SLESIS-R: an improved score for prediction of serious infection in patients with systemic lupus erythematosus based on the RELESSER prospective cohort.

OBJECTIVE: To develop an improved score for prediction of severe infection in patients with systemic lupus erythematosus (SLE), namely, the SLE Severe Infection Score-Revised (SLESIS-R) and to validate it in a large multicentre lupus cohort. METHODS: We used data from the prospective phase of RELESSER (RELESSER-PROS), the SLE register of the Spanish Society of Rheumatology. A multivariable logistic model was constructed taking into account the variables already forming the SLESIS score, plus all other potential predictors identified in a literature review. Performance was analysed using the C-statistic and the area under the receiver operating characteristic curve (AUROC). Internal validation was carried out using a 100-sample bootstrapping procedure. ORs were transformed into score items, and the AUROC was used to determine performance. RESULTS: A total of 1459 patients who had completed 1 year of follow-up were included in the development cohort (mean age, 49±13 years; 90% women). Twenty-five (1.7%) had experienced ≥1 severe infection. According to the adjusted multivariate model, severe infection could be predicted from four variables: age (years) ≥60, previous SLE-related hospitalisation, previous serious infection and glucocorticoid dose. A score was built from the best model, taking values from 0 to 17. The AUROC was 0.861 (0.777-0.946). The cut-off chosen was ≥6, which exhibited an accuracy of 85.9% and a positive likelihood ratio of 5.48. CONCLUSIONS: SLESIS-R is an accurate and feasible instrument for predicting infections in patients with SLE. SLESIS-R could help to make informed decisions on the use of immunosuppressants and the implementation of preventive measures.

Tocilizumab-related hypertriglyceridemia is independent of key molecules regulating lipid metabolism.

INTRODUCTION: Tocilizumab (TCZ) treatment is associated with dyslipidaemia, including a rise in triglycerides through a mechanism poorly understood. Three molecules play key roles in the regulation of triglyceride metabolism: apolipoprotein C-III (ApoC-III), angiopoietin-like protein 4(ANGPLT4) and lipoprotein lipase (LPL). The aim of this work was to analyse whether the changes in triglycerides shown by TCZ-treated RA patients could stem from the dysregulation that can occur in these regulatory molecules. METHODS: Twenty-seven RA patients included in the TOCRIVAR study who received TCZ (8 mg/kg IV/q4w) were evaluated at baseline and at Weeks 12, 24 and 52 of treatment. ANGPTL4, ApoC-III and LPL, a complete lipid profile and RA disease activity, were analysed at baseline and at each visit. Multivariable linear mixed models were performed to study changes over time in lipids and regulatory molecules. RESULTS: After 24 weeks of TCZ treatment, HDL cholesterol, apolipoprotein A1 and triglycerides increased, whereas lipoprotein (a) decreased significantly from baseline values. However, 1 year after TCZ, no significant differences in lipid pattern were observed with respect to baseline. Serum ANGPTL4 and Apo-CIII levels decreased gradually over time, both being significantly lower than baseline values at Week 52. LPL concentration did not change significantly during TCZ treatment. Remarkably, the elevation of triglycerides at Week 24 maintained its statistical significance after adjusting for the changes in ApoC-III, ANGPTL4 and LPL. CONCLUSION: In TCZ-treated RA patients basal serum levels of ANGPLT4 and ApoC-III, but not LPL, decreased significantly. However, the elevation of triglycerides after TCZ was not related to changes in these regulatory molecules.

Recommendations for prevention of infection in systemic autoimmune rheumatic diseases.

