Measured and Estimated Glomerular Filtration Rate to Evaluate Rapid Progression and Changes over Time in Autosomal Polycystic Kidney Disease: Potential Impact on Therapeutic Decision-Making.

Autosomal polycystic kidney disease (ADPKD) is the most common genetic form of kidney failure, reflecting unmet needs in management. Prescription of the only approved treatment (tolvaptan) is limited to persons with rapidly progressing ADPKD. Rapid progression may be diagnosed by assessing glomerular filtration rate (GFR) decline, usually estimated (eGFR) from equations based on serum creatinine (eGFRcr) or cystatin-C (eGFRcys). We have assessed the concordance between eGFR decline and identification of rapid progression (rapid eGFR loss), and measured GFR (mGFR) declines (rapid mGFR loss) using iohexol clearance in 140 adults with ADPKD with ≥3 mGFR and eGFRcr assessments, of which 97 also had eGFRcys assessments. The agreement between mGFR and eGFR decline was poor: mean concordance correlation coefficients (CCCs) between the method declines were low (0.661, range 0.628 to 0.713), and Bland and Altman limits of agreement between eGFR and mGFR declines were wide. CCC was lower for eGFRcys. From a practical point of view, creatinine-based formulas failed to detect rapid mGFR loss (-3 mL/min/y or faster) in around 37% of the cases. Moreover, formulas falsely indicated around 40% of the cases with moderate or stable decline as rapid progressors. The reliability of formulas in detecting real mGFR decline was lower in the non-rapid-progressors group with respect to that in rapid-progressor patients. The performance of eGFRcys and eGFRcr-cys equations was even worse. In conclusion, eGFR decline may misrepresent mGFR decline in ADPKD in a significant percentage of patients, potentially misclassifying them as progressors or non-progressors and impacting decisions of initiation of tolvaptan therapy.

Circulating interleukin-6 and cardiovascular disease risk in patients with rheumatoid arthritis with low disease activity due to active therapy.

OBJECTIVES: Interleukin-6 (IL-6) has been implicated in the pathophysiology of rheumatoid arthritis (RA) and in the development of atherosclerosis in the general population. In the present work we aimed to study if IL-6 serum levels have an influence on factors associated with cardiovascular (CV) disease in a cohort of Spanish patients with RA. METHODS: Cross-sectional study that encompassed 407 patients with RA. Serum IL-6 levels were assessed. Multivariable analysis was performed to examine the relationship of IL-6 to subclinical carotid atherosclerosis and classic CV risk factors, including a comprehensive lipid molecule profile and indices of insulin resistance and beta-cell function. RESULTS: Circulating levels of IL-6 showed a correlation with acute phase reactants, disease activity, and other features of RA. However, classic CV risk factors, lipid profile and indices of insulin resistance, as well as subclinical carotid atherosclerosis, were not associated with serum IL-6 levels. CONCLUSIONS: Although a direct association between IL-6 levels and traditional CV risk factors and subclinical carotid atherosclerosis was not observed, circulating IL-6 was associated with disease activity and acute-phase reactants, which have been associated with an increased risk of CV in these patients.

Interleukin-6 serum levels are associated with disease features and cardiovascular risk in patients with systemic sclerosis.

OBJECTIVES: Systemic sclerosis (SSc) is a chronic multisystem disease characterised by microcirculatory vascular dysfunction and progressive fibrosis of the skin and internal organs. Interleukin-6 (IL-6) is a proinflammatory cytokine that has been implicated in the pathogenesis of several autoimmune diseases and in the initiation and progression of the cardiovascular disease. In the present work we aimed to study the relationship of IL-6 with clinical manifestations and the cardiovascular risk in patients with SSc. METHODS: Cross-sectional study that included 53 individuals with SSc. A multivariate analysis was performed to study the relationship between IL-6 and disease characteristics and cardiovascular risk assessed by Systematic Coronary Risk Estimation (SCORE2) in SSc. RESULTS: The presence of digital ulcers, calcinosis, and anti-Scl70 antibody was associated with higher levels of IL-6. This was also the case for functional respiratory parameters where this association was found to be significant and negative after correction for covariates. In addition, the SCORE2 cardiovascular risk algorithm showed a positive and significant association with circulating IL-6. CONCLUSIONS: IL-6 levels are associated with disease manifestations and cardiovascular risk in patients with SSc.

