Autoimmune diseases: Diagnoses, prevalence, and treatments

Jen Radin, MPH, MBA, principal, Life Sciences & Health Care, Deloitte and Touche LLP

Somewhere between 23.5 and 50 million people in the US are living with one or more autoimmune diseases, making these conditions among the most widespread chronic illnesses.¹ The immune system is designed to protect the body from bacteria, viruses, and other potentially harmful invaders. An autoimmune disease is a condition in which the body’s immune system mistakenly attacks its own healthy cells, tissues, or organs. This can lead to a variety of symptoms including inflammation and tissue damage.

Along with being widespread in the US and globally, autoimmune diseases are among the most expensive to diagnose and treat. The direct cost of treating more than 100 known autoimmune diseases is estimated to be at least $100 billion per year.² And the impact of autoimmune diseases extends beyond direct care costs. Lost productivity at work, higher childcare expenses, and reduced quality of life for patients and their families can collectively drive indirect costs, which can be more than 40% of what patients spend on medical treatment.³

I recently had an opportunity to speak to Julie Syd Schwartzman-Morris, MD, a rheumatologist affiliated with Northwell Health who specializes in treating autoimmune diseases. Her primary focus is on spondylarthritis, a group of related inflammatory rheumatic diseases that primarily affect the joints of the spine and, in some cases, arm and leg joints, the eyes, or the intestines. She is part of the rheumatology faculty at Northwell and is also the vice chair for women in medicine for her department. Here is an excerpt from our conversation:

Jen: The prevalence of autoimmune diseases in the US could increase by 43% by 2030, according to Deloitte’s estimates. Are these diseases becoming more widespread, or are medical providers just getting better at detecting and diagnosing them?

Julie: It’s a little of both. In some cases, these diseases have been around a long time, but we didn’t look for them. We are also seeing some of the same conditions but are diagnosing them differently and earlier than in the past. Changing environmental factors could also be contributing to the expected increase. New types of therapies could be another factor. For example, some of the new immunotherapies used to treat certain cancers can trigger autoimmune diseases. There also can be misdiagnoses when people confuse inflammation with an autoimmune disease. This might lead to a higher frequency of diagnoses, but they might be inaccurate diagnoses. Not every condition that causes pain or inflammation is an autoimmune disease. There are other things that cause arthritis and joint syndromes, and they're not all autoimmune. In some cases, disorders of the nervous system can be confused with autoimmune diseases.

Jen: How has the treatment for autoimmune diseases changed?

Julie: For decades, we were treating these diseases with a group of medications called Disease-Modifying Antirheumatic Drugs (DMARDs), which weren't engineered specifically to treat one disease. Newer treatments, called biologics, are biologically engineered based on the immune pathways that trigger diseases. By definition, medications and therapeutics suppress the immune system or retrain it to stop fighting itself and basically calm down. However, those treatments can make the body susceptible to infection and other issues.

Jen: About 23.5 million people in the US have an autoimmune disease, and approximately 80% of them are women, according to Deloitte’s estimates. Why are so many autoimmune diseases more common in women than in men?

Julie: It's a challenging question to answer because it is multifactorial. It is often a combination of factors including hormones, genetic factors, environmental triggers, and infectious triggers. A lot of autoimmune diseases tend to appear in women of childbearing age. We think there is a link between increased estrogen and the autoimmune diseases that predominantly affect women. Psoriatic disease, which does not necessarily affect more women than men, is not hormonally related, whereas lupus and rheumatoid arthritis may be partially triggered by hormones. The link to environmental factors is somewhat of a black box when it comes to autoimmune diseases. Certain allergens, various infectious agents, and smoking could all trigger an underlying disease. Sarcoidosis [which affects the lymph nodes], for example, is known to be triggered by pathogens in the environment (e.g., dust, pollen, mold, viruses, bacteria, pesticides).⁴ We need to connect the dots. Sometimes medications can trigger drug-induced lupus or drug-induced vasculitis, which comes under that umbrella of environmental factors. But women generally aren’t exposed to more environmental pathogens than men, so there could be a link between hormones and the environment that prompts cells to attack. Diseases such as rheumatoid arthritis, lupus, and phospholipid antibody syndrome tend to be concentrated among people who are between 18 and 45, likely due to estrogen. Some people might go into remission when they go through menopause, but there are also people who are diagnosed later in their lives. Not everyone fits the curve.

