Grace E. Ahn

Northwestern University, Evanston, Illinois, United States

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Publications (3)4.17 Total impact

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    ABSTRACT: Objective: Fatigue is a common symptom in systemic lupus erythematosus (SLE), and engaging in physical activity may reduce fatigue. We aimed to characterize relationships between fatigue, other health status measures assessed with the Patient Reported Outcomes Measurement Information System (PROMIS) instruments, and accelerometer-based physical activity measurements in patients with SLE. The internal consistency of each PROMIS measure in our SLE sample was also evaluated. Methods: This cross-sectional study analyzed 123 adults with SLE. The primary fatigue outcome was Fatigue Severity Scale score. Secondary outcomes were PROMIS standardized T-scores in seven health status domains. Accelerometers were worn for seven days, and mean daily minutes of light, moderate/vigorous, and bouted (10 minutes) moderate/vigorous physical activity were estimated. Cronbach's alpha was determined for each PROMIS measure to assess internal consistency. Relationships between Fatigue Severity Scale, PROMIS, and physical activity were summarized with Spearman partial correlation coefficients (r), adjusted for average daily accelerometer wear time. Results: Mean Fatigue Severity Scale score (4.3, SD 1.6) was consistent with clinically relevant levels of fatigue. Greater daily and bouted moderate/vigorous physical activity minutes correlated with lower Mean Fatigue Severity Scale score (r = -0.20, p = 0.03 and r = -0.30, p = 0.0007, respectively). For PROMIS, bouted moderate/vigorous physical activity minutes correlated with less fatigue (r = -0.20, p = 0.03). PROMIS internal consistency was excellent, with Cronbach's alpha > 0.90 for each domain. Mean PROMIS T-scores for fatigue, pain interference, anxiety, sleep disturbance, sleep-related impairment, and physical function were worse than reported for the general US population. More moderate/vigorous physical activity minutes were associated with less pain interference (r = -0.22, p = 0.01). Both light physical activity and moderate/vigorous physical activity minutes correlated with better physical function (r = 0.19, p = 0.04 and r = 0.25, p = 0.006, respectively). Conclusion: More time spent in moderate/vigorous physical activity was associated with less fatigue (Fatigue Severity Scale and PROMIS), less pain interference, and better physical function (PROMIS). PROMIS had excellent internal consistency in our SLE sample, and six of seven PROMIS measures indicated poorer average health status in SLE patients compared with the general US population.
    No preview · Article · Feb 2016 · Lupus
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    ABSTRACT: Objective Most estimates of physical activity (PA) patterns in systemic lupus erythematosus (SLE) are based on subjective self-report measures prone to error. The aims of this study were to obtain objective measurements of PA using an accelerometer and estimates of energy expenditure based on the self-reported International Physical Activity Questionnaire (IPAQ), and to describe their relationship.Methods The “Activity in Lupus To Energize and Renew” (ALTER) study, a cross-sectional study of PA, included 129 persons with SLE. Accelerometer measures over 7 days included total daily activity counts and minutes of moderate-vigorous physical activity (MVPA). Each person completed the IPAQ via telephone interview. Spearman correlations (r) and 95% confidence intervals (CIs) assessed associations between accelerometer and IPAQ.Daily PA means (SD) from accelerometer measures were total daily activity counts, 502,910 (118,755) and MVPA, 40 (30) minutes. The median (interquartile range) MET-min per day for IPAQ intensities were: total 400 (159-693); walking, 83 (26-184); and moderate-vigorous, 231 (77-514), and domains were: work 0 (0-73); active transportation 28 (0-85); domestic and garden 77 (26-231); and leisure 57 (0-213). Associations between accelerometer measures and IPAQ were: 1) total daily count vs. IPAQ total, r=0.21, 95% CI: (0.03, 0.37); and 2) MVPA vs. IPAQ moderate-vigorous, r=0.16, 95% CI: (-0.02, 0.33).Conclusion Accelerometer measures and IPAQ energy expenditure estimates were moderately correlated. IPAQ provided descriptive PA data whereas accelerometers captured all daily activities and can help assess guideline attainment. The choice of IPAQ versus accelerometer measure should consider the purpose for which PA is measured. © 2014 American College of Rheumatology.
    No preview · Article · Sep 2014
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    Full-text · Article · Apr 2012 · Osteoarthritis and Cartilage
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    Grace E Ahn · Rosalind Ramsey-Goldman
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    ABSTRACT: Systemic lupus erythematosus is a chronic inflammatory autoimmune disease often characterized by fatigue, with significant effects on physical functioning and wellbeing. The definition, prevalence and factors associated with fatigue, including physical activity, obesity, sleep, depression, anxiety, mood, cognitive dysfunction, vitamin D deficiency/insufficiency, pain, effects of medications and comorbidities, as well as potential therapeutic options of fatigue in the systemic lupus erythematosus population are reviewed. Due to variability in the reliability and validity of various fatigue measures used in clinical studies, clinical trial data have been challenging to interpret. Further investigation into the relationships between these risk factors and fatigue, and improved measures of fatigue, may lead to an improvement in the management of this chronic inflammatory disease.
    Preview · Article · Apr 2012 · International Journal of Clinical Rheumatology