Establishment of new potential biomarkers for cardiometabolic diseases

Cardiometabolic diseases is a growing health issue worldwide. New knowledge about the pathophysiological processes have been gained and several research discoveries have contributed to better management of the diseases. Even so, the prognosis, diagnosis, and treatment of cardiometabolic diseases needs to be further improved. For this, the discovery and implementation of additional biomarkers is extremely relevant. New advancing technologies have increased the opportunities to perform discovery studies and to identify new potential biomarkers. However, for several reasons, only few biomarkers survive the long journey from discovery into clinical implementation and there is a need to make this process more efficient. The objective of the thesis was to evaluate new potential biomarkers to improve the diagnosis and management of cardiometabolic diseases. An additional aim was to establish an efficient process for rapid transfer of new potential biomarkers, identified in discovery studies into evaluation in the routine care setting. Four studies in different patient cohorts, characterized by separate designs, and reflecting diverse phases in the implementation of biomarkers for cardiometabolic diseases are presented. Lipoprotein (a) [Lp(a)] is a modified low-density lipoprotein (LDL) particle and its concentration in plasma is mainly genetically determined. High levels of Lp(a) is associated with an increased risk for cardiovascular diseases (CVD). Despite the fact that it is not yet clear whether reduction of plasma Lp(a) levels translate into a reduced CVD risk, more knowledge about its role as a risk factor in different cohorts and diagnoses is needed to better understand how patients with high Lp(a) levels should be managed. In Paper I we investigated the distribution of plasma Lp(a) levels and its association with CVD in a large cohort of patients who had their plasma levels of Lp(a) determined in routine care. Laboratory data from 23 398 patients was linked to data retrieved from National Board of Health and Welfare registers and National Quality registers. Lp(a) levels had a skewed distribution, increased with age, and was higher in females. Patients with Lp(a) levels in the 4th quartile had a 1.36-fold (95% Confidence Interval (CI) 1.14-1.61, p=0.001) increased risk for ischemic heart disease compared to patients belonging to the 1st quartile. The risk was independent of age, previous CVD, diabetes, and LDL-cholesterol levels. Hence, Lp(a) is an important risk factor for ischemic heart disease also in patients referred from hospitals, out-patient clinics, and general practitioners in the Region Stockholm. Very little is known about the role of Lp(a) as a risk factor for CVD in patients with type 1 diabetes. Therefore, in Paper II we investigated the association of Lp(a) with cardiovascular complications and metabolic control in 1860 subjects with type 1 diabetes. Lp(a) levels had a skewed distribution, increased with age, and was not influenced by sex. Patients with poor metabolic control (HbA1c >52 mmol/mol) had higher Lp(a) levels compared to patients with good metabolic control. Patients with high Lp(a) levels (>120 nmol/L) had a 1.51-fold (95 % CI 1.01-2.28, p=0.048) increased risk for any macrovascular diseases, a 1.68-fold (95% CI 1.12-2.50, p=0.01) increased risk for albuminuria, and a 2.03-fold (95 % CI 1.02-4.01, p=0.043) increased risk for calcified aortic valve disease compared to patients with very low levels (<10 nmol/L). In summary, Lp(a) is a relevant risk factor also in patients with type 1 diabetes. In Paper III we aimed to establish an efficient process for transfer of newly discovered potential biomarkers into evaluation in the routine care setting. The prototype was based on the evaluation of chemokine ligand 16 (CCL-16), previously identified as interesting biomarker for acute coronary syndrome (ACS) in a discovery project called Vinncardio, initiated by the Science for Life laboratory, Royal Institute of Technology (KTH), Stockholm, Sweden. Patients eligible for inclusion were identified when their plasma was analyzed for high sensitive Troponin T at the Karolinska University Laboratory, Stockholm, Sweden. The plasma samples were temporarily stored and meanwhile the patients received a letter of invitation to participate in the study. A positive response was retrieved from ~40 % and 1631 patients were included. No significant differences in CCL-16 were observed between patients with ACS and other diagnosis and CCL-16 do not appear to be a valid biomarker for ACS. Despite this negative result, we manage to establish a process for early evaluation of new potential biomarkers in routine care settings and to rapidly create a biobank and include patients referred to the hospital with an acute medical condition. Clinical randomized trials have shown that addition of ezetimibe to simvastatin treatment further improve the reduction of CVD events, especially in patients with type 2 diabetes where elevation of remnant-cholesterol is characteristic. Remnant-cholesterol is a new and interesting biomarker and mendelian randomization studies have identified it as an independent risk factor for CVD, also promoting and sustaining low grade inflammation. In Paper IV we aimed to in detail study how the lipoprotein metabolism is affected by simvastatin and ezetimibe treatment, alone or in combination, to gain further understanding of the molecular effects of these two widely used lipid lowering drugs. Forty patients eligible for cholecystectomy were randomized to four-week treatment before surgery to placebo, simvastatin (80 mg daily), ezetimibe (10 mg daily), or to combination of both. The combination of simvastatin and ezetimibe resulted in further reduction of cholesterol and cholesteryl esters in remnant- and LDL-particles, as well as reduction of apolipoprotein B (apoB) containing particles, and reduced apoB-containing lipoprotein affinity for arterial proteoglycans compared to simvastatin. These additional positive effects on atherogenic lipoproteins and especially remnant-particles can possibly explain the further reduction of CVD events previously observed, and the combination of ezetimibe and simvastatin seems to be the optimal treatment in conditions with elevated remnant-cholesterol. In conclusion, these four studies have provided further knowledge about the different biomarkers investigated. Also, they can contribute to an improved management of patients with cardiometabolic diseases and indicate the way to a rapid recruitment of patients in clinical studies. Hence, this thesis adds to a deeper understanding of the complexity in the process to validate and implement new biomarkers

