What should a cat eat at each CKD stage, from 1 to 4?

IRIS sorts chronic kidney disease into four stages using creatinine, SDMA and proteinuria. The renal diet is generally advised from stage 2. At stages 3 and 4 phosphorus restriction tightens and binders are often added. The stage is set by veterinary testing, never by eye (IRIS, 2023). Expert deep dive ### How does IRIS define the four stages? IRIS staging rests on fasting blood creatinine and SDMA, confirmed in a stable animal, then substaged by proteinuria and blood pressure. The four stages run from early damage (stage 1) to end-stage failure (stage 4). This framework, updated regularly by IRIS, structures the whole nutritional and medical plan (IRIS, 2023). The stage is no administrative detail: it sets when the renal diet starts, how hard phosphorus is restricted, and which blood phosphate target to aim for. ### How does the food change from stage to stage? The renal diet usually begins at stage 2. By stages 3 and 4 food alone rarely controls phosphate, so binders are added and appetite falls, which complicates intake. Striking fact: the general IRIS blood phosphate target is 2.7 to 4.6 mg/dL (0.9 to 1.5 mmol/L), but more permissive ceilings are realistic later, up to 5.0 mg/dL at stage 3 and 6.0 mg/dL at stage 4 (IRIS, 2023). Each stage carries its own blood-testing rhythm. Stage-by-stage detail sits in questions 12003 to 12006. Comparison table | IRIS stage | Dominant nutritional aim | Monitoring | |---|---|---| | Stage 1 | watch, hydrate, avoid excess phosphorus | close | | Stage 2 | introduce the renal diet | regular | | Stage 3 | strict renal diet, binders common | tightened | | Stage 4 | protect food intake above all | very close | Petipedia's take Petipedia presents IRIS staging as a veterinary decision framework, never a substitute for it in any individual animal.