Focal segmental glomerulosclerosis (FSGS), a disease caused by irreversible podocyte injury, is an important cause of proteinuria in dogs and humans. It is the most common non-immune complex glomerulopathy in dogs and has a previously reported prevalence of approximately 20 % in dogs biopsied for suspected glomerular disease, with females being over-represented. The purpose of this study was to retrospectively characterize the clinical presentation and prognosis of FSGS in dogs.
Clinical and histopathological data and cause of death were obtained by reviewing the records of dogs diagnosed with FSGS on renal biopsies submitted to the International Veterinary Renal Pathology Service (IVRPS) between January 2015 and May 2017. FSGS is a disease characterized by an absence of immune - complex deposits and the presence of a segmental consolidation of the glomerulus by extracellular matrix; it is often associated with adhesions to Bowman’s capsule and hyalinosis. Kaplan Meier survival analysis with log - rank test was used to determine whether International Renal Interest Society (IRIS) stage, urine protein : creatinine ratio (UPC), presence of severe hypoalbuminemia (< 2 g / dL), ascites or edema at biopsy, history of hypertension (HT), or percentage of global glomerulosclerosis (GS) on biopsy were associated with death from renal disease or any cause. A two - sample test of proportion was used to assess the significance of the male : female distribution.
Of 299 dogs with renal biopsies submitted to IVRPS with proteinuria during the study period, 77 (26 %) were diagnosed with FSGS. Median age was 9.5 years at biopsy (range 2.3 - 14.8 years), and 48 (62 %) of dogs were female (p = 0.04). Median serum creatinine concentration was 1.2 mg / dL (range 0.3 - 8.7 mg / dL). Median serum albumin concentration (Alb) was 2.8 g / dL (range 1.1 - 4.6 g / dL). HT was documented prior to or at the time of biopsy in 44 / 72 (61 %) of dogs. Median UPC was 5.9 (range 1.4 - 22) and 6 dogs were reported to have ascites / edema at biopsy. At the time of data collection, 23 dogs (30 %) were alive, 38 (49 %) were deceased and 16 (21 %) were lost to follow up. Of the 38 dogs that died (all cause death, AC), 18 (47 %) were renal-related deaths (RD). RD and AC dogs in IRIS stage 3 or 4 at biopsy had significantly shorter survival post - biopsy (SPB) than those in IRIS stage 1 or 2 (RD p < 0.001; AC p < 0.001). RD and AC dogs with Alb < 2 g / dL had significantly shorter SPB than dogs with Alb > 2 g / dL (RD p = 0.01; AC p = 0.004). RD and AC dogs with ascites / edema at time of biopsy had significantly shorter SPB compared to dogs without (RD p = 0.001; AC p = 0.03). AC dogs with history of HT had significantly shorter SPB compared with AC dogs without a history of HT (p = 0.03). RD dogs with GS affecting ≥ 25 % of glomeruli had significantly shorter SPB than RD dogs with < 25 % GS (p = 0.03). UPC was not significantly associated with SPB in RD or AC dogs.
In this retrospective study, FSGS had a similar prevalence to what has been previously reported. Females continued to be over-represented. Severe hypoalbuminemia and IRIS stages 3 or 4 were associated with a poorer prognosis in all dogs with FSGS. Hypertension was associated with a shorter survival in dogs that died of any cause, whereas biopsy samples with at least 25 % global glomerulosclerosis were associated with a poorer prognosis in dogs that were known to have renal-related deaths.
The Ohio State University
Dr. Sarah Lorbach is a 2014 graduate of The Ohio State University College of Veterinary Medicine. She worked for 1.5 yrs in Cincinnati, OH in emergency medicine before moving to Columbus, OH where she acquired a position in general practice. In addition, she began working for the International Veterinary Renal Pathology Service last year. Sarah recently matched to a veterinary internship at Friendship Hospital for Animals in D.C. and will be starting in June.
Friday, June 15
11:45 AM – 12:00 PM
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