Smaller nadroparin dose reductions required for patients with renal impairment: A multicenter cohort study.

BACKGROUND: Guidelines advise 50 % and 25 % dose reduction of the therapeutic nadroparin dose (86 IU/kg) in patients with eGFR 15-29 and 30-60 ml/min respectively. For monitoring, peak anti-Xa levels are suggested. Data lack whether this results in therapeutic anti-Xa levels or in anti-Xa levels that are comparable to those of patients without renal impairment. AIMS: To determine dose ranges in patients with renal impairment that result in therapeutic anti-Xa levels and to determine the percentage of the 86 IU/kg dose that results in anti-Xa levels normally occurring in patients without renal impairment. METHODS: A retrospective cohort study was conducted in five hospitals. Patients ≥18 years of age, with an eGFR ≥ 15 ml/min were included. The first correctly sampled peak (i.e. 3-5 h after ≥ third administration, regardless of dose per patient) was included. Simulated prediction models were developed using multiple linear regression. RESULTS: 770 patients were included. eGFR and hospital affected the association between dose and anti-Xa level. The doses for peak anti-Xa levels of 0.75 IU/ml differed substantially between hospitals and ranged from 55 to 91, 65-359 and 68-168 IU/kg in eGFR 15-29, 30-60 and > 60 ml/min/1.73m2, respectively. In eGFR 15-29 and 30-60 ml/min/1.73m2, doses of 75 % and 91 % of 86 IU/kg respectively, were needed for anti-Xa levels normally occurring in patients with eGFR > 60 ml/min. CONCLUSION: We advise against anti-Xa based dose-adjustments as long as anti-Xa assays between laboratories are not harmonized and an anti-Xa target range is not validated. A better approach might be to target levels similar to eGFR > 60 ml/min/1.73m2, which are achieved by smaller dose reductions.

Non-response in a pharmacy and patient-based intensive monitoring system: a quantitative study on non-response bias and reasons for non-response.

OBJECTIVE: Worldwide pharmacists play an increasingly important role in pharmacovigilance. Lareb Intensive Monitoring (LIM) in the Netherlands is a new form of active pharmacovigilance where pharmacists play a key role. Patients using drugs which are monitored are identified in the pharmacy and invited to participate in the active monitoring. Not all invited patients participate. This study aimed to investigate non-response bias in LIM, as well as reasons for non-response in order to identify barriers to participation. METHODS: The study population consisted of patients who received a first dispensation of an antidiabetic drug monitored with LIM between 1 July 2010 and 28 February 2011. Possible non-response bias was investigated by comparing age, gender and the number of drugs used as co-medication. Reasons for non-response were investigated using a postal questionnaire. KEY FINDINGS: Respondents were on average 4.5 years younger than non-respondents and used less co-medication. There were no differences regarding gender. The main reason for non-response was that information in the pharmacy was lacking. CONCLUSION: Differences between respondents and non-respondents should be taken into account when analysing and generalising data collected through LIM, as this might contribute to non-response bias. The relatively high response to the postal questionnaire, together with the answers about reasons for non-response, show that patients are willing to participate in a web-based intensive monitoring system, when they are informed and invited in the pharmacy.