Chronic inflammation and low-dose glucocorticoid effects on glucose metabolism in premenopausal females with rheumatoid arthritis free of conventional metabolic risk factors

The Use of Rheumatic Disease Comorbidity Index for Predicting Clinical Response and Retention Rate in a Cohort of Rheumatoid Arthritis Patients Receiving Tumor Necrosis Factor Alpha Inhibitors

Introduction

To retrospectively evaluate the impact of comorbidities on treatment choice, 12-month clinical response, and 24-month retention rate in a cohort of patients with rheumatoid arthritis (RA) treated with a first-line tumor necrosis factor alpha inhibitor (TNFi), by using for the first time the Rheumatic Disease Comorbidity Index (RDCI).

Methods

The study population was extracted from a local registry of RA patients receiving adalimumab or etanercept as first-line biologics between January 2001 and December 2013. The prevalence of comorbidities was computed, and patients were stratified according to RDCI for evaluating the role of comorbidities on TNFi choice, concomitant methotrexate, clinical response (1-year DAS28-ESR remission and low disease activity [LDA] and EULAR good-moderate response), and the 24-month retention rate.

Results

346 patients (172 adalimumab and 174 etanercept) were included. A significantly higher EULAR good/moderate response (P = 0.020) and DAS28-ESR remission (P = 0.003) were obtained according to RDCI (0, 1, 2, or ≥3). Lower RDCI (P = 0.022), male sex (P = 0.006), higher baseline DAS28-ESR (P = 0.001), ETN (P < 0.001), and concomitant methotrexate (P = 0.016) were predictors of EULAR good/moderate response. Elevated RDCI was a predictor of discontinuation of biologics (P = 0.036), whereas treatment with etanercept (P < 0.001) and methotrexate (P = 0.007) was associated with a lower risk of TNFi withdrawal.

Conclusions

Multimorbidity, measured by RDCI, is a negative predictor of TNFi persistence on treatment and of achieving a good clinical response. The use of RDCI may be very useful for identifying patients with RA carrying those comorbid conditions associated with poor prognostic outcomes and for defining new treatment targets in multimorbid RA patients.

Relationship Between Insulin Sensitivity and β-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 β 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.

Risk of Incident Diabetes Mellitus Associated With the Dosage and Duration of Oral Glucocorticoid Therapy in Patients With Rheumatoid Arthritis

Objective

To quantify the risk of incident diabetes mellitus (DM) associated with the dosage, duration, and timing of glucocorticoid (GC) use in patients with rheumatoid arthritis (RA).

Methods

We undertook a cohort study using 2 databases: a UK primary care database (the Clinical Practice Research Datalink [CPRD]) including 21,962 RA patients (1992–2009) and the US National Data Bank for Rheumatic Diseases (NDB) including 12,657 RA patients (1998–2013). Information on the dosage and timing of GC use was extracted. DM in the CPRD was defined using Read codes, at least 2 prescriptions for oral antidiabetic medication, or abnormal blood test results. DM in the NDB was defined through patient self‐reports. Data were analyzed using time‐dependent Cox models and a novel weighted cumulative dose (WCD) model that accounts for dosage, duration, and timing of treatment.

Results

The hazard ratio (HR) was 1.30 (95% confidence interval [95% CI] 1.17–1.45) and 1.61 (95% CI 1.37–1.89) in current GC users compared to nonusers in the CPRD and the NDB, respectively. A range of conventional statistical models consistently confirmed increases in risk with the GC dosage and duration. The WCD model showed that recent GC use contributed the most to the current risk of DM, while doses taken >6 months previously did not influence current risk. In the CPRD, 5 mg of prednisolone equivalent dose for the last 1, 3, and 6 months was significantly associated with HRs of 1.20, 1.43, and 1.48, respectively, compared to nonusers.

Conclusion

GC use is a clinically important and quantifiable risk factor for DM. Risk is influenced by the dosage and treatment duration, although only for GC use within the last 6 months.

Abnormal Glucose Metabolism in Rheumatoid Arthritis

The incidence of abnormal glucose metabolism in patients with rheumatoid arthritis was considerably higher than the general population. The persistent systemic inflammatory state in rheumatoid arthritis might be associated with the glucose metabolism dysfunction. In this context, insulin resistance, islet β cell apoptosis, inflammatory cytokines, and other aspects which were linked with abnormal glucose metabolism in rheumatoid arthritis were reviewed. This review will be helpful in understanding the abnormal glucose metabolism mechanism in patients with rheumatoid arthritis and might be conducive to finding an effective treatment.

