Leading Causes of Death in Cats: A Veterinarian's Guide to Disease Prevention and Care to Extend Their Lifespan

In recent years, thanks to advances in veterinary medicine and improvements in living environments, the average lifespan of cats has reached about 15 years. However, we must eventually say goodbye to the cats we love. Since many causes of death in cats are illness-related, knowing about these conditions may help extend their lives.

In this article, we will explain the leading causes of death in cats.

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Ranking of Causes of Death in Cats

There is data from a 2020 study on the causes of death in cats. This research was based on data collected from 40 animal hospitals nationwide.

Here are the top 3:

1. Urinary system diseases (29.8%)
2. Tumors (20.3%)
3. Circulatory system diseases (11.6%)

While the specific types of urinary diseases were not listed, it is presumed that chronic kidney disease, which is common in older cats, is the primary factor.

Causes of Death by Age Group (Kittens, Adults, and Seniors)

Based on the age at death in the aforementioned study, here are the causes of death by age group.

For kittens and young adult cats, infectious diseases, poisoning, and external trauma are common. For adult cats, tumors, respiratory diseases, and blood/immune system diseases are common. For senior cats, the causes mirror the top 3 overall: urinary diseases, tumors, and circulatory diseases.

Differences in Risk Between Indoor and Outdoor Cats

The average lifespan of a strictly indoor cat is about 15 years, compared to about 13 years for cats that go outside, a difference of two years. This difference is believed to be due to risks faced outdoors, such as traffic accidents, injuries from fights with other cats, and infectious diseases.

#1 Cause of Death: What Is Chronic Kidney Failure in Cats? Symptoms and Measures

Why Is Kidney Disease So Common in Cats?

There are many causes of chronic kidney disease in cats, including aging, genetics, changes in blood flow to the kidneys (high or low blood pressure), poisoning, infections, and urinary stones.

Because their ancestors lived in deserts, cats evolved to survive on very little water. Even modern cats tend not to drink much, which puts an added strain on their kidneys. This is thought to cause kidney damage as they grow older. Additionally, certain breeds like Persians and American Shorthairs may develop kidney disease from a young age due to a hereditary condition called polycystic kidney disease.

A few years ago, it was announced that a substance called AIM might be involved in kidney disease in cats. AIM helps clear waste products from the kidneys; cats are thought to be prone to chronic kidney disease because this substance does not function well in them.

Symptoms of Chronic Kidney Disease in Cats

Chronic kidney disease progresses gradually, and symptoms appear when the kidneys can no longer function sufficiently. Because symptoms are not very noticeable in the early stages, the disease is often quite advanced by the time they manifest.

Symptoms of chronic kidney disease in cats include increased thirst and urination, loss of appetite, vomiting, dehydration, lethargy, bad breath, and anemia.

When kidney function declines, the kidneys cannot concentrate urine, leading to frequent, dilute urination. This results in dehydration, which in turn causes the cat to drink more water. Furthermore, because toxins cannot be excreted via urine, the cat may lose its appetite or vomit. Changes in the oral environment can cause bad breath or stomatitis. Anemia also occurs due to a decrease in erythropoietin, a hormone produced by the kidneys that stimulates red blood cell production.

Measures to Slow Progression

Unfortunately, chronic kidney disease is incurable. However, its progression can be slowed with appropriate treatment, such as dietary therapy, medication, and subcutaneous fluids.

There are therapeutic diets for kidney disease that restrict phosphorus and sodium to reduce the burden on the kidneys. The appropriate food depends on the stage of the disease.

As kidney disease progresses, blood pressure often rises, which in turn causes further damage to the kidneys—a vicious cycle. Therefore, blood pressure medication is used. Appetite stimulants may be used to counteract loss of appetite, and erythropoietin preparations may be used for anemia. Other treatments include phosphorus/toxin binders, probiotic supplements, and antioxidant supplements.

You may associate kidney disease treatment with at-home subcutaneous fluid administration. When dehydration is severe, regular subcutaneous fluids become necessary.

It is important to have regular health checkups to detect the disease in its early stages. Chronic kidney disease onset increases in cats aged 7 and older. Therefore, we recommend one checkup per year until age 6, and two per year from age 7 onwards to ensure early detection.

#2 Cause of Death: Types of Cancer (Malignant Tumors) and Preventive Measures

Common Types of Cancer in Cats

There are various types of cancer that occur in cats; here are the five most common ones.

Lymphoma

This is the most common abdominal cancer in cats. Lymphocytes in the blood become cancerous. It can occur in various places, including the skin, lymph nodes, and internal organs, but the digestive type, which occurs in the intestinal tract, is particularly common.

