Correct use of non-indexed eGFR for drug dosing and renal drug-related problems at hospital admission.

PURPOSE

Two to seven percent of the German adult population has a renal impairment (RI) with an estimated glomerular filtration rate (eGFR) < 60 ml/min/1.73m. This often remains unrecognized and adjustment of drug therapy is lacking. To determine renal function in clinical routine, the CKD-EPI equation is used to calculate an indexed eGFR (ml/min/1.73m). For drug dosing, it has to be individualized to a non-indexed eGFR (ml/min) by the patient's body surface area. Here, we investigated the number of patients admitted to urological wards of a teaching hospital with RI between July and December 2016. Additionally, we correctly used the eGFR for drug and dosage adjustments and to analyse the use of renal risk drugs (RRD) and renal drug-related problems (rDRP).

METHODS

In a retrospective observational study, urological patients with pharmacist-led medication reconciliation at hospital admission and eGFR (CKD-EPI) of 15-59 ml/min/1.73m were identified. Indexed eGFR (ml/min/1.73m) was recalculated with body surface area to non-indexed eGFR (ml/min) for correct drug dosing. Medication at admission was reviewed for RRD and based on the eGFR for rDRP, e.g. inappropriate dose or contraindication.

RESULTS

Of 1320 screened patients, 270 (20.5%) presented with an eGFR of 15-59 ml/min/1.73m. After readjustment, 203 (15.4%) patients had an eGFR of 15-59 ml/min. Of these, 190 (93.6%) used ≥ 1 drugs at admission with 660 of 1209 (54.7%) drugs classified as RRD. At least one rDRP was identified in 115 (60.5%) patients concerning 264 (21.8%) drugs.

CONCLUSION

Renal impairment is a common risk factor for medication safety in urologic patients admitted to a hospital. Considerable shifts were seen in eGFR-categories when correctly calculating eGFR for drug dosing purposes. The fact that more than half of the study patients showed rDRP at hospital admission underlines the need to consider this risk factor appropriately.