Lupus nephritis (LN) is a main manifestation of systemic lupus erythematosus (SLE), which
will largely effect the prognosis of SLE patients. Our previous 10-year data showed that the
development of LN is most common in the first year of SLE, occupying about 17%. And our group
has established a prediction model to predict the 1-year probability of LN for SLE patients
without renal involvement. Our previous proof-of-concept trial and multicenter, randomized,
double-blind, placebo-controlled trial indicated that metformin seemed to have potential to
reduce the new-onset of LN in SLE patients (Unpublished data, in review). So the
investigators tried to illustrate whether metformin has effect to prevent the development of
lupus nephritis in high risk SLE patients based on LN prediction model.