Association of High Anti-Cyclic Citrullinated Peptide Seropositivity and Lean Mass Index With Low Bone Mineral Density in Rheumatoid Arthritis

Methotrexate & rheumatoid arthritis associated atherosclerosis: A narrative review of multidisciplinary approach for risk modification by the international board of experts

Rheumatoid arthritis (RA) is an idiopathic, autoimmune connective tissue disorder that primarily affects the synovial joints, causing symmetric, erosive-deforming polyarthritis. It is also associated with extra-articular manifestations, particularly cardiovascular (CV) diseases (CVD). CV risk modification in RA remains unsolved despite recent advances in the management of RA. RA is an independent risk factor for atherosclerosis. RA and atherosclerosis share similar pathophysiological features (such as the pro-inflammatory cascade activation including interleukin-6) and risk factors (such as microflora dysbacteriosis and smoking). Patients with RA experience an exacerbation of atherogenesis, with atheromas destabilization, endothelial dysfunction, vasculitis, and hypercytokinemia. Consequently, the inflammatory response associated with RA is the basis for CVD development. The treat-to-target strategy not only improved RA control but also had a favorable effect on the morpho-functional state of the CV system in patients living with RA. Thus, disease-modifying antirheumatic drugs (DMARDs) - in particular methotrexate - may have a beneficial effect on the prevention of CV events in RA. It must be mentioned that RA is a serious multi-system disease, not only because of a window period during which the course of RA can be reversed, but also due to early damage to the heart and blood vessels. For this reason, a thorough cardiological assessment must be performed for all patients with RA, regardless of sex, age, disease stage, and disease activity score.

Interplay of Systemic Immune-Inflammation Index and Serum Klotho Levels: Unveiling a New Dimension in Rheumatoid Arthritis Pathology

Aim: The association between the systemic immune-inflammation index (SII) and serum Klotho concentrations (pg/ml) in patients with rheumatoid arthritis (RA) has not been elucidated. The purpose of this study was to clarify the relationship between the SII and serum Klotho concentrations in RA patients. Methods: All data come from the National Health and Nutrition Examination Survey (NHANES) database in the United States, which included 982 RA patients (age range: 40 to 79 years). The measurement data of the SII and serum Klotho are all from the NHANES mobile examination centre. We constructed a multivariate linear regression model to evaluate the association between the SII and serum Klotho levels in RA patients and conducted a subgroup analysis to test the stability of the statistical results. Results: Multivariate linear regression results indicated a negative linear relationship between the SII and serum Klotho concentrations in RA patients (β = -6.33, 95% CI [confidence interval]: -10.15 to -2.53). Compared to the quartile 1 group, the quartile 4 group was associated with significantly lower (P<0.001) serum Klotho concentrations (β = -120.93, 95% CI: -174.84 to -67.02). Compared with the quartile 1 group, with the increase in the SII, the β value showed a decreasing trend (P trend < 0.001). The subgroup analysis showed that none of the covariates affected the stability of these results (all P for interaction ≥ 0.05). Conclusion: There is a significant negative linear association between the SII and serum Klotho concentrations in RA patients. The SII can serve as a predictive indicator of serum Klotho concentrations in RA patients, and Klotho may be a potential anti-inflammatory target for RA treatment.

Risk factors for osteoporosis and fractures in rheumatoid arthritis

People with rheumatoid arthritis (RA) have both disease-specific risk factors for osteoporosis and fractures in addition to those that affect the general population. Disease specific risks include directly pathogenic auto-antibodies, chronic exposure to systemic inflammation, and joint damage causing early disability. Risk factors that affect the general population which may have a higher prevalence in RA include smoking, calcium and vitamin D deficiency as well as hypogonadism. Additionally, chronic exposure to glucocorticoids results in reduced bone mineral density and body composition changes which can further increase fracture risk. In this review we discuss these risk-factors for osteoporosis as well as factors that may impact fall and fracture risk in people with RA.

Pathomechanisms of bone loss in rheumatoid arthritis

Rheumatoid arthritis (RA) is an autoimmune disease, in which the inflammatory processes involve the skeletal system and there is marked destruction of the bones and the surrounding structures. In this review, we discuss the current concepts of osteoimmunology in RA, which represent the molecular crosstalk between the immune and skeletal systems, resulting in the disruption of bone remodeling. Bone loss in RA can be focal or generalized, leading to secondary osteoporosis. We have summarized the recent studies of bone loss in RA, which focused on the molecular aspects, such as cytokines, autoantibodies, receptor activator of nuclear kappa-β ligand (RANKL) and osteoprotegerin (OPG). Apart from the above molecules, the role of aryl hydrocarbon receptor (Ahr), which is a potential key mediator in this process through the generation of the Th17 cells, is discussed. Hence, this review highlights the key insights into molecular mechanisms of bone loss in RA.

