To the editor:

The challenge posed by a pathology such as chronic kidney disease (CKD)1-3 imposes an adequate coordination of the nephrology departments and primary care (PC) centres.4 the recently issued «SEN-SEMFYC consensus document on chronic kidneys disease » represents a significant effort in this direction.

Aconcern arising when a standardised procedure to manage CKD is prepared is the potential saturation of nephrology outpatient clinics. In our experience, implementation of a common procedure with PC led to a 40% increase in the number of first visits in the first year. This has led us to be cautious about criteria to be agreed on. As regards values of the glomerular filtration rate estimated by the MDRD formula (eGFR), the document proposes referral of patients with eGFR < 45 mL/min/1.73 m2 in those older than 70 years and with eGFR < 30 mL/min/1.73 m2 in patients older of 70 years. Are these the most reasonable criteria for all departments?

In order to analyse their impact on the Alcañiz health sector (Teruel), covering an aged rural population of 83,456 inhabitants, we used our database of 18,922 patients over 18 years of age who were performed laboratory tests at our healthcare centres during 2006. CKD prevalence was 16.4%, and 208 patients would meet these referral criteria. Use of values proposed in our protocol (< 65 years, eGFR < 45 mL/min/1.73 m2; 65-80 years, eGFR > 30 mL/min/1.73 m2; > 80 years, eGFR < 20 mL/min/1,73 m2) would decrease this figure to 113 patients. The characteristics of both groups are shown in the table.

Result analysis suggests than in our health sector we could use the referral criteria in the consensus document in patients under 70 years of age, but always stressing that morbidity and mortality are particularly increased in males under 60 years of age with eGFR ranging from 45-60 mL/min/1.73 m2, who should be considered at a high cardiovascular risk.2However, application of such criteria would not be feasible to older patients, particularly those over 80 years of age. The excessive patient volume and the limited prevention of cardiovascular and renal risk we could achieve lead us to reconsider the question.5 In this case, adequate patient management and referral of patients with progressive kidney function impairment (since replacement therapy is often feasible) or requiring management of their complications (particularly anaemia) would be left at PC discretion.

Based on these data, we think that training and cooperation with PC and adjustment of criteria for referral to nephrology outpatient clinics based on the capacity of each department are essential for early detection and follow-up of CKD. Adequate management of CKD by PC in male patients younger than 60 years with eGFR values ranging from 45-60 mL/min/1.73 m2 and in those older than 75-80 years with eGFRs ranging from 20-30 mL/min/1.73 m2 is particularly relevant.