Arthritis & Rheumatism, Volume 63,
November 2011 Abstract Supplement

Abstracts of the American College of
Rheumatology/Association of Rheumatology Health Professionals
Annual Scientific Meeting
Chicago, Illinois November 4-9, 2011.


Defining Clinically Relevant Changes in Core Set Activity Measures for Adult and Juvenile Idiopathic Inflammatory Myopathies (IIM).

Rider1,  Lisa G., Lee2,  Julia A., Jansen2,  Anna V., Ruperto3,  Nicola, Huber4,  Adam M., Oddis5,  Chester V., Feldman6,  Brian M.

NIEHS NIH, Bethesda, MD
NIEHS, NIH, Bethesda, MD
PRINTO-IRCCS, Genova, Italy
Dalhousie University, Halifax, NS
University of Pittsburgh, Pittsburgh, PA
The Hospital for Sick Children, Toronto, ON
Corvallis, OR
University of Pittsburgh Medical Center, Pittsburgh, PA

Background/Purpose:

Both PRINTO and IMACS have established core set measures for assessment of patients with IIM in therapeutic trials, and developed preliminary definitions of improvement combining these. Our aim was to revisit the degree of clinically meaningful change and importance of each measure in defining clinically important change, as well as to define changes in these measures that represent moderate and major degrees of improvement.

Methods:

Twenty-nine pediatric and 21 adult rheumatologists and neurologists experienced in the care of IIM patients and the myositis core set measures completed a Delphi questionnaire regarding the amount of change in each core set domain deemed to be clinically significant in a trial setting.

Results:

Adult and pediatric specialists provided the percentage change in each core set domain in order to classify an IIM patient as minimally, moderately and majorly improved (see Table), with general agreement between the pediatric and adult specialists. Both groups required greater change in enzyme values, and pediatric specialists also suggested slightly greater degrees of change for patient global activity and physical function. Muscle strength was ranked as the most important core set measure, followed by MD Global Activity, and there was a suggestion that additional weight of 1.5–2 fold be given to both these measures in a definition of improvement or of moderate and major response. Both groups preferred a definition based on percentage change, or one that combined percentage with absolute change. Both adult and pediatric specialists suggested 2–4 measures be required to improve for the patient to be considered improved, except both groups preferred improvement in up to 5 measures for a major degree of change. More than 80% of participants felt that muscle strength and MD Global Activity must improve for the patient to be considered clinically improved, whereas for major improvement, physical function also has to improve in adults and extra-muscular activity in pediatric patients. Deterioration of a small degree (<= 20%) would be allowable in 1or 2 measures, but for major change no more than 1 measure may worsen, which cannot be MD Global Activity for pediatric or muscle strength for adult myositis patients.

Conclusion:

These data, along with these specialists' ratings of adult and juvenile IIM patient profiles, will be used to revise the definitions of improvement for adult and juvenile myositis, and to guide the development of new criteria for moderate and major degrees of improvement.

Core Set Domain (% Change, Median)Minimum Percent Change (Median)Moderate Percent Change (Median)Major Percent Change (Median)
AdultPediatricAdultPediatricAdultPediatric 
Physician global activity assessment20.020.030.040.050.060.0
Patient global activity assessment20.025.030.040.050.060.0
Muscle strength (MMT or CMAS)20.020.030.030.050.050.0
Physical function ([C]HAQ)20.027.530.040.050.060.0
Extra-skeletal muscle disease activity20.020.030.030.050.050.0
Laboratory Enzymes (CK, LDH, AST, ALT)30.030.040.050.060.070.0
CHQ Physical Score (HR-QOL)NA22.5NA40.0NA55.0

To cite this abstract, please use the following information:
Rider, Lisa G., Lee, Julia A., Jansen, Anna V., Ruperto, Nicola, Huber, Adam M., Oddis, Chester V., et al; Defining Clinically Relevant Changes in Core Set Activity Measures for Adult and Juvenile Idiopathic Inflammatory Myopathies (IIM). [abstract]. Arthritis Rheum 2011;63 Suppl 10 :240
DOI:

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