In the late stages of chronic kidney disease (CKD), classical nephroprotective strategies (RAAS blockade, low–protein diet) demonstrate lower effectiveness, especially given its limited duration. The efficacy of newly introduced drugs (SGLT2i, sacubitril, GLP-1 RA, nonsteroidal MRA and endothelin receptor antagonists) are not clear for the CKD late stages. In previous study, we presented an effectiveness assessment of the comprehensive nephroprotective protocol (doi: 10.5772/intechopen.1004361) based on a prospective follow-up of 100 patients compared with a matched historical cohort and a method for assessing the progression rate of CKD3B+ based on follow-up of 540 patients.

This study extension in post-COVID population presents an external validation of the method in parallel with additional parameters inclusion, and update of the significance assessment of components of nephroprotective strategy in CKD late stages.

Using the initial eGFR prediction formula [Y=-0,0007×X²+0.0155×X+0.7381, where Y is instantaneous rate of GFR decrease (ml/min/1.73m²/year), and X is the current eGFR] in the new patient population, systemic error was +1±5%, random error 10%. The tool for predicting eGFR decrease rate in a new group of 250 patients included the underlying disease, age and gender, taking into account previously obtained estimates in population of 5,644 patients, which improved the operational characteristics (system error 0±5%, random 8%).

Annual follow-up by protocol of 250 patients with baseline eGFR 32 (41-20) ml/min/1.73m² and proteinuria 0.61 (0.20-1.42) demonstrate a CKD progression retardation to 6.0±1.7 ml/min/1.73m²/year compared with the matched historical control group 9.0±1.9 ml/min/1.73m²/year, p<0.01.  The categorical analysis demonstrated the relative importance of the nephroprotection components in CKD3b-CKD5: