Figure 7.

Ratio of diabetic to control glomerular filtration rate (GFR) and transcapillary pressure difference (ΔP) for each of 20 published series where this comparison was possible. Ratios are shown instead of absolute changes because some studies reported GFR and others reported single-nephron GFR (SNGFR). Confidence intervals for this figure are SEs computed from reported variances and sample sizes and the following equation for computing variance of a ratio: $\mathit{V}\mathit{a}\mathit{r}\left(\frac{\mathit{y}}{\mathit{x}}\right)=\left(\frac{1}{{\mathit{x}}^2}\right)\mathit{V}\mathit{a}\mathit{r}\left(\mathit{y}\right)+\frac{{\mathit{y}}^2}{{\mathit{x}}^4}\mathit{V}\mathit{a}\mathit{r}\left(\mathit{x}\right).$ The blue curve was generated by the Brenner-Deen model and depicts the relative changes in GFR and ΔP where renal plasma flow and ultrafiltration coefficient are held constant starting from the base case where ΔP = 35 mmHg, plasma flow = 150 nL/min, plasma protein concentration = 5.6 g/dL, and ultrafiltration coefficient = 0.06 nL/s/mmHg. The cases shown in red are series in which effects of diabetes on GFR cannot be explained by associated changes in ΔP.