FGF23 and autosomal dominant polycystic kidney disease: An important difference between these two studies is that in the first study (74), which included 1,002 ADPKD patients followed-up for 5.4 years, FGF23 did not largely improve the prediction of a kidney function decline over htTKV, while, contrarily, in the second study (75), which monitored 192 ADPKD patients over 13 years, FGF23 emerged as a strong predictor of kidney function decline independently of htTKV or PKD genotype.