleeding After Aortic Valve Replacement

    There is a strong association between socioeconomic status (SES), bleeding risk and fatal intracranial hemorrhage after aortic valve replacement (AVR), new registry data suggest.

    The analysis, published online Monday and in the June 27 issue of the Journal of the American College of Cardiology, investigated the impact of patients’ SES on the risk of bleeding after mechanical AVR, after researchers noted that the impact of SES on anticoagulation-related adverse events in patients with mechanical heart valves was unknown.

    Led by Magnus Dalén, MD, PhD, from Karolinska University Hospital and the Karolinska Institutet, Stockholm, the team noted that anticoagulation in patients with mechanical valves is based on the use of a vitamin K antagonist (VKA) – with monitoring of the international normalized ratio (INR) to prevent valve thrombosis and thromboembolic events.

    “Because of the narrow therapeutic window, anticoagulation control with a VKA requires meticulous monitoring and can be challenging,” the team noted.

    “The time within the therapeutic range has been correlated with bleeding, thromboembolic events, and mortality,” they added, noting that factors associated with a reduced time within the VKA therapeutic range include a low SES measured at the neighborhood level.

    While it is established that SES can impact VKA therapeutic range, the team noted that whether low SES is associated with an increased risk of anticoagulation-related adverse events in patients with mechanical heart valves was “unknown.”

    Study setup

    Dalén and colleagues analyzed data from the SWEDEHEART registry, with additional baseline characteristics obtained from the Swedish National Patient Register.

    They included all patients aged 18-70 years who underwent AVR with a mechanical heart valve prosthesis in Sweden from January 1, 1997, to August 31, 2018, with patients who underwent concomitant surgery on other valves excluded.

    The primary outcome of this study was hospitalization for a bleeding event, and the secondary outcomes were ischemic stroke/transient ischemic attack (TIA) or embolism and cause-specific mortality (intracranial bleeding and ischemic stroke/emboli), said the team.

    “We also constructed a combined outcome: a composite of bleeding, stroke/TIA/embolism, and death from any cause,” they added.

    Household disposable income was categorized according to quartiles from lowest (Q1) to highest (Q4), with each quartile representing 25% of the study population.

    The mean age of the total study population was 56 years, said Dalén and colleagues, noting that  26% of the patients were female.

    Furthermore, patients in the highest income quartile were more often married, had a higher education level, had better renal function, had a lower incidence of diabetes and less often had alcohol use disorder, they said, adding that other baseline characteristics, such as age, left ventricular ejection fraction, heart failure, atrial fibrillation, previous stroke, liver disease and previous bleeding events, were similar among the four income quartiles.

    Key findings

    “In this nationwide population-based cohort study of patients who underwent surgical mechanical AVR, we observed a significant inverse association between income level and risk of bleeding,” said Dalén and colleagues.

    The team reported that among 5,974 patients, the absolute risk for bleeding after 20 years of follow-up was 20% (95% confidence interval [CI]: 17%–24%) in the lowest income quartile (Q1) and 16% (95% CI: 13%–20%) in the highest quartile (Q4).

    The risk of bleeding decreased with increasing income level and was significantly lower in patients in income level Q3 (HR: 0.77; 95% CI: 0.60–0.99) and Q4 (HR: 0.68; 95% CI: 0.50–0.92) than Q1.

    “We also observed that patients in the lowest income quartile had a 5-fold higher risk of death due to intracranial hemorrhage than individuals in the age- and sex-matched Swedish general population,” they said (standardized mortality ratio: 5.0; 95% CI: 3.3–7.4).

    The risk of death due to intracranial hemorrhage decreased with increasing income and was similar between the general population and the highest income quartile, said the authors.

    “These findings suggest suboptimal anticoagulation treatment in patients with a lower SES, highlighting the importance of strategies to optimize anticoagulation treatment in patients with a mechanical heart valve,” said Dalén and colleagues. “Our findings also highlight the importance of prosthetic valve selection in patients who are at increased risk of anticoagulation-related bleeding complications.”

    Societal inequities lead to health inequalities

    Writing in an accompanying editorial, Margaret C. Fang, MD, MPH, from the Department of Medicine at the University of California, San Francisco, noted that an elevated risk of bleeding is the most common and serious complication of anticoagulant treatment.

    “Assessing bleeding risk is a key step when deciding on the appropriateness of anticoagulation for an individual patient,” she said.

    The editorialist noted that the risk of poor outcomes due to intracranial hemorrhage was “especially high,” since people in the lowest income quartile had a fivefold higher risk of death from intracranial hemorrhage compared with the general population – whereas people in the highest income quartile were at 1.3 times the risk.

    “Because mechanical valves require life-long anticoagulation with VKAs, the authors suggest that the relationship between income and outcomes was potentially mediated through differences in anticoagulation control and adherence,” she noted, adding, however, that a significant limitation of the registry analysis is the lack of data on longitudinal medication administration and VKA control.

    “Without such information, it is speculative to say that bleeding was due to suboptimal anticoagulation management, although others have described links between area deprivation index, time in therapeutic range, and bleeding outcomes,” noted the expert commentator.

    However, Fang added that the study again highlights that social conditions are “deeply entwined with health” and that societal inequities can lead to health inequalities.

    “Clinicians should be aware that income insecurity is a risk factor for worse health outcomes such as bleeding and should explore potential barriers to optimal anticoagulation management when counseling their patients,” she said.

    “The future now depends on evaluating what policy interventions are effective in mitigating the negative effects of poverty and in promoting the highest quality, most equitable health care.”

    Sources:

    Dalén M, Persson M, Glaser N, et al. Socioeconomic Status and Risk of Bleeding After Mechanical Aortic Valve Replacement. J Am Coll Cardiol 2022;79:2502-2513.

    Fang MC. Social Determinants of Health, Income, and Anticoagulation Outcomes. J Am Coll Cardiol 2022;79:2514-2515.

    Image Credit: sirisakboakaew – stock.adobe.com

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