The Effect of Genotyping on the Number of Pharmacotherapeutic Gene-Drug Interventions in Chronic Kidney Disease Patients.

Patients with chronic kidney disease (CKD) stage 3-5 are polypharmacy patients. Many of these drugs are metabolized by cytochrome P450 (CYP450) and CYP450. Genetic polymorphism is well known to result in altered drug metabolism capacity. This study determined the added value of pharmacogenetic testing to the routine medication evaluation in polypharmacy patients with CKD. In adult outpatient polypharmacy patients with CKD3-5 disease, a pharmacogenetic profile was determined. Then, automated medication surveillance for gene-drug interactions was performed based on the pharmacogenetic profile and the patients' current prescriptions. Of all identified gene-drug interactions, the hospital pharmacist and the treating nephrologist together assessed clinical relevance and necessity of a pharmacotherapeutic intervention. The primary endpoint of the study was the total number of applied pharmacotherapeutic interventions based on a relevant gene-drug interaction. A total of 61 patients were enrolled in the study. Medication surveillance resulted in a total of 66 gene-drug interactions, of which 26 (39%) were considered clinically relevant. This resulted in 26 applied pharmacotherapeutic interventions in 20 patients. Systematic pharmacogenetic testing enables pharmacotherapeutic interventions based on relevant gene-drug interactions. This study showed that pharmacogenetic testing adds to routine medication evaluation and could lead to optimized pharmacotherapy in CKD patients.

Value of acute-phase reactants in monitoring disease activity and treatment response in idiopathic retroperitoneal fibrosis.

BACKGROUND: Prospective evaluation of the value of erythrocyte sedimentation rate (ESR) and C-reactive protein (CRP) levels in monitoring disease activity and treatment response in patients with idiopathic retroperitoneal fibrosis (RPF). METHODS: This study included 57 patients with idiopathic RPF receiving tamoxifen monotherapy with at least 8 months follow-up. Clinical, laboratory and radiological investigation was performed at presentation and at repeated follow-up. Remission was defined as significant clinical improvement within 6 weeks of treatment together with stable or decreasing mass size on follow-up computed tomography (CT) scanning at 4 months and definitive decrease in mass size on follow-up CT scanning at 8 months. RESULTS: ESR and CRP levels at presentation and their respective decreases over time correlated strongly with each other (P<0.001). Baseline ESR and CRP levels correlated with visual analogue scale (VAS) score for pain (ESR, P<0.01; CRP, P<0.001); baseline ESR levels also correlated with VAS score for discomfort (P<0.001). Short-term decreases in ESR or CRP levels at 6 weeks follow-up did not correlate with subsequent mass regression but decrease in ESR at 4 months and decrease in CRP at 4 and 8 months follow-up correlated with mass regression. Kaplan-Meier analysis showed no difference in remission rate between patients with normal or elevated baseline ESR or CRP (log-rank P=0.22/P=0.88) or between patients with or without (near-)normalization of ESR or CRP in first 6 weeks of treatment (log-rank P=0.12/P=0.32). CONCLUSIONS: Patients with idiopathic RPF who have elevated acute-phase reactant levels are more symptomatic. Neither acute-phase reactant levels or their initial changes can be taken as a major predictor for treatment success.

The ETS family member TEL binds to nuclear receptors RAR and RXR and represses gene activation.

Retinoic acid receptor (RAR) signaling is important for regulating transcriptional activity of genes involved in growth, differentiation, metabolism and reproduction. Defects in RAR signaling have been implicated in cancer. TEL, a member of the ETS family of transcription factors, is a DNA-binding transcriptional repressor. Here, we identify TEL as a transcriptional repressor of RAR signaling by its direct binding to both RAR and its dimerisation partner, the retinoid x receptor (RXR) in a ligand-independent fashion. TEL is found in two isoforms, created by the use of an alternative startcodon at amino acid 43. Although both isoforms bind to RAR and RXR in vitro and in vivo, the shorter form of TEL represses RAR signaling much more efficiently. Binding studies revealed that TEL binds closely to the DNA binding domain of RAR and that both Helix Loop Helix (HLH) and DNA binding domains of TEL are mandatory for interaction. We have shown that repression by TEL does not involve recruitment of histone deacetylases and suggest that polycomb group proteins participate in the process.

