Nat. Rev. Nephrol. doi:10.1038/nrneph.2016.135 Figure 5 Hypothetical inverse relationship between total kidney volume (TKV) and glomerular filtration rate (GFR) in patients with autosomal dominant polycystic kidney disease (ADPKD) Figure 5 | Hypothetical inverse relationship between total kidney volume (TKV) and glomerular filtration rate (GFR) in patients with autosomal dominant polycystic kidney disease (ADPKD). Increasing rates of TKV growth are shown by exponential-like curves. The corresponding GFR curves are based on the assumption that, in the absence of modifying factors, GFR decline is linked to the progressive increase in TKV in patients with ADPKD. At the age of 18 years, TKV is assumed to be 400 ml53 and GFR 120 ml/min/1.73 m2. GFR in each succeeding year is determined from the equation GFR = (GFRt-1) – (TKVt /400) where t is age and t-1 is age minus 1 year. GFR decline is determined by the fractional increase in TKV (TKVt /400). The model illustrates the initial decades during which GFR remains within normal limits shown by values above the dashed horizontal line depicting the lower limit of chronic kidney disease stage 1; the escalating rate of GFR decline over time; and the inverse relationship between GFR decline and the formation and expansion of cysts as measured by TKV. a | For a TKV increase of 5% per year, GFR reaches 0.0 ml/min/1.73 m2 at 57 years of age. b | For a TKV increase of 7% per year GFR reaches 0.0 ml/min/1.73 m2 at 50 years of age. c | For a TKV increase of 10% per year GFR reaches 0.0 ml/min/1.73 m2 at 43 years of age. Grantham, J. J. & Torres, V. E. (2016) The importance of total kidney volume in evaluating progression of polycystic kidney disease Nat. Rev. Nephrol. doi:10.1038/nrneph.2016.135