Top Chronic Diseases Every Med Student Should Know

America is a nation awash in lifestyle diseases, nearly all of which are chronic. From hypertension, which impacts close to half of all adults, to chronic kidney disease, affecting more than one in seven, chronic illness is everywhere. 

Regardless of the specialty, few doctors will get through a career without treating a patient dealing with one of these diseases. It’s crucial, then, that med students graduate with knowledge of the most common of these diseases. 

“Most students will finish with information about the most common chronic illnesses,” said Yalda Safai, MD, a New York-based psychiatrist with a master’s degree in public health. “But it’s important to be able to spot and diagnose these conditions properly, no matter what your area of specialty.” 

The illnesses may shift and change over time — consider type 2 diabetes, for instance, which in 1960 barely registered — but there is a set of current chronic illnesses that you should keep on your radar when treating patients. Missing a disease or misdiagnosing one can lead to more complications and potentially adverse outcomes.

Here’s what experienced physicians rank as the 10 most common you’ll encounter today: 

Hypertension: In a nation where about 50% of adults have high blood pressure, this one must be front and center with any patient you treat. “Once you develop hypertension, you’ll need to manage it for life,” said Safai. “You’ll generally see it in patients who are over 50, and at over 60, the prevalence is even higher.” 

Treatment varies by patient but be prepared to address it with lifestyle changes and/or medications.

Complications of high blood pressure include heart attack or stroke, eye problems, metabolic syndrome, kidney problems, and even changes with memory or understanding. 

Diabetes: The two types of diabetes — 1 and 2 — are illnesses for life. Type 1 generally appears early in life, although it’s not unheard of that an adult will develop it. Type 2 falls into the lifestyle illness category, and when poorly controlled, can lead to a wide array of complications. “These are diseases with a lot of evidence, but treatment is individualized,” said Kathryn Brandt, DO, department chair for primary care at the University of New England College of Osteopathic Medicine, Biddeford, Maine. “But you’re always looking at a combination of medication and behavioral management.” 

Chronic kidney disease: Likely more common than most people realize, chronic kidney disease affects a large part of the adult population, and many people don’t even know they have it. Depending on the stage of severity, chronic kidney disease arises from a variety of sources. 

“It can be easy to miss it — nine out of ten patients don’t realize they have the illness,” said Tim Pflederer, chief medical officer at Evergreen Nephrology, Nashville, Tennessee. “It can start very mild and progress over time. If the damaging factor goes untreated, it can lead to kidney failure.” 

Mental health illness: According to Brandt, most cases of depression and anxiety are diagnosed by a primary care physician, but not always. Both diagnoses are increasingly common: In 2022, about 1 in 5 adults experienced symptoms of anxiety or symptoms of depression. The highest rates tend to fall in the young adult age group, between 18 years and 29 years. 

“It’s very common now,” said Safai. “You need to have a basic understanding of what it is. In most cases, a primary physician can treat it, but if it becomes complex, it’s important to send a patient on to a specialist.” 

Other mental illnesses to keep an eye out for include schizophrenia, bipolar disease, eating disorders, and posttraumatic stress disorder. Having knowledge of each can potentially expedite the critical care your patients need and lead to better outcomes when caught early. 

Alzheimer’s disease/dementia: While not all forms of dementia are Alzheimer’s, it is a form of dementia that is on the rise. Currently nearly 7 million Americans are living with the disease, but by 2050 that number may hit 13 million. In 2021, Alzheimer’s was the fifth-leading cause of death in the 65 years or older population. 

“Know the early warning signs because there are treatments that are beginning to emerge,” said Brandt. “Cognitive change is a syndrome and it’s the job of a doctor to figure out what type of dementia and how to manage it.” 

Early warning signs of dementia and Alzheimer’s can include memory loss that disrupts daily life, poor judgment that leads to bad decisions, taking longer than normal to complete daily tasks, and losing track of dates or knowing a current location.

Asthma: A pulmonary condition characterized by chronic inflammation of the respiratory tubes, the Centers for Disease Control and Prevention estimates that 1 in 11 children and 1 in 12 adults have asthma in this country. There are two major categories, allergic and nonallergic. “It lives with you until the end of life,” said Safai. “Once you’ve had an attack, you risk death.”

While not a complicated disease, according to Safai, it’s important to have a basic understanding of asthma, especially because it’s one of the leading causes of emergency room visits in the country. 

Addiction: Unfortunately, substance abuse and addiction are highly prevalent in American society. Since 2000, drug overdose deaths in the United States are nearing 1 million. Whether addiction to alcohol, illicit or prescription drugs, it is a chronic condition to watch for in your patients, whether adult or youth. 

“Addiction and mental health often present together,” said Brandt. “We need to approach patients with dignity and understanding.” 

Like other chronic illnesses, treating addiction often involves a combination of behavioral management and medication in an evidence-based approach. Keep in mind that addiction is often a moving target, said Brandt, and adjust along with it. 

Osteoporosis: A very common condition in women who have gone through menopause due to loss of hormones, osteoporosis leads to brittle bones that can easily break. That said, it’s not just a disease that impacts women. About 10 million Americans have osteoporosis, and another 44 million have low bone density. Diet, exercise, and a healthy lifestyle are the best defense against the disease, but medications and hormones can also help when necessary.

Arthritis: Falling into two major buckets — osteo and rheumatoid — in 2022 arthritis affected 21% of women and 16% of men. Arthritis is often painful inflammation in the tissues surrounding joints. Osteoarthritis will more likely impact joints like knees or hips, whereas rheumatoid impacts multiple joints, with morning stiffness that lasts longer than it does with osteo. Rheumatoid is an autoimmune disease, whereas osteoarthritis often stems from wear and tear over time. 

“You should know how to differentiate the two types,” said Safai, “and treat accordingly.” 

Obesity: While there’s some debate over whether or not this condition should be classified as a chronic disease, obesity rates are at such high levels today in the United States — nearly more than 2 in 5 adults have obesity — it’s worth understanding it. Health risks associated with obesity include many of the diseases listed previously, and others. 

“It represents a complex pathophysiology that may involve cardiologists, endocrinologists, and others,” said Brandt. Knowing this, understanding the new medications designed to help with it, and knowing behavioral health modifications can be an assist to your patients who struggle with the illness.