What Does the RPDAI Mean in Relapsing Polychondritis?

The Relapsing Polychondritis Disease Activity Index (RPDAI) is a scoring system doctors use to measure how active your relapsing polychondritis is at a given time ^[1]. By translating your symptoms and examination findings into a numerical score, the RPDAI helps your care team track whether your inflammation is improving, worsening, or remaining stable over time ^[1].

Living with a rare, unpredictable disease like relapsing polychondritis is stressful, and it can be frustrating when your daily symptoms do not perfectly match a single number on a chart ^[2]. Understanding how this score works—and what it does not measure—can help you have more productive conversations with your care team.

How the RPDAI is Scored

The RPDAI is calculated based on symptoms and clinical findings that have occurred or worsened over the past 28 days ^[1]. It evaluates 27 specific items across the major organ systems affected by relapsing polychondritis ^[1]. Each item is assigned a weight between 1 and 24 points based on its severity and impact, with a maximum possible total score of 265 ^[1].

While the exact 27 items are detailed on a specialized worksheet used by your doctor, the clinical domains (categories) evaluated generally include ^[1]:

• Ears and Nose: Inflammation, redness, or pain in the cartilage.
• Airways and Respiratory: Breathing difficulties, cough, or hoarseness.
• Eyes (Ocular): Inflammation, redness, or vision changes.
• Hearing and Balance (Audiovestibular): Hearing loss or dizziness.
• Joints (Articular): Swelling or arthritis symptoms.
• Skin: Rashes or other skin involvement.
• Cardiovascular and Neurological: Involvement of the heart, blood vessels, or nervous system.

Important: You should not try to calculate this score yourself. Not every symptom you experience is caused by active relapsing polychondritis, and a doctor’s examination is required to properly assign points ^[1].

How to Interpret Your Score

Your RPDAI score is not a percentage, and it is not a standalone measure of your overall prognosis ^[1]. Instead, it is most useful for looking at trends:

• Comparing Past Scores: Your doctor will compare your current score with your past scores to see if your inflammation is trending up or down.
• Identifying the Source: Two people with a score of 30 might have entirely different organs involved. Understanding which items contributed to your score is more important than the final number.
• Research Associations: In research studies, groups of patients with higher scores before starting treatment were sometimes observed to have a higher risk of future flares ^[3]. However, this is an observation in large groups, not a personal prediction for your individual future.
• No Universal Cutoff: There is no universally agreed-upon “cutoff” score that perfectly separates active disease from remission ^[4]. Therefore, you should never make changes to your medications based solely on your score.

What the RPDAI Can and Cannot Do

The RPDAI is a valuable tool for standardizing assessments—especially in clinical research—but it has important limitations:

• It does not measure irreversible damage: Active inflammation is different from permanent structural damage. Symptoms caused by permanent changes—such as a collapsed airway or a saddle-nose deformity (collapse of the bridge of the nose)—are not the same as a new flare. However, active inflammation and permanent damage can happen at the same time, and a symptom alone cannot always tell them apart. To track permanent changes, doctors use a completely separate tool called the Relapsing Polychondritis Damage Index (RPDAM) ^[5].
• It misses the full patient experience: The RPDAI focuses on physical signs of active inflammation. It does not directly capture your level of fatigue, chronic pain, or overall quality of life ^[6][2]. Research shows that patient experiences often differ significantly from a physician’s assessment ^[7].
• It may miss hidden inflammation: Because the index relies heavily on reported symptoms and physical exams, it might not detect “silent” inflammation deep within the body ^[8]. For instance, a normal score does not automatically rule out early airway involvement. When clinically indicated, your doctor may recommend targeted testing, such as pulmonary function tests or specific imaging scans, to get a complete picture ^[9].

A Piece of the Puzzle

Your care team should combine the RPDAI with other evaluations, including:

• Your Personal Report: A detailed discussion about your fatigue, pain, and how the disease affects your daily life.
• Laboratory Tests: Doctors often check inflammatory markers like the erythrocyte sedimentation rate (ESR) or C-reactive protein (CRP) level ^[10][4]. While these markers often correlate with RPDAI scores in research, they are not perfect. You can have a normal ESR or CRP even during a flare, and these levels can be elevated for reasons unrelated to your disease.
• Targeted Testing: Depending on your specific symptoms, your doctor may order breathing tests, hearing exams, or imaging (like CT or MRI) to evaluate specific organs ^[8].

Seek Urgent Care for Severe Symptoms: Because airway and cardiovascular involvement in relapsing polychondritis can become serious quickly, do not wait for a routine appointment or an RPDAI calculation if you experience alarming changes. Seek emergency medical care for new or rapidly worsening shortness of breath, noisy breathing (stridor), inability to speak in full sentences, blue lips, severe chest pain, sudden vision loss, or new neurological symptoms.