4.47
3
0
0
0
4.47
3
0
0
0
The DAS28 (Disease Activity Score 28) is the most widely used composite measure of disease activity in rheumatoid arthritis (RA). Originally developed at the University of Nijmegen in the Netherlands, DAS28 combines four clinical and laboratory parameters into a single numerical score that quantifies the inflammatory burden of RA and guides treatment decisions.
Rheumatoid arthritis affects approximately 0.5-1% of the global population, with women affected 2-3 times more frequently than men. It is a chronic autoimmune disease characterized by symmetric polyarthritis that, if inadequately treated, leads to progressive joint destruction, disability, and reduced life expectancy. Modern RA management is guided by the treat-to-target strategy, which relies heavily on objective disease activity measurement using tools like DAS28.
The DAS28-ESR formula incorporates four components: the tender joint count (TJC28) and swollen joint count (SJC28) assessed across 28 joints, the erythrocyte sedimentation rate (ESR) as a marker of systemic inflammation, and the patient global assessment of disease activity on a 100-mm visual analog scale (VAS). Each component is weighted mathematically to reflect its relative contribution to overall disease activity.
The 28-joint count includes specific joints bilaterally: shoulders, elbows, wrists, metacarpophalangeal joints (MCP 1-5), proximal interphalangeal joints (PIP 1-5), and knees. Notably, the hips, ankles, and feet are excluded from the 28-joint count, which has been a point of criticism as these joints can be significantly affected in RA.
DAS28 scores range from 0 to approximately 9.4, with defined thresholds for clinical interpretation: remission (DAS28 < 2.6), low disease activity (2.6 to 3.2), moderate disease activity (3.2 to 5.1), and high disease activity (> 5.1). These thresholds directly inform treatment decisions. Current guidelines recommend escalating therapy until patients achieve remission or low disease activity.
The DAS28 is endorsed by the European League Against Rheumatism (EULAR), the American College of Rheumatology (ACR), and is required by many regulatory agencies for clinical trial enrollment and drug approval studies. A change in DAS28 of 1.2 or more is considered a clinically significant improvement, while a change of 0.6 is considered moderate improvement. Serial DAS28 measurements over time allow rheumatologists to objectively track treatment response.
The DAS28-ESR is calculated using the formula:
DAS28 = 0.56 x sqrt(TJC28) + 0.28 x sqrt(SJC28) + 0.70 x ln(ESR) + 0.014 x GH
Activity levels: 1=Remission (<2.6), 2=Low (2.6-3.2), 3=Moderate (3.2-5.1), 4=High (>5.1).
A DAS28 score below 2.6 indicates remission — the treatment target in modern RA management. Scores of 2.6-3.2 indicate low disease activity, which may be an acceptable alternative target. 3.2-5.1 indicates moderate activity, typically warranting treatment adjustment. Scores above 5.1 indicate high disease activity, requiring urgent therapy escalation. Activity Level: 1=Remission, 2=Low, 3=Moderate, 4=High. Remission Status: 1=Yes, 0=No.
Inputs
Results
4 tender joints, 2 swollen joints, ESR 25, and patient global 50. DAS28 = 3.88, moderate disease activity.
Inputs
Results
No tender or swollen joints, ESR 8, patient global 10. DAS28 = 1.60, in remission.
DAS28 (Disease Activity Score 28) is a validated composite measure of rheumatoid arthritis disease activity that combines tender joint count, swollen joint count, ESR, and patient global assessment into a single score ranging from 0 to approximately 9.4.
The 28-joint count includes bilateral shoulders, elbows, wrists, MCP joints 1-5, PIP joints 1-5, and knees. The feet, ankles, hips, and DIP joints are not included.
Treat-to-target is the modern approach to RA management where therapy is adjusted every 3-6 months until a specific disease activity target (usually remission or low disease activity by DAS28) is achieved and maintained.
Yes, DAS28-CRP uses C-reactive protein instead of ESR and has a slightly different formula. DAS28-CRP may be preferred when ESR is unreliable (anemia, paraproteinemia). The thresholds differ slightly between versions.
A decrease of 1.2 or more from baseline is considered a good response. A decrease of 0.6-1.2 is a moderate response. Less than 0.6 is no response. These EULAR response criteria guide treatment decisions.
ESR reflects systemic inflammation and is elevated in active RA. Including ESR adds an objective laboratory measure to complement the clinical assessment, reducing reliance on subjective measures alone.
It is the patient's self-assessment of overall disease activity on a 100-mm visual analog scale (VAS), where 0 represents no disease activity and 100 represents maximum disease activity. It captures the patient's perspective.
Yes, conditions like fibromyalgia can elevate the tender joint count and patient global assessment without true RA inflammation, potentially inflating DAS28. Ultrasound or other imaging may help distinguish.
In active disease, DAS28 should be measured every 1-3 months to guide treatment adjustments. In stable remission or low disease activity, every 3-6 months is typically sufficient.
DAS28 excludes feet and ankles, may be influenced by non-inflammatory pain, relies partly on subjective measures, and may not fully capture radiographic progression. Complementary measures like ultrasound and HAQ are often used alongside.
Roboculator Team
The Roboculator Team explains calculations, planning tools, and practical formulas in clear language for real-life situations.
How helpful was this calculator?
Be the first to rate!
Wells Score (DVT & PE)
Orthopedics & Rheumatology - Bone & Joint Calculators
PERC Rule (Pulmonary Embolism)
Orthopedics & Rheumatology - Bone & Joint Calculators
Ottawa Ankle Rules
Orthopedics & Rheumatology - Bone & Joint Calculators
Ottawa Knee Rules
Orthopedics & Rheumatology - Bone & Joint Calculators
Canadian C-Spine Rule
Orthopedics & Rheumatology - Bone & Joint Calculators
NEXUS Criteria (C-spine)
Orthopedics & Rheumatology - Bone & Joint Calculators