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.

Personalized Therapeutic Strategies in the Management of Osteoporosis in Patients with Autoantibody-Positive Rheumatoid Arthritis

Bone mineral density (BMD) reduction and fragility fractures still represent a major source of morbidity in rheumatoid arthritis (RA) patients, despite adequate control of the disease. An increasing number of clinical and experimental evidence supports the role of autoantibodies, especially anti-citrullinated protein antibodies (ACPAs), in causing localized and generalised bone loss in ways that are both dependent on and independent of inflammation and disease activity. The human receptor activator of nuclear factor kappa B and its ligand—the so-called RANK-RANKL pathway—is known to play a key role in promoting osteoclasts’ activation and bone depletion, and RANKL levels were shown to be higher in ACPA-positive early untreated RA patients. Thus, ACPA-positivity can be considered a specific risk factor for systemic and periarticular bone loss. Through the inhibition of the RANK-RANKL system, denosumab is the only antiresorptive drug currently available that exhibits both a systemic anti-osteoporotic activity and a disease-modifying effect when combined with conventional synthetic or biologic disease-modifying anti-rheumatic drugs (DMARDs). Thus, the combination of DMARD and anti-RANKL therapy could be beneficial in the prevention of fragility fractures and structural damage in the subset of RA patients at risk of radiographic progression, as in the presence of ACPAs.

Low cumulative disease activity is associated with higher bone mineral density in a majority Latinx and Asian US rheumatoid arthritis cohort

OBJECTIVE

Prior studies have found conflicting results when evaluating the association between rheumatoid arthritis (RA) disease activity and bone mineral density (BMD). Whether or not cumulative RA disease activity is associated with BMD remains unanswered.

METHODS

Data were from the University of California San Francisco RA Cohort from years 2006-2018. Those with BMD measures and at least two study visits prior to BMD measure were included in the study. The association between low cumulative disease activity, as measured by DAS28ESR, with the primary outcome of femoral neck BMD was assessed using multivariable linear regression. Sensitivity analyses were performed substituting CDAI for the disease activity measure as well as total hip and lumbar spine BMD as outcomes.

RESULTS

161 participants with RA were studied. The cohort was 62.4 ± 10.2 years old and 88% female. Hispanic/Latino (N = 73, 45%) and Asian (N = 59, 37%) were the most common racial/ethnic groups in our cohort. Mean RA duration was 10.5 ± 7.3 years and 83% were ACPA positive. Low disease activity was independently associated with higher femoral neck BMD compared to the moderate/high disease activity group (β= 0.071 [95%CI: 0.021 to 0.122], p = 0.020). The relationship between low cumulative disease activity was similar when CDAI and other BMD sites were substituted in the multivariable models.

CONCLUSION

Low cumulative disease activity as measured by DAS28ESR was associated with higher femoral neck BMD, independent of traditional osteoporosis risk factors (e.g., age, sex, BMI) in a unique RA cohort. Results were similar when evaluating cumulative low CDAI and other BMD sites.

Impact of Anti-Citrullinated Protein Antibodies on Progressive Systemic Bone Mineral Density Loss in Patients With Early Rheumatoid Arthritis After Two Years of Treat-to-Target

Objectives

To investigate the association of anti-citrullinated protein antibodies (ACPA) with changes in systemic bone mineral density (BMD) in patients with early rheumatoid arthritis (RA) after two years of treat-to-target.

Methods

BMD was measured at the lumbar spine (LS) and femoral neck (FN) in 100 patients with recent onset RA at baseline and after 24 months of treatment aimed at low disease activity (LDA) according to the 28-joints disease activity score (DAS28 <3.2). Multivariable regression analyses were performed to determine independent associations between autoantibodies and other disease and treatment-related parameters with BMD loss.

Results

After 24 months, the majority of the patients were at least in LDA (78%), with slightly more ACPA-positive subjects achieving the target. The BMD had significantly decreased at both the LS (mean [SD] percent loss -1.8 [6.2], p=0.03) and the FN (-2.4 [7.3], p=0.03) in ACPA-positive but not in ACPA-negative patients. Consequently, the proportion of patients with reduced BMD (Z score ≤-1) after 24 months was significantly higher among ACPA-positive patients at both the spine (39.5% vs 19.3%, p=0.05) and the hip (37.2% vs 12.2%, p=0.007). The association between ACPA and BMD loss was independent of other variables including age, gender, disease activity, cumulative dose of glucocorticoids and duration of therapy with bisphosphonates at the LS but not the FN.

