About 85% of the study patients were women, and almost all were Caucasian; patients were followed for a median of 10.6 years. The number of male patients increased over time, from 6.6% in P1 to 12% in P2 and 19.6% in P3. The researchers noted an increasingly longer lag time between SLE and lupus nephritis diagnosis from 1970–2016 (P<0.0001). Age of lupus nephritis occurrence rose from 28.4 years in P1 to 29 years in P2 and 34.4 in P3 (P<0.001).
Researchers observed a progressive decrease in mean serum creatinine at diagnosis over time (1.8 mg/dL in P1, 1.2 mg/dL in P2 and 1.0 mg/dL in P3), as well as a significant decrease in the frequency of acute nephritic syndrome and rapidly progressive renal insufficiency. Significant growth was found in the prevalence of isolated urinary abnormalities from P1–P3.
Treatment & Outcomes
Among all time periods, more than two-thirds of patients were treated with methylprednisolone pulses as induction therapy. In P1, 29% of patients received induction therapy with corticosteroids alone, compared with 17.9% in P2 and 5.4% in P3. Immunosuppressive drug use grew more common over time, and they were added for maintenance therapy in 30.5%, 65.5% and 89.1% of patients in P1, P2 and P3, respectively. Cyclophosphamide was used by 50% or more of patients in each time period, and there was a decrease in the use of azathioprine as induction therapy from P1–P3; this was counterbalanced by an increase in the use of mycophenolate mofetil.