Lay summary
More than ten per cent of adults will develop chronic kidney disease. The effectiveness of many treatments used to improve outcomes in kidney disease are tested against surrogate (indirect) markers of health (e.g., cholesterol levels or blood pressure). Unexpectedly, subsequent systematic analysis has identified little evidence to show that treatment strategies based on these surrogate markers translate to improved health for patients. Serum creatinine and proteinuria levels are commonly-used markers of kidney function to guide treatment. We will use systematic review methods to summarise the quality of evidence for using proteinuria and serum creatinine as markers of treatment effectiveness in clinical trials. We will determine whether using these markers to guide clinical care improves patient health or, conversely, leads to treatment-related harm or excessive use of ineffective medication. These summaries will help clinicians and patients make better shared decisions about which therapeutic strategies actually improve clinical outcomes in kidney disease.