717 research outputs found
Patient-reported reasons for declining or discontinuing statin therapy: Insights from the PALM registry
Background: Many adults eligible for statin therapy for cardiovascular disease prevention are untreated. Our objective was to investigate patient‐reported reasons for statin underutilization, including noninitiation, refusal, and discontinuation.Methods and Results: This study included the 5693 adults recommended for statin therapy in the PALM (Patient and Provider Assessment of Lipid Management) registry. Patient surveys evaluated statin experience, reasons for declining or discontinuing statins, and beliefs about statins and cardiovascular disease risk. Overall, 1511 of 5693 adults (26.5%) were not on treatment. Of those not on a statin, 894 (59.2%) reported never being offered a statin, 153 (10.1%) declined a statin, and 464 (30.7%) had discontinued therapy. Women (relative risk: 1.22), black adults (relative risk: 1.48), and those without insurance (relative risk: 1.38) were most likely to report never being offered a statin. Fear of side effects and perceived side effects were the most common reasons cited for declining or discontinuing a statin. Compared with statin users, those who declined or discontinued statins were less likely to believe statins are safe (70.4% of current users vs. 36.9% of those who declined and 37.4% of those who discontinued) or effective (86.3%, 67.4%, and 69.1%, respectively). Willingness to take a statin was high; 67.7% of those never offered and 59.7% of patients who discontinued a statin would consider initiating or retrying a statin.Conclusions: More than half of patients eligible for statin therapy but not on treatment reported never being offered one by their doctor. Concern about side effects was the leading reason for statin refusal or discontinuation. Many patients were willing to reconsider statin therapy if offered
Statin use and adverse effects among adults \u3e 75 years of age: Insights from the Patient and Provider Assessment of Lipid Management (PALM) registry
Background: Current statin use and symptoms among older adults in routine community practice have not been well characterized since the release of the 2013 American College of Cardiology/American Heart Association guideline. Methods and results: We compared statin use and dosing between adults \u3e75 and ≤75 years old who were eligible for primary or secondary prevention statin use without considering guideline-recommended age criteria. The patients were treated at 138 US practices in the Patient and Provider Assessment of Lipid Management (PALM) registry in 2015. Patient surveys also evaluated reported symptoms while taking statins. Multivariable logistic regression models examined the association between older age and statin use and dosing. Among 6717 people enrolled, 1704 (25%) were \u3e75 years old. For primary prevention, use of any statin or high-dose statin did not vary by age group: any statin, 62.6% in those \u3e75 years old versus 63.1% in those ≤75 years old (P=0.83); high-dose statin, 10.2% versus 12.3% in the same groups (P=0.14). For secondary prevention, older patients were slightly less likely to receive any statin (80.1% versus 84.2% [P=0.003]; adjusted odds ratio, 0.81; 95% confidence interval, 0.66-1.01 [P=0.06]), but were much less likely to receive a high-intensity statin (23.5% versus 36.2% [PP=0.0001]). Among current statin users, older patients were slightly less likely to report any symptoms (41.3% versus 46.6%; P=0.003) or myalgias (27.3% versus 33.3%; Conclusions: Overall use of statins was similar for primary prevention in those aged \u3e75 years versus younger patients, yet older patients were less likely to receive high-intensity statins for secondary prevention. Statins appear to be similarly tolerated in older and younger adult
Measurement of low‐density lipoprotein cholesterol levels in primary and secondary prevention patients: Insights from the PALM registry
Background The 2013 American College of Cardiology/American Heart Association Guideline on the Treatment of Blood Cholesterol to Reduce Atherosclerotic Cardiovascular Risk in Adults recommended testing low-density lipoprotein cholesterol ( LDL -C) to identify untreated patients with LDL -C ≥190 mg/dL, assess lipid-lowering therapy adherence, and consider nonstatin therapy. We sought to determine whether clinician lipid testing practices were consistent with these guidelines. Methods and Results The PALM (Patient and Provider Assessment of Lipid Management) registry enrolled primary and secondary prevention patients from 140 US cardiology, endocrinology, and primary care offices in 2015 and captured demographic data, lipid treatment history, and the highest LDL -C level in the