{
  "abstract": "Objectives To describe histological findings and renal outcomes in patients with systemic lupus erythematosus (SLE) undergoing kidney biopsy with proteinuria <500 mg/day, and to identify features associated with proliferative lupus nephritis (LN).Methods Single-centre retrospective study at a tertiary referral hospital including patients with SLE who underwent kidney biopsy with proteinuria <500 mg/day. Clinical, serological, urinary and histological data were analysed. Proliferative LN was defined as ISN/RPS class III or IV, with or without class V.Results Twenty-six patients were included; 88.5% were women, with a median age of 34.5 years. Lupus nephritis was identified in 25 patients (96%). Histology showed class I in 19.2%, class II in 26.9% and proliferative LN in 50%. 46.2% of biopsies were performed at SLE diagnosis.Patients with proliferative LN had higher proteinuria despite values <500 mg/day (430 vs 280 mg/day; p=0.012), and all cases occurred at proteinuria >300 mg/day. Proliferative LN was associated with higher clinical SLEDAI scores, higher anti–double-stranded DNA levels (p=0.001) and more frequent complement consumption. Renal function did not differ between groups. All patients with proliferative LN had active urinary sediment, and cylindruria was observed exclusively in this group (p=0.007).In proliferative LN, the median NIH activity index was 7 (IQR 4–8), whereas the chronicity index was low at 1 (IQR 0–2). Interstitial fibrosis and tubular atrophy were absent in most cases and, when present, were uniformly mild. At the end of follow-up, 12 of 13 patients with proliferative LN maintained preserved renal function (eGFR >60 mL/min/1.73 m2).Abstract LBA:01:32 Table 1Conclusions Proliferative lupus nephritis is common in patients with SLE and proteinuria <500 mg/day and, in this cohort, occurred exclusively at proteinuria >300 mg/day. Integration of proteinuria with clinical and serological activity,particularly SLEDAI, anti–double-stranded DNA antibodies and complement levels,improves identification of patients at risk. Early kidney biopsy allows detection of active proliferative LN before irreversible renal damage and is associated with favourable renal outcomes.",
  "authors": [
    {
      "affiliations": [
        "Bellvitge University Hospital, Barcelona, Spain"
      ],
      "name": "Paola Vidal Montal"
    },
    {
      "affiliations": [
        "Bellvitge University Hospital, Barcelona, Spain"
      ],
      "name": "Aina Fabregat Escañuela"
    },
    {
      "affiliations": [
        "Bellvitge University Hospital, Barcelona, Spain"
      ],
      "name": "Xavier Fulladosa"
    },
    {
      "affiliations": [
        "Bellvitge University Hospital, Barcelona, Spain"
      ],
      "name": "Olga Capdevila"
    },
    {
      "affiliations": [
        "Bellvitge University Hospital, Barcelona, Spain"
      ],
      "name": "Monica Cubells"
    },
    {
      "affiliations": [
        "Bellvitge University Hospital, Barcelona, Spain"
      ],
      "name": "Javier Narváez"
    }
  ],
  "title": "LBA:01:32 Proliferative lupus nephritis is common below the 500 mg/day proteinuria threshold",
  "uid": "56e69e1d-8eca-5577-bc83-a08729ffbd61"
}