Calcium channel blockers, NOS1AP, and heart-rate-corrected QT prolongation.

OBJECTIVES: To study whether NOS1AP single nucleotide polymorphisms (SNPs), rs10494366 T>G and rs10918594 C>G, modify the heart-rate-corrected QT (QTc) prolonging effect of calcium channel blockers. BACKGROUND: Common variation in the NOS1AP gene has been associated with QT interval variation in several large population samples. NOS1 is presumed to influence intracellular calcium. METHODS: The prospective population-based Rotterdam Study includes 16 603 ECGs from 7565 participants (>or=55 years), after exclusion of patients with left ventricular hypertrophy, left and right bundle branch block, as well as carriers of pacemakers. The endpoint was the length of the QTc interval in calcium channel blocker users and non-users with the minor alleles compared with the major alleles (wild type). We used a repeated-measurement analysis, adjusted for all known confounders. RESULTS: Use of verapamil was associated with a significant QTc interval prolongation [6.0 ms 95% confidence interval (CI) 1.7; 10.2] compared with non-users. Furthermore, users of verapamil with the rs10494366 GG genotype showed significantly more QTc prolongation than users with the TT genotype [25.4 ms (95% CI: 5.9-44.9)] (P value for multiplicative interaction 0.0038). Users of isradipine with the GG genotype showed more QTc prolongation than users with the TT genotype [19.8 ms (95% CI: 1.9-37.7)]; however, SNP rs10494366 did not modify the effect on QTc interval on a multiplicative scale (P=0.3563). SNP rs10918594 showed similar results. CONCLUSION: In conclusion, we showed that the minor alleles of both NOS1AP SNPs significantly potentiate the QTc prolonging effect of verapamil.

Psychotropic drugs associated with corrected QT interval prolongation.

AIMS: To study whether listed putative corrected QT (QTc)-prolonging psychotropic drugs indeed prolong the QTc interval under everyday circumstances and to evaluate whether this is a class effect or an individual drug effect, we conducted a prospective population-based cohort study. METHODS: This study was conducted as part of the Rotterdam Study and included 3377 men and 4845 women (>or=55 years) who had triennial electrocardiograms (ECGs). The primary end points of the study were the length of the QTc interval at each ECG, the difference in QTc interval between consecutive ECGs within one person, and the risk of an abnormally prolonged QTc interval. Drug use at the index date was obtained from automated dispensing records. The associations were examined by means of a repeated measurement analysis, adjusted for age, sex, diabetes mellitus, hypertension, myocardial infarction, heart failure, and use of class 1 QTc-prolonging drugs. RESULTS: Of the 8222 participants, 813 participants (9.9%) developed QTc prolongation during follow-up and 492 participants (74.4% women) used psychotropic drugs at the time of an ECG. Starting tricyclic antidepressants increased the QTc interval significantly with 6.9 milliseconds (95% confidence interval [CI], 3.1-10.7 milliseconds) between consecutive ECGs in comparison with consecutive ECGs of participants not using tricyclic antidepressants, in particular starting amitriptyline (8.5 milliseconds; 95% CI, 2.8-14.2 milliseconds), maprotiline (13.9 milliseconds; 95% CI, 3.6-24.3 milliseconds), and nortriptyline (35.3 milliseconds; 95% CI, 8.0-62.6 milliseconds). Starting lithium also increased the QTc interval significantly (18.6 milliseconds; 95% CI, 4.8-32.4 milliseconds). CONCLUSIONS: In this population-based prospective cohort study, we confirmed the importance of antidepressants and antipsychotics as potential contributors to QTc prolongation. Especially, starting tricyclic antidepressant drugs (as a class) is associated with a significant intraindividual increase in the QTc interval in comparison to the change in nonusers. The tricyclic antidepressants seem to prolong the QTc interval as a class effect.

C-reactive protein levels, haplotypes, and the risk of incident chronic obstructive pulmonary disease.