Conclusions

ACPA are associated with ongoing BMD loss at the spine despite suppression of inflammation and adoption of prophylactic measures. ACPA-positive RA patients should be therefore strictly monitored for the development of osteoporosis.

Association Between Bone Mineral Density and Autoantibodies in Patients With Rheumatoid Arthritis

Objective

Autoantibodies, such as anti–citrullinated protein antibodies (ACPAs), have been described as inducing bone loss in rheumatoid arthritis (RA), which can also be reflected by bone mineral density (BMD). We therefore examined the association between osteoporosis and autoantibodies in two independent RA cohorts.

Methods

Dual x‐ray absorptiometry (DXA) of the lumbar spine and left hip was performed in 408 Dutch patients with early RA during 5 years of follow‐up and in 198 Swedish patients with early RA during 10 years of follow‐up. The longitudinal effect of ACPAs and other autoantibodies on several BMD measures was assessed using generalized estimating equations.

Results

In the Dutch cohort, significantly lower BMD at baseline was observed in ACPA‐positive patients compared to ACPA‐negative patients, with an estimated marginal mean BMD in the left hip of 0.92 g/cm² (95% confidence interval [95% CI] 0.91–0.93) versus 0.95 g/cm² (95% CI 0.93–0.97) (P = 0.01). In line with this, significantly lower Z scores at baseline were noted in the ACPA‐positive group compared to the ACPA‐negative group (estimated marginal mean Z score in the left hip of 0.18 [95% CI 0.08–0.29] versus 0.48 [95% CI 0.33–0.63]) (P < 0.01). However, despite clear differences at baseline, ACPA positivity was not associated with greater decrease in absolute BMD or Z scores over time. Furthermore, there was no association between BMD and higher levels of ACPAs or other autoantibodies (rheumatoid factor and anti–carbamylated protein antibodies). In the Swedish cohort, ACPA‐positive patients tended to have a higher prevalence of osteopenia at baseline (P = 0.04), but again, ACPA positivity was not associated with an increased prevalence of osteopenia or osteoporosis over time.

Conclusion

The presence of ACPAs is associated with significantly lower BMD at baseline, but not with greater BMD loss over time in treated RA patients. These results suggest that ACPAs alone do not appear to contribute to bone loss after disease onset when disease activity is well‐managed.

Osteoporosis and fractures in rheumatoid arthritis

PURPOSE OF REVIEW

Rheumatoid arthritis (RA) is associated with increased risk for osteoporotic fracture. We highlight RA-specific risk factors for bone mineral density (BMD) loss and fractures and considerations regarding the diagnosis and treatment of osteoporosis in patients with RA.

RECENT FINDINGS

Anticitrullinated protein antibody (ACPA) positivity, although associated with low BMD in early RA, is not associated with accelerated BMD loss over time when compared to ACPA negative individuals. Studies have found reduced BMD in individuals on low doses of glucocorticoids (GCs). Poor functional status and frailty are additional important risk factors for low BMD and fractures. Heightened fracture risk in RA may be mitigated by tight disease control, and biologic therapies are associated with more stable BMD compared to nonbiologic therapies. Evidence-based guidelines specific for treating osteoporosis in patients with RA do not exist. Thus, treatment decisions are based on general osteoporosis guidelines, taking into account additional RA-specific risk factors.

SUMMARY

Recent studies have advanced knowledge of RA-specific risk factors for BMD loss and fractures. Future studies applying these findings to modify established fracture risk algorithms as well as evaluating osteoporosis treatments in RA cohorts are needed to reduce the risk of disabling fractures in these patients.

Establishment and verification of an osteoporosis risk model in patients with rheumatoid arthritis: a valuable new model

To establish a model for osteoporosis risk in patients with rheumatoid arthritis and validate the model. A newly generated predictive model has been suggested to have good differentiation, calibration, and clinical validity and may be a useful clinical model for predicting osteoporosis in patients with rheumatoid arthritis.

PURPOSE

To establish a prediction model for osteoporosis risk in patients with rheumatoid arthritis and validate the model internally and externally.

METHODS

A total of 270 patients with rheumatoid arthritis who underwent bone mineral density measurement at our hospital from June 2019 to June 2020 were enrolled in the study. The patients were divided into two groups according to their entry time: a training set containing the first 2/3 of the patients (n = 180) and a validation set containing the remaining 1/3 of the patients (n = 90). Binary logistic regression analysis was used to establish the regression models, and the concordance index (C-index), calibration plot, and decision curve analysis were used to evaluate the prediction model.

