What Is Rheumatology? A Research Guide

Rheumatology is the branch of medicine and biomedical science concerned with arthritis and other rheumatic diseases: conditions that affect the joints, muscles, bones, tendons and connective tissue, and in many cases the immune system and internal organs as well. It is both a clinical specialty, in which physicians called rheumatologists diagnose and manage these conditions, and a research discipline that draws on immunology, genetics, epidemiology, pharmacology and clinical trial science. (The word comes from the Greek rheuma, a flowing or flux.) This guide explains what rheumatology covers and how its subfields divide up, then adds the research-administration layer that generic overviews leave out: who funds the field, how treatment response is measured in trials, how classification criteria work, and typical training paths. It is educational, not medical advice.

What Is Rheumatology?

Rheumatic diseases are a varied group, but the discipline is organized around a few recurring questions:

What drives inflammation in the joint and elsewhere? Many rheumatic diseases are autoimmune or autoinflammatory, meaning the immune system attacks the body’s own tissues or is inappropriately activated. Immune mechanisms are the basic-science foundation of the specialty (see What Is Immunology?).
How is a disease recognized and told apart from its mimics? Diagnosis relies on history, examination, laboratory tests such as autoantibodies and inflammatory markers, and imaging. Because many conditions overlap in symptoms, researchers also use formal classification criteria, described below.
How is damage prevented? Much of modern rheumatology is about controlling inflammation early enough to prevent permanent joint or organ damage, using disease-modifying drugs and, increasingly, targeted biologic and small-molecule therapies.
How are function and quality of life measured? Pain, stiffness, fatigue and physical function are often reported by patients themselves, so patient-reported outcome measures sit alongside joint counts and laboratory results (see the visual analogue scale guide and estimating the minimal clinically important difference).

Scope: Which Conditions Does Rheumatology Cover?

Rheumatology is usually described as covering inflammatory arthritis, connective tissue diseases, vasculitis, crystal and degenerative joint disease, and some bone and soft-tissue disorders. Illustrative examples include:

Inflammatory arthritis — rheumatoid arthritis, psoriatic arthritis, axial spondyloarthritis and juvenile idiopathic arthritis.
Systemic autoimmune and connective tissue diseases — systemic lupus erythematosus, Sjögren’s disease, systemic sclerosis (scleroderma) and the inflammatory myopathies such as dermatomyositis and polymyositis.
Vasculitis — inflammation of blood vessels, including giant cell arteritis and ANCA-associated vasculitis.
Crystal arthritis — gout and pseudogout, caused by crystal deposition in joints.
Osteoarthritis and other degenerative or mechanical conditions — the most common form of arthritis, studied by rheumatologists alongside orthopedic surgeons, physiatrists and physical therapists.
Metabolic bone disease and soft-tissue pain syndromes — for example osteoporosis, which is shared with endocrinology, and fibromyalgia.

Which of these a given clinician treats varies by country and health system, so the boundaries drawn in this guide are descriptive rather than definitive.

Major Subfields of Rheumatology Research

Autoimmune and inflammatory disease biology — how immune cells, cytokines and autoantibodies produce tissue damage in diseases such as rheumatoid arthritis and lupus.
Genetics and genomics — genome-wide association studies and sequencing to identify risk variants (see What Is Genomics?).
Musculoskeletal biology — the normal structure and function of bone, cartilage, joints and muscle, and how they degrade in osteoarthritis and bone disease.
Pediatric rheumatology — juvenile arthritis, childhood lupus and related conditions, usually studied in small, multi-center networks because individual diseases are uncommon.
Clinical trials and outcomes research — endpoint development, treatment strategies, and comparative effectiveness.
Epidemiology and registries — who develops these diseases, how they progress, and long-term safety of therapies (see What Is Epidemiology? and What Is Biostatistics?).
Pharmacology and drug development — conventional synthetic drugs, biologics, biosimilars and targeted small molecules (see What Is Pharmacology?).
Organ involvement in systemic illness — for example lupus nephritis, where the field meets nephrology.

How Rheumatology Relates to Neighboring Disciplines

Rheumatology sits between several fields. Immunology supplies much of its mechanistic vocabulary; nephrology, neurology and other organ specialties share patients whose systemic disease affects the kidney or nervous system (see What Is Neurology?); endocrinology overlaps on bone health; and pharmacology, biostatistics and epidemiology support its trials and registries. For the wider map of fields, see What Is Biology? and the overview of the branches of science. Movement and rehabilitation science, which supports people living with arthritis, is covered in What Is Kinesiology?.