past 2 years. Core laboratory lipid levels were drawn at enrollment. Among 7627 patients, 2787 (36.5%) had no LDL -C levels measured in the 2 years before enrollment. Patients without chart-documented LDL -C levels were more often women, nonwhite, uninsured, and non-college graduates (all P\u3c0.01). Patients without prior lipid testing were less likely to receive statin treatment (72.6% versus 76.0%; P=0.0034), a high-intensity statin (21.5% versus 24.3%; P=0.016), nonstatin lipid-lowering therapy (24.8% versus 27.3%; P=0.037), and had higher core laboratory LDL -C levels at enrollment (median 97 versus 92 mg/dL; P\u3c0.0001) than patients with prior LDL -C testing. Of 166 individuals with core laboratory LDL -C levels ≥190 mg/dL, 36.1% had no LDL -C measurement in the prior 2 years, and 57.2% were not on a statin at the time of enrollment. Conclusions In routine clinical practice, LDL -C testing is associated with higher-intensity lipid-lowering treatment and lower achieved LDL -C level
Modeling the interaction between tubuloglomerular feedback and myogenic mechanisms in the control of glomerular mechanics
Introduction: Mechanical stresses and strains exerted on the glomerular cells have emerged as potentially influential factors in the progression of glomerular disease. Renal autoregulation, the feedback process by which the afferent arteriole changes in diameter in response to changes in blood pressure, is assumed to control glomerular mechanical stresses exerted on the glomerular capillaries. However, it is unclear how the two major mechanisms of renal autoregulation, the afferent arteriole myogenic mechanism and tubuloglomerular feedback (TGF), each contribute to the maintenance of glomerular mechanical homeostasis.Methods: In this study, we made a mathematical model of renal autoregulation and combined this model with an anatomically accurate model of glomerular blood flow and filtration, developed previously by us. We parameterized the renal autoregulation model based on data from previous literature, and we found evidence for an increased myogenic mechanism sensitivity when TGF is operant, as has been reported previously. We examined the mechanical effects of each autoregulatory mechanism (the myogenic, TGF and modified myogenic) by simulating blood flow through the glomerular capillary network with and without each mechanism operant.Results: Our model results indicate that the myogenic mechanism plays a central role in maintaining glomerular mechanical homeostasis, by providing the most protection to the glomerular capillaries. However, at higher perfusion pressures, the modulation of the myogenic mechanism sensitivity by TGF is crucial for the maintenance of glomerular mechanical homeostasis. Overall, a loss of renal autoregulation increases mechanical strain by up to twofold in the capillaries branching off the afferent arteriole. This further corroborates our previous simulation studies, that have identified glomerular capillaries nearest to the afferent arteriole as the most prone to mechanical injury in cases of disturbed glomerular hemodynamics.Discussion: Renal autoregulation is a complex process by which multiple feedback mechanisms interact to control blood flow and filtration in the glomerulus. Importantly, our study indicates that another function of renal autoregulation is control of the mechanical stresses on the glomerular cells, which indicates that loss or inhibition of renal autoregulation may have a mechanical effect that may contribute to glomerular injury in diseases such as hypertension or diabetes. This study highlights the utility of mathematical models in integrating data from previous experimental studies, estimating variables that are difficult to measure experimentally (i.e. mechanical stresses in microvascular networks) and testing hypotheses that are historically difficult or impossible to measure
Renal Heme Oxygenase-1 Induction with Hemin Augments Renal Hemodynamics, Renal Autoregulation, and Excretory Function
Heme oxygenases (HO-1; HO-2) catalyze conversion of heme to free iron, carbon monoxide, and biliverdin/bilirubin. To determine the effects of renal HO-1 induction on blood pressure and renal function, normal control rats (n=7) and hemin-treated rats (n=6) were studied. Renal clearance studies were performed on anesthetized rats to assess renal function; renal blood flow (RBF) was measured using a transonic flow probe placed around the left renal artery. Hemin treatment significantly induced renal HO-1. Mean arterial pressure and heart rate were not different (115±5 mmHg versus 112±4 mmHg and 331±16 versus 346±10 bpm). However, RBF was significantly higher (9.1±0.8 versus 7.0±0.5 mL/min/g, P<0.05), and renal vascular resistance was significantly lower (13.0±0.9 versus 16.6±1.4 [mmHg/(mL/min/g)], P<0.05). Likewise, glomerular filtration rate was significantly elevated (1.4±0.2 versus 1.0±0.1 mL/min/g, P<0.05), and urine flow and sodium excretion were also higher (18.9±3.9 versus 8.2±1.0 μL/min/g, P<0.05 and 1.9±0.6 versus 0.2±0.1 μmol/min/g, P<0.05, resp.). The plateau of the autoregulation relationship was elevated, and renal vascular responses to acute angiotensin II infusion were attenuated in hemin-treated rats reflecting the vasodilatory effect of HO-1 induction. We conclude that renal HO-1 induction augments renal function which may contribute to the antihypertensive effects of HO-1 induction observed in hypertension models
