Combined application of eGFR and albuminuria for the precise diagnosis of stage 2 and 3a CKD in the elderly.

BACKGROUND: Estimated glomerular filtration rate (eGFR) is the sole diagnostic criterion for stage 3a chronic kidney disease (CKD). Because eGFR decreases with age, its prognostic utility in the elderly is controversial. Albuminuria is an important prognostic factor. To confirm that eGFR use may lead to the overdiagnosis of CKD and to examine the utility of eGFR combined with albuminuria for diagnosing stage 3a CKD in the elderly.

METHODS: This study included 365 elderly patients (age ≥ 65 years) who were diagnosed with stage 2 or 3a CKD. All patients had 3 years of consecutive data at our hospitals from 2000 to 2012. For each eGFR level, patients were divided into normalbuminuria (NOR, urinary albumin excretion rate [UAER] < 30 mg/24 h), microalbuminuria (30 ≥ UAER < 299 mg/24 h), and macroalbuminuria groups (UAER ≥ 300 mg/24 h).

RESULTS: Albuminuria was associated with eGFR loss but not baseline eGFR level. When stage 2 NOR was used as a reference, the multivariable adjusted odds ratio (OR) for rapid kidney function decline (RKFD) of stage 3a NOR was 1.329 (95 % confidence interval (CI): 0.334-5.281, P = 0.686). ORs for other groups were significantly higher. In stage 3a NOR, higher ORs for RKFD were associated with younger age groups.

CONCLUSIONS: Lot of elderly patients with stage 3a CKD and normal albuminuria levels may be over-diagnosed. Albuminuria may be combined with eGFR for improved diagnosis and treatment of stage 3 CKD in the elderly.