Analytical and Biological Variability of a Commercial Modified Aptamer Assay in Plasma Samples of Patients with Chronic Kidney Disease.

BACKGROUND: We carried out a study of the aptamer proteomic assay, SomaScan V4, to evaluate the analytical and biological variability of the assay in plasma samples of patients with moderate to severe chronic kidney disease (CKD). METHODS: Plasma samples were selected from 2 sources: (a) 24 participants from the Chronic Renal Insufficiency Cohort (CRIC) and (b) 49 patients from the Brigham and Women's Hospital-Kidney/Renal Clinic. We calculated intra-assay variability from both sources and examined short-term biological variability in samples from the Brigham clinic. We also measured correlations of aptamer measurements with traditional biomarker assays. RESULTS: A total of 4656 unique proteins (4849 total aptamer measures) were analyzed in all samples. Median (interquartile range [IQR] intra-assay CV) was 3.7% (2.8-5.3) in CRIC and 5.0% (3.8-7.0) in Brigham samples. Median (IQR) biological CV among Brigham samples drawn from one individual on 2 occasions separated by median (IQR) 7 (4-14) days was 8.7% (6.2-14). CVs were independent of CKD stage, diabetes, or albuminuria but were higher in patients with systemic lupus erythematosus. Rho correlations between aptamer and traditional assays for biomarkers of interest were cystatin C = 0.942, kidney injury model-1 = 0.905, fibroblast growth factor-23 = 0.541, tumor necrosis factor receptors 1 = 0.781 and 2 = 0.843, P < 10-100 for all. CONCLUSIONS: Intra-assay and within-subject variability for SomaScan in the CKD setting was low and similar to assay variability reported from individuals without CKD. Intra-assay precision was excellent whether samples were collected in an optimal research protocol, as were CRIC samples, or in the clinical setting, as were the Brigham samples.

Urinary Tubular Injury Biomarkers Are Associated With ESRD and Death in the REGARDS Study.

INTRODUCTION: Urinary neutrophil gelatinase-associated lipocalin (uNGAL) and urinary kidney injury molecule-1 (uKIM-1) are established markers of subclinical acute kidney injury. In persons with reduced estimated glomerular filtration rate (eGFR) and albuminuria who are at high risk for end-stage renal disease (ESRD) and death, the associations of these urinary markers with incident ESRD or death is an area of active investigation. METHODS: Among 1472 black and white participants from the REasons for Geographic and Racial Differences in Stroke (REGARDS) study with eGFR ≤60 ml/min per 1.73 m2 (Chronic Kidney Disease Epidemiology Collaboration [CKD-EPI] cystatin, 2012) and albumin-to-creatinine ratio (ACR) ≥30 mg/g, we evaluated the associations of baseline uNGAL and uKIM-1 with progression to ESRD and all-cause death. Cox models were sequentially adjusted for urinary creatinine, traditional risk factors, C-reactive protein, ACR, and eGFR. RESULTS: There were 257 ESRD events and 819 deaths over a median follow-up of 5.7 and 6.5 years, respectively. In demographic adjusted models, higher levels of uNGAL were associated with increased risk of ESRD and death, but these associations were attenuated in fully adjusted models including baseline eGFR for both ESRD (hazard ratio [HR] = 1.06 per doubling, 95% confidence interval [CI] 0.98-1.14) and death (HR = 1.04, 95% CI = 1.00-1.08). Higher levels of uKIM-1 were associated with increased risk of ESRD and death in demographic-adjusted models, and although attenuated in fully adjusted models, remained statistically significant for both ESRD (HR = 1.24 per doubling, 95% CI = 1.08-1.42) and death (HR = 1.10, 95% CI =1.03-1.19). CONCLUSION: In this cohort of high-risk patients with baseline eGFR ≤60 ml/min per 1.73 m2 and albuminuria, renal tubular injury is associated with higher mortality and progression to ESRD. Further studies are necessary to investigate the mechanism underlying this increased risk.

Simplified guideline for prescribing medical cannabinoids in primary care.

