Heart Failure with Coexisting Conditions

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These articles provide education to enhance your healthcare partnership. All treatment decisions should involve your healthcare team. Use this knowledge to have informed discussions, not replace medical care.

In Brief

Heart failure rarely stands alone. It travels with diabetes, chronic kidney disease, atrial fibrillation, iron deficiency, obesity, and more — and these other conditions don’t just sit quietly alongside it. They drive heart failure, and it drives them, through biology shared across the heart, the kidneys, and the body’s metabolism. That has two practical consequences. First, a therapy aimed at one organ can help another, while a treatment that suits one condition can be risky in a second — so the conditions have to be managed together. Second, the day-to-day work of heart failure care — which medications, which monitoring, which specialists — is shaped throughout by whatever else a person is living with. This article is about those coexisting conditions and how they change ongoing care. (The main causes of heart failure, including coronary artery disease and high blood pressure, were covered earlier in the series.)

The Heart Is Never Treated Alone

Heart failure is seldom a solitary diagnosis. The same forces that damage the heart — high blood pressure, high blood sugar, inflammation, and vascular injury — also damage the kidneys and disrupt metabolism, so these conditions cluster together because they share roots. A person with heart failure very often also has some combination of diabetes, chronic kidney disease, and an irregular rhythm, each making the others worse.

That clustering changes how heart failure is treated. A plan that manages the heart while ignoring the kidneys, the blood sugar, and the rhythm addresses only a fraction of the problem. There is an encouraging side, though: because these systems are connected, a treatment that helps one can help several — which is much of what the last decade of heart failure research has shown.

Diabetes and the Heart

The link between diabetes and heart failure runs in both directions. As Article 3 described, diabetes injures the heart two ways — by accelerating the coronary artery disease that causes heart attacks, and by directly damaging the heart muscle, a condition called diabetic cardiomyopathy.[2] Diabetes raises the risk of developing heart failure roughly two- to fourfold, and heart failure worsens the metabolic environment in return.

The therapeutic side of this connection reshaped the field. The SGLT2 inhibitors — a class developed to lower blood sugar by making the kidneys excrete glucose — were found, in large trials, to protect the heart and kidneys through benefits that reach beyond lowering blood sugar. In the trials that established them, they reduced worsening heart failure and cardiovascular death whether or not the person had diabetes.[3] A therapy born in diabetes care became one of the four core heart failure treatments of Article 6 — and, in doing so, blurred the old boundary between a “diabetes drug” and a “heart drug.”

That story carries a practical lesson many people miss: in someone with heart failure, the diabetes plan itself should be chosen with the heart and kidneys in view. Some glucose-lowering treatments help heart failure; others are less suitable. One older class, the thiazolidinediones, makes the body hold on to fluid and can worsen heart failure in people who already have symptoms, so it is generally avoided in this setting.[1] And blood-sugar targets are not one-size-fits-all — in older, frailer, or more advanced patients, aiming too tightly can do more harm than good. The diabetes plan therefore has to be built with the heart, the kidneys, age, frailty, and the risk of low blood sugar all in view.

The Heart and the Kidneys: The Cardiorenal Link

The heart and kidneys are so tightly coupled that clinicians speak of the cardiorenal system as a unit. Heart failure can impair kidney function through several routes — less effective blood flow reaching the kidneys, congestion backing up into them, and hormonal changes — and failing kidneys in turn hold on to sodium and fluid, raise blood pressure, and complicate heart failure treatment. Each can pull the other down.

This coupling shapes treatment day to day, and two points are worth understanding because they cause a great deal of needless worry.

A change in kidney numbers does not always mean harm. As Article 5 noted, kidney function guides which heart failure medications are safe and at what dose, so it is checked often. But a rise in creatinine — the usual measure of kidney function — does not automatically mean a medication is damaging the kidneys or must be stopped. Some rises reflect expected changes in blood flow during decongestion, or after starting medications that protect the heart over the long term, rather than direct injury to the kidneys; others are clinically important. The care team reads the number in context — its size, its direction over time, the degree of congestion, the blood pressure, the potassium, and the reason the medication was started — rather than reacting to a single value.

Potassium links kidney function to medication safety. Several heart failure medications raise potassium — the renin-angiotensin blockers and mineralocorticoid receptor antagonists of Article 6 — while diuretics can lower it, and kidney disease makes high potassium more likely. Because both high and low potassium can trigger dangerous heart rhythms, it is monitored alongside kidney function, and it sometimes limits how far a helpful medication can be pushed. It shows the pattern that runs through all of these conditions: one of them can change what is safe when treating another.

Here again, treatments cross over. The SGLT2 inhibitors protect the kidneys as well as the heart. Finerenone, a nonsteroidal mineralocorticoid receptor antagonist, has an established role in chronic kidney disease associated with type 2 diabetes and has also been shown to reduce worsening heart failure events in people with mildly reduced or preserved ejection fraction[4] — a single drug spanning heart, kidney, and metabolism.

