Sarcopenia May Be a Risk Factor for Osteoporosis in Chinese Patients with Rheumatoid Arthritis

Development and validation of a predictive model assessing the risk of sarcopenia in rheumatoid arthritis patients

Background

Sarcopenia is linked to an unfavorable prognosis in individuals with rheumatoid arthritis (RA). Early identification and treatment of sarcopenia are clinically significant. This study aimed to create and validate a nomogram for predicting sarcopenia risk in RA patients, providing clinicians with a reliable tool for the early identification of high-risk patients.

Methods

Patients with RA diagnosed between August 2022 and January 2024 were included and randomized into training and validation sets in a 7:3 ratio. Least Absolute Shrinkage and Selection Operator (LASSO) regression analysis and multifactorial logistic regression analysis were used to screen the risk variables for RA-associated muscle loss and to create an RA sarcopenia risk score. The predictive performance and clinical utility of the risk model were evaluated by plotting the receiver operating characteristic curve and calculating the area under the curve (AUC), along with the calibration curve and clinical decision curve (DCA).

Results

A total of 480 patients with RA were included in the study (90% female, with the largest number in the 45-59 age group, about 50%). In this study, four variables (body mass index, disease duration, hemoglobin, and grip strength) were included to construct a nomogram for predicting RA sarcopenia. The training and validation set AUCs were 0.915 (95% CI: 0.8795-0.9498) and 0.907 (95% CI: 0.8552-0.9597), respectively, proving that the predictive model was well discriminated. The calibration curve showed that the predicted values of the model were basically in line with the actual values, demonstrating good calibration. The DCA indicated that almost the entire range of patients with RA can benefit from this novel prediction model, suggesting good clinical utility.

Conclusion

This study developed and validated a nomogram prediction model to predict the risk of sarcopenia in RA patients. The model can assist clinicians in enhancing their ability to screen for RA sarcopenia, assess patient prognosis, make early decisions, and improve the quality of life for RA patients.

Risk Factors and Clinical Outcomes Associated With Sarcopenia in Rheumatoid Arthritis: A Systematic Review and Meta-analysis

ABSTRACT

Sarcopenia is underrecognized in patients with rheumatoid arthritis (RA). Risk factors of sarcopenia and its impact on outcomes in RA patients are relatively unknown. We conducted a systematic review to identify factors and outcomes associated with sarcopenia in RA. We conducted this review according to PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) 2020 guidelines. We searched PubMed, Embase, CINAHL, and Web of Science databases by combining the following search concepts: (1) RA and (2) sarcopenia. Articles were included if they included RA patients, assessed for sarcopenia using a consensus working group definition, and assessed for clinical outcomes. Meta-analysis was performed using studies that shared the same sarcopenia definition and consistency in reporting patient or disease variables. Our search identified 3602 articles. After removal of duplicates, title and abstract screen, and full-text review, 16 articles were included for final analysis. All studies had observational study designs. The pooled prevalence of sarcopenia ranged from 24% to 30%, depending on the criteria for sarcopenia used. Factors associated with sarcopenia included higher 28-joint Disease Activity Scale scores (+0.39; 95% confidence interval, +0.02 to +0.77) and baseline methotrexate use (odds ratio, 0.70; 95% confidence interval, 0.51-0.97). Baseline glucocorticoid use had a positive correlation with sarcopenia in multiple studies. Several studies found lower bone mineral density and higher incidence of falls and fractures in patients with sarcopenia. Sarcopenia is prevalent in RA, and it may be associated with higher RA disease activity, lower bone mineral density, and increased falls and fractures. Therefore, early screening of sarcopenia in RA patients is important to incorporate into clinical rheumatology practice.

Adipokines in Rheumatoid Arthritis: Emerging Biomarkers and Therapeutic Targets

Rheumatoid arthritis (RA) is a chronic inflammatory disease manifested by joint involvement, extra-articular manifestations, and general symptoms. Adipose tissue, previously perceived as an inert energy storage organ, has been recognised as a significant contributor to RA pathophysiology. Adipokines modulate immune responses, inflammation, and metabolic pathways in RA. Although most adipokines have a pro-inflammatory and aggravating effect on RA, some could counteract this pathological process. The coexistence of RA and sarcopenic obesity (SO) has gained attention due to its impact on disease severity and outcomes. Sarcopenic obesity further contributes to the inflammatory milieu and metabolic disturbances. Recent research has highlighted the intricate crosstalk between adipose tissue and skeletal muscle, suggesting potential interactions between these tissues in RA. This review summarizes the roles of adipokines in RA, particularly in inflammation, immune modulation, and joint destruction. In addition, it explores the emerging role of adipomyokines, specifically irisin and myostatin, in the pathogenesis of RA and their potential as therapeutic targets. We discuss the therapeutic implications of targeting adipokines and adipomyokines in RA management and highlight the challenges and future directions for research in this field.

