What is the prognostic value of reduced eGFR?

UNLABELLED

Introduction of the definition and classification of chronic kidney disease (CKD) according to the KDOQI guidelines in 2002 served as a turning point in nephrology. On one hand, the new definition has allowed for the standardization of terminology, on the other hand, however, it has led to a rapid growth in CKD diagnoses. Another issue is the strengthening of the assumption, that diagnosis of CKD is associated with further progressive kidney dysfunction until reaching the end stage renal disease (ESRD). Clinical practice, however, provides evidence that not all patients diagnosed with CKD reach ESRD and eventually require renal replacement therapy (RRT), and in many cases CKD does not progress.

AIM

The aim of the study was to assess practical information for a clinician provided by eGFR and its changes during the follow-up of a patient as regards the RRT prognosis and mortality risk.

MATERIALS AND METHODS

The study group consisted of patients with CKD treated in the regional outpatient clinic. Progression was assessed by determining a linear trend line for eGFR results. Based on its course and the value of the coefficient of determination R2, four types of eGFR trajectories were identified: linear progression type (G2), nonlinear progression type (G1), improvement type (G3), undetermined eGFR change type (G4).

RESULTS

The study group consisted of 65 patients 58.5% females, age mean 69 ± 12.8 years. The mean annual eGFR change in the entire group was -1.67±11.7 ml/min/1.73m2/year. During the study, 6.2% of patients began RRT (hemodialysis), and 9.2% died. Despite the evident tendency towards higher mortality in the group characterized by progression (G1+G2) as compared to the group without progression (G3+G4), the difference did not reach statistical significance (p=0.617). However, the comparison of groups with the baseline eGFR value above and below 45 ml/min/1.73 m2 differentiated the two groups that statistically differed in mortality (p=0.044).

CONCLUSIONS

The baseline eGFR was not a significant predictor of future renal outcomes (ESRD, RRT). However, eGFR below 45 ml/min/ 1.73m2 was associated with a significantly higher mortality risk (p=0.036). Moreover, the groups with the fastest and with improved eGFR were characterized by the highest mortality.