Relationship between Disease Characteristics and Circulating Interleukin 6 in a Well-Characterized Cohort of Patients with Systemic Lupus Erythematosus.

Interleukin-6 (IL-6) is a proinflammatory cytokine that mediates pleiotropic functions in immune responses and inflammatory diseases. The literature lacks studies, with a clinical perspective, on the relationship between IL-6 serum levels and the characteristics of the disease in patients with systemic lupus erythematosus (SLE). In the present work, we aimed to analyze the association between circulating IL-6 and disease manifestations in a well-characterized series of patients with SLE. Serum IL-6 levels and disease activity (SLEDAI-2K), severity (Katz) and damage index (SLICC-DI), complete lipid profile, and subclinical carotid atherosclerosis were evaluated in 284 patients with SLE. In addition, a complete characterization of the complement system was performed in samples from patients with SLE. A multivariate linear regression analysis was carried out to study the relationship between clinical and laboratory characteristics of the disease and IL-6 levels. Age (beta coef. 0.07 [95%CI 0.01-0.1] pg/mL, p = 0.014), C-reactive protein (beta coef. 0.21 [95%CI 0.16-0.25] pg/mL, p < 0.01), and male gender (beta coef. 2 [95%CI 0.3-0.5] pg/mL, p = 0.024), were positively associated with higher IL-6 levels in SLE patients. Most disease characteristics and damage and activity indices did not show significant relationships with IL-6. However, after multivariate analysis, IL-6 was associated with lower serum levels of HDL cholesterol (beta coef. -0.04 [95%CI -0.08-(-0.1)] pg/mL, p = 0.011), and apolipoprotein A1 (beta coef. -0.02 [95%CI -0.04-(-0.001)] pg/mL, p = 0.035). In contrast, the alternative complement cascade, C1inh, and C3a were all positively and independently associated with higher serum levels of IL-6. Moreover, stratification of the Systematic Coronary Risk Assessment 2 (SCORE2) results according to different categories of cardiovascular risk was associated with higher circulating serum IL-6 levels (beta coef. 0.2 [95%CI 0.02-0.4], pg/mL, p = 0.028). In conclusion, in a large series of SLE patients, IL-6 was not associated with disease-related features of SLE, including damage, severity, or activity indices. However, an association was found between serum IL-6 levels and circulating C3a and cardiovascular risk. Our study emphasizes the importance that IL-6 could have in cardiovascular disease and complement system disruption of SLE patients. Therapies targeting IL-6 could have a role in these two clinical manifestations of patients with SLE.

Estimated glomerular filtration rate by formulas in patients with cirrhosis: An unreliable procedure.

BACKGROUND & AIMS: In cirrhosis, the reliability of formulas that estimate renal function, either those specifically developed in this population or the classic equations, has not been properly quantified. We studied the agreement between estimated (eGFR) and measured glomerular filtration rate (mGFR) in cirrhosis. METHODS: Renal function was estimated with 56 formulas including specific equations: Glomerular Filtration Rate Assessment in Liver Disease (GRAIL), Royal Free Hospital Cirrhosis (RFHC) and Mindikoglu-eGFR, and measured with a gold standard procedure; plasma clearance of iohexol using dried blood spots sampling in a group of cirrhotics. The agreement eGFR-mGFR was evaluated with specific tests: total deviation index (TDI), concordance correlation coefficient (CCC) and coverage probability (CP). We defined acceptable agreement as values: TDI < 10%, CCC ≥ 0.9 and CP > 90%. RESULTS: A total of 146 patients (age 65 ± 9 years, 81% male) were evaluated; 61 (42%) Child A, 67 (46%) Child B and 18 (12%) Child C. Median MELD-Na was 14 (9-15). The agreement between eGFR and mGFR was poor: TDI averaged was of 73% (90% of the estimations ranged from ±73% of mGFR); CCC averaged was 0.7 indicating low concordance and CP averaged 22% indicating that 78% of the estimations have an error > 10%. Specific formulas showed also poor agreement: TDI was 82%, 70% and 37% for the GRAIL, RFHC and Mindikoglu equations, respectively. CONCLUSIONS: Overall, formulas poorly estimated renal function in cirrhotic patients. Specific formulas designed for cirrhosis did not outperform classic equations. eGFR must be considered with caution in cirrhotic patients.