Mammary Cancer

Cancer that occurs in the mammary glands. The risk increases if a cat has not been spayed and continues to experience heat cycles. About 90% of mammary lumps in cats are malignant, and metastasis has often already begun by the time they are discovered.

Mast Cell Tumor

This occurs when mast cells in the blood become cancerous. There are visceral types (internal organs) and cutaneous types (skin). The cutaneous type is usually not aggressive but causes itching, etc. In the visceral type, tumors form in internal organs, causing symptoms.

Squamous Cell Carcinoma

Cancer derived from squamous cells in the skin. It frequently occurs on the cat's face. It tends to occur in areas with thin fur and is more common in white cats.

Fibrosarcoma

Cancer derived from fibroblasts in the skin. It tends to occur on the limbs, abdomen, and face. Surgery is the first-line treatment, but it is known for being prone to recurrence. While a link to vaccines has been suggested, the exact cause is unknown.

Health Checks for Early Detection

Close observation is key to early cancer detection. Check their food and water intake, urine/feces volume, color, and shape, activity levels, vomiting, lumps or swelling on the body, weight loss, abdominal swelling, or signs of pain. If you notice any changes, consult your veterinarian immediately.

Cancer is more common in senior cats aged 7 and older. It is also important to have health checkups once a year until age 6 and twice a year from age 7 onwards.

#3 Cause of Death: Causes of Heart Disease and Easy-to-Miss Signs

What Is Hypertrophic Cardiomyopathy, the Most Common Heart Disease in Cats?

Hypertrophic cardiomyopathy (HCM) is the most common heart disease in cats. It is a condition where the heart muscle (myocardium) becomes abnormally thick, most often in the left ventricle. This thickening prevents the heart from pumping blood effectively, which can lead to difficulty breathing due to pulmonary edema, or the accumulation of fluid in the chest or abdomen. Blood clots can also form in the heart; these can lodge in the hind limbs (thromboembolism), causing the legs to become cold and paralyzed. HCM can sometimes be asymptomatic, leading to incidental diagnosis.

While the exact cause of feline HCM is not fully clear, it is believed to involve genetics, as larger breeds like Maine Coons and Norwegian Forest Cats are more predisposed. While these breeds may develop it as young as 2 years old, it is generally seen in older cats.

Even Without Symptoms, Beware! The Importance of Regular Checkups

Feline HCM does not always manifest with symptoms; reports suggest that up to 15% of cats may have asymptomatic cardiomyopathy. The scary thing about asymptomatic HCM is that it can cause sudden death. Therefore, do not assume your cat is healthy just because they have no symptoms—regular health checkups and heart examinations are essential.

Dietary Weight Management Is Key

There is no way to prevent HCM. Once diagnosed, it requires lifelong treatment, and sudden death can still occur. Treatment involves not just medication but also weight control. Since obesity puts a strain on the heart, it is essential to maintain an appropriate weight. As intense exercise can stress a cat with cardiomyopathy, focus on adjusting food intake to manage weight.

What Owners Can Do to Reduce Causes of Death

When to Schedule Regular Health Checkups

Health checkups are necessary for every cat. Cats are considered seniors from age 7, and kidney disease, tumors, cardiomyopathy, and various other conditions often manifest during this stage. Therefore, we recommend one checkup per year until age 6, and two per year from age 7 onwards.

Reviewing Diet and Exercise Habits

The link between obesity and disease has been pointed out for many conditions. For example, research results show that diabetes and cancer are related to obesity. Furthermore, obesity puts physical stress on the body, which can exacerbate illnesses. Therefore, manage your cat's weight with diet control to avoid obesity. Moderate exercise can help relieve stress and prevent obesity. While exercise may be detrimental for cats currently undergoing treatment for certain illnesses, it is vital for healthy cats.

Creating a Low-Stress Environment

High stress leads to a weakened immune system and can trigger various illnesses. Common stressors include multi-cat households, living environment, and infections. In multi-cat households, cats may be forced into too close proximity, increasing stress levels. Furthermore, failing to provide enough litter boxes, food stations, water bowls, and hiding spots can cause significant stress.

External parasites like fleas and ticks, as well as infections, not only lower a cat's immune system but also cause stress. Since some infections can contribute to the development of tumors, regular prevention is necessary. Keeping cats strictly indoors is important, as outdoor cats are at a much higher risk of infection.

Summary

The top three causes of death in cats are chronic kidney disease, cancer, and hypertrophic cardiomyopathy. While these diseases are difficult to prevent, early detection through regular health checkups is possible. Don't wait to see if things get better; instead, prioritize annual checkups until age 6, and bi-annual checkups from age 7 onwards, even if your cat shows no symptoms.