Standardization of serum creatinine is essential for accurate use of unbiased estimated GFR equations: evidence from three cohorts matched on renal function

peer reviewedABSTRACT Background Differences in the performance of estimated glomerular filtration rate (eGFR) equations have been attributed to the mathematical form of the equations and to differences between patient demographics and measurement methods. We evaluated differences in serum creatinine (SCr) and eGFR in cohorts matched for age, sex, body mass index (BMI) and measured GFR (mGFR). Methods White North Americans from Minnesota (n = 1093) and the Chronic Renal Insufficiency Cohort (CRIC) (n = 1548) and White subjects from the European Kidney Function Consortium (EKFC) cohort (n = 7727) were matched for demographic patient characteristics (sex, age ± 3 years, BMI ± 2.5 kg/m2) and renal function (mGFR ± 3 ml/min/1.73 m2). SCr was measured with isotope dilution mass spectrometry (IDMS)-traceable assays in the Minnesota and EKFC cohorts and with non-standardized SCr assays recalculated to IDMS in the CRIC. The Minnesota cohort and CRIC shared a common method to measure GFR (renal clearance of iothalamate), while the EKFC cohort used a variety of exogenous markers and methods, all with recognized sufficient accuracy. We compared the SCr levels and eGFR predictions [for Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) and EKFC equations] of patients fulfilling these matching criteria. Results For 305 matched individuals, mean SCr (mg/dL) was not different between the Minnesota and EKFC cohorts (females 0.83 ± 0.20 versus 0.86 ± 0.23, males 1.06 ± 0.23 versus 1.12 ± 0.37; P &gt; .05) but significantly different from the CRIC [females 1.13 ± 0.23 (P &lt; .0001), males 1.42 ± 0.31 (P &lt; .0001)]. The CKD-EPI equations performed better than the EKFC equation in the CRIC, while the opposite was true in the Minnesota and EKFC cohorts. Conclusion Significant differences in SCr concentrations between the Minnesota and EKFC cohorts versus CRIC were observed in subjects with the same level of mGFR and equal demographic characteristics and can be explained by the difference in SCr calibration

Modeling geographic vaccination strategies for COVID-19 in Norway.