RESULTS

Five variables, including age (X1), course of disease (X2), the disease activity score using 28 joint counts (DAS28) (X4), anti-cyclic citrullinated peptide antibody (CCP) (X7), and 7-joint ultrasonic bone erosion (X14), were selected to enter the model. The prediction model is Logit Y = - 12.647 + 0.133X1 + 0.011X2 + 0.754X4 + 0.001X7 + 0.605X14. The model had good differentiation; the C-index in the internal verification was 0.947 (95% CI is 0.932-0.977) and the C-index in the external verification was 0.946 (95% CI is 0.940-0.994). The calibration plot of the model showed excellent consistency between the prediction probability and actual probability. When > 0.483 was taken as the cutoff value for the diagnosis of osteoporosis, the sensitivity, specificity, positive likelihood ratio, negative likelihood ratio, and Jordan index of the model were 90.24%, 87.76%, 7.37, 0.11, and 78.00%, respectively.

CONCLUSION

A newly generated predictive model has been suggested to have good differentiation, calibration, and clinical validity and may be a useful clinical model for predicting osteoporosis in patients with rheumatoid arthritis.

Sex differences in frailty and its association with low bone mineral density in rheumatoid arthritis

Objectives

Frailty in the general population is associated with poor health outcomes including low bone mass and osteoporotic fracture. The relationship between frailty and low bone mineral density (BMD) in rheumatoid arthritis (RA) is unknown. This study examined associations between frailty and BMD in RA, controlling for established osteoporosis risk factors.

Methods

We performed a cross-sectional analysis of a longitudinal RA cohort (n = 138; 117 female, 21 male). Participants fulfilled ACR RA classification criteria. Frailty was evaluated using the Fried Index, categorizing each participant as robust, pre-frail or frail. To identify independent predictors of BMD, we performed a multivariable linear regression analysis. Because risk factors for low BMD differ between sexes, we performed additional sex-stratified multivariable analyses.

Results

Mean age and disease duration were 58.0 ± 10.8 and 19 ± 10.9 years, respectively. The majority of participants were categorized as pre-frail (70%) or frail (10%). Females had higher rates of frailty than males. In the whole cohort, both pre-frail and frail had independent negative associations with BMD (β = −0.074 and −0.092 respectively, p < 0.05). In sex-stratified analyses, frailty did not have a significant association with BMD in females, but had a strong independent negative association in males (β = −0.247, p = 0.001).

Conclusion

Frailty was associated with BMD in patients with RA. Females had higher rates of frailty than males, yet frailty was independently associated with BMD in males but not in females. Frailty appears to be an important factor associated with low BMD; sex may influence this relationship in RA.

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Frailty was independently associated with lower femoral neck BMD in RA participants.

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Frailty was independently associated with lower BMD in males, not females.

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Of the frailty components, weakness had the strongest negative association with BMD.

Increased risk of osteoporotic vertebral fracture in rheumatoid arthritis patients with new-onset cardiovascular diseases: a retrospective nationwide cohort study in Taiwan

INTRODUCTION

Both cardiovascular diseases (CVD) and osteoporosis are common comorbidities in rheumatoid arthritis (RA) patients. Although accumulating evidence indicates a link between CVD and osteoporotic fracture, whether CVD contributes to osteoporotic fracture risk in RA has yet to be explored. We examined the incidence rate and risk factors of osteoporotic vertebral fracture in RA patients with new-onset CVD (RA-CVD) and evaluated the effects of medications on such fracture risk.

METHODS

A retrospective study was conducted using a nationwide database from 2000 to 2010: 1267 RA-CVD and 1267 non-CVD patients were enrolled from 30,507 patients with newly diagnosed RA. The main outcome was the development of osteoporotic vertebral fracture. After being adjusted for age, gender, and comorbidities, the Cox proportional hazard model was used to identify independent factors contributing to osteoporotic vertebral fracture.

RESULTS

The adjusted hazard ratio (aHR) of developing osteoporotic vertebral fracture was 1.47-fold greater in RA-CVD group than in non-CVD group (95% confidence interval 1.19-1.81, p < 0.001). Both the age above 40 years and female gender were significant risk factors for developing osteoporotic vertebral fracture in RA-CVD patients. Using patients not taking medication as a reference group, the aHR of osteoporotic vertebral fracture was significantly lower in those receiving statins (0.50), low-dose corticosteroids (0.57), or hydroxychloroquine (0.12).

CONCLUSIONS

The risk of osteoporotic vertebral fracture was significantly increased in RA-CVD patients, particularly women above 40 years of age, and could be reduced by statin therapy. However, the protective effect of low-dose corticosteroids or hydroxychloroquine on osteoporotic vertebral fracture risk needs further validation.