OBJECTIVE: To develop a clinical practice guideline for a simplified approach to medical cannabinoid use in primary care; the focus was on primary care application, with a strong emphasis on best available evidence and a promotion of shared, informed decision making. METHODS: The Evidence Review Group performed a detailed systematic review of 4 clinical areas with the best evidence around cannabinoids: pain, nausea and vomiting, spasticity, and adverse events. Nine health professionals (2 generalist family physicians, 2 pain management-focused family physicians, 1 inner-city family physician, 1 neurologist, 1 oncologist, 1 nurse practitioner, and 1 pharmacist) and a patient representative comprised the Prescribing Guideline Committee (PGC), along with 2 nonvoting members (pharmacist project managers). Member selection was based on profession, practice setting, location, and lack of financial conflicts of interest. The guideline process was iterative through content distribution, evidence review, and telephone and online meetings. The PGC directed the Evidence Review Group to address and provide evidence for additional questions as needed. The key recommendations were derived through consensus of the PGC. The guideline was drafted, refined, and distributed to a group of clinicians and patients for feedback, then refined again and finalized by the PGC. RECOMMENDATIONS: Recommendations include limiting medical cannabinoid use in general, but also outline potential restricted use in a small subset of medical conditions for which there is some evidence (neuropathic pain, palliative and end-of-life pain, chemotherapy-induced nausea and vomiting, and spasticity due to multiple sclerosis or spinal cord injury). Other important considerations regarding prescribing are reviewed in detail, and content is offered to support shared, informed decision making. CONCLUSION: This simplified medical cannabinoid prescribing guideline provides practical recommendations for the use of medical cannabinoids in primary care. All recommendations are intended to assist with, not dictate, decision making in conjunction with patients.

Lignes directrices simplifiées en matière de prescription de cannabinoïdes médicaux en soins de première ligne.

OBJECTIF: Élaborer des lignes directrices de pratique clinique visant à simplifier l'approche à l'emploi de cannabinoïdes à des fins médicales en soins de première ligne; le projet visait l'application en soins de première ligne, en insistant fortement sur les meilleures données probantes disponibles, et la promotion de la prise de décision éclairée et partagée. MÉTHODES: Le Groupe d'examen des données a effectué une revue systématique détaillée de 4 domaines cliniques dotés des meilleures données probantes en matière de cannabinoïdes : douleur, nausées et vomissements, spasticité et événements indésirables. Neuf professionnels de la santé (2 omnipraticiens, 2 médecins de famille spécialisés en gestion de la douleur, 1 médecin de famille en milieu urbain, 1 neurologue, 1 oncologue, 1 infirmière praticienne et 1 pharmacien) et une représentante de patients composaient le Comité des lignes directrices en matière de prescription (CLDP), de même que 2 membres sans droit de vote (pharmaciens gestionnaires de projet). Les membres ont été sélectionnés en fonction de leur profession, et de leur contexte et de leur lieu de pratique, de même qu'en fonction de l'absence d'un conflit d'intérêts de nature financière. Les lignes directrices sont le fruit d'un processus itératif incluant la distribution de contenu, l'examen minutieux des données probantes, et des rencontres téléphoniques et en ligne. Le CLDP a confié au Groupe d'examen des données la responsabilité de répondre aux questions additionnelles et de fournir des données probantes, au besoin. Les principales recommandations découlent d'un consensus au sein du CLDP. Les lignes directrices ont été rédigées, peaufinées et distribuées à un groupe de cliniciens et de patients aux fins de commentaires, puis ont été peaufinées à nouveau et finalisées par le CLDP. RECOMMANDATIONS: Les recommandations consistent à limiter la consommation générale de cannabinoïdes médicaux, mais elles décrivent aussi l'emploi restreint potentiel dans un petit sous-groupe de conditions de santé pour lesquelles des données probantes existent (douleur neuropathique, douleur en soins palliatifs et en fin de vie, nausées et vomissements induits par la chimiothérapie, et spasticité causée par la sclérose en plaques ou une lésion de la moelle épinière). L'article examine en détail d'autres points importants en matière de prescription, et offre du contenu étayant la prise de décision éclairée et partagée. CONCLUSION: Ces lignes directrices simplifiées en matière de prescription de cannabinoïdes médicaux offrent des recommandations pratiques quant à l'emploi de cannabinoïdes en soins de première ligne. Toutes les recommandations visent à contribuer à la prise de décision conjointement avec le patient et non à la dicter.

