Abstract: TH-PO164

Incidence of Focal Segmental Glomerulosclerosis in Olmsted County

Session Information

Category: Glomerular

  • 1005 Clinical Glomerular Disorders

Authors

  • Hommos, Musab S., Mayo Clinic, Rochester, Minnesota, United States
  • Fervenza, Fernando C., Mayo Clinic, Rochester, Minnesota, United States
  • De Vriese, An S., AZ Sint-Jan, Bruges, Bruges, Belgium
  • Alexander, Mariam P., Mayo Clinic, Rochester, Minnesota, United States
  • Sethi, Sanjeev, Mayo Clinic, Rochester, Minnesota, United States
  • Vaughan, Lisa E., Mayo Clinic, Rochester, Minnesota, United States
  • Bharucha, Kharmen Adil, Mayo Clinic, Rochester, Minnesota, United States
  • Zand, Ladan, Mayo Clinic, Rochester, Minnesota, United States
  • Lepori, Nicola, Ospedale Brotzu, ----Cagliari, Italy
  • Rule, Andrew D., Mayo Clinic, Rochester, Minnesota, United States
Background

Focal segmental glomerulosclerosis (FSGS) incidence is increasing. However, previous studies reported trends in relative disease frequencies and presented FSGS as a single disease entity. We now know that FSGS is a histological pattern of injury caused by a variety of conditions. Thus, we evaluated the incidence of primary vs. secondary FSGS in a population-based study.

Methods

Olmsted County residents with native kidney biopsy between 1994 and 2013 that showed FSGS as the only glomerulopathy were identified. Primary FSGS was defined as having nephrotic syndrome (serum albumin ≤3.5g/dl and proteinuria ≥3.5g/24h), foot process effacement ≥ 80% and no identifiable causes. Age and sex adjusted incidence rate per 100,000 person-years was calculated. Poisson regression models estimated the change in incidence rate over time.

Results

Among 370 adults biopsied during this period, 281 had glomerular disease of which 46 (16%) had FSGS as the only glomerulopathy.(Table 1) Estimated native kidney biopsy incidence rates were significantly higher in 2004-2013 compared to 1994-2003 (22.9 vs. 14.7 per 100,000 person-years, 17% increase per 5 years, p<0.001). Total FSGS incidence rates also increased over the same time period from 1.4 in 1994-2003 to 3.2 per 100,000 person-years in 2004-2013 (41% increase per 5 years, p=0.02). Secondary FSGS accounted for 9/12 (75%) of cases during 1994-2003 and 25/34 (74%) of cases during 2004-2013.

Conclusion

The majority of cases are secondary FSGS. While the incidence of FSGS has increased over the past two decades, the proportion of primary and secondary FSGS has remained stable. Further studies are needed to understand the causes of this increasing Incidence though increasing biopsy rates may be a contributor. Importantly, primary FSGS rate remains low (0.85 per 100,000 person-years).