OBJECTIVES: To develop recommendations for the prevention of infection in adult patients with systemic autoimmune rheumatic diseases (SARD). METHODS: Clinical research questions relevant to the objective of the document were identified by a panel of experts selected based on their experience in the field. Systematic reviews of the available evidence were conducted, and evidence was graded according to the Scottish Intercollegiate Guidelines Network criteria. Specific recommendations were made. RESULTS: Five questions were selected, referring to prevention of infection by Pneumocystis jirovecii with trimethoprim/sulfamethoxazole, primary and secondary prophylactic measures against hepatitis B virus, vaccination against human papillomavirus, vaccination against Streptococcus pneumoniae and vaccination against influenza virus, making a total of 18 recommendations, structured by question, based on the evidence found for the different SARD and/or expert consensus. CONCLUSIONS: There is enough evidence on the safety and efficacy of vaccinations and other prophylactic measures against the microorganisms reviewed in this document to specifically recommend them for patients with SARD.

Recommendations for prevention of infection in systemic autoimmune rheumatic diseases. / Recomendaciones SER sobre prevención de infección en enfermedades reumáticas autoinmunes sistémicas.

OBJECTIVES: To develop recommendations for the prevention of infection in adult patients with systemic autoimmune rheumatic diseases (SARD). METHODS: Clinical research questions relevant to the objective of the document were identified by a panel of experts selected based on their experience in the field. Systematic reviews of the available evidence were conducted, and evidence was graded according to the Scottish Intercollegiate Guidelines Network criteria. Specific recommendations were made. RESULTS: Five questions were selected, referring to prevention of infection by Pneumocystis jirovecii with trimethoprim/sulfamethoxazole, primary and secondary prophylactic measures against hepatitis B virus, vaccination against human papillomavirus, vaccination against Streptococcus pneumoniae and vaccination against influenza virus, making a total of 18 recommendations, structured by question, based on the evidence found for the different SARD and/or expert consensus. CONCLUSIONS: There is enough evidence on the safety and efficacy of vaccinations and other prophylactic measures against the microorganisms reviewed in this document to specifically recommend them for patients with SARD.

Relevance of gastrointestinal manifestations in a large Spanish cohort of patients with systemic lupus erythematosus: what do we know?

OBJECTIVE: SLE can affect any part of the gastrointestinal (GI) tract. GI symptoms are reported to occur in >50% of SLE patients. To describe the GI manifestations of SLE in the RELESSER (Registry of SLE Patients of the Spanish Society of Rheumatology) cohort and to determine whether these are associated with a more severe disease, damage accrual and a worse prognosis. METHODS: We conducted a nationwide, retrospective, multicentre, cross-sectional cohort study of 3658 SLE patients who fulfil ≥4 ACR-97 criteria. Data on demographics, disease characteristics, activity (SLEDAI-2K or BILAG), damage (SLICC/ACR/DI) and therapies were collected. Demographic and clinical characteristics were compared between lupus patients with and without GI damage to establish whether GI damage is associated with a more severe disease. RESULTS: From 3654 lupus patients, 3.7% developed GI damage. Patients in this group (group 1) were older, they had longer disease duration, and were more likely to have vasculitis, renal disease and serositis than patients without GI damage (group 2). Hospitalizations and mortality were significantly higher in group 1. Patients in group 1 had higher modified SDI (SLICC Damage Index). The presence of oral ulcers reduced the risk of developing damage in 33% of patients. CONCLUSION: Having GI damage is associated with a worse prognosis. Patients on a high dose of glucocorticoids are at higher risk of developing GI damage which reinforces the strategy of minimizing glucocorticoids. Oral ulcers appear to decrease the risk of GI damage.

Higher Prevalence and Degree of Insulin Resistance in Patients With Rheumatoid Arthritis Than in Patients With Systemic Lupus Erythematosus.