A paradigm change to inform fibromyalgia research priorities by engaging patients and health care professionals.

Background: Research objectives should be focused toward advancing knowledge that has meaningful impact on health. However, research agendas are mostly driven by the health care community, with limited input from patients. Aims: In this study, prioirities of uncertainties for the management of fibromyalgia (FM) that could propel future research were identified by a defined process using the James Lind Alliance Priority Setting Partnership (JLA-PSP) methodology. Methods: As a first step, a survey was distributed across Canada that engaged patients, caregivers, and health care professionals to provide narrative input to eight open-ended questions regarding FM care. Responses were thematically condensed and synthesized into an initial list of 43 uncertainties used to guide a comprehensive literature search. Questions already effectively addressed in the literature were excluded, leaving 25 uncertainties that were ranked during a one-day consensus workshop. Results: Three broad themes emerged: the value of personalized targeted treatment and subgrouping of patients; the efficacy of various self-management strategies and educational initiatives; and identification of the ideal health care setting to provide FM care. Opioids and cannabinoids were the only specific pharmacologic interventions ranked as needing further research. Conclusions: The prioritized questions highlight the importance of recognizing the heterogeneity of FM symptoms, the need for a personalized treatment approach, and a better understanding of the value of self-management strategies. This is the first study that uses an established and transparent methodology to engage all FM stakeholders to help inform researchers and funding bodies of clinically relevant research priorities.

Contexte: Les objectifs en matière de recherche devraient se concentrer sur l'avancement des connaissances qui ont des effets significatifs sur la santé. Toutefois, les programmes de recherche sont surtout définis par le milieu des soins de santé, tandis que la contribution des patients demeure limitée.Objectifs: Dans cette étude, les incertitudes prioritaires pour la prise en charge de la fibromylagie, qui pourraient donner lieu à de futures études, ont été déterminées selon un processus fondé sur la méthodologie du Partenariat d'établissement des priorités de la James Lind Alliance.Méthodes: Comme première étape, une enquête a été distribuée partout au Canada auprès de patients, de prestataires de soins et de professionnels de la santé afin d'obtenir leurs réponses sous forme narrative à huit questions ouvertes concernant les soins relatifs à la fibromyalgie. Les réponses ont été regroupées par thèmes et résumées dans une liste initiale de 43 incertitudes qui a été utilisée pour orienter une recherche exhaustive de la littérature. Les questions déjà abordées de manière efficace dans la littérature ont été exclues, tandis que les 25 incertitudes restantes ont été classées dans le cadre d'un atelier de recherche de consensus d'une journée.Résultats: Trois grands thèmes se sont démarqués : l'utilité des traitements ciblés personnalisés et de la division des patients en sous-groupes; l'efficacité de diverses stratégies d'auto-prises en charge et initiatives éducatives; et la détermination du cadre de soins de santé idéal pour dispenser les soins relatifs à la fibromyalgie.Conclusions: Les questions priorisées soulignent l'importance de reconnaître l'hétérogénéité des symptômes de la fibromyalgie, la nécessité d'une approche de traitement personnalisé et une meilleure compréhension de l'utilité des stratégies d'auto-prise en charge. Il s'agit de la première étude à utiliser une méthodologie établie et transparente pour impliquer toutes les parties concernées par la fibromyalgie pour aider à faire connaître aux chercheurs et aux agences de financement les priorités pertinentes sur le plan clinique.

Associations of pentraxin-3 with cardiovascular events, incident heart failure, and mortality among persons with coronary heart disease: data from the Heart and Soul Study.

