The presence of muscle weakness in scleroderma associates with several features of worse disease burden and independently associates with disability as measured by the Health Assessment Questionnaire Disability Index (HAQ DI), a recent study found. Researchers evaluated a cohort of 1,718 scleroderma patients who had available data on muscle strength and disability. They found:

• Of the total cohort, 22.8% (392 of 1,718) had muscle weakness, as defined by a Medsger muscle severity score of ≥1.
• This subset was more likely than those without weakness to have diffuse cutaneous scleroderma (55.6% vs 35.1%), higher modified Rodnan skin thickness scores (mean ± SD 16.3 ± 13.7 vs 10.3 ± 10.6), shorter disease duration (mean ± SD 5.21 ± 6.75 years vs 6.22 ± 7.67 years), synovitis (17.7% vs 11.4%), forced vital capacity <70% (46.2% vs 30.6%), and higher creatine kinase values (mean ± SD 441 ± 1,211 vs 151 ± 255).