RATIONALE: Chronic obstructive pulmonary disease (COPD) is characterized by substantial chronic inflammation in the pulmonary compartment as well as in the systemic circulation. OBJECTIVES: To investigate potentially causal association, we examined whether serum levels of high-sensitivity C-reactive protein (hsCRP) and variations in the CRP gene are associated with the risk of developing COPD. METHODS: This study is part of the Rotterdam Study, a prospective population-based cohort study among subjects aged 55 years or older. At baseline, 6,836 subjects without COPD had a blood sample available for assessment of hsCRP serum levels and haplotypes of the CRP gene. We analyzed the association between hsCRP levels, CRP gene haplotypes, and incident COPD with Cox proportional hazard models, adjusted for age, sex, and other confounders. MEASUREMENTS AND MAIN RESULTS: High levels of hsCRP (>3 mg/L) were associated with a significantly increased risk of incident COPD (hazard ratio [HR], 1.7; 95% confidence interval [CI], 1.16-2.49) compared with persons with low levels (<1 mg/L). The risk remained increased after adjusting for potential confounders and introducing a latency period of 3 years. The risk was most pronounced in former smokers (HR, 2.2; 95% CI, 1.12-3.74). hsCRP was not a risk factor in never smokers. No CRP single nucleotide polymorphism or haplotype was associated with a significantly increased or decreased COPD risk. CONCLUSIONS: Increased hsCRP levels are predictive for the occurrence of COPD in smokers. However, haplotypes of the CRP gene, which influence hsCRP levels, are not associated with an altered risk of developing COPD.

Common variation in the NOS1AP gene is associated with reduced glucose-lowering effect and with increased mortality in users of sulfonylurea.

OBJECTIVE: The single nucleotide polymorphism rs10494366 in the nitric oxide synthase 1 adaptor protein (NOS1AP) gene is associated with QTc prolongation, through an effect on the intracellular Ca levels. As sulfonylurea stimulate insulin secretion by an increased influx of Ca, we hypothesized that this polymorphism is associated with the glucose-lowering effect and mortality risk in sulfonylurea users. METHODS: Associations between the NOS1AP polymorphism, prescribed doses, and mortality rates in sulfonylurea, metformin, and insulin users were assessed in the Rotterdam Study, a population-based cohort study of 7983 elderly people. RESULTS: We identified 619 participants who were prescribed oral antidiabetic drugs during follow-up. In glibenclamide users carrying the TG genotype, the prescribed doses were higher compared with the glibenclamide users carrying the TT genotype [0.38 defined daily dose units, 95% confidence interval (CI) 0.14-0.63]. Glibenclamide users with the TG or GG genotype had an increased mortality risk compared with glibenclamide users with the TT genotype [hazard ratio (HR) 2.80, 95% CI: 1.09-7.22]. Tolbutamide users with the TG or GG genotype (HR: 0.30, 95% CI: 0.14-0.63) and glimepiride users with the TG or GG genotype (HR: 0.18, 95% CI: 0.04-0.74) had a decreased mortality risk compared with tolbutamide and glimepiride users with the TT genotype. CONCLUSION: In participants with the TG or GG genotype at rs10494366 in the NOS1AP gene, glibenclamide is less effective in reducing glucose levels and mortality rates were higher compared with glibenclamide users with the TT genotype. In tolbutamide and glimepiride users, the TG and GG genotype were associated with a reduced mortality rate.

Common ATP-binding cassette B1 variants are associated with increased digoxin serum concentration.

BACKGROUND AND OBJECTIVE: Digoxin is a known substrate of ATP-binding cassette B1 (ABCB1/MDR1). The results of studies on the association between ABCB1 polymorphisms and digoxin kinetics, however, remain contradictory. Almost all studies were small and involved only single dose kinetics. The goal of this study was to establish ABCB1 genotype effect on digoxin blood concentrations in a large cohort of chronic digoxin users in a general Dutch European population. METHODS: Digoxin users were identified in the Rotterdam Study, a prospective population-based cohort study of individuals aged 55 years and above. Digoxin blood levels were gathered from regional hospitals and laboratories. ABCB1 single nucleotide polymorphisms (SNPs) 1236C-->T, 2677G-->T/A, and 3435C-->T were assessed on peripheral blood DNA using Taqman assays. We studied the association between the ABCB1 genotypes and haplotypes, and digoxin blood levels using linear regression models adjusting for potential confounders. RESULTS: Digoxin serum levels and DNA were available for 195 participants (56.4% women, mean age 79.4 years). All three ABCB1 variants were significantly associated with serum digoxin concentration (0.18-0.21 microg/l per additional T allele). The association was even stronger for the 1236-2677-3435 TTT haplotype allele [0.26 mug/l (95% CI 0.14-0.38)], but absent for other haplotypes (CGC allele considered referent), suggesting an interaction of SNPs in a causal haplotype instead of individual SNP effects. CONCLUSION: We found that the common ABCB1 1236C-->T, 2677G-->T, and 3435C-->T variants and the associated TTT haplotype were associated with higher digoxin serum concentrations in a cohort of elderly European digoxin users in the general population.