Obesity is the main determinant of insulin resistance more than the circulating pro-inflammatory cytokines levels in rheumatoid arthritis patients

BACKGROUND

Systemic blockade of TNF-α in Rheumatoid arthritis with insulin resistance seems to produce more improvement in insulin sensitivity in normal weight patients with Rheumatoid arthritis than in obese patients with Rheumatoid arthritis, suggesting that systemic-inflammation and obesity are independent risk factors for insulin resistance in Rheumatoid arthritis patients.

OBJECTIVES

To evaluate the insulin resistance in: normal weight patients with Rheumatoid arthritis, overweight patients with Rheumatoid arthritis, obese Rheumatoid arthritis patients, and matched control subjects with normal weight and obesity; and its association with major cytokines involved in the pathogenesis of the disease.

METHODS

Assessments included: body mass index, insulin resistance by Homeostasis Model Assessment, ELISA method, and enzymatic colorimetric assay.

RESULTS

Outstanding results from these studies include: (1) In Rheumatoid arthritis patients, insulin resistance was well correlated with body mass index, but not with levels of serum cytokines. In fact, levels of cytokines were similar in all Rheumatoid arthritis patients, regardless of being obese, overweight or normal weight (2) Insulin resistance was significantly higher in Rheumatoid arthritis with normal weight than in normal weight (3) No significant difference was observed between insulin resistances of Rheumatoid arthritis with obesity and obesity (4) As expected, levels of circulating cytokines were significantly higher in Rheumatoid arthritis patients than in obesity.

CONCLUSIONS

Obesity appears to be a dominant condition above inflammation to produce IR in RA patients. The dissociation of the inflammation and obesity components to produce IR suggests the need of an independent therapeutic strategy in obese patients with RA.

Chronotherapy with low-dose modified-release prednisone for the management of rheumatoid arthritis: a review

To date, rheumatoid arthritis (RA) remains a debilitating, life-threatening disease. One major concern is morning symptoms (MS), as they considerably impair the patients’ quality of life and ability to work. MS change in a circadian fashion, resembling the fluctuations of inflammatory cytokines such as interleukin-6, whose levels are higher in RA patients compared to healthy donors. Conversely, serum levels of the potent anti-inflammatory glucocorticoid cortisol are similar to that of healthy subjects, suggesting an imbalance that sustains a pro-inflammatory state. From a therapeutic point of view, administering synthetic glucocorticoids (GCs) to RA patients represents an optimal strategy to provide for the inadequate levels of cortisol. Indeed, due to their high efficacy in RA, GCs remain a cornerstone more than 60 years after their first introduction, and despite the development of a wide range of targeted agents. However, to improve safety, low-dose GCs have been introduced, that have demonstrated high efficacy in reducing disease activity, radiological progression, and improving patients’ signs and symptoms especially in early RA when added to conventional disease-modifying antirheumatic drugs. A further improvement has been provided by the development of modified-release prednisone, which, by taking advantage of the circadian fluctuations of inflammatory cytokines, cortisol and MS, is given at bedtime to be released approximately 4 hours later. Several studies have already demonstrated the efficacy of this agent on disease activity, MS, and quality of life in the setting of established RA. Moreover, preliminary studies have shown that this new formulation not only has no impact on the adrenal function, but likely improves it. This review is a comprehensive, updated summary of the current evidence on the use of GCs in RA, with focus on the efficacy and safety of low-dose prednisone and modified-release prednisone, the latter representing a rational, cost-effective, and tailored approach to maximize the benefit/risk ratio in RA patients.