Proprotein convertase subtilisin/kexin type 9 in the dyslipidaemia of patients with axial spondyloarthritis is related to disease activity.

OBJECTIVE: Proprotein convertase subtilisin/kexin type 9 (PCSK9) is a serine protease that regulates cholesterol metabolism and has been linked to cardiovascular (CV) risk. The purpose of the present study was to examine whether PCSK9 levels are related to abnormalities in the lipid profile and the development of atherosclerosis that occurs in patients with axial SpA (axSpA). METHODS: We performed a cross-sectional study that encompassed 545 individuals; 299 patients with axSpA and 246 statin use-matched controls. PCSK9 and standard lipid profiles were analysed in patients and controls. Carotid intima-media thickness (cIMT) and carotid plaques were assessed in patients. A multivariable analysis, adjusted for standard CV risk factors, was performed to evaluate the influence of PCSK9 on axSpA-related dyslipidaemia and subclinical carotid atherosclerosis. RESULTS: Total cholesterol, high-density lipoprotein and low density lipoprotein cholesterol, lipoprotein (a) and apolipoprotein A1 were significantly lower in axSpA patients than controls. PCSK9 serum levels [ß coefficient -44 ng/dl (95% CI -60, -27), P = 0.000] were also downregulated in axSpA patients after fully multivariable adjustment. ASDAS-CRP was found to be independently and significantly related to PCSK9 [ß coefficient 10 ng/dl (95% CI 1, 18), P = 0.023] after analysing fully adjusted models that took age, sex and the rest of the lipid profile molecules into account. Whereas patients taking prednisone showed higher serum levels of PCSK9 [55 ng/ml (95% CI 24, 8), P = 0.001], those under anti-TNF-α therapies exhibited lower levels [ß coefficient -26 ng/ml (95% CI -43, -9], P = 0.003]. CONCLUSION: PCSK9 is downregulated in patients with axSpA. Disease activity is positive and significantly related to PSCK9. Anti-TNF-therapy yields a reduction in PCSK9 serum levels.

Beta-cell function is disrupted in patients with systemic lupus erythematosus.

OBJECTIVES: To investigate how markers of beta-cell secretion (proinsulin-processing metabolites) are expressed in SLE patients and their potential relation to features associated with the disease such as activity or damage. METHODS: One hundred and forty-four SLE patients and 69 nondiabetic sex- and age-matched controls were assessed. Beta-cell secretion molecules, as measured by insulin, split and intact proinsulins, and C-peptide levels were analysed in both groups. Multiple regression analysis was performed to compare proinsulin propeptides between groups and to explore the interrelations with SLE features. Analyses were adjusted for glucocorticoid intake and for insulin resistance classic risk factors. RESULTS: Fully multivariable analysis demonstrated that regardless of glucocorticoid use, SLE patients exhibited higher levels of split proinsulin. Likewise, the split proinsulin-to-insulin ratio was upregulated in patients with SLE undergoing glucocorticoid therapy [beta coeficient 0.19 (95% Confidence Interval 0.07, 0.30), P = 0.002] or not [beta coef. 0.09 (95% CI: 0.01, 0.17), P = 0.025]. Similar results were found for the intact proinsulin-to-insulin ratio, although differences were only statistically significant for patients taking glucocorticoids [beta coef. 0.08 (95% CI: 0.03, 0.12), P = 0.001]. SLE damage score was associated with higher serum levels of intact [beta coef. 0.51 (95% CI 0.17, 0.86) pmol/l, P = 0.004] and split proinsulins [beta coef. 1.65 (95% CI 0.24, 3.06) pmol/l, P = 0.022] after multivariable analysis, including disease duration and prednisone use. CONCLUSION: Among patients with SLE, proinsulin-processing metabolites, a marker of beta-cell disruption, are upregulated compared with matched controls. This disproportionate hyperproinsulinemia can be explained by the damage produced by the disease and occurs independently of prednisone use.

Chronic kidney disease staging with cystatin C or creatinine-based formulas: flipping the coin.

