Every doctor evaluates how active the lupus is in their own way. In a survey study nearly 70% of rheumatologists said they had their own system of assessing disease activity (DA). Only 11% of rheumatologists used labs or standardized disease activity tools for measuring disease activity (Strand V et al A&R 2014). Most rheumatologist that do perform standardized DA measurement do so because they are either participating in research or clinical trials for lupus.
Tracking disease activity in lupus is important for several reasons. Standardized DA measurements are require rheumatologists training, time and particpation. They are complex and hard to integrate into routine care visits. Their completion requires a rheumatologist trained in performing of these standardized evaluation to perform systematic general and organ specific history, examination, and several blood and urine tests. In some scenarios, lupus patients may not have access to a rheumatologist, doctor or the labs needed to complete these assessments. On the other hand patient reported disease evaluations correlate poorly with doctors measurement of disease activity.
To facilitate measurement of disease activity keeping in mind above limitations, we developed a simple tool that can be used as a surrogate for disease activity in Lupus. It involves patient particpation in the form of answering some questions, two lab tests and minimal involvement of the doctor. It is easy to perform and can be easily integrated into busy practices, or those with limited resources. A health care provider input is required to confirm attribution to lupus in case of abnormal labs (low C3/C4 and proteinuria) by exclusion of other confounding reasons, and confirmation of patients responses in regards to their current steroid use.
SIMPLE index was derived using observational data from 1,150 patients with lupus from various countries. (Jolly M et al A&R.2014). We have confirmed its correlation with SELENA-SLEDAI to exceed 0.55 in a different patient group (Gandhi N et al. J Clin Rheum 2018) and in another external study including private practice and academic center lupus patients (n=201) (Collins C et al. A&R.2015). In the latter study, correlation of SIMPLE index with BILAG was 0.63 (n 56) (Narayanan S et al. ISPOS.2016. Test retest reliability was 0.76 (Chatham WW et al. EULAR 2016). Pilot data shows improvement in SIMPLE Index with improvement in disease.