PTH and chronic kidney disease: The effect on survival and on low PTH concentrations compared to normal dietary phosphorus intake (0.42% or 1.56% dry matter) was reported in the earliest study in cats with surgically induced CKD.140 Survival time did not differ between treatment groups though this could be accounted for by the short follow-up time (65–343 days) and the slowly progressive nature of CKD in cats.140 Renal histopathology was however remarkably different between dietary treatment groups.