A 52-year-old man visited me for a routine health check. He felt well, had no obvious symptoms and believed his parameters were reasonably under control. He was taking medication for high blood pressure and following a fairly balanced diet. Yet his blood reports revealed something concerning: his kidney function was declining. There had been no dramatic warning signs. No persistent pain. No obvious change in his daily routine. Just a subtle but progressive deterioration in his kidney function, reflected in successive blood tests.

We evaluated possible reasons. Was his blood pressure adequately controlled? Could diabetes, an underlying medical condition, dehydration or medication use be contributing to the decline?…