Frequency of osteoporosis in Chinese patients with rheumatoid arthritis: a meta-analysis

OBJECTIVE

To evaluate the current frequency of osteoporosis (OP) in Chinese patients with rheumatoid arthritis (RA) through meta-analysis.

METHODS

The databases of PubMed, Web of Science, Cochrane Library, CNKI, Wan Fang, CBM, and VIP were searched for relevant literature regarding the occurrence of OP in Chinese patients with RA from January 1, 2000, to September 15, 2022. The literature was screened using inclusion and exclusion criteria, and qualifying articles were subjected to data extraction, quality evaluation, and meta-analysis using Stata 17.0 software.

RESULTS

Altogether, 44 publications were included in this study, with a total sample size of 12,264 RA cases and 4532 patients with OP. Meta-analysis revealed that the frequency of OP in patients with RA was 37.67% [95% CI: 34.38%, 40.97%], while subgroup analysis showed that the frequency in South China was 49.43% [95% CI: 40.53%, 58.32%]. Also, the frequency in men was 29.29% [95% CI: 22.42%, 36.16%], which was significantly lower than in women (41.89% [95% CI: 36.87%, 46.90%]). The incidence rate in pre-menopausal women was only 15.19% [95% CI: 8.79%, 21.59%], much lower than the figure of 54.29% [95% CI: 45.28%, 63.30%] for post-menopausal women. Additionally, the frequency rates in the low, intermediate, and high disease activity groups were 24.52% [95% CI: 11.52%, 37.52%)], 27.67% [95% CI: 13.50%, 41.85%], and 57.96% [95% CI: 37.35%, 78.56%], respectively.

CONCLUSION

The frequency of OP in the Chinese RA population is higher than the world average, and patients with RA should receive standardized anti-RA therapy at an early stage, with emphasis on bone health in postmenopausal women, patients with high disease activity or longer disease duration.

Mechanisms of Systemic Osteoporosis in Rheumatoid Arthritis

Rheumatoid arthritis (RA), an autoimmune disease, is characterized by the presence of symmetric polyarthritis predominantly of the small joints that leads to severe cartilage and bone destruction. Based on animal and human data, the pathophysiology of osteoporosis, a frequent comorbidity in conjunction with RA, was delineated. Autoimmune inflammatory processes, which lead to a systemic upregulation of inflammatory and osteoclastogenic cytokines, the production of autoantibodies, and Th cell senescence with a presumed disability to control the systemic immune system's and osteoclastogenic status, may play important roles in the pathophysiology of osteoporosis in RA. Consequently, osteoclast activity increases, osteoblast function decreases and bone metabolic and mechanical properties deteriorate. Although a number of disease-modifying drugs to treat joint inflammation are available, data on the ability of these drugs to prevent fragility fractures are limited. Thus, specific treatment of osteoporosis should be considered in patients with RA and an associated increased risk of fragility fractures.

The effect of disease-modifying anti-rheumatic drugs on skeletal muscle mass in rheumatoid arthritis patients: a systematic review with meta-analysis

INTRODUCTION

Rheumatoid arthritis (RA) is an autoimmune disease, characterized by chronic and systemic inflammation. Besides, it is known that RA patients may present several comorbidities, such as sarcopenia, a condition where patients present both muscle mass and muscle quality impairment. RA treatment is mostly pharmacological and consists in controlling systemic inflammation and disease activity. Despite that, the effect of pharmacological treatment on sarcopenia is not well characterized.

OBJECTIVE

To summarize the effects of disease-modifying anti-rheumatic drugs (DMARDs) on skeletal muscle tissue in rheumatoid arthritis (RA) patients.

METHODS

A systematic review of randomized clinical trials and observational studies was conducted using MEDLINE, Embase, Cochrane Library, and Web of Science. We selected studies with rheumatoid arthritis patients treated with disease-modifying anti-rheumatic drugs (DMARDs) that analyzed muscle mass parameters such as lean mass and appendicular lean mass. Methodological quality was assessed using the Newcastle-Ottawa Quality Assessment Scale. Standardized mean difference (SMD) and 95% confidence intervals (CI) were set. A meta-analysis of observational studies was performed using the R software, and we considered significant statistics when p < 0.05.

RESULTS

Nine studies were included in this systematic review. In the meta-analysis, DMARD treatment had no positive difference (p = 0.60) in lean mass. In the same way, in the appendicular lean mass parameter, our results showed that DMARDs did not have changes between baseline and post-treatment analysis (p = 0.93).

CONCLUSION

There is no evidence of a significant effect of DMARD therapy, either synthetic or biological, on muscle mass. However, this association should be investigated with more studies.