Background/Purpose:

Systemic Lupus Erythematosus (SLE) is a complex autoimmune disease that affects women of childbearing age. Lupus nephritis is a major cause of morbidity and mortality in SLE and is characterized by unpredictable exacerbations and remissions. Following induction therapy of lupus nephritis, patients are generally maintained in remission by either mycophenolate mofetil or azathioprine. Pre-pregnancy planning is an important aspect of the clinical management of lupus nephritis. Due to potential teratogenicity, the use of mycophenolate mofetil is contraindicated during pregnancy. The aim of this research was to determine the rate of flare of lupus nephritis precipitated by switching from mycophenolate mofetil to azathioprine in pre-pregnancy planning and factors associated with or predictive of flare.

Methods:

We retrospectively reviewed the clinical data and obstetric outcomes of eight female lupus nephritis patients in the maintenance phase of therapy who were switched from mycophenolate mofetil to azathioprine in pre-pregnancy planning.

Results:

62% (n=5) of patients did not experience a flare of nephritis when their medication was switched and of these 80% (n=4) had uneventful pregnancies. 38% (n=3) patients developed significant lupus nephritis flares when switched from mycophenolate mofetil to azathioprine. Two of these patients achieved pregnancy; one was delivered at 35 weeks by Caesarean section and the other by induction at 37 weeks, both due to pre-eclampsia. Both experienced post partum flare of nephritis, one requiring cyclophosphamide and the other was controlled with an increased corticosteroid dose and reintroduction of an angiotensin-converting-enzyme inhibitor.

Urinary protein creatinine ratio was significantly higher at time of medication switching in those who experienced renal flare (p=0.027). Serum creatinine, haemoglobin and serum albumin levels did not significantly differ between the two groups. Age at diagnosis, duration of disease, age at medication switch and duration since renal biopsy were not significantly different between the two groups. C3 levels, anti-dsDNA antibody % binding titres and ESR were significantly higher at time of medication switching in those who experienced renal flare (p=0.03, 0.024 and 0.049 respectively). C4 levels did not significantly differ between the two groups.

Conclusion:

When switching apparently stable patients from mycophenolate mofetil to azathioprine it is important that adequate time and consideration is given to ensure the patient is stable on their new medication regimen before proceeding to pregnancy. Current recommendations advise that stable remission of renal disease is achieved for at least 6 months before conception. This study has found that urinary protein creatinine ratio, anti-dsDNA antibody titres and C3 levels are important predictors of flare in this subset of patients.

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« Back to 2013 ACR/ARHP Annual Meeting

ACR Meeting Abstracts - https://acrabstracts.org/abstract/lupus-nephritis-flares-precipitated-by-switching-from-mycophenolate-mofetil-to-azathioprine-in-pre-pregnancy-planning/