By Nicole Lou, Senior Staff Writer, MedPage Today
October 14, 2026
The American heart failure (HF) population is navigating a quiet, systemic crisis. New data presented at the Heart Failure Society of America (HFSA) annual conference in Phoenix reveals that cardiovascular inflammation—a potent but often overlooked driver of poor patient outcomes—is alarmingly prevalent among U.S. patients.
The findings, drawn from a critical subanalysis of the POSEIDON registry, underscore a significant disconnect: while clinical data clearly identifies a high "inflammatory burden" in the U.S., the medical community currently lacks the targeted pharmacotherapy required to effectively extinguish this fire.
The POSEIDON Registry: Unveiling the U.S. Inflammatory Landscape
The POSEIDON study stands as the largest global registry to date focusing on inflammation in patients with atherosclerotic cardiovascular disease (ASCVD) and heart failure. Spanning 18 countries and enrolling 18,904 adults between 2023 and 2025, the study provides a comprehensive window into the biological reality of modern heart failure care.
Marat Fudim, MD, MHS, of Duke University Medical Center, presented the U.S. specific sub-cohort data at the HFSA meeting. The results were striking. Researchers utilized high-sensitivity C-reactive protein (hsCRP)—a standard, reliable biomarker for systemic inflammation—as their primary metric. An hsCRP level of ≥2 mg/L was used to categorize patients as being at elevated inflammatory risk.
In the United States, the prevalence of this elevated state was stark:
- HFpEF (Heart failure with preserved ejection fraction): 50.8% of patients showed elevated hsCRP.
- HFmrEF (Heart failure with mildly reduced ejection fraction): 44.7% of patients showed elevated hsCRP.
- HFrEF (Heart failure with reduced ejection fraction): 50.3% of patients showed elevated hsCRP.
When compared to the global POSEIDON cohort, the U.S. figures reveal a clear outlier. Internationally, the prevalence of elevated hsCRP hovered around 38% across all HF categories. The American cohort, therefore, is significantly more inflamed, suggesting that environmental factors, dietary habits, and the high prevalence of metabolic comorbidities—such as obesity, diabetes, and chronic kidney disease (CKD)—are driving a unique and dangerous inflammatory state.
Chronology of a "Tricky Field": The Rise and Fall of Anti-Inflammatory Hope
The pursuit of inflammation-targeting therapies in cardiology has been marked by a series of high-profile "near misses" and clinical disappointments.
The Early Efforts
For decades, researchers have hypothesized that by dampening the immune response, they could mitigate the progression of heart failure. However, early trials throughout the 2000s were frequently neutral or even outright harmful, leading many investigators to step back from the field.
The Modern "Stifled" Enthusiasm
More recently, the industry pinned its hopes on highly specific pathways, particularly interleukin-6 (IL-6) inhibition. The promise was that by targeting a single, potent cytokine, clinicians could lower hsCRP and, by extension, major adverse cardiovascular events (MACE).
The story took a definitive turn in September 2026. Novo Nordisk, a leader in metabolic and cardiovascular research, announced the premature discontinuation of two pivotal trials: HERMES and ATHENA. These placebo-controlled studies were designed to evaluate ziltivekimab—an IL-6 inhibitor—in HF patients with high hsCRP. The decision to stop was based on clear evidence of futility.
This followed the disappointing results of the ZEUS trial, which also failed to demonstrate a reduction in MACE among patients with ASCVD and CKD using the same drug. For clinicians like Dr. Fudim, these results have left the clinical landscape feeling "stifled." The dream of a "magic bullet" targeting a single inflammatory pathway has, for now, been shelved.
The Clinical Conundrum: Why Is Inflammation So Persistent?
During his presentation at the HFSA conference, Dr. Fudim addressed the reality of "residual inflammatory risk." Even when patients are placed on rigorous, guideline-directed medical therapy (GDMT)—including ACE inhibitors, beta-blockers, and SGLT2 inhibitors—the inflammation frequently persists.
"Now, what does that mean? I don’t know how to address it, but all I can tell you is that we are very inflamed as a nation of HF patients," Fudim noted.
The data confirms that the inflammation is not occurring in a vacuum. It is deeply tied to the metabolic health of the patient. The study identified that those with higher hsCRP levels also consistently showed higher insulin and diuretic use. This links the inflammatory state directly to the "metabolic syndrome" cluster that plagues the American healthcare system.
Amanda Vest, MBBS, MPH, of the Cleveland Clinic, served as the discussant for the session. She echoed the frustration of the field, noting the ongoing, painful discrepancy: "How do you put it together? This demonstration of high inflammatory burden, what we know from other cohorts about its mortality implications, and yet these disappointing interventional trials?"
Implications for Future Research: Moving Toward a Broader Approach
If the path of single-pathway inhibition (like IL-6) is effectively closed, where does the future of heart failure treatment lie?
Dr. Fudim argues that the industry must pivot toward a broader, more holistic strategy. Instead of "snipping" a single branch of the inflammatory tree, he suggests that future therapies should aim to address the entire "inflammatory environment."
The Potential of GLP-1 Receptor Agonists
One of the most promising avenues currently under investigation is the use of GLP-1 receptor agonists. While originally developed for type 2 diabetes and obesity, these agents have demonstrated a unique ability to reduce systemic inflammation.
"GLPs reduce inflammation, but they do it differently," Fudim explained. "It’s going to be a whole array of inflammatory environments, not just IL-6."
However, this shift in strategy comes with a caveat. Dr. Fudim cautioned that clinicians must be judicious. The immune system is not an enemy to be eradicated; it is a complex, evolved survival mechanism. "If you have an agent that can target multiple pathways, you might be okay. But at the same time, be careful how much you suppress or interfere with the immune system. It was given to us for a reason."
A Practical Use for hsCRP Today
While the search for a new, revolutionary drug continues, the POSEIDON data offers an immediate, practical application for clinicians. Dr. Fudim advocates for the use of hsCRP as a "jumping board" in daily practice.
Even without a specific "anti-inflammatory pill," measuring hsCRP helps the cardiologist:
- Risk Stratification: Identifying patients who are at the highest risk for future adverse events.
- Patient Motivation: Using the biomarker as a tangible metric to encourage lifestyle interventions, such as supervised exercise and medically supervised weight loss.
- Holistic Management: Recognizing that high hsCRP may be a signal to look deeper into a patient’s management of comorbidities like CKD and diabetes.
Conclusion: The Long Road Ahead
The POSEIDON registry has effectively diagnosed a major issue within the American heart failure population: they are, as a group, in a state of high inflammatory risk that current standard treatments are not fully mitigating.
While the failure of recent, high-profile clinical trials in the IL-6 space has caused a retreat from narrow-focus drug development, it has also cleared the way for a more nuanced understanding of heart failure. The future of the field likely lies in therapies that address the systemic, metabolic drivers of inflammation rather than single, isolated pathways.
For the patients currently living with heart failure, the takeaway is clear: while the "magic bullet" remains elusive, the path to better outcomes is increasingly linked to aggressive, multi-disciplinary management of the metabolic factors that fuel the body’s fire. The "silent storm" of inflammation is no longer hidden, and the medical community is now tasked with finding a more comprehensive way to weather it.
