Rate and predictors of chronic organ damage accrual in active lupus nephritis: a single centre experience over 18 years of observation

Objectives: We aimed to identify the rates and predictors of chronic damage accrual and mortality in lupus nephritis (LN). Methods: We retrospectively measured SLICC/ACR Damage Index (SDI) in biopsy proven active LN with at least 5 years follow-up. We searched for the predictors of first SDI increase and death at univariate and multivariate regression analysis. Then, we considered clinical/biochemical/histological features at diagnosis, corticosteroids dose and proportion of follow-up in complete renal remission. Results: 187 patients (91.4% females, age 28.1 years, 95.7% Caucasians) were included. After a median follow-up of 18.6 years, 26 patients (13.9%) died, 116 (62%) accrued damage. SDI annual rate has significantly reduced over the last decades (from a mean of 0.14±0.17 in 1970-1985, to 0.09±0.21 in 1986-2001, to 0.07±0.1 in 2002-2019; p=0.0032). SDI increases occurred more frequently in renal (22.5%), ocular (18.2%), cardiovascular, neuropsychiatric (13.4% both) and malignancy (12.8%) domains. First SDI increase free survival was 73.3%, 59.8%, 49.9% and 38% at 5,10,15 and 20 years. At multivariate analysis, hypertension (HR:1.699, CI:1.126-2.457, p=0.011), presentation with acute renal dysfunction (HR:1.587,CI:1.082-2.327, p=0.018) and average prednisone dose >5mg/day (HR:3.378, CI:1.984-5.751, p<0.0001) independently predicted damage. Achievement of complete renal remission (HR:0.993, CI:0.987-0.999, p<0.039) reduced the risk of damage. Age (HR:1.063, CI:1.027-1.099, p=0.0004), hypertension (HR:3.096, CI:1.211-7.912, p=0.019), and no immunosuppressors as maintenance therapy (HR:4.168, CI:1.212-14.336, p=0.024) predicted mortality at multivariate analysis. Conclusions: Besides arterial hypertension, presentation with acute renal dysfunction and corticosteroids dose predict SDI increase in LN, while achieving renal remission prevents damage. Aggressive therapy to induce remission in the acute phases of LN and low corticosteroids dose in maintenance therapy may prevent the increase of chronic damage.