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

The impact of obesity on body surface area adjusted estimated glomerular filtration rate in patients with chronic kidney disease

BACKGROUND

Assessment of kidney function is necessary for prescribing renally excreted drugs. The estimated glomerular filtration rate (eGFR) routinely reported by laboratories is indexed to a body surface area (BSA) of 1.73 m2. In obese patients, the indexed eGFR may underestimate directly measured GFR.

AIMS

To determine the prevalence of obesity in patients with chronic kidney disease (CKD) and examine the effect of adjusting the indexed eGFR for patient BSA (deindexing) across CKD Stages 2-5.

METHODS

We conducted a cross-sectional study of 575 adults with stable CKD from two general nephrology clinics over 6 months. Dialysis and kidney transplant patients were excluded. We used four equations (Mosteller, Dubois, Haycock and Schlich) to determine BSA based on actual body weight and applied Bland-Altman plots and piecewise linear regression to examine the relationship between deindexed and indexed eGFR.

RESULTS

The median age was 68 years (58% male). The prevalence of overweight and obesity was 31% and 47% respectively. Mean body mass index was 29.7 kg/m2. The Schlich equation for BSA produced the smallest adjustment in eGFR, while the Haycock equation produced the largest adjustment. Males experienced the largest change in eGFR from deindexing because of larger BSAs. Although bias became increasingly positive with higher eGFR, the linear regression stratified by CKD stage indicated that deindexing had little impact with eGFR <45 mL/min/1.73 m2.

CONCLUSIONS

In CKD, deindexing the Chronic Kidney Disease Epidemiology Collaboration eGFR may not be necessary when the eGFR is <45 mL/min/1.73 m2, particularly if the patient is female.

Renal drug dosage adjustments and adverse drug events in patients with chronic kidney disease admitted to the hospital: a cross-sectional study

BACKGROUND

The study aimed to evaluate the agreement of prescribed drug dosages with renal dosing recommendations and describe adverse drug events (ADEs) contributing to hospital admissions of patients with chronic kidney disease (CKD).

METHODS

This cross-sectional study focused on CKD patients admitted to University Hospital Hradec Králové, with an estimated glomerular filtration rate below 60 ml/min. The necessity for renal dosage adjustments was determined using the Summary of Product Characteristics (SmPC). For medications requiring renal dosage adjustment according to SmPC, agreement between the prescribed and recommended renal dosage was assessed. ADEs were adjudicated using the OPERAM drug-related hospital admissions adjudication guide.

RESULTS

Of 375 CKD patients, 112 (30%, 95% CI 25-34) were prescribed drug dosages in disagreement with SmPC renal dosage recommendations. Perindopril, metformin, and ramipril were most frequently dosed in disagreement with SmPC. ADE-related hospital admissions occurred in 20% (95% CI 16-24) of CKD patients.

CONCLUSION

CKD patients are often prescribed medication dosages in disagreement with SmPC renal dosing recommendations. Besides explicit factors, treatment goals, feasibility of monitoring and alternative treatment must be weighed when assessing drug and dosage appropriateness. Gastrointestinal bleeding was the most frequent ADE that contributed to hospital admissions of CKD patients.

Using Machine Learning to Identify Patients at High Risk of Inappropriate Drug Dosing in Periods with Renal Dysfunction

Purpose

Dosing of renally cleared drugs in patients with kidney failure often deviates from clinical guidelines, so we sought to elicit predictors of receiving inappropriate doses of renal risk drugs.

Patients and methods

We combined data from the Danish National Patient Register and in-hospital data on drug administrations and estimated glomerular filtration rates for admissions between 1 October 2009 and 1 June 2016, from a pool of about 2.6 million persons. We trained artificial neural network and linear logistic ridge regression models to predict the risk of five outcomes (>0, ≥1, ≥2, ≥3 and ≥5 inappropriate doses daily) with index set 24 hours after admission. We used time-series validation for evaluating discrimination, calibration, clinical utility and explanations.

Results

Of 52,451 admissions included, 42,250 (81%) were used for model development. The median age was 77 years; 50% of admissions were of women. ≥5 drugs were used between admission start and index in 23,124 admissions (44%); the most common drug classes were analgesics, systemic antibacterials, diuretics, antithrombotics, and antacids. The neural network models had better discriminative power (all AUROCs between 0.77 and 0.81) and were better calibrated than their linear counterparts. The main prediction drivers were use of anti-inflammatory, antidiabetic and anti-Parkinson's drugs as well as having a diagnosis of chronic kidney failure. Sex and age affected predictions but slightly.

Conclusion

Our models can flag patients at high risk of receiving at least one inappropriate dose daily in a controlled in-silico setting. A prospective clinical study may confirm that this holds in real-life settings and translates into benefits in hard endpoints.

Feasibility of the MELD score as a screening tool for pharmacists to identify patients with impaired hepatic function at hospital admission

WHAT IS KNOWN AND OBJECTIVE

Hepatic impairment (HI) is a known risk factor for drug safety. The MELD score (Model-for-endstage-liver-disease), calculated from serum creatinine, bilirubin and International Normalized Ratio (INR), is a promising screening tool corresponding to Child-Pugh Score (CPS) for drug adjustment. We tested the feasibility of MELD as an automatic screening tool accounting for correct calculation, interfering factors (IF) and detection of patients corresponding to CPS-B/C potentially requiring drug adjustment.