Background: Chronic kidney disease (CKD) affects 10-13% of the population worldwide. CKD classification stratifies patients in five stages of risk for progressive renal disease based on estimated glomerular filtration rate (eGFR) by formulas and albuminuria. However, the reliability of formulas to reflect real renal function is a matter of debate. The effect of the error of formulas in the CKD classification is unclear, particularly for cystatin C-based equations. Methods: We evaluated the reliability of a large number of cystatin C and/or creatinine-based formulas in the definition of the stages of CKD in 882 subjects with different clinical situations over a wide range of glomerular filtration rates (GFRs) (4.2-173.7 mL/min). Results: Misclassification was a constant for all 61 formulas evaluated and averaged 50% for creatinine-based and 35% for cystatin C-based equations. Most of the cases were misclassified as one stage higher or lower. However, in 10% of the subjects, one stage was skipped and patients were classified two stages above or below their real stage. No clinically relevant improvement was observed with cystatin C-based formulas compared with those based on creatinine. Conclusions: The error in the classification of CKD stages by formulas was extremely common. Our study questions the reliability of both cystatin C and creatinine-based formulas to correctly classify CKD stages. Thus the correct classification of CKD stages based on estimated GFR is a matter of chance. This is a strong limitation in evaluating the severity of renal disease, the risk for progression and the evolution of renal dysfunction over time.

Insulin resistance in systemic lupus erythematosus patients: contributing factors and relationship with subclinical atherosclerosis.

OBJECTIVES: Insulin resistance (IR) plays a role in the increased cardiovascular risk of systemic lupus erythematosus (SLE) patients. This study aimed to determine the potential association of IR with disease activity, drug exposure and subclinical atherosclerosis in patients with SLE. METHODS: This cross-sectional study encompassed 87 non-diabetic SLE patients and 82 sex-matched controls. Insulin and C-peptide serum levels, IR indexes by homeostatic model assessment (HOMA2) (both insulin-based: HOMA2-IR, and with C-peptide: HOMA2-IR-C-peptide) and lipid profiles were assessed in patients and controls. Activity (SLEDAI), severity (Katz) and damage (SLICC) index scores, as well as carotid intima-media thickness (cIMT) and carotid plaques, were determined in SLE patients. A multivariable regression analysis, adjusted for classic IR related factors, was performed to evaluate the differences in IR indexes between patients and controls and how IR is associated with disease-related characteristics, including carotid ultrasound results, in SLE patients. RESULTS: SLE patients had higher C-peptide serum levels (2.61±1.51 vs. 1.34±0.62 ng/ml, p=0.00) and elevated HOMA2-IRC-peptide index (1.90±1.12 vs. 0.97±0.45, p=0.00) than controls. These differences remained statistically significant after adjusting for classic cardiovascular risk factors and prednisone intake. Traditional IR-related factors, such as body mass index, waist circumference or hypertension, and prednisone intake were significantly associated with HOMA2-IR and HOMA2-IRC-peptide in SLE patients. SLICC damage index was independently associated with HOMA2-IR-C-peptide. The presence of carotid plaques and cIMT values were associated with IR indexes in SLE patients only in the univariate analysis. CONCLUSIONS: C-peptide serum levels are independently up-regulated in SLE patients. Although classic IR factors and prednisone are associated with IR, SLE damage over time also contributes to IR in an independent way.

The error of estimated GFR in predialysis care.

The error of estimated glomerular filtration rate (eGFR) and its consequences in predialysis are unknown. In this prospective multicentre study, 315 predialysis patients underwent measured GFR (mGFR) by the clearance of iohexol and eGFR by 52 formulas. Agreement between eGFR and mGFR was evaluated by concordance correlation coefficient (CCC), total deviation index (TDI) and coverage probability (CP). In a sub-analysis we assessed the impact of eGFR error on decision-making as (i) initiating dialysis, (ii) preparation for renal replacement therapy (RRT) and (iii) continuing clinical follow-up. For this sub-analysis, patients who started RRT due to clinical indications (uremia, fluid overload, etc.) were excluded. eGFR had scarce precision and accuracy in reflecting mGFR (average CCC 0.6, TDI 70% and cp 22%) both in creatinine- and cystatin-based formulas. Variations -larger than 10 ml/min- between mGFR and eGFR were frequent. The error of formulas would have suggested (a) premature preparation for RTT in 14% of stable patients evaluated by mGFR; (b) to continue clinical follow-up in 59% of subjects with indication for RTT preparation due to low GFRm and (c) to delay dialysis in all asymptomatic patients (n = 6) in whom RRT was indicated based on very low mGFR. The error of formulas in predialysis was frequent and large and may have consequences in clinical care.