Vaccination was a key intervention in controlling the COVID-19 pandemic globally. In early 2021, Norway faced significant regional variations in COVID-19 incidence and prevalence, with large differences in population density, necessitating efficient vaccine allocation to reduce infections and severe outcomes. This study explored alternative vaccination strategies to minimize health outcomes (infections, hospitalizations, ICU admissions, deaths) by varying regions prioritized, extra doses prioritized, and implementation start time. Using two models (individual-based and meta-population), we simulated COVID-19 transmission during the primary vaccination period in Norway, covering the first 7 months of 2021. We investigated alternative strategies to allocate more vaccine doses to regions with a higher force of infection. We also examined the robustness of our results and highlighted potential structural differences between the two models. Our findings suggest that early vaccine prioritization could reduce COVID-19 related health outcomes by 8% to 20% compared to a baseline strategy without geographic prioritization. For minimizing infections, hospitalizations, or ICU admissions, the best strategy was to initially allocate all available vaccine doses to fewer high-risk municipalities, comprising approximately one-fourth of the population. For minimizing deaths, a moderate level of geographic prioritization, with approximately one-third of the population receiving doubled doses, gave the best outcomes by balancing the trade-off between vaccinating younger people in high-risk areas and older people in low-risk areas. The actual strategy implemented in Norway was a two-step moderate level aimed at maintaining the balance and ensuring ethical considerations and public trust. However, it did not offer significant advantages over the baseline strategy without geographic prioritization. Earlier implementation of geographic prioritization could have more effectively addressed the main wave of infections, substantially reducing the national burden of the pandemic

Performance of creatinine-based equations to estimate glomerular filtration rate in White and Black populations in Europe, Brazil and Africa.

peer reviewed("[en] BACKGROUND: A new Chronic Kidney Disease Epidemiology Collaboration equation without the race variable has been recently proposed (CKD-EPIAS). This equation has neither been validated outside USA nor compared with the new European Kidney Function Consortium (EKFC) and Lund-Malmö Revised (LMREV) equations, developed in European cohorts. METHODS: Standardized creatinine and measured glomerular filtration rate (GFR) from the European EKFC cohorts (n = 13 856 including 6031 individuals in the external validation cohort), from France (n = 4429, including 964 Black Europeans), from Brazil (n = 100) and from Africa (n = 508) were used to test the performances of the equations. A matched analysis between White Europeans and Black Africans or Black Europeans was performed. RESULTS: In White Europeans (n = 9496), both the EKFC and LMREV equations outperformed CKD-EPIAS (bias of -0.6 and -3.2, respectively versus 5.0 mL/min/1.73 m², and accuracy within 30% of 86.9 and 87.4, respectively, versus 80.9%). In Black Europeans and Black Africans, the best performance was observed with the EKFC equation using a specific Q-value (= concentration of serum creatinine in healthy males and females). These results were confirmed in matched analyses, which showed that serum creatinine concentrations were different in White Europeans, Black Europeans and Black Africans for the same measured GFR, age, sex and body mass index. Creatinine differences were more relevant in males. CONCLUSION: In a European and African cohort, the performances of CKD-EPIAS remain suboptimal. The EKFC equation, using usual or dedicated population-specific Q-values, presents the best performance in the whole age range in the European and African populations included in this study.","[en] ",""

Effective cholesterol lowering after myocardial infarction in patients with nephrotic syndrome may require a multi-pharmacological approach : a case report