OBJECTIVE: Since insulin resistance (IR) is highly prevalent in patients with systemic lupus erythematosus (SLE) and rheumatoid arthritis (RA), we aimed to determine whether differences in IR exist between the two conditions. METHODS: We conducted a cross-sectional study comprising 413 subjects without diabetes (186 with SLE and 227 with RA). Glucose, insulin, and C-peptide serum levels, as well as IR by the homeostatic model assessment (HOMA2) were studied. A multivariable regression analysis was performed to evaluate the differences in IR indexes between patients with SLE and RA, as well as to determine if IR risk factors or disease-related characteristics are differentially associated with IR in both populations. RESULTS: The insulin:C-peptide molar ratio was upregulated in patients with RA compared to patients with SLE (ß 0.009, 95% CI 0.005-0.014, P < 0.001) after multivariable analysis. HOMA2 indexes related to insulin sensitivity (HOMA2-%S) were found to be lower (ß -27, 95% CI -46 to -9, P = 0.004) and ß cell function (HOMA2-%B) showed higher IR indexes (ß 38, 95% CI 23-52, P < 0.001) in RA than in SLE patients after multivariable analysis. Patients with RA more often fulfilled the definition of IR than those with SLE (OR 2.15, 95% CI 1.25-3.69, P = 0.005). The size effect of IR factors on IR indexes was found to be equal in both diseases. CONCLUSION: IR sensitivity is lower and ß cell function is higher in RA than in SLE patients. The fact that traditional IR factors have an equal effect on IR in both SLE and RA supports the contention that these differences are related to the diseases themselves.

Differences in Capacity of High-Density Lipoprotein Cholesterol Efflux Between Patients With Systemic Lupus Erythematosus and Rheumatoid Arthritis.

OBJECTIVE: Cholesterol efflux capacity (CEC) is the ability of high-density lipoprotein (HDL) cholesterol to accept cholesterol from macrophages. Lipid profiles and CEC appear to be altered in patients with systemic lupus erythematosus (SLE) and rheumatoid arthritis (RA) due to disease activity and inflammation. CEC has been linked to cardiovascular events in the general population and to subclinical atherosclerosis in SLE and RA patients. The aim of this study was to establish whether CEC varies between patients with SLE and those with RA. METHODS: The study encompassed 460 individuals (195 SLE patients and 265 patients with RA). CEC (using an in vitro assay) and concentrations of lipoprotein serum were assessed in both populations. A multivariable regression analysis was performed to study whether CEC differs between SLE patients and RA patients. RESULTS: Comparison of lipid patterns revealed that patients with RA have lower HDL cholesterol and higher apolipoprotein B serum levels than SLE patients. CEC was downregulated in SLE patients compared to patients with RA (ß -12 [95% confidence interval -13, -10], P < 0.001). It occurred independently of traditional cardiovascular risk factors, statin use, disease-related data, and other variations in the lipid profile related to the diseases. CONCLUSION: Patients with RA have a more proatherogenic lipid pattern compared to those with SLE. However, CEC seems to be more damaged in SLE patients than in RA patients.

Proprotein convertase subtilisin/kexin type 9 is related to disease activity and damage in patients with systemic erythematosus lupus.

BACKGROUND: Proprotein convertase subtilisin/kexin type 9 (PCSK9) is a serine protease that regulates cholesterol metabolism through low-density lipoprotein receptor degradation and that has been linked to cardiovascular (CV) disease. The purpose of the present study was to examine whether PCSK9 levels are disrupted compared with controls in patients with systemic lupus erythematosus (SLE). We additionally sought to establish whether PCSK9 is related to both the abnormalities in the lipid profile and to the disease activity or damage of patients with SLE. METHODS: We performed a cross-sectional study that encompassed 366 individuals: 195 SLE patients and 171 age-, sex-, and statin intake-matched controls. PCSK9, lipoproteins serum concentrations, and lipid profiles were assessed in patients and controls. A multivariable analysis, adjusted for standard CV risk factors, was performed to evaluate the role of PCSK9 in SLE-related dyslipidemia. RESULTS: Most lipid related-molecules were decreased in patients with SLE compared with controls. This downregulation included PCSK9, with PCSK9 levels being lower in patients than controls in the full multivariable analysis, including the modifications in lipid profiles that the disease itself produces {beta coefficient -73 [95% confidence interval (CI) -91 to -54] ng/ml, p ⩽ 0.001}. Both SLICC and SLEDAI scores were independently and positively related to PCSK9. Patients currently on hydroxychloroquine exhibited decreased levels of PCSK9 compared with those that were not taking hydroxychloroquine [beta coefficient -30 (95% CI -54 to -6) ng/ml, p = 0.015]. CONCLUSION: PCSK9 is downregulated in SLE compared with controls, but SLE patients with higher disease activity and damage exhibited higher PSCK9 serum levels.