Relationship of Blood Inflammatory Composite Markers with Cardiovascular Risk Factors and Subclinical Atherosclerosis in Patients with Rheumatoid Arthritis.

The neutrophil-to-lymphocyte ratio (NLR), monocyte-to-lymphocyte ratio (MLR), platelet-to-lymphocyte ratio (PLR), and systemic immune-inflammatory index (SIRI, neutrophils × monocytes/lymphocytes) have been described as potential blood-derived inflammatory biomarkers in several diseases. Rheumatoid arthritis is an inflammatory disease that has been related to an increased risk of cardiovascular (CV) disease. In the present work, we analyze how these hematological composite scores of inflammation are related to classic CV risk factors and subclinical atherosclerosis in patients with RA. In this cross-sectional study that included 430 patients with RA, the NLR, MLR, PLR, and SIRI scores were calculated. Multivariable analysis was performed to examine the relationships of these composite blood scores with subclinical carotid atherosclerosis and with traditional cardiovascular factors, producing a complete profile of lipid molecules and insulin resistance or indices of beta-cell function, and a Systematic Coronary Risk Assessment (SCORE2) calculation. C-reactive protein and disease activity were significantly and positively associated with the four blood composite scores. SCORE2 was significantly associated with higher values of SIRI, NLR, and MLR, but not PLR. These relationships were maintained when SCORE 2 was considered categorical; patients in the very high CV risk category had higher values in all hematological composite scores, except PLR. In the multivariable analysis, SIRI and NLR were independently associated with higher levels of beta cell dysfunction. In conclusion, SCORE2 and the values of the hematological composite scores were positively correlated in patients with RA. In addition, there were some relationships of these scores with traditional CV risk factors, with their association with beta cell dysfunction being the most consistent.

Exercise and Prediabetes After Renal Transplantation (EXPRED-I): A Prospective Study.

BACKGROUND: Post-transplant diabetes mellitus (PTDM) beyond 12 months (late PTDM) is a severe complication after renal transplantation. Late PTDM develops mostly in subjects with prediabetes. Although exercise may have a potential role in preventing late PTDM, there are no previous data on the effect of exercise in patients with prediabetes. MATERIAL AND METHODS: The design was a 12-month exploratory study to test the capacity of exercise in reverting prediabetes in order to prevent late-PTDM. The outcome was the reversibility of prediabetes, assessed every 3 months with oral glucose tolerance tests (OGTT). The protocol included an incremental plan of aerobic and/or strength training as well as an active plan for promoting adherence (telephone calls, digital technology, and visits). A priori, a sample size cannot be calculated which makes this an exploratory analysis. Based on previous studies, the spontaneous reversibility of prediabetes was 30% and the reversibility induced by exercise will account for another 30%, a total reversibility of 60% (p value < 0.05, assuming a potency of 85%). Ad interim analysis was performed during follow-up to test the certainty of this sample calculation. Patients beyond 12 months after renal transplantation with prediabetes were included. RESULTS: The study was interrupted early due to efficacy after the evaluation of the follow-up of 27 patients. At the end of follow-up, 16 (60%) patients reverted to normal glucose levels at fasting (from 102.13 mg/dL ± 11 to 86.75 ± 6.9, p = 0.006) and at 120 min after the OGTTs (154.44 mg/dL ± 30 to 113.0 ± 13.1, p = 0.002) and 11 patients had persistent prediabetes (40%). Also, insulin sensitivity improved with the reversibility of prediabetes, compared to those with persistent prediabetes: 0.09 [0.08-0.11] versus 0.04 [0.01-0.07], p = 0.001 (Stumvoll index). Most needed at least one increment in the prescription of exercise and compliance. Finally, measures aimed at the improvement of compliance were successful in 22 (80%) patients. CONCLUSION: Exercise training was effective to improve glucose metabolism in renal transplant patients with prediabetes. Exercise prescription must be conducted considering both the clinical characteristics of the patients and pre-defined strategy to promote adherence. The trial registration number of the study was NCT04489043.

Inflammation on the Waiting List Is a Risk Factor for New-Onset Prediabetes and Post-Transplant Diabetes Mellitus: A Prospective Study.