Background Nephrotic syndrome causes severe hypercholesterotaemia due to increased production and altered clearance of lipoproteins from the liver. It is challenging for patients with nephrotic syndrome and coronary heart disease to meet LDL-cholesterol (LDL-C) goals for secondary prevention with conventional lipid-lowering therapy. Case summary We present a man with nephrotic syndrome caused by focal segmental glomerular sclerosis (FSGS) and hypercholesterolaemia. He presented at the emergency room (ER) with an ST-elevation myocardial infarction at the age of 26. On follow-up, the patient had persistent hyperchotesterotaemia [LDL-C 3.9 mmot/L and tipoprotein(a) 308 nmol/L] despite a combination of lipid-lowering therapy with atorvastatin 80 mg/day and ezetimibe 10 mg/ day. Addition of the proprotein convertase subtilisin/kexin type 9 (PCSK9) inhibitory antibody evolocumab 140 mg bi-monthly did not improve cholesterol levels. However, after addition of the sodium-glucose cotransporter 2 (SGLT2) inhibitor empagtiflozin 10 mg/day on top of other anti-proteinuric treatments, the patients proteinuria was reduced and a dramatic drop in LDL-C level by 3.2 -0.6 mmoUL (-81%) was observed when evolocumab was re-introduced. Discussion We show that target LDL-C levels were obtained in this patient with therapy-resistant FSGS and hypercholesterolaemia following multi-pharmacological treatment with SGLT2 and PCSK9 inhibitors on top of conventional lipid-lowering therapy. The SGLT2-inhibitor reduced proteinuria and, speculatively, also reduced urinary loss of PCSK9antibody. Therefore, in patients with nephrotic syndrome and cardiovascular disease novel therapeutic options to manage proteinuria could be considered to improve the efficacy of the lipid-lowering therapy, especially when the protein-based PCSK9 inhibitors are used

Så kan formel för vuxna skatta glomerulär filtration hos barn

Age-adjustment of creatinine, i.e. recalculation of childhood levels of creatinine to corresponding levels at 18 years of age and applied in the adult revised Lund-Malmö GFR equation led to markedly improved accuracy in Swedish children (n=1 718) at measured GFR <75 mL/min/1.73 m2 (n=318) and preserved high accuracy at ≥75 mL/min/1.73 m2 (n=1 400). The adjusted LMR equation performed as well as dedicated paediatric equations based on height. The proposed adjustment strategy has four strengths: (i) the original coefficients of the adult GFR equation can be used, (ii) the same equation can be used across the entire lifespan without artificial changes in estimated GFR when switching from paediatric to adult care, (iii) the lack of height factor makes it easier to automatically report estimated GFR by the laboratories and (iv) age-adjusted creatinine values imply that well-established creatinine reference intervals for adults can also be used for children

Validation of standardized creatinine and cystatin C GFR estimating equations in a large multicentre European cohort of children

Background: Most validations of paediatric glomerular filtration rate (GFR) estimating equations using standardized creatinine (CR) and cystatin C (CYS) assays have comprised relatively small cohorts, which makes accuracy across subgroups of GFR, age, body mass index (BMI) and gender uncertain. To overcome this, a large cohort of children referred for GFR determination has been established from several European medical centres. Methods: Three thousand four hundred eight measurements of GFR (mGFR) using plasma clearance of exogenous substances were performed in 2218 children aged 2–17 years. Validated equations included Schwartz-2009CR/2012CR/CYS/CR+CYS, FASCR/CYS/CR+CYS, LMRCR, Schwartz-LyonCR, BergCYS, CAPACYS, CKD-EPICYS, AndersenCR+CYS and arithmetic means of the best single-marker equations in explorative analysis. Five metrics were used to compare the performance of the GFR equations: bias, precision and three accuracy measures including the percentage of GFR estimates (eGFR) within ± 10% (P10) and ± 30% (P30) of mGFR. Results: Three of the cystatin C equations, BergCYS, CAPACYS and CKD-EPICYS, exhibited low bias and generally satisfactory accuracy across all levels of mGFR; CKD-EPICYS had more stable performance across gender than the two other equations. Among creatinine equations, Schwartz-LyonCR had the best performance but was inaccurate at mGFR < 30 mL/min/1.73 m2 and in underweight patients. Arithmetic means of the best creatinine and cystatin C equations above improved bias compared to the existing composite creatinine+cystatin C equations. Conclusions: The present study strongly suggests that cystatin C should be the primary biomarker of choice when estimating GFR in children with decreased GFR. Arithmetic means of well-performing single-marker equations improve accuracy further at most mGFR levels and have practical advantages compared to composite equations

