Pragmatiske studier – hva er det?

Konseptet pragmatiske studier ble foreslått av Schwartz og Lellouch i 1967 og problematiserte to viktige aspekter ved utprøving av ny behandling, nemlig forståelse og beslutning (1). Tradisjonelle forklarende effektstudier (explanatory trials) har som mål å øke vår forståelse ved å vise om en behandling virker per se, ofte under optimale forhold med nøye utvalgte studiedeltakere og utfallsmål. Pragmatiske studier skal derimot vise om en behandling virker i den kliniske hverdagen, helst på alle typer av aktuelle pasienter. Større bredde i pasientutvalget kan potensielt gjøre det vanskeligere å påvise klinisk relevante forskjeller, og studiene må av denne grunn ofte inkludere et stort antall pasienter. Den ideelle pragmatiske studien inkluderer en uselektert pasientgruppe som er aktuell for en type klinisk behandling, med endepunkter og oppfølging som i størst mulig grad foregår i den kliniske rutinen. Resultatene gir oss virkelighetsdata som kan understøtte beslutningen om å innføre en ny behandlingsform på generelt grunnlag. Pragmatiske studier er av interesse for beslutningstakere, fordi denne studieformen også tar sikte på å besvare spørsmål om kostnadseffekt av ny behandling som skal benyttes i alle deler av helsetjenesten

The predictive value of NT-proBNP and hs-TnT for risk of death in cardiac surgical patients

Background: European System for Cardiac Operative Risk Evaluation II (EuroSCORE II) is used for risk stratification before cardiac surgery, but whether N-terminal pro-B-type natriuretic peptide (NT-proBNP) and high-sensitivity troponin T (hs-TnT) may add prognostic information to EuroSCORE II is not known. Methods: Preoperative (n = 640) and postoperative (n = 629) blood samples were available from cardiac surgical patients with 961-day follow-up (FINNAKI Heart study; cohort #1). The accuracy of a parsimonious risk model with NT-proBNP measurements was also tested in 90 patients with respiratory failure after cardiac surgery (FINNALI study; cohort #2). Results: Sixty-one patients (9.5%) died during follow-up in cohort #1. Preoperative NT-proBNP and hs-TnT concentrations correlated (rho = 0.58; p <0.001) and were higher in non-survivors compared to survivors: median 2027 (Q1-3 478-5387) vs. 373 (134-1354) ng/L [NT-proBNP] and 39 (16-191) vs. 13 (8-32) ng/L [hs-TnT]; p <0.001 for both. Preoperative NT-proBNP concentrations were associated with time to death after adjustment for EuroSCORE II (HR [lnNT-proBNP] 1.33 [95% CI 1.08-1.64]), p = 0.008 and reclassified patients on top of EuroSCORE II (net reclassification index 0.39 [95% CI 0.14-0.64], p = 0.003). Pre-and postoperative NT-proBNP concentrations were closely correlated (rho = 0.80, p <0.001) and postoperative NT-proBNP concentrations were also associated with long-term mortality after adjustment for EuroSCORE II. A parsimonious risk model that included age, creatinine clearance, chronic pulmonary disease, and NT-proBNP measurements provided comparable prognostic accuracy as EuroSCORE II in cohort #1 and #2 for risk of long-term mortality. hs-TnT measurements did not add to NT-proBNP measurements Conclusion: NT-proBNP measurements could improve and simplify risk prediction in cardiac surgical patients.Peer reviewe

The prevalence of cardiac complications and their impact on outcomes in patients with non-traumatic subarachnoid hemorrhage.

Subarachnoid hemorrhage (SAH) is a serious condition, and a myocardial injury or dysfunction could contribute to the outcome. We assessed the prevalence and prognostic impact of cardiac involvement in a cohort with SAH. This is a prospective observational multicenter study. We included 192 patients treated for non-traumatic subarachnoid hemorrhage. We performed ECG recordings, echocardiographic examinations, and blood sampling within 24 h of admission and on days 3 and 7 and at 90 days. The primary endpoint was the evidence of cardiac involvement at 90 days, and the secondary endpoint was to examine the prevalence of a myocardial injury or dysfunction. The median age was 54.5 (interquartile range [IQR] 48.0-64.0) years, 44.3% were male and the median World Federation of Neurological Surgeons (WFNS) score was 2 (IQR 1-4). At day 90, 22/125 patients (17.6%) had left ventricular ejection fractions ≤ 50%, and 2/121 patients (1.7%) had evidence of a diastolic dysfunction as defined by mitral peak E-wave velocity by peak e' velocity (E/e') > 14. There was no prognostic impact from echocardiographic evidence of cardiac complications on neurological outcomes. The overall prevalence of cardiac dysfunction was modest. We found no demographic or SAH-related factors associated with 90 days cardiac dysfunction