Jen: Given the prevalence of autoimmune diseases among women, do you think it is important to include women in clinical trials?

Julie: It is important to be gender and racially inclusive regarding who is enrolled in clinical trials. Many of these diseases affect women predominantly. For example, conducting a lupus-specific drug trial using men would be useless because they represent just 10% of that population that has that disease.⁵ But other autoimmune diseases, like vasculitis and psoriatic disease, don't have a female predominance.⁶ It is important to ensure that the patients enrolled in the clinical trials accurately reflect the populations that are most affected by the disease.

Jen: There is a wide range of autoimmune diseases like lupus or Hashimoto parotiditis, where there is a clear path to diagnosis. Are there some autoimmune conditions where diagnosis is a process of elimination?

Julie: Many diseases have specific diagnostic criteria that have to be met to make the diagnosis. Some require a physical exam, an evaluation of symptoms, labs. For a rheumatologist, it usually isn’t difficult to diagnose lupus. There are specific auto-antibodies that are clearly associated with that disease. Some diseases are under the umbrella of autoimmunity and are a little less concrete. Diagnosing sarcoidosis might require a biopsy. Sometimes we get a sense of what the patient has and are able to rule out the causes. But patients can have more than one disease. Rheumatoid arthritis patients might also have fibromyalgia.

Jen: There is a growing shortage of rheumatologists or endocrinologists.⁷ What can be done to help address that?

Julie: This can be particularly challenging in rural settings, and especially in pediatric rheumatology. Specialists tend to be concentrated in urban areas. There has been a push on the heels of the pandemic to increase the use of telehealth, particularly in rural areas. There seems to be interest in training rheumatologists to offer telehealth visits to people in remote areas and to train primary care doctors to assess patients and prescribe medications for autoimmune diseases. It is almost ingrained in primary care that anyone who is diagnosed with a disease—whether diabetes or joint pain—needs to be treated by a specialist. But that shouldn’t be the case. Specialists like me are often at the end of a long line of doctors who have seen a patient. We have to synthesize their medical history, exams, laboratory findings, and imaging to determine the issue. Collaboration with primary care and specialists will help facilitate earlier diagnoses and treatments.

Conclusion

Autoimmune diseases affect millions of people each year, with a disproportionate number being women. Advances in diagnostics and therapeutics may have improved outcomes for many, yet these conditions tend to remain expensive and complex to manage, with diagnosis and treatment often requiring a nuanced, multidisciplinary approach. Given recent scientific discoveries in this space, it is projected to be a therapeutic area ripe for innovation and investment. In addition, by expanding access to specialized care (virtual and in person) and ensuring research reflects the needs of those who are affected and those at risk, autoimmune diseases can be identified earlier, managed more effectively, and far less disruptive to everyday life.

The executive’s participation in this article is solely for educational purposes based on their knowledge of the subject and the views expressed by them are solely their own. This article should not be deemed or construed to be for the purpose of soliciting business for any of the companies mentioned, nor does Deloitte advocate or endorse the services or products provided by these companies.

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Endnotes:
¹NIH strategic plan for autoimmune disease research, National Institutes of Health, 2024
²Autoimmune disease patients hit hurdles in diagnosis, cost, and care, National Public Radio/KFF News, November 18, 2024
³A global assessment of incidence trends of autoimmune diseases, ScienceDirect, October 2023
⁴Fungal exposure in the homes of patients with sarcoidosis, Environmental Watch, January 20, 2011
⁵Understanding lupus and gender, healthline, January 25, 2023
⁶Differences between the sexes in rheumatic disease, April 27, 2023
⁷Tackling the rheumatology workforce shortage, The Rheumatologist, December 2024

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