BACKGROUND: Pentraxin-3 (PTX3) is an inflammatory marker thought to be more specific to vascular inflammation than C-reactive protein (CRP). Whether PTX3 is independently associated with adverse events among persons with stable coronary heart disease (CHD), independently of CRP, and whether kidney dysfunction influences these associations are not known. METHODS: We evaluated the associations of baseline PTX3 levels with all-cause mortality, cardiovascular (CV) events (myocardial infarction, stroke, or CHD death), and incident heart failure (HF) during 37 months among ambulatory persons with stable CHD participating in the Heart and Soul Study. Cox proportional hazards models were adjusted for age, sex, race, hypertension, diabetes, smoking, and CRP. RESULTS: Among 986 persons with stable CHD, each 1 unit increase in log PTX3 at baseline was associated with an 80% increased risk of all-cause mortality (hazard ratio [HR] 1.8, 95% CI 1.5-2.1), a 50% increased risk of CV events (HR 1.5, 95% CI, 1.2-1.9), and an 80% greater risk of incident HF (HR 1.8, 95% CI, 1.3-2.5). Further adjustment for estimated glomerular filtration rate (eGFR) attenuated these associations to 1.6 (1.3-1.9) for mortality, 1.3 (1.0-1.6) for CV events and 1.5 (1.1-2.1) for incident HF. Stratification by eGFR >60 mL/min per 1.73m(2) or <60 mL/min per 1.73m(2) did not affect these associations (P interaction > .3 for all outcomes). CONCLUSIONS: Among persons with stable CHD, higher PTX3 concentrations were associated with increased risk for all-cause mortality, CV events, and incident HF independently of systemic inflammation. Adjustment for eGFR modestly attenuated these associations, suggesting that future studies of PTX3 should adjust for kidney function.

Kidney function decline in the elderly: impact of lipoprotein-associated phospholipase A(2).

BACKGROUND: Whether lipoprotein-associated phospholipase A(2) (Lp-PLA(2)) levels are associated with kidney function decline has not been well studied. METHODS: We investigated associations of Lp-PLA(2) antigen and activity with kidney function decline and rapid decline over 5.7 years in the Cardiovascular Health Study (n = 4,359). We estimated kidney function by cystatin C (eGFRcys) in repeated measures, and defined rapid decline as ≥3 ml/min/1.73 m(2) per year. We stratified by baseline preserved GFR (≥60 ml/min/1.73 m(2)). RESULTS: Mean age was 72 ± 5 years. Average eGFRcys decline was -1.79 ml/min/1.73 m(2) (SD = 2.60) per year. Among persons with preserved GFR, compared to the lowest quartile of Lp-PLA(2) antigen, eGFRcys decline was faster among persons in the second, ß -0.31 (95% CI -0.52, -0.10), third -0.19 (-0.41, 0.02) and fourth quartiles -0.26 (-0.48, -0.04) after full adjustment. Persons in the highest quartile of Lp-PLA(2) antigen had increased odds of rapid decline 1.34 (1.03, 1.75), compared to the lowest. There was no significant association between levels of Lp-PLA(2) activity and eGFRcys decline or rapid decline. Associations were not statistically significant among persons with low eGFR (<60 ml/min/1.73 m(2)) at baseline. CONCLUSION: Higher levels of Lp-PLA(2) antigen but not activity were significantly associated with faster rates of kidney function decline. These findings may suggest a novel vascular pathway for kidney disease progression.

Kidney function and multiple hemostatic markers: cross sectional associations in the multi-ethnic study of atherosclerosis.