Impaired HDL cholesterol efflux capacity in systemic lupus erythematosus patients is related to subclinical carotid atherosclerosis.

OBJECTIVES: Lipid profiles appear to be altered in SLE patients due to disease activity and inflammation. Cholesterol efflux capacity (CEC) is the ability of high-density lipoprotein cholesterol to accept cholesterol from macrophages. CEC has been linked to cardiovascular events in the general population and is impaired in SLE patients. The aim of this study was to establish whether CEC is related to subclinical carotid atherosclerosis in SLE patients. METHODS: The present report is of a cross-sectional study that encompassed 418 individuals: 195 SLE patients and 223 controls. CEC, using an in vitro assay, and lipoprotein serum concentrations were assessed in patients and controls. Carotid intima-media thickness and carotid plaques were evaluated in SLE patients. A multivariable analysis was performed to study the relationship of CEC to SLE-related data, lipid profile and subclinical carotid atherosclerosis. RESULTS: CEC was downregulated in SLE patients [8.1 (4.2) % vs 16.9 (10.4) %, P = 0.004). This occurred independently of traditional cardiovascular risk factors, statin use or other variations in the lipid profile related to the disease. Traditional cardiovascular risk factors, both in patients and controls, and SLE-related data such as activity, severity or damage were not associated with CEC. After multivariable regression analysis including lipid profile-related molecules, CEC was inversely and independently associated with the presence of carotid plaques in SLE patients [odds ratio 0.87 (95% CI: 0.78, 0.97), P = 0.014]. CONCLUSION: CEC is impaired in SLE patients independently of other inflammation-related lipid profile modifications that occur during the disease. CEC is associated with carotid plaques in SLE patients.

Comparable effects of traditional cardiovascular risk factors on subclinical atherosclerosis in systemic lupus erythematosus and rheumatoid arthritis.

OBJECTIVES: Patients with rheumatoid arthritis (RA) or systemic lupus erythematosus (SLE) have an increased premature prevalence of atherosclerosis. We aimed to determine whether there are differences in the prevalence of classic cardiovascular risk factors between SLE and RA. We also analysed the effect of traditional cardiovascular risk factors on the development of subclinical atherosclerosis in both conditions and if some disease-characteristic features are associated with these traditional cardiovascular risk factors. METHODS: This was a cross-sectional study encompassing 602 individuals, 276 SLE and 326 RA patients. Subclinical atherosclerosis (presence of carotid plaques and carotid intima-media thickness [cIMT]) was determined by carotid ultrasonography. A multivariable regression analysis was performed to evaluate whether classic cardiovascular-related risk factors differentially influence subclinical carotid atherosclerosis in SLE compared to RA patients. RESULTS: Age (interaction factor [if] p=0.000), hypertension (if p=0.034), and diabetes (if p=0.037) had a higher effect on cIMT in RA than in SLE subjects. However, these traditional cardiovascular factors did not yield different effects on the presence of carotid plaques in RA and SLE when the univariate interaction was analysed. In addition, no differences were found in the influence of hypertension, diabetes, dyslipidaemia or current smoking on cIMT or carotid plaque after adjusting for demographics, the presence of other traditional cardiovascular factors, and disease-related data. Moreover, the additive effect of several cardiovascular risk factors on the subclinical carotid atherosclerosis did not differ between the two diseases. CONCLUSIONS: The influence of traditional cardiovascular risk factors on cIMT and carotid plaque is similar in RA and SLE.

