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Kidney Week

Abstract: TH-PO605

Changing Phenotypes and Clinical Outcomes over Time in Microscopic Polyangiitis

Session Information

Category: Glomerular Diseases

  • 1402 Glomerular Diseases: Clinical, Outcomes, and Trials

Authors

  • Uzzo, Martina, Department of Medicine and Surgery, University of Milano-Bicocca, Monza, Italy
  • Maggiore, Umberto, Nephrology and Dialysis Unit, Department of Medicine and Surgery, University of Parma, Parma, Italy
  • Sala, Filippo Maria, Department of Medicine and Surgery, University of Milano-Bicocca, Monza, Italy
  • Reggiani, Francesco, Nephrology and Dialysis Unit, IRCCS Humanitas Research Hospital, Milano, Italy
  • L'Imperio, Vincenzo, Department of Medicine and Surgery, Pathology, University of Milano-Bicocca, IRCCS Fondazione San Gerardo dei Tintori, Monza, Italy
  • Calatroni, Marta, Nephrology and Dialysis Unit, IRCCS Humanitas Research Hospital, Milano, Italy
  • Moroni, Gabriella, Nephrology and Dialysis Unit, IRCCS Humanitas Research Hospital, Milano, Italy
  • Sinico, Renato Alberto, Nephrology and Dialysis Unit, IRCCS Humanitas Research Hospital, Milano, Italy
Background

Diagnosis and management of Microscopic Polyangiitis (MPA) have evolved considerably over the last decades, but it is unknown whether clinical, histological presentation and patient and renal outcomes have changed accordingly.

Methods

We compared clinical-histopathological characteristic at diagnosis, and the risk of death and of end stage kidney disease (ESKD) in patients diagnosed with MPA between 1980 and 2022, after grouping them in two periods (p): p1980–2001 and p2002–2022. We compared the mortality rate between the two periods using Kaplan-Meier estimator and Cox-regression and competing risks of ESKD and death using the Aalen-Johansen estimator, Fine-Gray multiple regression and multi-state models.

Results

Out of 187 patients, 77 were in p1980-2001, and 110 in p2002-2022. Patients in p2002-2022 were older (66.2(14.0) vs 57.7(15.8); P<0.001), had a better kidney function (eGFR 25.9(24.8) vs 21.5(28.2) mL/min/1.73m2; P=0.011) and a lower prevalence of the Berden sclerotic class (4.8 vs 18.2%; P=0.006). Despite a similar crude and adjusted patient survival, the risk of ESKD decreased during p2002-2022, compared to p1980-2001 (0.30 [95%CI:0.16-0.57; P<0.001]) (Figure). The result remained significant after accounting for death after ESKD in multistate models and after adjusting for potential confounders (0.33 [95%CI:0.18-0.63; P<0.001]).

Conclusion

Clinical presentation of MPA has become less severe over the last decades, leading to a reduced risk of ESKD, despite a comparable risk of death. Older age, changing clinical patterns and better kidney function at the time of diagnosis do not fully account for the reduction in ESKD, which may be instead related to new induction and maintenance therapies as well as to a greater awareness of the disease.