Is there any science behind preferring lozartani over amlodipine for kidney protection? nephrologists are the ones doing it. please enlighten me. thank you?

If you only have hypertension and there is nothing wrong with your kidneys and/or urine, optimal blood pressure control with either losartan or amlodipine is fine. For black people, losartan won't be the first antihypertensive drug but amlodipine is. However, if you have diabetes mellitus, we will prefer using losartan. So, the drug of choice has to be individualized, not losartan or ARB for all.

The idea to use the combo is to get the BP down to prevent damage to the heart and Kidneys. Nephrologist and other docs do that