Date: Monday, November 6, 2017
Session Type: ACR Poster Session B
Session Time: 9:00AM-11:00AM
Juvenile myositis (JM) is marked by skin rashes, proximal muscle weakness, and deconditioning causing potentially severe disability. Studies examining long-term physical function in JM remain scant. This study aims to define longitudinal predictors of physical function in JM.
JM patient data collected prospectively at routine clinic visits from January 2000 to June 2014 at Ann & Robert H. Lurie ChildrenÕs Hospital of Chicago was used in this study. Only patient visits with documented Childhood Health Assessment Questionnaire (CHAQ) summary scores were included for analysis. Demographic/clinical variables were extracted, including: gender, race, duration of untreated disease, Disease Activity Score (DAS) – muscle/skin domains, Childhood Myositis Assessment Scale (CMAS), muscle enzymes (i.e. CPK, AST, LDH, aldolase), nailfold capillary end row loops (NFC-ERL), von Willebrand factor antigen (vWFAg), calcinosis, lipodystrophy, possible markers of disease severity (i.e. NK cell absolute counts, TNFalpha-308A allele), and treatments. Descriptive statistics were calculated. CHAQ was dichotomized (0 vs. >0) as most scores equaled zero. Generalized estimating equations for binary data specifying logit link function were used to evaluate effects for each covariate with a main effect for time. Covariates were univariably analyzed at p < 0.10, with all univariably significant covariates entered into a multivariable model for CHAQ > 0 using a manual backward selection method.
Table 1 describes the study sample (i.e. n = 187 patients with 2293 study visits and median follow-up 3.58 years). The following univariably significant covariates (at p < 0.10) were included in the multivariable model: time (years from visit 0) (p <0.0001), black race (p = 0.035), DAS-skin (p = 0.006), DAS-muscle (p <0.0001), CMAS (p <0.0001), LDH (p = 0.005), aldolase (p = 0.013), NFC-ERL (p = 0.002), abnormal vWFAg (p = 0.0001), lipodystrophy (p <0.0001), cyclosporine (p = 0.0725), and IV solumedrol (p = 0.0002). Complete data for the multivariable model was available for 892 study visits from all 187 unique patients. Significant adjusted associations persisted in the multivariable model for CMAS (OR: 0.91, p <0.0001), aldolase (OR: 1.1, p = 0.0024), and lipodystrophy (OR: 2.2, p = 0.0126), with a trend towards significance for NFC-ERL (OR: 0.84, p = 0.0502).
To our knowledge, this is the largest longitudinal study of prospectively collected physical function data yet reported in JM. Measures of muscle weakness/inflammation (i.e. CMAS, aldolase) predict long-term physical function. The relationships between lipodystrophy, vasculopathy (i.e. NFC-ERL), and physical function warrant closer attention and replication.
To cite this abstract in AMA style:Ardalan K, Palac HL, Lee J, Wolfe M, Morgan GA, Pachman LM. Longitudinal Predictors of Physical Function in Juvenile Myositis [abstract]. Arthritis Rheumatol. 2017; 69 (suppl 10). https://acrabstracts.org/abstract/longitudinal-predictors-of-physical-function-in-juvenile-myositis/. Accessed September 25, 2021.
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