Atrial Fibrillation: A Rhythm That Worsens Heart Failure

Atrial fibrillation — a common irregular, often rapid heart rhythm — and heart failure each worsen the other. Atrial fibrillation makes the heart pump less efficiently and can, on its own, weaken it over time; heart failure, by stretching and stressing the heart, promotes atrial fibrillation. Each is both cause and consequence of the other, and having both is worse than having either alone.

Managing the rhythm means controlling the heart rate or restoring a normal rhythm. In selected patients — particularly some with reduced ejection fraction — a procedure called catheter ablation, which uses targeted energy to interrupt the abnormal electrical signals, can improve symptoms, and in specific trial populations has reduced hospitalization and death compared with medication alone.[5]

But atrial fibrillation carries a second, separate danger that must be addressed regardless of how the rhythm is managed: it sharply raises the risk of stroke, because blood can pool and clot in the quivering upper chambers. For many people with heart failure and atrial fibrillation, stroke prevention includes anticoagulation — often called blood thinners — chosen on the basis of overall clot risk and individual bleeding considerations, and decided on its own terms with the care team. One point is easy to get wrong and important to state plainly: restoring a normal rhythm, or an apparently successful ablation, does not by itself remove the need for anticoagulation. That decision rests on a person’s overall stroke risk and clinical picture, not simply on whether symptoms have disappeared or the rhythm appears controlled.

The Quieter Companions

Several other conditions travel with heart failure and matter because they are common, consequential, and often treatable.

Iron deficiency is common — and it can be present even when it has not caused anemia. It is defined by blood tests (ferritin and transferrin saturation), so a normal hemoglobin does not rule it out. Low iron worsens symptoms and exercise capacity, and in appropriately selected iron-deficient patients, intravenous iron can improve functional status and quality of life, with trials also showing fewer heart failure hospitalizations in some settings.[6] It is a treatable problem that is easy to miss.

Obesity is not merely an adjacent risk factor. In the preserved-ejection-fraction heart failure of Article 2, obesity is, for many people, a central driver of the disease — and now a treatment target in its own right. In obesity-related preserved-ejection-fraction heart failure, semaglutide (a GLP-1 receptor agonist) has been shown to improve symptoms, physical limitations, and weight;[7] tirzepatide has also improved symptoms and weight and, in the SUMMIT trial, reduced worsening heart failure events.[8] It is one of the clearest recent examples of how much weight and metabolism can matter in this kind of heart failure.

Sleep-disordered breathing is common in heart failure — but obstructive and central sleep apnea are different conditions, and treatment depends on identifying which pattern is present. Symptoms such as loud snoring, witnessed breathing pauses, disrupted sleep, or excessive daytime sleepiness may prompt evaluation, but testing is needed to tell the obstructive and central patterns apart, because treatment differs.

Anemia — a low blood count — is also common, and it rarely has a single cause: iron deficiency, kidney disease, bleeding, and chronic inflammation can each contribute, often together. Because the right treatment depends on the cause, finding out why matters more than the number alone.

Lung disease. Chronic obstructive pulmonary disease (COPD) and heart failure frequently coexist, and both cause breathlessness — which can make it hard to tell which is responsible for a given symptom. Sorting out how much each contributes is part of good care. And, contrary to a persistent old worry, when there is a clear cardiac reason to use them — particularly in reduced-ejection-fraction heart failure, where they are foundational — the cardioselective beta-blockers can often be used safely in people who also have COPD. Lung disease should not automatically rule out a beneficial heart treatment.

When Treatments Pull in Different Directions

Coexisting conditions do more than pile up. Because they interact, treating one condition can change the safety, dosing, or monitoring of treatment for another — so the plan has to fit them all at once. A few common examples:

• Treating congestion can improve kidney function in some people even when creatinine rises at first, while congestion left in place can itself worsen the kidneys.
• Relieving congestion with diuretics can shift kidney numbers and potassium.
• Kidney function and potassium can limit how far some heart failure medications are pushed.
• Anticoagulation for atrial fibrillation adds bleeding risk that has to be weighed.
• Anemia may be driven by iron deficiency, kidney disease, or bleeding — each handled differently.
• Diabetes medications should be chosen with the heart and kidneys in mind.
• Low blood pressure can limit how much treatment can be intensified.

These tradeoffs are why heart failure care requires judgment across the whole clinical picture, and often involves coordination among several clinicians.

What Tends to Be Watched

Because the conditions are linked, a handful of things recur throughout heart failure care — not a fixed checklist to memorize, but a map of why the same tests keep appearing:

• kidney function and potassium (and other electrolytes)
• blood-sugar control, in people with diabetes
• iron studies, when iron deficiency is suspected
• blood count, when anemia or bleeding is a concern
• heart rate and rhythm
• weight and signs of congestion
• blood pressure
• symptoms that suggest sleep-disordered breathing

Seeing why each is followed turns a confusing series of tests into something that makes sense: each one checks a different part of the same connected system.

Why This Changes Care

These connections are why heart failure care often extends beyond cardiology — to primary care and, when needed, kidney, diabetes, lung, or sleep specialists. The goal is not to accumulate specialists, but to make sure treatment choices and monitoring are coordinated across the conditions that affect one another. And there is a real upside to how linked these conditions are: some therapies deliver benefits across more than one of them, while others make treatment of the whole picture safer or more effective.