Validation of standardized creatinine and cystatin C GFR estimating equations in a large multicentre European cohort of children

BACKGROUND: Most validations of paediatric glomerular filtration rate (GFR) estimating equations using standardized creatinine (CR) and cystatin C (CYS) assays have comprised relatively small cohorts, which makes accuracy across subgroups of GFR, age, body mass index (BMI) and gender uncertain. To overcome this, a large cohort of children referred for GFR determination has been established from several European medical centres. METHODS: Three thousand four hundred eight measurements of GFR (mGFR) using plasma clearance of exogenous substances were performed in 2218 children aged 2-17 years. Validated equations included Schwartz-2009CR/2012CR/CYS/CR+CYS, FASCR/CYS/CR+CYS, LMRCR, Schwartz-LyonCR, BergCYS, CAPACYS, CKD-EPICYS, AndersenCR+CYS and arithmetic means of the best single-marker equations in explorative analysis. Five metrics were used to compare the performance of the GFR equations: bias, precision and three accuracy measures including the percentage of GFR estimates (eGFR) within ± 10% (P10) and ± 30% (P30) of mGFR. RESULTS: Three of the cystatin C equations, BergCYS, CAPACYS and CKD-EPICYS, exhibited low bias and generally satisfactory accuracy across all levels of mGFR; CKD-EPICYS had more stable performance across gender than the two other equations. Among creatinine equations, Schwartz-LyonCR had the best performance but was inaccurate at mGFR < 30 mL/min/1.73 m2 and in underweight patients. Arithmetic means of the best creatinine and cystatin C equations above improved bias compared to the existing composite creatinine+cystatin C equations. CONCLUSIONS: The present study strongly suggests that cystatin C should be the primary biomarker of choice when estimating GFR in children with decreased GFR. Arithmetic means of well-performing single-marker equations improve accuracy further at most mGFR levels and have practical advantages compared to composite equations.status: publishe

Estimating glomerular filtration rate at the transition from pediatric to adult care

The current Kidney Disease Improving Global Outcomes (KDIGO) guidelines recommend the use of the bedside creatinine-based Chronic Kidney Disease in Children (CKiD) equation to estimate glomerular filtration rate (GFR) in children and the Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) equation in adults. However, this approach causes implausible changes in estimated GFR (eGFR) at the transition from pediatric to adult care. We investigated the performance of the KDIGO strategy and various creatinine-based eGFR equations in a cross-sectional dataset of 5,764 subjects (age 10-30 years), using directly measured GFR (mGFR) as reference. We also evaluated longitudinal GFR slopes in 136 subjects who transitioned to adult care. Implausible changes in eGFR resulted from the large overestimation (bias=+21 mL/min/1.73m2) and poor precision of the CKD-EPI equation in the 18-20 year age group, compared to CKiD in the 16-18 year age group (bias=-2.7 mL/min/1.73m2), resulting in a mean change of 23 mL/min/1.73m2 at the transition to adult care. Averaging the CKiD and CKD-EPI estimates in young adults only partially mitigated this issue. The Full Age Spectrum equation (with and without height), the Lund-Malmö Revised equation, and an age-dependent weighted average of CKiD and CKD-EPI resulted in much smaller changes in eGFR at the transition (change of 0.6, -2.1, -0.9 and -1.8 mL/min/1.73m2, respectively). The longitudinal analysis revealed a significant difference in average GFR slope between mGFR and the KDIGO strategy (-2.2 vs. +2.9 mL/min/1.73 m2/year), which was not observed with the other approaches. These results suggest that the KDIGO recommendation for GFR estimation at the pediatric-adult care transition should be revisited.status: publishe