Estimated glomerular filtration rate (eGFR) and albuminuria must be evaluated in patients with chronic kidney disease (CKD) in order to properly stratify risk and decide whether or not a referral to a nephrologist is required. If the eGFR is less than 30 ml/min/1.73m2 or the urine albumin/creatinine ratio is greater than or equal to 300 mg/g, a referral to nephrology is suggested by the Kidney Disease: Improving Global Outcomes clinical practice guidelines for CKD. Patients with chronic kidney disease (CKD) who were being closely monitored by their primary care physicians were discovered using a nationwide claims database of US citizens covered by commercial insurance or Medicare Advantage. Researchers looked at how often these individuals visited a nephrologist over the course of a year and how that number varied by eGFR and albuminuria stage. 

After adjusting for age, sex, race/ethnicity, diabetes, heart failure, and coronary artery disease, they used multivariable logistic regression to analyze the probabilities of obtaining nephrology care by CKD category. Of the 291,155 individuals diagnosed with CKD, 55% had seen a nephrologist according to the guidelines’ suggested referral criteria. Compared to individuals with a UACR greater than or equal to 300 mg/g (51%; 8789/17290), those with an eGFR less than 30 were more likely to receive the nephrology care suggested by guidelines (64%; 11,330/17738). About 59% were not checked for albuminuria. 

Patients with an estimated glomerular filtration rate (eGFR) of less than 30 ml/min/1.73 m2 who did not undergo albuminuria testing had a significantly decreased adjusted likelihood of receiving care from a nephrologist. Diabetes status-stratified analysis showed the same general trends. Patients who met laboratory criteria for referral to nephrology were just half as likely to actually be seen by a nephrologist as the general population. However, identifying primary care patients at high risk of kidney failure who need to be referred to a nephrologist may be hindered by the low utilization of albuminuria tests.