Immunotherapy, Cancer and Rheumatological Diseases: A Review of the Literature and a Series of Cases in a University Hospital. / Inmunoterapia, cáncer y enfermedades reumatológicas: revisión de la literatura y serie de casos en un hospital universitario.

The appearance in the field of oncology of therapeutic molecules in the form of monoclonal antibodies, whose objective is to stimulate the patient's own immune system to be responsible for destroying cancer cells, has revolutionized the treatment of many cancers in recent years. This type of therapy, called immunotherapy, is also characterized by presenting side effects in the form of autoimmune diseases that we are still beginning to understand. From the point of view of the immune-mediated rheumatological side effects, we can find musculoskeletal manifestations, mechanical, inflammatory or systemic autoimmune diseases. The therapeutic approach to these side effects remains uncertain due to the absence of clinical trials and validated recommendations. The multidisciplinary management is crucial to successfully treat such cases. In the following manuscript, we will describe our case reports of rheumatologic immune-related adverse events in a university hospital.

Can we validate a clinical score to predict the risk of severe infection in patients with systemic lupus erythematosus? A longitudinal retrospective study in a British Cohort.

OBJECTIVE: Severe infections are a major cause of morbidity and mortality in patients with systemic lupus erythematosus (SLE). Our primary objective was to use data from a large Spanish cohort to develop a risk score for severe infection in SLE, the SLE Severe Infection Score (SLESIS) and to validate SLESIS in a separate cohort of 699 British patients. DESIGN AND SETTING: Retrospective longitudinal study in a specialist tertiary care clinic in London, UK. PARTICIPANTS: Patients fulfilling international classification criteria for SLE (n=209). This included 98 patients who had suffered severe infections (defined as infection leading to hospitalisation and/or death) and 111 randomly selected patients who had never suffered severe infections. OUTCOMES: We retrospectively calculated SLESIS at diagnosis for all 209 patients. For the infection cases we also calculated SLESIS just prior to infection and compared it to SLESIS in 98 controls matched for disease duration. We carried out receiver operator characteristic (ROC) analysis to quantify predictive value of SLESIS for severe infection. RESULTS: Median SLESIS (IQR) at diagnosis was higher in the infection group than in the control group (4.27 (3.18) vs 2.55 (3.79), p=0.0008). Median SLESIS prior to infection was higher than at diagnosis (6.64 vs 4.27, p<0.001). In ROC analysis, predictive value of SLESIS just before the infection (area under the curve (AUC)=0.79) was higher than that of SLESIS at diagnosis (AUC=0.63). CONCLUSIONS: We validated the association of SLESIS with severe infection in an independent cohort. Calculation of SLESIS at each clinic visit may help in management of infection risk in patients with SLE. Prospective studies are needed to confirm these findings.

Red cell distribution width correlates with fatigue levels in a diverse group of patients with systemic lupus erythematosus irrespective of anaemia status.

OBJECTIVES: Fatigue remains a debilitating feature of systemic lupus erythematosus (SLE). Although in some cases this may be the result of intercurrent fibromyalgia, mood disorder or untreated metabolic syndrome, in many cases the cause is unclear. The aim of this study was to investigate the relationship between fatigue and red cell distribution width (RDW), a measure of variability in erythrocyte size and volume. METHODS: A total of 225 patients were recruited from three clinics in England and Australia. Patients completed the Functional Assessment of Chronic Illness Therapy (FACIT) Fatigue Score or 12-item Short Form survey (SF-12) to measure fatigue, which was compared with RDW and haemoglobin. In a subgroup of 72 patients, markers of disease activity were also assessed for correlation with fatigue using univariate and multivariate analysis with fatigue as the dependent variable. RESULTS: In all three groups, significant correlations between fatigue and RDW were observed (p<0.001; p=0.02; p<0.001 respectively) and this was preserved in multivariate analysis. There was no correlation between fatigue and haemoglobin in two groups (with the correlation between RDW and fatigue remaining significant in non-anaemic patients in the third group). In subgroup analysis, fatigue was not associated with any measures of disease activity. CONCLUSIONS: We report a reproducible, statistically significant association between RDW and fatigue levels in a diverse population of patients with SLE. The findings of this study raise the possibility of a potential novel biological basis for fatigue in those in whom there is a lack of an alternate explanation.