METHODS

We retrospectively calculated MELD for a 3-month cohort of surgical patients and assessed need for adjustment of MELD parameters to standard values. IF for INR (oral anticoagulants) and serum creatinine (renal insufficiency (RI; eGFR<60 ml/min/1.73m²); as well as drugs elevating creatinine levels (DECL)) and the number of patients with MELD scores corresponding to CPS-B/C were analysed. For MELD ≥7.5, liver and bile diagnoses were recorded.

RESULTS AND DISCUSSION

Of 1183 patients, MELD was calculable for 761 (64%; median 7.5, range 6.4-36.8). Parameters had to be adjusted for 690 (91%) patients. IF of parameters were RI in 172 (23%), INR-elevating drugs in 105 (14%) and DECL in 33 (4%) patients. Of 335 (44%) patients with MELD ≥7.5, 122 (36%) had documented liver or bile diagnoses. MELD 10-<15 (corresponding to CPS-B) was found for 105 (14%), MELD ≥15 (corresponding to CPS-C) for 66 (9%) of the 761 patients with a calculated MELD. Referred to all patients, drug adjustments due to possible HI were recommendable for 14% of patients with suspected CPS-B/C.

WHAT IS NEW AND CONCLUSION

MELD is a feasible screening tool for HI as a risk factor for drug safety at hospital admission when appropriately considering correct parameter adjustment and RI and INR-elevating drugs as IF. Further evaluation of sensitivity and specificity is needed.

Population pharmacokinetic modeling of GS-441524, the active metabolite of remdesivir, in Japanese COVID-19 patients with renal dysfunction

Remdesivir, a prodrug of the nucleoside analog GS‐441524, plays a key role in the treatment of coronavirus disease 2019 (COVID‐19). However, owing to limited information on clinical trials and inexperienced clinical use, there is a lack of pharmacokinetic (PK) data in patients with COVID‐19 with special characteristics. In this study, we aimed to measure serum GS‐441524 concentrations and develop a population PK (PopPK) model. Remdesivir was administered at a 200 mg loading dose on the first day followed by 100 mg from day 2, based on the package insert, in patients with an estimated glomerular filtration rate (eGFR) greater than or equal to 30 ml/min. In total, 190 concentrations from 37 Japanese patients were used in the analysis. The GS‐441524 trough concentrations were significantly higher in the eGFR less than 60 ml/min group than in the eGFR greater than or equal to 60 ml/min group. Extracorporeal membrane oxygenation in four patients hardly affected the total body clearance (CL) and volume of distribution (V_d) of GS‐441524. A one‐compartment model described serum GS‐441524 concentration data. The CL and V_d of GS‐441524 were significantly affected by eGFR readjusted by individual body surface area and age, respectively. Simulations proposed a dose regimen of 200 mg on day 1 followed by 100 mg once every 2 days from day 2 in patients with an eGFR of 30 ml/min or less. In conclusion, we successfully established a PopPK model of GS‐441524 using retrospectively obtained serum GS‐441524 concentrations in Japanese patients with COVID‐19, which would be helpful for optimal individualized therapy of remdesivir.

Implementation of a renal pharmacist consultant service - Information sharing in paper versus digital form

WHAT IS KNOWN AND OBJECTIVE

Renal impairment (RI) and renal drug-related problems (rDRP) often remain unrecognized in the community setting. A "renal pharmacist consultant service" (RPCS) at hospital admission can support patient safety by detecting rDRP. However, the efficient information sharing from pharmacists to physicians is still discussed. The aim of the study was to test the implementation of a RPCS and its effectiveness on prescription changes and to evaluate two ways of written information sharing with physicians.

METHODS

Urological patients with eGFR_non-indexed of 15-59 ml/min and ≥1 drug were reviewed for manifest and potential rDRP at admission by a pharmacist. Written recommendations for dose or drug adaptation were forwarded to physicians comparing two routes: July-September 2017 paper form in handwritten chart; November 2017-January 2018 digital PDF document in the electronic patient information system and e-mail alert. Prescription changes regarding manifest rDRP were evaluated and compared with a previous retrospective study without RPCS.

RESULTS AND DISCUSSION

The RPCS detected rDRP in 63 of 234 (26.9%) patients and prepared written recommendations (median 1 rDRP (1-5) per patient) concerning 110 of 538 (20.5%) drugs at admission. For manifest rDRP, acceptance rates of recommendations were 62.5% (paper) vs 42.9% (digital) (P = 0.16). Compared with the retrospective study without RPCS (prescription changes in 21/76 rDRP; 27.6%), correct prescribing concerning manifest rDRP significantly increased by 27.1%.

WHAT IS NEW AND CONCLUSION

A RPCS identifies patients at risk for rDRP and significantly increases appropriate prescribing by physicians. In our hospital (no electronic order entry, electronic chart or ward pharmacists), consultations in paper form seem to be superior to a digital PDF document.