Background and aims In Philippine setting, management of lupus nephritis (LN) is primarily driven by clinical parameters more than kidney biopsy because of limited resources. This paper describes clinico-pathologic correlations in a cohort of Filipino patients with LN.

Methods Study population included LN patients who underwent kidney biopsy at University of Santo Tomas (UST) Hospital, Manila, Philippines from 2005 to 2015.Pathologic diagnoses utilised International Society of Nephrology/Renal Pathology Society (ISN/RPS) 2003 classification, including activity and chronicity indices. Correlations of histopathologic classification with demographic and systemic lupus erythematosus (SLE) characteristics were performed using linear and multinomial regression analysis.

Results Included were 101 LN patients (94 females, 72 adults) with mean age 25.2±11.5 (9–61) at SLE diagnosis and 3.08±6.02 (<1–12) years disease duration from SLE diagnosis to biopsy. Most common ISN/RPS classification was Class IV in 57 (56.4%) patients and Class III in 33 (32.7%). Average activity index was 6.64±2.22 (0-12), chronicity index, 3.54±2.02 (0-9); Class IV and V correlated with higher activity index scores, p=0.001. Mean uPCR was 2.61+1.44 (0.03–7.43) mg/mg with highest uPCR in Class IV, followed by classes III and V. Mean estimated glomerular filtration rate (eGFR) was 63.02±34.25 (9-139) mL/min, with inverse correlation between eGFR and histologic activity, p=0.003. Extra renal manifestations included arthritis (61%), malar rash (59%) and photosensitivity (50%), with mean SLEDAI score of 11.07±3.78; these did not correlate with histologic indices.

Conclusions This study shows good correlation of clinical renal parameters with histopathology, supporting the rationale of current Philippine practice to perform kidney biopsies as clinically indicated rather than routinely.