[Occult renal failure in primary care. A women's problem?]

Chronic renal failure is becoming a public health problem. The estimation of glomerular filtration rate (GFR) using the MDRD-4 equation is important to find out patients with impaired renal function. The aim of this study was to determinate the rate of patients took care in Primary Care with "occult" renal failure, defined as a GFR less than 60 mL/min/1.73m2, and serum creatinine levels in the normal range of the laboratory (< 1.3 mg/dL for men, and < 1.2 mg/dL for women).

Patients over 18 years-old took cared in Primary Care of the health area of Plasencia (Caceres), who were measured serum creatinine level between March to July 2006. We estimated GFR using MDRD-4 formula and classified the level of kidney function according to the NKF-DOQI guidelines.

We estimated GFR in 13.784 analyses. In 1.042 the GFR was less than 60 mL/min/1.73m2, from 960 patients (6.96%). Mean age 76.8 years (range 40-98 years). 418 keep normal serum creatinine levels (43.5%).

Renal impairment seems to be prevalent in the general population took care in Primary Care. An elevated rate of patients with renal failure present serum creatinine levels in the laboratory normal range, "occult" renal failure. The systematic estimation of GFR using MDRD formula is necessary to detect this patients with renal impairment.