INTRODUCTION: Inflammation is a risk factor for diabetes in the general population. The role of inflammation in prediabetes or post-transplant diabetes mellitus (PTDM) is not clear. We evaluated the association between inflammatory markers in patients on the waiting list for renal transplantation and the onset of prediabetes and PTDM 12 months after transplantation. METHODS: This is a post hoc analysis of a prospective study that included nondiabetic patients on the waiting list for kidney transplantation who underwent an oral glucose tolerance test (OGTT) and were followed up to 12 months after transplantation. At this time, those patients without PTDM underwent another OGTT. At pre-transplantation, five cytokines: TNFα, IL6, IL1ß, CRP, MCP1 were determined. The association between inflammation and prediabetes/PTDM was evaluated using multiple regression models. RESULTS: 110 patients on the waiting list were enrolled: 74 had normal glucose metabolism and 36 had prediabetes or occult diabetes. At 12 months, 53 patients had normal glucose metabolism, 25 prediabetes, and 32 PTDM. In multiple regression analysis, pre-transplant inflammation was not a risk factor for prediabetes or PTDM. This was attributed to the high interrelation between obesity, prediabetes, and inflammation: about 75% of the cases had these conditions. In a sub-analysis, we analyzed only patients without prediabetes and occult diabetes on the waiting list and found that TNFα levels and BMI at pre-transplantation were independently associated with the onset of prediabetes or PTDM 1 year after transplantation. CONCLUSIONS: Pre-transplant inflammation and BMI are risk factors for prediabetes and PTDM in patients without glucose metabolism alterations.

Apolipoprotein C-III is linked to the insulin resistance and beta-cell dysfunction that are present in rheumatoid arthritis.

BACKGROUND: Insulin resistance and beta-cell dysfunction are manifestations of rheumatoid arthritis (RA). Apolipoprotein C-III (ApoC3) has been associated with such insulin resistance and beta-cell dysfunction in the general population. Our purpose was to study whether ApoC3 is also related to the insulin resistance and beta-cell dysfunction that are present in patients with RA. METHODS: Three hundred thirty-eight non-diabetic patients with RA who had a glycemia lower than 110 mg/dl were recruited. Insulin, C-peptide, and ApoC3 were assessed. Insulin resistance and beta-cell function were calculated using the Homeostasis Model Assessment (HOMA2) indices. A multivariable regression analysis was performed to study the relationship of ApoC3 with those molecules and indices adjusting for classic factors associated with insulin resistance that included glucocorticoids. RESULTS: ApoC3 was related to significant higher levels of circulating insulin (beta coef. 0.37 [95%CI 0.01-0.73] µU/ml, p = 0.044) and C-peptide (beta coef. 0.13 [95%CI 0.05-0.22] ng/ml, p = 0.003), and higher insulin resistance -HOMA2-IR- (beta coef. 0.05 [95%CI 0.00-0.09], p = 0.041) and beta-cell dysfunction -HOMA2-%B- (beta coef. 2.94 [95%CI 0.07-5.80], p = 0.044) indices. This was found after a fully multivariable analysis that included, among others, prednisone intake and the classic factors associated with carbohydrate metabolism such as triglycerides, waist circumference, and obesity. CONCLUSION: ApoC3, insulin resistance, and beta-cell dysfunction are independently associated in patients RA.

Apolipoprotein C-III in patients with systemic lupus erythematosus.

BACKGROUND: Systemic lupus erythematosus (SLE) has been associated with atherosclerotic cardiovascular disease (CV) and an altered lipid profile. High levels of apolipoprotein C-III (ApoC3) are associated with elevated triglyceride levels and an increased risk of CV. In the present study, we aimed to study circulating ApoC3 in patients with SLE and describe its relationship with the manifestations of the disease. METHODS: This is a cross-sectional study that included 186 patients with SLE. Disease-related data, CV comorbidity, full lipid profile, and serum levels of ApoC3 were assessed. A multivariable regression analysis was performed to study how ApoC3 was related to SLE features. RESULTS: Classic CV risk factors were significantly and strongly associated with circulating ApoC3. After a fully multivariable analysis that included classic CV risk factors and lipid profile molecules, SLICC damage (beta coef. 0.10 [95% CI 0.02-0.19] mg/dl, 0.020) and Katz severity (beta coef. 0.11 [95% CI 0.03-0.19] mg/dl, p = 0.011) indices and SLEDAI activity score (beta coef. 0.05 [95% CI 0.05-0.08] mg/dl, p = 0.004) were all independently associated with higher levels of circulating ApoC3. CONCLUSION: Among SLE patients, disease activity, severity, and disease damage are independently associated with higher ApoC3 serum levels.