Plasma linoleic acid levels and cardiovascular risk factors:results from the Norwegian ACE 1950 Study

Background A high intake of linoleic acid (LA), the major dietary polyunsaturated fatty acid (PUFA), has previously been associated with reduced cardiovascular (CV) morbidity and mortality in observational studies. However, recent secondary analyses from clinical trials of LA-rich diet suggest harmful effects of LA on CV health. Methods A total of 3706 participants, all born in 1950, were included in this cross-sectional study. We investigated associations between plasma phospholipid levels of LA and CV risk factors in a Norwegian general population, characterized by a relative low LA and high marine n-3 PUFA intake. The main statistical approach was multivariable linear regression. Results Plasma phospholipid LA levels ranged from 11.4 to 32.0 wt%, with a median level of 20.8 wt% (interquartile range 16.8–24.8 wt%). High plasma LA levels were associated with lower serum low-density lipoprotein cholesterol levels (standardized regression coefficient [Std. β-coeff.] −0.04, p = 0.02), serum triglycerides (Std. β-coeff. −0.10, p < 0.001), fasting plasma glucose (Std. β-coeff. −0.10, p < 0.001), body mass index (Std. β-coeff. −0.13, p < 0.001), systolic and diastolic blood pressure (Std. β-coeff. −0.04, p = 0.03 and Std. β-coeff. −0.02, p = 0.02, respectively) and estimated glomerular filtration rate (Std. β-coeff. −0.09, p < 0.001). We found no association between plasma LA levels and high-density lipoprotein cholesterol levels, glycated hemoglobin, carotid intima-media thickness, or C-reactive protein. Conclusion High plasma LA levels were favorably associated with several CV risk factors in this study of a Norwegian general population

Application of non-HDL cholesterol for population-based cardiovascular risk stratification: results from the Multinational Cardiovascular Risk Consortium.

BACKGROUND: The relevance of blood lipid concentrations to long-term incidence of cardiovascular disease and the relevance of lipid-lowering therapy for cardiovascular disease outcomes is unclear. We investigated the cardiovascular disease risk associated with the full spectrum of bloodstream non-HDL cholesterol concentrations. We also created an easy-to-use tool to estimate the long-term probabilities for a cardiovascular disease event associated with non-HDL cholesterol and modelled its risk reduction by lipid-lowering treatment. METHODS: In this risk-evaluation and risk-modelling study, we used Multinational Cardiovascular Risk Consortium data from 19 countries across Europe, Australia, and North America. Individuals without prevalent cardiovascular disease at baseline and with robust available data on cardiovascular disease outcomes were included. The primary composite endpoint of atherosclerotic cardiovascular disease was defined as the occurrence of the coronary heart disease event or ischaemic stroke. Sex-specific multivariable analyses were computed using non-HDL cholesterol categories according to the European guideline thresholds, adjusted for age, sex, cohort, and classical modifiable cardiovascular risk factors. In a derivation and validation design, we created a tool to estimate the probabilities of a cardiovascular disease event by the age of 75 years, dependent on age, sex, and risk factors, and the associated modelled risk reduction, assuming a 50% reduction of non-HDL cholesterol. FINDINGS: Of the 524 444 individuals in the 44 cohorts in the Consortium database, we identified 398 846 individuals belonging to 38 cohorts (184 055 [48·7%] women; median age 51·0 years [IQR 40·7-59·7]). 199 415 individuals were included in the derivation cohort (91 786 [48·4%] women) and 199 431 (92 269 [49·1%] women) in the validation cohort. During a maximum follow-up of 43·6 years (median 13·5 years, IQR 7·0-20·1), 54 542 cardiovascular endpoints occurred. Incidence curve analyses showed progressively higher 30-year cardiovascular disease event-rates for increasing non-HDL cholesterol categories (from 7·7% for non-HDL cholesterol <2·6 mmol/L to 33·7% for ≥5·7 mmol/L in women and from 12·8% to 43·6% in men; p<0·0001). Multivariable adjusted Cox models with non-HDL cholesterol lower than 2·6 mmol/L as reference showed an increase in the association between non-HDL cholesterol concentration and cardiovascular disease for both sexes (from hazard ratio 1·1, 95% CI 1·0-1·3 for non-HDL cholesterol 2·6 to <3·7 mmol/L to 1·9, 1·6-2·2 for ≥5·7 mmol/L in women and from 1·1, 1·0-1·3 to 2·3, 2·0-2·5 in men). The derived tool allowed the estimation of cardiovascular disease event probabilities specific for non-HDL cholesterol with high comparability between the derivation and validation cohorts as reflected by smooth calibration curves analyses and a root mean square error lower than 1% for the estimated probabilities of cardiovascular disease. A 50% reduction of non-HDL cholesterol concentrations was associated with reduced risk of a cardiovascular disease event by the age of 75 years, and this risk reduction was greater the earlier cholesterol concentrations were reduced. INTERPRETATION: Non-HDL cholesterol concentrations in blood are strongly associated with long-term risk of atherosclerotic cardiovascular disease. We provide a simple tool for individual long-term risk assessment and the potential benefit of early lipid-lowering intervention. These data could be useful for physician-patient communication about primary prevention strategies. FUNDING: EU Framework Programme, UK Medical Research Council, and German Centre for Cardiovascular Research

