Most people with myelodysplastic syndromes (MDS) die from complications of bone marrow failure rather than from cancer spreading to other organs. In a large study of 2,877 MDS patients, 83% of documented deaths were directly caused by the disease itself, primarily through three mechanisms: transformation to acute myeloid leukemia (47%), infection (27%), and bleeding (10%). The remaining deaths were tied to other health conditions, particularly cardiovascular disease.
Understanding these causes can help patients and families anticipate what lies ahead, make informed decisions about care, and have more productive conversations with their medical teams.
Bone Marrow Failure Is the Central Problem
MDS is fundamentally a disease of the bone marrow. The marrow produces defective blood cells or too few of them, leading to dangerously low counts of red blood cells, white blood cells, and platelets. Each of these shortfalls creates a distinct life-threatening risk. Low white blood cells leave the body unable to fight infection. Low platelets make uncontrolled bleeding possible. Low red blood cells starve the heart and organs of oxygen. Many MDS patients don’t progress to leukemia at all but still die from these consequences of failing marrow.
A study focused specifically on lower-risk MDS found that infection was the most common cause of death at 38%, followed by leukemia transformation at 15% and hemorrhage at 13%. This underscores that even in patients whose disease appears less aggressive on paper, the inability to produce healthy blood cells is what ultimately proves fatal.
Infection: The Most Common Killer
Infections are the leading cause of death across all MDS risk categories. When the bone marrow can’t produce enough functional white blood cells, even a routine bacterial infection can become overwhelming. Infections occur at a rate of roughly one per patient per year in MDS, and the body’s weakened defenses make each episode potentially dangerous.
Bacterial pneumonia is the most frequent serious infection, followed by skin infections and bloodstream infections. One older but often-cited study found that infection accounted for 64% of deaths in MDS patients, outpacing even leukemia transformation. The numbers vary across studies depending on the patient population, but the pattern is consistent: a weakened immune system turns otherwise treatable infections into emergencies. Fever in a person with MDS is always taken seriously for this reason, as what looks like a mild illness can escalate to sepsis within hours.
Transformation to Acute Myeloid Leukemia
Historically, 30 to 40% of MDS patients eventually progress to acute myeloid leukemia (AML), a fast-moving blood cancer that is much harder to treat than MDS itself. When this happens, the bone marrow becomes flooded with immature, nonfunctional cells that crowd out normal blood production entirely.
Not all patients follow the same path. Some jump directly from lower-risk MDS to AML, while others first pass through a higher-risk MDS stage. In a large cohort study, patients who progressed from low-risk MDS directly to AML had a median survival of about 43 months from their original diagnosis, compared with roughly 81 months for those whose disease stayed stable. After AML develops, survival is often measured in months, particularly in older patients who can’t tolerate intensive chemotherapy.
AML transformation is the single largest cause of death in higher-risk MDS. The leukemia itself kills through the same mechanisms as advanced marrow failure: severe infection, uncontrolled bleeding, and organ damage from the sheer burden of abnormal cells.
Fatal Bleeding Events
Bleeding causes 10 to 20% of MDS deaths. The culprit is twofold: the bone marrow produces too few platelets, and the platelets it does produce often don’t function properly. About 19% of MDS patients experience significant bleeding at some point during their disease.
The most dangerous bleeding events are internal. Gastrointestinal hemorrhage and bleeding within the brain are the most common fatal sites. Unlike a cut or nosebleed, these can’t be stopped with external pressure and may cause rapid deterioration. Patients with very low platelet counts receive transfusions to reduce the risk, but transfusions provide only temporary protection and become less effective over time.
Cardiovascular Disease and Chronic Anemia
Not all MDS deaths are caused by the disease directly. Cardiovascular disease is a significant contributor, especially in older patients with lower-risk MDS who may live for years with chronic anemia. When the blood can’t carry enough oxygen, the heart works harder to compensate. Over months and years, this extra strain can lead to heart failure, heart attacks, and strokes.
A nationwide registry study of 831 MDS patients with known causes of death found that those with pre-existing heart disease were about three times more likely to die from cardiovascular causes. Age over 70 roughly doubled the risk. Notably, the study also found that treatment with drugs designed to boost red blood cell production (erythropoiesis-stimulating agents) was independently associated with a nearly twofold increase in cardiovascular deaths, though the reasons for this connection are still debated. For patients already at risk for heart problems, the combination of chronic anemia and its treatments creates a dangerous feedback loop.
Iron Overload From Transfusions
Many MDS patients depend on regular red blood cell transfusions for months or years. Each unit of transfused blood delivers 200 to 250 milligrams of iron, and the body has no efficient way to get rid of it. A patient receiving four units per month accumulates roughly 9.6 grams of excess iron per year, nearly six times what the body would normally store.
This iron deposits in organs, particularly the liver and heart. Over time, it causes tissue damage through a process called oxidative stress, where toxic iron compounds generate harmful molecules that injure cells. The result can be liver dysfunction, heart failure, and hormonal imbalances. Studies consistently show that MDS patients with iron overload have a higher risk of death than those without it. Iron chelation therapy can help remove excess iron, but it adds another layer of treatment burden to an already complex regimen, and not all patients tolerate it well.
What the Final Weeks Look Like
The end-of-life experience for MDS patients often involves high-intensity medical care. Data from a large Medicare database found that 28% of MDS patients were admitted to an ICU within their last 30 days of life, and about 35% received life-sustaining treatments such as mechanical ventilation or vasopressors during that same window. These numbers reflect how quickly MDS complications can escalate, particularly when a severe infection or bleeding event occurs.
Hospice enrollment, when it happens, tends to come very late. Among MDS patients who entered hospice, the median time from enrollment to death was just 4 to 5 days. Palliative care referrals also come late, with a median of about 12 days before death. Only about 49% of MDS patients in the study used hospice at all.
Patients who had earlier conversations about their goals of care experienced a meaningfully different end of life. Those who completed a portable medical order (a document specifying treatment preferences) more than 30 days before death were about 80% less likely to be admitted to the ICU, 80% less likely to receive life-sustaining treatments, and nearly three times more likely to use hospice services. These findings suggest that early planning doesn’t just change paperwork. It changes the actual experience of dying.
How Prognosis Varies by Risk Category
MDS is not one disease but a spectrum, and life expectancy varies enormously depending on where a patient falls. The Revised International Prognostic Scoring System (IPSS-R) groups patients into categories based on their blood counts, bone marrow findings, and genetic abnormalities. Patients in the very low risk group have a median survival of nearly 9 years. Those in the good risk category survive a median of about 5.3 years. Intermediate-risk patients average around 3 years, though this group is highly variable: favorable subgroups within it survive closer to 6 years, while adverse subgroups survive about 2.3 years.
These timelines matter because they shape which cause of death is most likely. Patients with higher-risk MDS are more likely to die from leukemia transformation or acute marrow failure. Patients with lower-risk disease, who live longer, are more likely to die from chronic complications like cardiovascular disease, iron overload, or infections that accumulate over years of impaired immunity. Understanding your risk category helps frame not just how long you might live, but what you’re most likely to face.