DAS28 ESR For Rheumatoid Arthritis Calculator

Assesses rheumatoid arthritis (RA) diseases activity given the erythrocyte segmentation rate (ESR).

Read more about this monitoring tool adapted from the original DAS28 score in the text below the form.


The DAS28 ESR calculator is based on the original DAS28 rheumatoid arthritis disease activity score but instead of C-reactive protein, the erythrocyte sedimentation rate is used as marker of inflammation.

The other three criteria remain the same (count of tender and swollen joints and general health assessment).

The 28 joints evaluated in the score are:

■ Proximal interphalangeal (10);

■ Metacarpophalangeal (10);

■ Wrists (2);

■ Elbows (2);

■ Shoulders (2);

■ Knees (2).


The DAS28 ESR formula is:

DAS28 ESR = 0.56 x sqrt(TJc) + 0.28 x sqrt (SJc) + 0.70 x ln(ESR) + 0.014 x GH

The following table introduces the correlation between DAS28 ESR results and rheumatoid arthritis disease activity:

Present DAS28-ESR Interpretation
<2.6  Remission
≥2.6 but ≤3.2 Low
>3.2 but ≤5.1 Moderate
>5.1 Active

1Tender joint count (0 – 28)
2Swollen joint count (0 – 28)
3Erythrocyte sedimentation rate
4Global health (0 – 100)*
*Scale where 0 is very good and 100 is very bad.
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Steps on how to print your input & results:

1. Fill in the calculator/tool with your values and/or your answer choices and press Calculate.

2. Then you can click on the Print button to open a PDF in a separate window with the inputs and results. You can further save the PDF or print it.

Please note that once you have closed the PDF you need to click on the Calculate button before you try opening it again, otherwise the input and/or results may not appear in the pdf.


 

DAS28 ESR explained

This is a disease activity score based on the erythrocyte sedimentation rate (as inflammation marker) and used in the monitoring of rheumatoid arthritis activity.

There are four variables used:

■ Number of tender joints (TJc);

■ Number of swollen joints (SJc);

■ Erythrocyte sedimentation rate laboratory value (ESR);

■ Global health assessment (GH).

In the global health assessment the patient is asked to assign an imaginary position to the perceived level of health, between very good and very bad, on a 100 mm ruler.

The assessor will then measure where the indicated point is on the ruler and assign a numeric value between 0 and 100.

The formula used in the rheumatoid arthritis calculator is the following:

DAS28 ESR = 0.56 x sqrt (TJc) + 0.28 x sqrt (SJc) + 0.70 x ln(ESR) + 0.014 x GH

The 28 joints evaluated in the score are:

■ Proximal interphalangeal (10);

■ Metacarpophalangeal (10);

■ Wrists (2);

■ Elbows (2);

■ Shoulders (2);

■ Knees (2).

There is another method, the DAS28-CRP with the same usage in rheumatoid arthritis monitoring, but using a different blood marker of inflammation, the C-reactive protein.

The two scores, the DAS28 CRP and ESR were found to be of similar specificity and sensitivity. However, the ESR results tend to be higher than the CRP ones, especially in female subjects.

 

Result interpretation

The score is interpreted compared to a cut-off point of remission, established at 2.6. However, this is not always accurate as patients with this score are likely to continue presenting at least 2 swollen joints.

The table below introduces the possible score intervals and their disease activity interpretation:

Present DAS28-ESR Interpretation
<2.6 Remission
≥2.6 but ≤3.2 Low
>3.2 but ≤5.1 Moderate
>5.1 Active

DAS28 score also carries the limitation that in some cases, although the number of swollen, tender joints is high, the resultant score may be low (indicating remission) because of the other items in the composite index.

 

About the study

The DAS28 ESR was created following a prospective study by van der Heijde et al. in which 113 patients with early rheumatoid arthritis were analysed.

Where treatment was initiated with slow acting antirheumatic drugs, high disease activity was established.

Where treatment with slow acting antirheumatic drugs remained unchanged for at least one year, was stopped or not even initiated, low disease activity was established.

Therefore, two patient groups were formed. Factor and discriminant analysis were used to go through a large number of clinical and laboratory variables.

The resultant score consisted of the Ritchie index, swollen joints, erythrocyte sedimentation rate, and general health, ordered in declining importance.

 

Original source

van der Heijde DM, van 't Hof MA, van Riel PL, Theunisse LA, Lubberts EW, van Leeuwen MA, van Rijswijk MH, van de Putte LB. Judging disease activity in clinical practice in rheumatoid arthritis: first step in the development of a disease activity score. Ann Rheum Dis. 1990; 49(11):916-20.

Validation

Elizabeth M. A. Hensor E.M.A, Emery P. Bigham S et al. Discrepancies in categorizing rheumatoid arthritis patients by DAS-28(ESR) and DAS-28(CRP): can they be reduced? Oxford Journals Medicine & Health Rheumatology; 49(8):1521-1529.

Other references

1. Sengul I, Akcay-Yalbuzdag S, Ince B, Goksel-Karatepe A, Kaya T. Comparison of the DAS28-CRP and DAS28-ESR in patients with rheumatoid arthritis. Int J Rheum Dis. 2015; 18(6):640-5.

2. Anderson J, Caplan L, Yazdany J et al. Rheumatoid Arthritis Disease Activity Measures: American College of Rheumatology Recommendations for Use in Clinical Practice. Arthritis Care Res (Hoboken). 2012; 64(5): 640–647.


App Version: 1.0.1

Coded By: MDApp

Specialty: Rheumatology

System: Musculoskeletal

Objective: Evaluation

Type: Calculator

No. Of Variables: 4

Year Of Study: 1990

Abbreviation: DAS28 ESR

Article By: Denise Nedea

Published On: May 25, 2017 · 07:12 AM

Last Checked: May 25, 2017

Next Review: May 25, 2018