Effect of IL-6 Receptor Blockade on Proprotein Convertase Subtilisin/Kexin Type-9 and Cholesterol Efflux Capacity in Rheumatoid Arthritis Patients.

The aim of the work was to examine whether abnormalities in the lipid profile that tocilizumab (TCZ), an anti-IL-6 receptor Ab, exerts in rheumatoid arthritis (RA) patients is related to changes in either proprotein convertase subtilisin/kexin-9 (PCSK9) serum concentrations or in serum cholesterol efflux capacity (CEC). TOCRIVAR is a one-year prospective clinical trial that analyzes the influence of TCZ on cardiovascular risk factors. Twenty-seven RA patients receiving TCZ (8 mg/kg IV/q4w) were assessed at baseline and weeks 12, 24, and 52. Disease activity indexes, adiposity composition, physical activity, serum CEC, PCSK9, and lipoproteins serum concentrations were assessed at every visit. Basal high-sensitivity C-reactive protein (hs-CRP) and disease activity were markedly reduced throughout one-year TCZ treatment. While initially total cholesterol and LDL cholesterol increased their plasma concentration, decreasing to basal afterwards, lipoprotein(a) was significantly lower than basal in all visits of the study. CEC increased after 24 week of treatment proportionally to hs-CRP reduction, and remained significantly higher after week 52 [median % change 32 (3-141), p=0.021]. Interestingly, variations in LDL cholesterol basal concentration along the one year of TCZ treatment correlated directly with changes of PCSK9 serum concentration (r=0.37, p=0.003). Basal abdominal adiposity, BMI, and physical activity remained stable during the study. Long-term TCZ-treated RA patients show an increment in CEC inversely proportional to hs-CRP reduction and changes in LDL cholesterol that might be explained, at least in part, by variations in PCSK9 plasma concentration. Overall, TCZ treatment produces a favorable qualitative net effect in terms of atherogenic implication in RA patients.

Disease Damage Influences Cardiovascular Risk Reclassification Based on Carotid Ultrasound in Patients with Systemic Lupus Erythematosus.

OBJECTIVE: Composite scores of cardiovascular (CV) risk factors underestimate the CV risk in patients with systemic lupus erythematosus (SLE). Carotid artery ultrasound (US) was found useful in identifying high CV-risk patients with inflammatory arthritis. We assessed the effect of carotid US assessments on the CV risk stratification of patients with SLE. METHODS: This cross-sectional study included 276 patients with SLE. These indices were measured: lipid profile, Systematic COronary Risk Evaluation (SCORE) risk calculation, and disease activity (SLE Disease Activity Index), severity (Katz), and damage [Systemic Lupus International Collaborating Clinics (SLICC)/American College of Rheumatology Damage Index]. Carotid plaques were assessed by US. A multivariable regression analysis, adjusted for classic CV-related factors, was performed to evaluate how risk reclassification was influenced by disease characteristics in patients with SLE. RESULTS: Thirty-six percent of patients had carotid plaques. However, only 6% of them fulfilled the definitions for high or very high risk according to the SCORE risk charts. Following carotid US assessment, 32% of the patients were reclassified as very high risk. Disease duration (OR 1.04, 95% CI 1.00-1.07, p = 0.025) and a SLICC > 0 (OR 2.48 95% CI 1.15-5.34, p = 0.020) were independently associated with a higher risk of reclassification. A predictive model for reclassification included age (cutoff 52 yrs, sensitivity 60%, specificity 86%), disease duration (cutoff 24 yrs, sensitivity 40%, specificity 82%), presence of hypertension, SLICC > 0, waist circumference (cutoff 102 cm, sensitivity 48%, specificity 84%), and C3 (cutoff 127 mg/dl, sensitivity 52%, specificity 92%) and triglyceride (cutoff 140 mg/dl, sensitivity 68%, specificity 79%) serum levels. CONCLUSION: Reclassification into a very high-risk category is frequent after carotid US assessments in patients with SLE. This is independently influenced by disease damage.

