Background/Purpose:

An easy, quick tool, requiring minimal training or physician input for disease activity (DA) assessment in SLE, would have potentially greater uptake for routine use among rheumatologists and primary care physicians. Furthermore, integration into busy work flow processes would be easier for the same reason. Most DA tools for SLE are complex, require training and physician time; and are not performed during routine care visits for most SLE patients. SIMPLE (Simple Disease Assessment for People with Lupus Erythematosus) ¹ is a numeric composite index based on patient reported questions and two laboratory values, and requires minimal input from health care provider which can be provided by nurse or a physician extender.  Here, we prospectively evaluate the correlation of SIMPLE index with physician based DA measure. 

Methods:

Fifty consenting patients meeting ACR classification criteria for SLE were recruited from two academic center clinics.  Primary outcome of interest was correlation between Simple Index (SI) and SELENA-SLEDAI (SS). Secondary outcome of interest was correlation between SI and Physician Global Assessment (PGA).  Patients filled the self-reported components of SI in the waiting room prior to their visit. PGA, SS and total numeric BILAG were assessed at the same visit by the physician. Descriptive and spearman correlational analyses were obtained. Stratified analysis by fibromyalgia status (FMS) was also conducted. P value of ≤0.05 was considered significant on two tailed tests. We considered correlation coefficient of <0.30, 0.30 to 0.49 and >0.50 as weak, moderate and strong correlation, respectively. 

Results:

Mean (SD) age was 41.4+13 yrs, and 90% participants were women. Ethnic background of the participants was as follows:  56% Blacks, 24% Whites, 10% Asians and 10% others. Median (IQR) SI was 27.8 (18.3). Range for SI was 58.4. Median (IQR) values of PGA, total SS, total numeric BILAG and SDI were 0.5 (0.8), 4.0(6.0), 10.5(9.0) and 1.0(1.0), respectively.  Spearman correlation coefficient between SI and PGA and SS were 0.547 (p 0.001), 0.545(p 0.001), respectively. In a sub analysis excluding fibromyalgia patients, these correlations were 0.718(p 0.001, n=34), 0.622(p 0.001, n=36) respectively. 

Conclusion:

SIMPLE index is strongly correlated with PGA and SS in SLE, and the correlation is even stronger is SLE patients without FMS. It is quick, easy and requires minimal physician input. Larger and longitudinal studies that include patients with greater DA and test responsiveness are currently ongoing.

Reference:

¹ Simple Disease Assessment for People with Lupus Erythematosus. A&R. 2014; 66 (11):s312

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ACR Meeting Abstracts - https://acrabstracts.org/abstract/further-validation-of-simple-index-as-a-simple-disease-activity-assessment-tool-for-sle/