Energy production predication via Internet of Thing based machine learning system
© 2019 Elsevier B.V. Wind energy is an interesting source of alternative energy to complement the Brazilian energy matrix. However, one of the great challenges lies in managing this resource, due to its uncertainty behavior. This study addresses the estimation of the electric power generation of a wind turbine, so that this energy can be used efficiently and sustainable. Real wind and power data generated in set of wind turbines installed in a wind farm in Ceará State, Brazil, were used to obtain the power curve from a wind turbine using logistic regression, integrated with Nonlinear Autoregressive neural networks to forecast wind speeds. In our system the average error in power generation estimate is of 29 W for 5 days ahead forecast. We decreased the error in the manufacturer\u27s power curve in 63%, with a logics regression approach, providing a 2.7 times more accurate estimate. The results have a large potential impact for the wind farm managers since it could drive not only the operation and maintenance but management level of energy sells
Role of atrial natriuretic peptide in mediating the blood pressure-independent natriuresis elicited by systemic inhibition of nitric oxide
While it is clearly recognized that increased intrarenal nitric oxide (NO) levels elicit natriuresis, confounding data showing that systemic nitric oxide synthase inhibition (NOSi) also increases sodium excretion (U(Na)V) poses a conundrum. This response has been attributed to the associated increases in arterial pressure (AP); however, the increases in AP and in U(Na)V are temporally dissociated. The changes in regional renal haemodynamics induced by NOSi could also contribute to the alterations of U(Na)V. To evaluate the roles of AP and non-AP mechanisms mediating the natriuresis, N(ω)-nitro-l-arginine methyl ester hydrochloride (L-NAME) was infused i.v. at doses ranging from 5 to 50 μg/kg/min in anaesthetized rats. U(Na)V, perfusion of the cortex (cortical blood flow, CBF) and medulla (medullary blood flow, MBF) with laser-Doppler flowmetry and glomerular filtration rate (GFR) were measured. U(Na)V increased from 0.6 ± 0.2 to 1.6 ± 0.1 μmol/kg/min (P < 0.05) with the lower nonpressor doses. With the higher doses, AP increased from 116 ± 4 to 122 ± 4 mmHg and U(Na)V increased from 1.1 ± 0.3 to 3.3 ± 0.7 μmol/min/g (P < 0.002). U(Na)V increased similarly in a group where renal AP was maintained at baseline levels. The associated reductions in CBF (17 ± 5 and 38 ± 5 %) and MBF (27 ± 6 and 52 ± 6 %) would be expected to attenuate rather than contribute to the natriuresis. Plasma atrial natriuretic peptide (ANP) concentrations increased significantly following NOSi. Anantin, a natriuretic peptide receptor-A blocker, prevented or reversed the L-NAME-induced natriuresis without altering the L-NAME-induced changes in AP or CBF. The results indicate that increased ANP and related natriuretic peptides mediate the AP-independent natriuresis, at least partly, elicited by systemic L-NAME infusion and help resolve the conundrum of natriuresis during systemic NOSi
Disponibilidad y costos de producción de biomasa forestal como materia prima para la producción de bioetanol
La biomasa forestal es una alternativa ecológica y económicamente viable para la generación de bioetanol debido a que su fuente es abundante, renovable y contribuye a la reducción de gases efecto invernadero. En este estudio, se propone y analiza una metodología para la estimación de la disponibilidad y costos de producción del uso potencial de la biomasa forestal como materia prima para la producción de bioetanol en bosques de pinos del estado de Durango, México. Se usó información del Inventario Forestal Periódico, programas de manejo forestal y datos de empresas de aserraderos e industriales forestales para estimar la biomasa forestal que incluye los restos de aprovechamientos forestales (puntas, ramas) y desperdicios industriales (aserrín, costeras). Se utilizaron simulaciones Monte Carlo para estimar