The angiopoietin-like protein 4, apolipoprotein C3, and lipoprotein lipase axis is disrupted in patients with rheumatoid arthritis.

BACKGROUND: Modulators of triglyceride metabolism include lipoprotein lipase (LPL), angiopoietin-like protein 4 (ANGPTL4), and apolipoprotein C-3 (ApoC3). There is evidence on the influence of this triangle of molecules on an increased risk of atherosclerotic cardiovascular disease (CV) in the general population. Patients with rheumatoid arthritis (RA) present changes in lipid profiles and accelerated CV disease. In the present study, we set out to study whether the ANGPTL4, ApoC3, and LPL axis differs in subjects with RA compared to controls. In a further step, we investigated the relationship of this axis with subclinical atherosclerosis in patients with RA. METHODS: Cross-sectional study that included 569 individuals, 323 patients with RA and 246 age-matched controls. ANGPTL4, ApoC3 and LPL, and standard lipid profiles were analyzed in patients and controls. Carotid intima-media thickness (cIMT) and carotid plaques were assessed in RA patients. A multivariable analysis was performed to assess whether the ANGPTL4, ApoC3, and LPL axis was altered in RA and to study its relationship with RA dyslipidemia and subclinical carotid atherosclerosis. RESULTS: Most lipid profile molecules did not differ between patients and controls. Despite this, and after fully multivariable analysis including CV risk factors, use of statins, and changes in the lipid profile caused by the disease itself, patients with RA showed higher serum levels of ANGPTL4 (beta coef. 295 [95% CI 213-376] ng/ml, p<0.001) and ApoC3 (beta coef. 2.9 [95% CI 1.7-4.0] mg/dl, p<0.001), but lower circulating LPL (beta coef. -174 [95% CI -213 to -135] ng/ml, p<0.001). ANGPTL4 serum levels were positively and independently associated with a higher cIMT in patients with RA after fully multivariable adjustment. CONCLUSION: The axis consisting in ANGPTL4, ApoC3, and LPL is disrupted in patients with RA. ANGPTL4 serum levels are positively and independently associated with a higher cIMT in RA patients.

Interleukin 1 receptor antagonist relation to cardiovascular disease risk in patients with rheumatoid arthritis.

Interleukin (IL) 1, and its family member, IL-1 receptor antagonist (IL-1ra), are involved in the pathogenesis and inflammation perpetuation of patients with rheumatoid arthritis (RA). Besides, IL-1 has been linked to an increased risk and greater severity of cardiovascular (CV) disease. We aimed to study if IL-1ra is related to the CV manifestations-including lipid pattern and insulin resistance or subclinical atherosclerosis-that accompanies the disease in a large series of patients with RA. Cross-sectional study that encompassed 430 patients with RA. Serum IL-1ra levels were assessed. A multivariable analysis was performed to analyze the relation of IL-1ra to subclinical carotid atherosclerosis, and to traditional CV factors including a complete lipid molecules profile and insulin resistance or beta cell function indices. Body mass index, abdominal circumference, and the presence of obesity were significantly and positively associated with circulating IL-1ra. Similarly, erythrocyte sedimentation rate, and disease activity scores were significantly related to higher IL-1ra serum levels after adjustment for confounders. Neither carotid intima-media thickness nor the presence of carotid plaque were associated with serum levels of IL-1ra. However, after multivariable analysis circulating IL-1ra was independently and positively associated with higher serum levels of total cholesterol, triglycerides, and apolipoproteins B and C-III. Similarly, IL-1ra was related to higher levels of beta-cell function in the univariable analysis, although, in this case, significance was lost after adjustment. Among patients with RA, IL-1ra is associated with both disease activity and several traditional CV risk factors such as obesity and the presence of higher lipid levels. Our findings suggest that IL-1ra can represent a link between the inflammation and the CV disease risk that are present in patients with RA.