Clinical Bottom Line

Heart failure care is shaped by the conditions around it. Diabetes and chronic kidney disease change which treatments are chosen and what must be monitored; atrial fibrillation creates separate decisions about rhythm and about stroke prevention, which anticoagulation addresses on its own terms; iron deficiency can matter even without anemia; and obesity and sleep-disordered breathing may be active treatment targets rather than background facts. The practical lesson is that each condition should be treated with the others in view — because the safest, most effective plan is built across the whole clinical picture, not organ by organ.

What Comes Next

This article covered the conditions that accompany heart failure. Article 12, the last in the series, turns to how care aligns with a person’s own priorities as heart failure progresses — advance care planning and goals of care, and how palliative care works alongside cardiac treatment rather than instead of it: why these conversations, held early, lead to better care on a person’s own terms, and why planning ahead is not giving up.

Key Terms

Diabetic cardiomyopathy: Injury to the heart muscle from diabetes itself, occurring independent of blocked arteries, high blood pressure, or valve disease.

SGLT2 inhibitor: A medication class (dapagliflozin, empagliflozin) developed for diabetes that protects both the heart and the kidneys in heart failure, with or without diabetes.

Cardiorenal: Relating to the tightly coupled relationship between the heart and the kidneys, in which trouble in one worsens the other.

Potassium: A blood salt that both heart failure and its treatments can push too high or too low; because either extreme can cause dangerous rhythms, it is monitored closely, especially when kidney function is impaired.

Finerenone: A nonsteroidal mineralocorticoid receptor antagonist (a drug that blocks the effects of the hormone aldosterone), first established in diabetic kidney disease and since shown to reduce worsening heart failure events in mildly reduced or preserved ejection fraction; an example of a treatment spanning heart, kidney, and metabolism.

Atrial fibrillation: A common irregular, often rapid heart rhythm that both worsens and results from heart failure, and that raises the risk of stroke.

Catheter ablation: A procedure that uses targeted energy to interrupt the abnormal electrical signals causing atrial fibrillation; in selected patients it can improve symptoms and, in some trial populations, outcomes.

Anticoagulation: Medication — often called blood thinners — used to prevent the strokes caused by clots forming in atrial fibrillation; decided on its own terms, based on stroke risk and bleeding considerations, and not removed simply because the rhythm improves.

Iron deficiency: A common, correctable problem in heart failure that can be present without anemia; it is assessed with ferritin and transferrin saturation, and intravenous iron can improve symptoms and function.

Sleep-disordered breathing: Repeated pauses in breathing during sleep, common in heart failure; obstructive and central sleep apnea are different conditions whose treatment differs.

References

1. Heidenreich PA, Bozkurt B, Aguilar D, et al. 2022 AHA/ACC/HFSA Guideline for the Management of Heart Failure: A Report of the American College of Cardiology/American Heart Association Joint Committee on Clinical Practice Guidelines. Circulation. 2022;145:e895–e1032. https://doi.org/10.1161/CIR.0000000000001063
2. Dunlay SM, Givertz MM, Aguilar D, et al. Type 2 Diabetes Mellitus and Heart Failure: A Scientific Statement from the American Heart Association and the Heart Failure Society of America. Circulation. 2019;140(7):e294–e324. https://doi.org/10.1161/CIR.0000000000000691
3. McMurray JJV, Solomon SD, Inzucchi SE, et al. Dapagliflozin in Patients with Heart Failure and Reduced Ejection Fraction (DAPA-HF). N Engl J Med. 2019;381(21):1995–2008. https://doi.org/10.1056/NEJMoa1911303
4. Solomon SD, McMurray JJV, Vaduganathan M, et al. Finerenone in Heart Failure with Mildly Reduced or Preserved Ejection Fraction (FINEARTS-HF). N Engl J Med. 2024;391(16):1475–1485. https://doi.org/10.1056/NEJMoa2407107
5. Marrouche NF, Brachmann J, Andresen D, et al. Catheter Ablation for Atrial Fibrillation with Heart Failure (CASTLE-AF). N Engl J Med. 2018;378(5):417–427. https://doi.org/10.1056/NEJMoa1707855
6. Ponikowski P, Kirwan BA, Anker SD, et al. Ferric carboxymaltose for iron deficiency at discharge after acute heart failure (AFFIRM-AHF): a multicentre, double-blind, randomised, controlled trial. Lancet. 2020;396(10266):1895–1904. https://doi.org/10.1016/S0140-6736(20)32339-4
7. Kosiborod MN, Abildstrøm SZ, Borlaug BA, et al. Semaglutide in Patients with Heart Failure with Preserved Ejection Fraction and Obesity (STEP-HFpEF). N Engl J Med. 2023;389(12):1069–1084. https://doi.org/10.1056/NEJMoa2306963
8. Packer M, Zile MR, Kramer CM, et al. Tirzepatide for Heart Failure with Preserved Ejection Fraction and Obesity (SUMMIT). N Engl J Med. 2025;392(5):427–437. https://doi.org/10.1056/NEJMoa2410027

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