Influence of Insulin Resistance and TNF-α on the Inflammatory Process, Oxidative Stress, and Disease Activity in Patients with Rheumatoid Arthritis

The aim of this study was to evaluate the involvement of TNF-α and insulin resistance (IR) in the inflammatory process, oxidative stress, and disease activity in patients with rheumatoid arthritis (RA). This cross-sectional study included 270 subjects (control group, n = 97) and RA patients (n = 173). RA patients were divided into four groups: the first group without IR and not using antitumor necrosis factor-α (TNF−) (G1, IR− TNF−); the second group without IR and using anti-TNF-α (G2, IR− TNF+); the third group with IR and not using anti-TNF-α (G3, IR+ TNF−); and the fourth group with IR and using anti-TNF-α (G4, IR+ TNF+). G3 and G4 had higher (p < 0.05) advanced oxidation protein products (AOPPs) and oxidative stress index (OSI) compared to G1. G4 group presented higher (p < 0.05) AOPPs and OSI than G2. TRAP was significantly lower in G3 compared to G1. Plasma TNF-α levels were significantly higher in G4 and G2 compared to G1 (p < 0.0001) and G3 (p < 0.0001 and p < 0.01, resp.). The presence of insulin resistance was robustly associated with both oxidative stress and TNF-α levels. More studies are warranted to verify if IR can be involved in therapeutic failure with TNF-α inhibitors. This trial is registered with Brazilian Clinical Trials Registry Register number RBR-2jvj92.

A physiology-based model describing heterogeneity in glucose metabolism: the core of the Eindhoven Diabetes Education Simulator (E-DES)

Current diabetes education methods are costly, time-consuming, and do not actively engage the patient. Here, we describe the development and verification of the physiological model for healthy subjects that forms the basis of the Eindhoven Diabetes Education Simulator (E-DES). E-DES shall provide diabetes patients with an individualized virtual practice environment incorporating the main factors that influence glycemic control: food, exercise, and medication. The physiological model consists of 4 compartments for which the inflow and outflow of glucose and insulin are calculated using 6 nonlinear coupled differential equations and 14 parameters. These parameters are estimated on 12 sets of oral glucose tolerance test (OGTT) data (226 healthy subjects) obtained from literature. The resulting parameter set is verified on 8 separate literature OGTT data sets (229 subjects). The model is considered verified if 95% of the glucose data points lie within an acceptance range of ±20% of the corresponding model value. All glucose data points of the verification data sets lie within the predefined acceptance range. Physiological processes represented in the model include insulin resistance and β-cell function. Adjusting the corresponding parameters allows to describe heterogeneity in the data and shows the capabilities of this model for individualization. We have verified the physiological model of the E-DES for healthy subjects. Heterogeneity of the data has successfully been modeled by adjusting the 4 parameters describing insulin resistance and β-cell function. Our model will form the basis of a simulator providing individualized education on glucose control.

Adipose depots, not disease-related factors, account for skeletal muscle insulin sensitivity in established and treated rheumatoid arthritis

OBJECTIVE

In prior reports, individuals with rheumatoid arthritis (RA) exhibited increased insulin resistance. However, those studies were limited by either suboptimal assessment methods for insulin sensitivity or a failure to account for important determinants such as adiposity and lack of physical activity. Our objectives were to carefully assess, compare, and determine predictors of skeletal muscle insulin sensitivity in RA, accounting for adiposity and physical activity.

METHODS

Thirty-nine individuals with established (seropositive or erosions) and treated RA and 39 controls matched for age, sex, race, body mass index, and physical activity underwent a frequently sampled intravenous glucose tolerance test to determine insulin sensitivity. Inflammation, body composition, and physical activity were assessed with systemic cytokine measurements, computed tomography scans, and accelerometry, respectively. Exclusions were diabetes, cardiovascular disease, medication changes within 3 months, and prednisone use over 5 mg/day. This investigation was powered to detect a clinically significant, moderate effect size for insulin sensitivity difference.

RESULTS

Despite elevated systemic inflammation [interleukin (IL)-6, IL-18, tumor necrosis factor-α; p < 0.05 for all], persons with RA were not less insulin sensitive [SI geometric mean (SD): RA 4.0 (2.4) vs control 4.9 (2.1)*10(-5) min(-1)/(pmol/l); p = 0.39]. Except for visceral adiposity being slightly greater in controls (p = 0.03), there were no differences in body composition or physical activity. Lower insulin sensitivity was independently associated with increased abdominal and thigh adiposity, but not with cytokines, disease activity, duration, disability, or disease-modifying medication use.

CONCLUSION

In established and treated RA, traditional risk factors, specifically excess adiposity, play more of a role in predicting skeletal muscle insulin sensitivity than do systemic inflammation or other disease-related factors.