costos de producción de la recolección, extracción y transporte de la biomasa a centros de transformación. Los resultados indican que alrededor de 322.000 toneladas pueden utilizarse para la producción de 38 millones de litros de etanol por año. Las simulaciones Monte Carlo indican que el costo promedio de residuos forestales es de US 0,20 L–1 etanol) mientras que el de residuos industriales es de US 0,19 L–1 etanol). Los factores más importantes en el análisis de sensibilidad fueron el costo pagado a dueños del material, eficiencia tecnológica y distancia de transporte. En el corto plazo, el uso de la biomasa forestal para la generación de biocombustibles tiene varios retos entre los que se encuentran los costos de transporte y la competencia generada por industrias similares como pulpa, papel y tableros aglomerados. Como alternativa se encuentra el desarrollo de biorefinerías integradoras y el uso de medios de transporte más eficientes.La biomasa forestal es una alternativa ecológica y económicamente viable para la generación de bioetanol debido a que su fuente es abundante, renovable y contribuye a la reducción de gases efecto invernadero. En este estudio, se propone y analiza una metodología para la estimación de la disponibilidad y costos de producción del uso potencial de la biomasa forestal como materia prima para la producción de bioetanol en bosques de pinos del estado de Durango, México. Se usó información del Inventario Forestal Periódico, programas de manejo forestal y datos de empresas de aserraderos e industriales forestales para estimar la biomasa forestal que incluye los restos de aprovechamientos forestales (puntas, ramas) y desperdicios industriales (aserrín, costeras). Se utilizaron simulaciones Monte Carlo para estimar costos de producción de la recolección, extracción y transporte de la biomasa a centros de transformación. Los resultados indican que alrededor de 322.000 toneladas pueden utilizarse para la producción de 38 millones de litros de etanol por año. Las simulaciones Monte Carlo indican que el costo promedio de residuos forestales es de US 0,20 L–1 etanol) mientras que el de residuos industriales es de US 0,19 L–1 etanol). Los factores más importantes en el análisis de sensibilidad fueron el costo pagado a dueños del material, eficiencia tecnológica y distancia de transporte. En el corto plazo, el uso de la biomasa forestal para la generación de biocombustibles tiene varios retos entre los que se encuentran los costos de transporte y la competencia generada por industrias similares como pulpa, papel y tableros aglomerados. Como alternativa se encuentra el desarrollo de biorefinerías integradoras y el uso de medios de transporte más eficientes
Intensity of lipid lowering with statin therapy in patients with cerebrovascular disease versus coronary artery disease: Insights from the PALM Registry
Background Current treatment guidelines strongly recommend statin therapy for secondary prevention. However, it remains unclear whether patients\u27 perceptions of cardiovascular risk, beliefs on cholesterol, or the intensity of prescribed statin therapy differs for patients with coronary artery disease (CAD) versus cerebrovascular disease (CeVD) versus both CAD and CeVD (CAD&CeVD). Methods and Results The PALM (Patient and Provider Assessment of Lipid Management) registry collected data on statin use, intensity, and core laboratory low-density lipoprotein cholesterol levels for 3232 secondary prevention patients treated at 133 US clinics. Among individuals with CeVD only (n=403), CAD only (n=2202), and CeVD&CAD (n=627), no significant differences were observed in patient-perceived cardiovascular disease risk, beliefs on cholesterol lowering, or perceived effectiveness and safety of statin therapy. However, patients with CeVD only were less likely to receive any statin therapy (76.2% versus 86.2%; adjusted odds ratio 0.64, 95% CI 0.45-0.91), or guideline-recommended statin intensity (34.6% versus 50.4%; adjusted odds ratio 0.60, 95% CI 0.45-0.81) than those with CAD only. Individuals with CeVD only were also less likely to achieve low-density lipoprotein cholesterol \u3c100 mg/dL (59.2% versus 69.7%; adjusted odds ratio 0.79, 95% CI 0.64-0.99) than individuals with CAD alone. There were no significant differences in the use of any statin therapy or guideline-recommended statin intensity between individuals with CAD&CeVD and those with CAD only. Conclusions Despite lack of significant differences in patient-perceived cardiovascular risk or statin beliefs, patients with CeVD were significantly less likely to receive higher intensity statin or achieve low-density lipoprotein cholesterol \u3c100 mg/dL than those with CAD only
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