[Occult renal disease and drug prescription in primary care].

OBJECTIVE: To study the prevalence of chronic kidney disease (CKD) [glomerular filtration rate (GFR) <60ml/min/1.73m(2)] and occult kidney disease (OKD) (normal serum creatinine values with GFR <60) in elderly patients.

DESIGN: Retrospective, observational study.

SETTING: Four primary care centres in the province of Huesca, Spain.

PARTICIPANTS: About 4014 patients older than 65 years were randomly selected.

MAIN MEASUREMENTS: GFR was calculated for all subjects using the four-variable modified MDRD equation. We registered all drugs prescriptions to the patients during a period of twelve months focusing on the potential nephrotoxic drugs.

RESULTS: After exclusions, GFR was estimated in 3286 patients (1424 men of 75.49+/-6.6 years and 1862 women of 76.29+/-7.04 years; P=.001). The prevalence of CKD was 21.2%. A total of 10.1% of patients (12.8% of women and 6.44% of men) had OKD. We recorded the complete drug prescription in 269 patients. Mean of all different drugs that were prescribed by patient-year was 10.69+/-5.92 (men 9.55+/-5.57 and women 11.11+/-6; P=.05)]. A large number of patients were treated with potentially dangerous drugs, particularly the non-steroidal anti-inflammatory drugs with 165 cases (61.34%), and 72% were exposed to drugs that can lead to hyperkalaemia.

CONCLUSIONS: We conclude that GFR estimation by clinical laboratories in the setting of primary care can contribute to prevent the adverse effects of inappropriate drug prescriptions.