Disease Activity Is More Associated with IL-1 Than with IL-6 in Patients with Rheumatoid Arthritis.

Interleukin-1 receptor antagonist (IL-1ra) concentration reflects and is proportional to IL-1 production. Both IL-1 and IL-6 are involved in the pathogenesis of rheumatoid arthritis (RA). However, the relationship of serum levels of these two cytokines to each other in RA patients is not well-understood. In this study, our objective was to analyze the possible linear correlation between IL-1ra and IL-6 in patients with RA, and how both are related to the inflammatory activity of the disease. IL-6 and IL-1ra levels were measured in 407 patients with RA. Linear regression and partial correlations were conducted to analyze the relationship between both cytokines, and their association with RA characteristics. No correlation was found between serum levels of IL-6 and IL-1ra (Pearson's r 0.031, p = 0.61). However, disease activity and acute phase reactants were positively and significantly associated with both cytokines. Nevertheless, after controlling for covariates, disease activity scores were more strongly associated with IL-1ra compared to IL-6. Circulating IL-6 and IL-1ra do not correlate with each other in RA patients. Although both are associated with disease activity and acute phase reactants, the relationship of disease activity to IL-1ra is greater than that to IL-6.

Estimated GFR in autosomal dominant polycystic kidney disease: errors of an unpredictable method.

BACKGROUND: Autosomal dominant polycystic kidney disease (ADPKD) causes about 10% of cases of end stage renal disease. Disease progression rate is heterogeneous. Tolvaptan is presently the only specific therapeutic option to slow kidney function decline in adults at risk of rapidly progressing ADPKD with chronic kidney disease (CKD) stages 1-4. Thus, a reliable evaluation of kidney function in patients with ADPKD is needed. METHODS: We evaluated the agreement between measured (mGFR) and estimated glomerular filtration rate (eGFR) by 61 formulas based on creatinine and/or cystatin-C (eGFR) in 226 ADPKD patients with diverse GFR values, from predialysis to glomerular hyperfiltration. Also, we evaluated whether incorrect categorization of CKD using eGFR may interfere with the indication and/or reimbursement of Tolvaptan treatment. RESULTS: No formula showed acceptable agreement with mGFR. Total Deviation Index averaged about 50% for eGFR based on creatinine and/or cystatin-C, indicating that 90% of the estimations of GFR showed bounds of error of 50% when compared with mGFR. In 1 out of 4 cases with mGFR < 30 ml/min, eGFR provided estimations above this threshold. Also, in half of the cases with mGFR between 30 and 40 ml/min, formulas estimated values < 30 ml/min. CONCLUSIONS: The evaluation of renal function with formulas in ADPKD patients is unreliable. Extreme deviation from real renal function is quite frequent. The consequences of this error deserve attention, especially in rapid progressors who may benefit from starting treatment with tolvaptan and in whom specific GFR thresholds are needed for the indication or reimbursement. Whenever possible, mGFR is recommended.

Estimated GFR Slope in Kidney Transplant Patients: When the Error Is Random.

BACKGROUND: The evaluation of renal function changes over time is crucial in day-to-day renal transplant care, and the slope of renal function is a major outcome in clinical trials. Little is known about the reliability of estimated glomerular filtration rate (eGFR) in reflecting real glomerular filtration rate (GFR) changes. METHODS: We analyzed the variability of eGFR slope by 63 equations in estimating measured GFR (mGFR) changes in 110 renal transplant patients. The agreement between eGFR and mGFR slopes was evaluated by the concordance correlation coefficient and the limits of agreement. Patients were grouped based on mGFR slope in rapid GFR loss: faster than -3 mL/min/y; stable renal function: -3 to +3 mL/min/y; and improvement in GFR: higher than +3 mL/min/y. RESULTS: Concordance correlation coefficient averaged 0.36 and limits of agreement ±10 mL/min/y, indicating very poor agreement between eGFR and mGFR slopes. The eGFR slope classified patients into the same group of mGFR slope only in 25% of the cases. In about two-thirds of patients, the eGFR slope was either markedly faster or slower than the mGFR slope. In half of these cases, the discrepancy between mGFR and eGFR slopes was ≥50%. CONCLUSIONS: Formulas are neither accurate nor precise in reflecting real GFR decline in renal transplant patients, making them unreliable for clinical practice and trials.