BACKGROUND: Defined as estimated glomerular filtration rate (eGFR) < 60 ml/min/1.73 m2, chronic kidney disease (CKD) is strongly and independently associated with cardiovascular and overall mortality. We hypothesized that reduced kidney function would be characterized by abnormalities of hemostasis. METHODS: We tested cross-sectional associations between (eGFR) and multiple hemostatic markers among 6751 participants representing a broad spectrum of kidney function in the Multi-Ethnic Study of Atherosclerosis (MESA). Kidney function was measured using cystatin C (eGFRcys) or creatinine, using CKD Epidemiology Collaboration (eGFRcr). Hemostatic markers included soluble thrombomodulin (sTM), soluble tissue factor (sTF), D-Dimer, von Willebrand factor (vWF), factor VIII, plasmin-antiplasmin complex (PAP), tissue factor pathway inhibitor (TFPI), plasminogen activator inhibitor-1 (PAI-1), and fibrinogen. Associations were tested using multivariable linear regression with adjustment for demographics and comorbidities. RESULTS: In comparison to persons with eGFRcys >90 ml/min/1.73 m2, subjects with eGFRcys < 60 ml/min/1.73 m2 had adjusted levels of sTM, sTF, D-Dimer, PAP, Factor VIII, TFPI, vWF and fibrinogen that were respectively 86%, 68%, 44%, 22%, 17%, 15%, 12% and 6% higher. Subjects with eGFRcys 60-90 ml/min/1.73 m2 had adjusted levels that were respectively 16%, 14%, 12%, 6%, 6%, 6%, 11% and 4% higher (p < 0.05 for all). Percent differences were not significantly different when groups were categorized by eGFRcr. CONCLUSIONS: Throughout a broad spectrum of kidney function, lower eGFR was associated with higher levels of hemostatic markers. Dysregulation of hemostasis may be a mechanism by which reduced kidney function promotes higher cardiovascular risk.

Racial differences in the association of pentraxin-3 with kidney dysfunction: the Multi-Ethnic Study of Atherosclerosis.

BACKGROUND: Pentraxin-3 (PTX3), an inflammatory marker thought to be related to vascular inflammation, is elevated in advanced chronic kidney disease (CKD). Whether PTX3 is associated with mild to moderate kidney dysfunction is unknown. METHODS: We tested associations of proteins in the pentraxin family [PTX3, C-reactive protein (CRP) and serum amyloid protein (SAP)] with estimated glomerular filtration rate by cystatin C (eGFRcys) and microalbuminuria among 2824 participants in the Multi-Ethnic Study of Atherosclerosis. Associations were tested using multivariable linear regression with adjustment for demographics (age, gender, annual income), comorbidities (diabetes, hypertension, smoking, body mass index, low-density lipoprotein, high-density lipoprotein, triglycerides, ACE inhibitor and statin use) and systemic inflammation [interleukin-6 (IL-6)]. RESULTS: Among the 2824 participants, mean age was 62 years and mean eGFRcys was 94 mL/min/1.73 m(2); 25% were white, 25% Chinese, 25% African-American and 25% Hispanic. Among all participants after full adjustment, higher PTX3 was associated with lower eGFRcys independently of IL-6 (ß - 3.0 mL/min/1.73 m(2) per unit increase in lnPTX3, P < 0.001). In contrast, CRP and SAP were associated with eGFRcys in demographic adjusted models, but these associations were attenuated after adjustment for comorbidities and IL-6 (lnCRP ß - 0.06, P = 0.9; lnSAP ß - 0.35, P = 0.7). There was a significant interaction with race/ethnicity (P < 0.001) in the association of PTX3 and eGFRcys. After adjustment for demographics, comorbidities and IL-6, this association was significant in blacks (ß - 5.7 mL/min/1.73 m(2) per unit increase in lnPTX3, P = 0.002) but not in Hispanics (ß - 2.4, P = 0.1), Chinese (ß - 0.91, P = 0.5) or whites (ß - 0.26, P = 0.9). PTX3 and CRP, but not SAP, had correlations with microalbuminuria in unadjusted models (Spearman coefficients PTX3 0.05, P = 0.005; CRP 0.07, P < 0.001; SAP 0.013, P = 0.5), but these were attenuated after full adjustment. CONCLUSIONS: Endovascular inflammation may be an important mechanism associated with early kidney dysfunction, particularly among blacks. This mechanism appears to be independent of IL-6-regulated pathways.