Adverse drug reaction-related hospitalisations: a population-based cohort study.

PURPOSE: To evaluate the extent, characteristics and determinants of adverse drug reaction (ADR)-related hospitalisations on a population-based level in 2003. METHODS: We performed a cohort study in the Integrated Primary Care Information (IPCI) database, a general practitioners (GPs) research database with longitudinal data from electronic patient records of a group of 150 GP throughout the Netherlands. Hospital discharge letters and patient records were reviewed to evaluate ADR-related hospitalisations applying WHO causality criteria. The prevalence of ADR-related hospitalisations per total admissions and the incidence per drug group were calculated. Avoidability and seriousness of the ADRs causing admission were assessed applying the algorithm from Hallas. RESULTS: We identified 3515 hospital admissions, 1277 elective and 2238 acute. Of the acute admissions, 115 were caused by an ADR giving a prevalence of 5.1% (95% confidence intervals (CI): 4.3-6.1%). The prevalence of ADR-related acute admissions increased with age up to 9.8% (95%CI: 7.5-12.7) for persons >75 years. The ADRs that most frequently caused hospitalisations were gastro-intestinal bleeding with anti-thrombotics, bradycardia/hypotension with cardiovascular drugs and neutropenic fever with cytostatics. The incidence rate of ADR-related hospitalisations per drug group was highest for anti-thrombotics and anti-infectives and was relatively low for cardiovascular drugs. Fatality as a direct consequence of the ADR-related admission was 0.31%. In elderly patients 40% of the ADRs causing hospitalisation were judged to be avoidable. CONCLUSIONS: The extent and potential avoidability of ADR-related hospitalisations is still substantial, especially in elderly patients. Measures need to be put into place to reduce the burden of ADRs.

Common NOS1AP variants are associated with a prolonged QTc interval in the Rotterdam Study.

BACKGROUND: QT prolongation is an important risk factor for sudden cardiac death. About 35% of QT-interval variation is heritable. In a recent genome-wide association study, a common variant (rs10494366) in the nitric oxide synthase 1 adaptor protein (NOS1AP) gene was found to be associated with QT-interval variation. We tested for association of 2 NOS1AP variants with QT duration and sudden cardiac death. METHODS AND RESULTS: The Rotterdam Study is a population-based, prospective cohort study of individuals > or = 55 years of age. The NOS1AP variants rs10494366 T>G and rs10918594 C>G were genotyped in 6571 individuals. Heart rate-corrected QT interval (QTc) was determined with ECG analysis software on up to 3 digital ECGs per individual (total, 11,108 ECGs from 5374 individuals). The association with QTc duration was estimated with repeated-measures analyses, and the association with sudden cardiac death was estimated by Cox proportional-hazards analyses. The rs10494366 G allele (36% frequency) was associated with a 3.8-ms (95% confidence interval, 3.0 to 4.6; P=7.8x10(-20)) increase in QTc interval duration for each additional allele copy, and the rs10918594 G allele (31% frequency) was associated with a 3.6-ms (95% confidence interval, 2.7 to 4.4; P=6.9x10(-17)) increase per additional allele copy. None of the inferred NOS1AP haplotypes showed a stronger effect than the individual single-nucleotide polymorphisms. There were 233 sudden cardiac deaths over 11.9 median years of follow-up. No significant association was observed with sudden cardiac death risk. CONCLUSIONS: Common variants in NOS1AP are strongly associated with QT-interval duration in an elderly population. Larger sample sizes are needed to confirm or exclude an effect on sudden cardiac death risk.