Implication of CXCL5 (epithelial neutrophil-activating peptide 78) in the development of insulin resistance in patients with rheumatoid arthritis.

OBJECTIVES: The chemokine molecule CXCL5 (C-X-C motif chemokine ligand 5, also known as epithelial neutrophil activating peptide 78 -ENA78-) constitutes a link between obesity, inflammation and insulin resistance (IR) in the general population. CXCL5 has also been found to play a role in rheumatoid arthritis (RA) pathogenesis. Since chronic inflammation promotes IR and impairs pancreatic beta cell function in RA patients, we assessed the role of CXCL5 in the development of IR in RA. METHODS: Cross-sectional study that encompassed 141 non-diabetic patients with RA. IR assessed by homeostatic model assessment (HOMA2), insulin and C-peptide serum levels and lipid profile, and CXCL5 serum levels were studied. Regression analysis was performed to evaluate how CXCL5 was related to IR, disease activity, and disease characteristics in RA patients. RESULTS: HOMA2-IR indexes showed high values for both IR and beta cell production (%B), and low insulin sensitivity (%S) in patients with RA. C reactive protein (beta coef. 0.2 [95%CI -1.5-1.9], p=0.80) and disease activity through DAS28 (beta coef. 13 [95%CI -14-41], p=0.34) revealed no relation with CXCL5. Other disease characteristics, such as disease duration, serological status, or use of methotrexate or anti-TNF alpha therapies, were not associated with CXCL5 serum levels. While glucocorticoids were related to insulin, C-peptide serum levels, and HOMA2-IR and HOMA2-%B-C peptide, the use of prednisone was not associated with CXCL5 serum levels. Insulin and C peptide serum levels and IR indexes showed strong correlations among each other, but not with CXCL5 (insulin r2=-0.034, p=0.69; C peptide r2=-0.050, p=0.56). CONCLUSIONS: CXCL5 is not related to IR in RA patients. Therefore, the mechanisms leading to IR in patients with RA may be different from those in the general population.

Relationship Between Insulin Sensitivity and ß-Cell Secretion in Nondiabetic Subjects with Rheumatoid Arthritis.

OBJECTIVE: In nondiabetic healthy individuals, insulin secretion and sensitivity are linked by a negative feedback loop characterized by a hyperbolic function. We aimed to study the association of traditional insulin resistance (IR) factors with insulin secretion and sensitivity, and to determine whether the hyperbolic equilibrium of this relation is preserved in patients with rheumatoid arthritis (RA). METHODS: This was a cross-sectional study encompassing 361 nondiabetic individuals: 151 with RA and 210 controls. Insulin, C-peptide, and IR indices by homeostatic model (HOMA2) were assessed. A multivariable analysis was performed to evaluate the differences in the correlation of traditional IR-related factors with glucose homeostasis molecules, as well as IR indices between patients and controls. Nonlinear regression analysis was used to assess the hyperbolic relation of insulin sensitivity and secretion. RESULTS: HOMA2-IR indices were higher in patients with RA than controls. Hepatic insulin extraction, as assessed by the insulin:C-peptide molar ratio, was lower in patients with RA after multivariable analysis (0.08 ± 0.02 vs 0.14 ± 0.07, p < 0.001). Traditional IR-related factors showed significantly lower adjusted correlation coefficients with IR indices in patients with RA. The association between insulin sensitivity and secretion showed a different hyperbolic relation in patients with RA: the variability explained by the curve was lower in RA (nonlinear r2 = 0.845 vs r2 = 0.928, p = 0.001) and ß coefficients (-0.74, 95% CI -0.77 to -0.70 vs -1.09, 95% CI -1.17 to -1.02, ng/ml, p < 0.001) were different in RA. CONCLUSION: The traditional factors associated with IR in healthy individuals are less related to IR in patients with RA. Insulin sensitivity and secretion yield a different hyperbolic equilibrium in RA.