Methods and Tools

Autoantibody and biomarker testing — rheumatoid factor, anti-cyclic citrullinated peptide (anti-CCP) antibodies, antinuclear antibodies (ANA) and acute-phase reactants such as C-reactive protein, used in diagnosis, classification and monitoring.
Imaging — radiography, ultrasound and magnetic resonance imaging to detect synovitis, erosions and structural change.
Tissue sampling and molecular profiling — synovial and kidney biopsies combined with single-cell and spatial methods to map disease pathways.
Prospective cohorts and registries — long-running observational studies that capture real-world treatment, outcomes and safety.
Patient-reported outcomes — validated questionnaires for pain, function and fatigue, increasingly collected electronically (see the dictionary entry on ePRO).
Animal and cell models — arthritis and lupus models in rodents and human cell systems, conducted under the same oversight as other vertebrate research (see the animal research ethics guide).
Randomized controlled trials — the standard for testing new therapies, usually with a placebo-controlled or active-comparator design (see also non-inferiority vs. superiority trial design).

Classification Criteria and Trial Endpoints

Two related ideas matter a great deal to anyone reviewing a rheumatology protocol. The first is the difference between diagnostic and classification criteria. Classification criteria are standardized rules designed to define homogeneous groups of patients for research; they are not intended to replace a clinician’s diagnostic judgment. Two widely cited examples are the 2010 ACR/EULAR classification criteria for rheumatoid arthritis, which combine joint involvement, serology (rheumatoid factor or anti-CCP), acute-phase reactants and symptom duration into a score from 0 to 10, with a score of 6 or more classifying a patient as having definite rheumatoid arthritis, and the 2019 EULAR/ACR classification criteria for systemic lupus erythematosus, which require a positive ANA as an entry criterion and then add weighted clinical and immunologic domains, classifying patients who reach at least 10 points. Enrollment criteria in many trials are written directly in these terms.

The second is response measurement. For rheumatoid arthritis, the American College of Rheumatology response definition, developed by Felson and colleagues and published in 1995, counts a patient as an “ACR20” responder when tender and swollen joint counts each improve by at least 20 percent and at least three of five further measures also improve by at least 20 percent: patient global assessment, physician global assessment, patient-reported pain, a physical function questionnaire, and an acute-phase reactant (C-reactive protein or erythrocyte sedimentation rate). Stricter ACR50 and ACR70 thresholds follow the same pattern. The ACR20 became the most frequently used response definition in rheumatoid arthritis trials and has commonly served as a primary outcome in regulatory submissions. Composite disease activity indices such as the DAS28 are also widely used in rheumatoid arthritis to support treat-to-target strategies.

These endpoints are composites, which raises design and analysis questions covered in the dictionary entry on composite endpoints and in the guide to surrogate endpoint validation. Because several components are subjective (patient and physician global assessments), blinding and placebo handling matter more here than in trials that rely on laboratory endpoints alone. Administrators should expect protocols to specify the exact version of each criterion set, since criteria are periodically revised.

How Rheumatology Research Is Funded

In the US, the National Institute of Arthritis and Musculoskeletal and Skin Diseases (NIAMS), part of the National Institutes of Health, is the lead federal institute for this territory. It was established in 1986, authorized by the Health Research Extension Act of 1985. Its stated mission is to support research into the causes, treatment and prevention of arthritis and musculoskeletal and skin diseases, to train basic and clinical scientists to carry out that research, and to disseminate information on research progress. NIAMS also supports basic research on the normal structure and function of bones, joints, muscles and skin, and its research spans disciplines including immunology, genetics, molecular biology, structural biology, biochemistry, physiology, virology and pharmacology.

Several features of the funding landscape are worth knowing:

Extramural and intramural programs. NIAMS funds investigators at universities and medical centers and also runs an intramural research program on the NIH campus.
Public-private consortia. NIAMS participates in the Accelerating Medicines Partnership (AMP), managed through the Foundation for the NIH. The AMP Autoimmune and Immune-Mediated Diseases (AMP AIM) program focuses on rheumatoid arthritis, systemic lupus erythematosus, psoriasis, psoriatic arthritis and Sjögren’s disease, with the aim of mapping the cell types, cell states and cell-to-cell interactions that drive inflammation. It is supported by NIAMS together with several other NIH institutes and offices and a set of public and private partners.
Multiple institutes share the territory. Autoimmunity, eye disease, dental and craniofacial manifestations and women’s health all intersect with other institutes and offices, so a single project may be of interest to more than one.
Standard NIH mechanisms. Investigators use the R01 for independent projects, cooperative agreements such as the U01 for consortia, and mentored career awards such as the K99/R00 (see also career development K awards). Applications are reviewed in study sections, and competitiveness varies by institute and year (see NIH paylines for FY2026).
Data sharing. NIH-funded projects generating scientific data must plan for sharing (see the NIH Data Management and Sharing Plan guide).

