Arthritis & Rheumatism, Volume 62,
November 2010 Abstract Supplement

Abstracts of the American College of
Rheumatology/Association of Rheumatology Health Professionals
Annual Scientific Meeting
Atlanta, Georgia November 6-11, 2010.


The American Myositis Activities ProfileA Valid Disease-Specific Activity/Participation Measure.

Alexanderson,  Helene, Reed,  Ann M., Ytterberg,  Steven R.

Department of Medicine, Karolinska Institutet, Department of Physical Therapy, Karolinska University Hospital, Solna, Stockholm, Sweden
Rheumatology Division, Mayo Clinic, Rochester, MN

Background:

The Myositis Activities Profile is an activity limitation measure developed and validated for patients with polymyositis and dermatomyositis in Sweden. It was recently translated into American English.

Objectives:

To evaluate validity and reliability of the American version of the disease-specific 31-item Myositis Activities Profile (MAP) in patients with polymyositis (PM) and dermatomyositis (DM) in the USA.

Methods:

Patients diagnosed with PM or DM seen during March-May 2007 and May-July 2008 were included. To assess content validity 30 strategically chosen patients as to gender, age, ethnicity, disease activity, disease duration and employment status were selected. They rated difficulty and importance of each activity of the American MAP on a 10-grade scale and were invited to suggest additional items. Based on the initial findings a second draft of the American MAP was developed. For construct validity purpose unselected patients with PM and DM (n=64) were included. The six-item core set for myositis disease activity, the Manual Muscle test (MMT) and measures of muscle endurance using the Functional Index 2 (FI-2) were performed. Patients filled out the second draft of the American MAP, the Health Assessment Questionnaire (HAQ) and rated disease impact on general well-being. All patients with stable disease activity and medication for three months (n=48) were given another copy of the American MAP to fill out one week later.

Results:

The median value for pooled difficulty and importance of each item was 5.00 (2.10–5.95) for the 31 activities in the first draft of the American MAP. Although two activities were rated < 5.0; "Standing for a longer period" and "Using public transportation" they were still taken to the second draft of the MAP as they were considered relevant to patients living in larger cities. Five patients suggested the activity "Opening jars" which was added to the Movement subscale, giving a 32-item second draft of the American MAP. Correlations between median of subscales of the American MAP and disease impact on general well-being and the HAQ were rs= 0.68 and rs 0.70 respectively. There were lower correlations between the American MAP and MMT 8 (rs=-0.36), the FI-2 (ranging between rs=-0.29 to -0.44) and physician's global assessment of disease activity (rs 0.40). Thirty-three patients sent back questionnaires to assess test-retest reliability. Weighted Kappa (Kw) ranged between 0.65 and 0.81 for the 4 subscales and between 0.52 and 0.73 for the four single items of the American MAP without systematic variations, p>0.05. The single item 'avoid overexertion' were excluded due to poor test-retest reliability (Kw=0.52) giving a 31-item final draft of the American MAP.

Conclusion:

The American MAP seems to be a valid and reliable outcome measure assessing activity / participation in patients with adult PM and DM in the USA and could potentially improve clinical assessment of treatment of these patients although further studies are needed to establish sensitivity to change of the American MAP.

To cite this abstract, please use the following information:
Alexanderson, Helene, Reed, Ann M., Ytterberg, Steven R.; The American Myositis Activities ProfileA Valid Disease-Specific Activity/Participation Measure. [abstract]. Arthritis Rheum 2010;62 Suppl 10 :2068
DOI: 10.1002/art.29833

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