Amylin in the insulin resistance of patients with rheumatoid arthritis.

OBJECTIVES: Amylin, which is co-secreted with insulin, plays a role in glycemic regulation and is impaired in type 2 diabetes. In the present study we assess, for the first time, the implication of amylin in the development of insulin resistance (IR) in rheumatoid arthritis (RA). METHODS: This was a cross-sectional study involving 361 non-diabetic individuals, 151 patients with RA and 210 sex-matched controls. Insulin, C-peptide, amylin, lipoprotein serum concentrations, and IR indexes by homeostatic model assessment (HOMA2) were evaluated in patients and controls. A multivariable analysis, adjusted for IR-related factors, was performed to determine the differences between patients and controls vis-à-vis amylin and how it is related to IR in RA. RESULTS: Insulin, C-peptide and HOMA2-IR indexes were higher in RA patients than in controls. Amylin serum levels were found to be upregulated in RA patients compared to controls (1.36 ± 0.81 vs. 1.79 ± 1.51 ng/ml, p=0.011), although this difference was lost after adjusting for covariates (p=0.46). While amylin positively correlated with the presence of rheumatoid factor (beta coef. 0.90 [95%CI -0.23-1.56], p=0.009) and SDAI (beta coef 0.01 [95%CI 0.00-0.03], p=0.034), no significant association with other disease activity scores, glucocorticoid intake, methotrexate use or TNF-alpha inhibitors was found. CONCLUSIONS: IR in RA does not appear to be mediated by amylin. This would imply that the mechanisms associated with IR in RA patients differ from those at work in type 2 diabetes.

Incretins in patients with rheumatoid arthritis.

BACKGROUND: The precise mechanism linking systemic inflammation with insulin resistance (IR) in rheumatoid arthritis (RA) remains elusive. In the present study, we determined whether the incretin-insulin axis and incretin effect are disrupted in patients with RA and if they are related to the IR found in these patients. METHODS: We conducted a cross-sectional study that encompassed 361 subjects without diabetes, 151 patients with RA, and 210 sex-matched control subjects. Insulin, C-peptide, glucagon-like peptide-1 (GLP-1), gastric inhibitory polypeptide (GIP), dipeptidyl peptidase 4 (DPP-4) soluble form, and IR indexes by homeostatic model assessment (HOMA2) were assessed. A multivariable analysis adjusted for IR-related factors was performed. Additionally, ten patients and ten control subjects underwent a 566-kcal meal test so that we could further study the postprandial differences of these molecules between patients and control subjects. RESULTS: Insulin, C-peptide, and HOMA2-IR indexes were higher in patients than in control subjects. This was also the case for GLP-1 (0.49 ± 1.28 vs. 0.71 ± 0.22 ng/ml, p = 0.000) and GIP (0.37 ± 0.40 vs. 1.78 ± 0.51 ng/ml, p = 0.000). These differences remained significant after multivariable adjustment including glucocorticoid intake. Disease Activity Score in 28 joints with erythrocyte sedimentation rate (ß coefficient 46, 95% CI 6-87, p = 0.026) and Clinical Disease Activity Index (ß coefficient 7.74, 95% CI 1.29-14.20, p = 0.019) were associated with DPP-4 serum levels. GLP-1 positively correlated with ß-cell function (HOMA2 of ß-cell production calculated with C-peptide) in patients but not in control subjects (interaction p = 0.003). The meal test in patients with RA revealed a higher total and late response AUC for glucose response, a later maximal response of C-peptide, and a flatter curve in GIP response. CONCLUSIONS: The incretin-insulin axis, both during fasting and postprandial, is impaired in patients with RA.