Global Effect of Modifiable Risk Factors on Cardiovascular Disease and Mortality.

BACKGROUND: Five modifiable risk factors are associated with cardiovascular disease and death from any cause. Studies using individual-level data to evaluate the regional and sex-specific prevalence of the risk factors and their effect on these outcomes are lacking. METHODS: We pooled and harmonized individual-level data from 112 cohort studies conducted in 34 countries and 8 geographic regions participating in the Global Cardiovascular Risk Consortium. We examined associations between the risk factors (body-mass index, systolic blood pressure, non-high-density lipoprotein cholesterol, current smoking, and diabetes) and incident cardiovascular disease and death from any cause using Cox regression analyses, stratified according to geographic region, age, and sex. Population-attributable fractions were estimated for the 10-year incidence of cardiovascular disease and 10-year all-cause mortality. RESULTS: Among 1,518,028 participants (54.1% of whom were women) with a median age of 54.4 years, regional variations in the prevalence of the five modifiable risk factors were noted. Incident cardiovascular disease occurred in 80,596 participants during a median follow-up of 7.3 years (maximum, 47.3), and 177,369 participants died during a median follow-up of 8.7 years (maximum, 47.6). For all five risk factors combined, the aggregate global population-attributable fraction of the 10-year incidence of cardiovascular disease was 57.2% (95% confidence interval [CI], 52.4 to 62.1) among women and 52.6% (95% CI, 49.0 to 56.1) among men, and the corresponding values for 10-year all-cause mortality were 22.2% (95% CI, 16.8 to 27.5) and 19.1% (95% CI, 14.6 to 23.6). Harmonized individual-level data from a global cohort showed that 57.2% and 52.6% of cases of incident cardiovascular disease among women and men, respectively, and 22.2% and 19.1% of deaths from any cause among women and men, respectively, may be attributable to five modifiable risk factors. (Funded by the German Center for Cardiovascular Research (DZHK); ClinicalTrials.gov number, NCT05466825.)

Novel biomarkers of cardiovascular disease: Applications in clinical practice

Measurement of biomarkers has revolutionized the work-up of patients with suspected cardiovascular disease. The most widely used contemporary cardiovascular biomarkers are the natriuretic peptides in the diagnosis and prognosis of heart failure and cardiac troponins in the diagnosis of acute myocardial infarction. Numerous other biomarkers pertaining to diagnosis, prognosis, and risk prediction have been identified, but few have made their way to clinical practice. In this review, we will initially describe the fundamental approach to evaluate a novel biomarker. Before implementation of a biomarker into clinical practice, several stringent criteria related to its clinical utility are required. Essential statistical metrics such as discrimination, calibration, and reclassification are required to properly evaluate prediction models. We will then discuss the biomarkers according to main groups of cardiovascular pathology:1.  myocardial injury (cardiac troponins, heart-type fatty acid-binding protein, cardiac myosin binding protein-C);2.  myocardial stress (A-type and B-type natriuretic peptides, mid-regional pro-adrenomedullin, copeptin); 3.  inflammation (C-reactive protein, interleukin 6, growth differentiation factor 15, soluble suppressor of tumorigenicity 2, galectin-3);4.  platelet activation (soluble CD40 ligand, P-selectin);5.  plaque instability (lipoprotein-associated phospholipase A2, matrix metalloproteinase-9);6.  systemic stress (catecholamines, granin proteins);7.  calcium homeostasis (secretoneurin). Finally, we will discuss novel applications of cardiovascular biomarkers, more specifically prediction of ventricular arrhythmias, and the use of biomarkers in composite risk prediction models