Outside NIH, disease-focused charities, professional societies and industry sponsors also fund fellowships, pilot grants and trials. Funding opportunities and priorities change, so confirm current details with the funder before building a budget or timeline around them.

A Brief History

The organized profession is relatively young. In the United States, the professional society now called the American College of Rheumatology was originally named the American Rheumatism Association. In Europe, the European League Against Rheumatism, now the European Alliance of Associations for Rheumatology (EULAR), was founded in 1947. A therapeutic landmark came in November 1998, when the US Food and Drug Administration approved etanercept, a TNF inhibitor and an early biologic response modifier for rheumatoid arthritis; it was approved for patients who had not responded adequately to disease-modifying drugs, alone or combined with methotrexate. Since then biologics have broadened to many targets, and biosimilar versions have followed (see the dictionary entry on FDA biosimilars). Conventional drugs such as methotrexate and hydroxychloroquine remain central. The field’s recent direction has been toward earlier treatment, defined targets, and molecular profiling to match patients to therapies.

Career and Training Pathways

The clinical path in the US runs through medical school, an internal medicine residency (or pediatrics, for pediatric rheumatology) and a rheumatology fellowship. The American Board of Internal Medicine requires prior internal medicine certification, completion of accredited fellowship training, an unrestricted medical license and a passing score on the Rheumatology Certification Examination. Fellowship training must be accredited by the Accreditation Council for Graduate Medical Education (ACGME) or an equivalent Canadian body; the American Board of Internal Medicine requires 24 months of total fellowship training in rheumatology, and many programs include research time. Requirements differ outside the US, so check national regulators.

The research path usually runs through graduate study in immunology, cell and molecular biology, genetics, bioengineering or epidemiology, followed by postdoctoral training. Many academic investigators are physician-scientists who combine clinical fellowship with research training supported by mentored K awards or professional-society fellowship grants.

Societies and Journals

Major professional bodies include the American College of Rheumatology (ACR), the European Alliance of Associations for Rheumatology (EULAR), and many national and regional societies. The ACR and EULAR jointly develop classification criteria, as noted above. Leading journals include Arthritis & Rheumatology and Arthritis Care & Research (published for the ACR), Annals of the Rheumatic Diseases (EULAR), The Journal of Rheumatology, Rheumatology and The Lancet Rheumatology.

Why Rheumatology Matters for Research Administration

Research offices supporting this field meet recurring issues: long-term safety follow-up for immunosuppressive therapies, which affects budgets and data and safety monitoring plans; multi-site pediatric studies that depend on small patient populations; biobanking and consent for genetic and tissue samples; subjective and composite endpoints that need careful specification; and industry-sponsored trials with registration and reporting duties (see clinical trial registration and reporting compliance). Understanding the vocabulary above makes it easier to read a protocol, budget for visits and assessments, and anticipate review questions.

Frequently Asked Questions

What is rheumatology in simple terms?

Rheumatology is the study and treatment of arthritis and related diseases of the joints, muscles, bones and connective tissue, including many autoimmune conditions such as rheumatoid arthritis and lupus. It covers how these diseases arise, how they are diagnosed and measured, and how they are managed.

What does a rheumatologist do?

A rheumatologist is a physician who has completed specialty training in diagnosing and managing rheumatic diseases. Their work typically includes evaluating joint, muscle and systemic symptoms, interpreting laboratory and imaging results, and prescribing and monitoring disease-modifying therapies. Individual patients should consult their own clinician for care.

Is rheumatology the same as immunology?

No, though they overlap. Immunology studies the immune system broadly; rheumatology is a clinical specialty focused on rheumatic and musculoskeletal diseases, many of which are immune-mediated.

Is arthritis the same as rheumatology?

No. Arthritis is a group of conditions involving joint inflammation or damage; rheumatology is the field that studies and treats arthritis and many related disorders that affect other tissues too.

What is the difference between classification and diagnostic criteria?

Classification criteria define consistent patient groups for research and trials; diagnostic criteria guide an individual clinician’s decisions. The 2010 ACR/EULAR rheumatoid arthritis criteria and 2019 EULAR/ACR lupus criteria are classification criteria.

What is an ACR20 response?

It is a composite trial outcome in rheumatoid arthritis: at least 20 percent improvement in tender and swollen joint counts and in at least three of five other measures, defined by the American College of Rheumatology and published in 1995.

Who funds rheumatology research in the US?

The lead federal funder is the National Institute of Arthritis and Musculoskeletal and Skin Diseases (NIAMS) within NIH, alongside other NIH institutes, disease charities, professional societies and industry sponsors.

Related Guides

This guide is part of a series on scientific disciplines from a research-administration perspective. See the overview of the branches of science, What Is Immunology?, What Is Nephrology?, What Is Endocrinology? and What Is Neurology?.