Distinct biomarkers for different bones in osteoporosis with rheumatoid arthritis

Background

Rheumatoid arthritis (RA) is known to cause secondary osteoporosis and fragility fractures. This study aimed to identify biomarkers predictive of bone mineral density (BMD) change at three anatomical sites in patients with RA.

Methods

We conducted a prospective longitudinal study in patients with RA. In 2012, we recruited 379 patients from an RA cohort, 329 of whom underwent evaluation of blood and urine biomarkers together with measurement of BMD in the lumbar spine, proximal femur, and distal forearm. The BMD in these three regions was reassessed in 2014. We performed multivariate linear regression analysis to identify those factors associated with BMD change.

Results

The averages of age, body mass index, and disease activity score in 28 joints (DAS28) at baseline were 63.2 (minimum to maximum, 32–85), 21.3 (12.3–30.0), and 3.2 (0.1–5.9), respectively. Univariate analysis showed that the annual BMD change was significantly associated with the use of steroid, bisphosphonate (BP) or vitamin D (VitD), and serum homocysteine in the lumber spine; DAS28, the use of BP or VitD, CRP, and anti-cyclic citrullinated peptide antibody (ACPA) in the proximal femur; and the dosage of MTX, the use of BP or VitD, and serum tartrate-resistant acid phosphatase 5b (TRACP-5b) in the distal forearm, respectively.

Conclusions

Predictive biomarkers for BMD change in RA patients differ at each anatomical site. Practitioners should treat each anatomical site with different markers and prescribe osteoporosis drugs to prevent fractures for RA patients.

Relationship between bone mineral density and anti-citrullinated protein antibody and rheumatoid factor in patients with rheumatoid arthritis

Objective

Rheumatoid arthritis (RA) is one of the causes of osteoporosis, and it leads to systemic bone loss. The anti-citrullinated protein antibody (ACPA) and rheumatoid factor (RF) are associated with local and systemic low bone mineral density and osteoclast-mediated bone resorption independently of inflammation in patients with RA. In this article, we aimed to evaluate the relationship between the ACPA, RF, and systemic bone mineral density in patients with RA.

Methods

Ninety-three patients (6 male, 87 female) with RA were included in the study. The disease activity score 28-erythrocyte sedimentation rate and titers of RF, ACPA, and bone mineral density of the total hip, femoral neck, and lumbar areas were evaluated. The independent samples t-test, Mann-Whitney U-test, Spearman’s correlation, and multivariable regression analysis were used for the statistical analysis.

Results

The RF and ACPA were positive in 40.9% and 48.4% of patients with RA, respectively. Disease activity was negatively correlated with the T- and Z-scores. The T- and Z-scores were lower in the seropositive group than in the seronegative group. The ACPA was negatively correlated with the T- and Z-scores of the femoral neck. There was a significant difference for the Z-score of the femoral neck in patients with ACPA and RF-positive patients compared to seronegative patients with RA.

Conclusion

A low bone mineral density, especially in the femoral neck, is associated with the presence of ACPA and RF. It would be a more appropriate approach to carefully monitor osteoporosis in seropositive RA patients.

Anti-citrullinated protein antibodies are associated with osteopenia but not with pain at diagnosis of rheumatoid arthritis: data from the BARFOT cohort

BACKGROUND

Anti-citrullinated protein antibodies (ACPA) have been suggested to have a potential role in both bone loss and pain in rheumatoid arthritis (RA), based on studies in vitro and in animal models. Here we addressed if anti-cyclic citrullinated (anti-CCP) antibodies were associated with osteopenia or pain in patients with RA, at the time for diagnosis.

METHODS

Baseline data from the BARFOT (Better Anti-Rheumatic PharmacOTherapy) cohort, which consists of patients with RA with a disease duration of 1 year or less, were analyzed. To be included, they should have been assessed by anti-CCP, dual-energy X-ray absorptiometry (DEXA) of lumbar spine and hip, and/or digital X-ray radiogrammetry (DXR) of the metacarpal bones. Osteopenia was defined as a z-score < - 1 SD. Pain VAS > 40 mm, was defined as patient unacceptable pain. Multiple logistic regression analyses were performed to assess whether anti-CCP was independently associated with osteopenia or unacceptable pain.

RESULTS

Of the 657 patients, 65% were women, 58% were anti-CCP positive, 37% had osteopenia in the lumbar spine, and 29% had osteopenia in the hip. Sixty-one percent had unacceptable pain at diagnosis. Patients positive for anti-CCP had significantly more frequently osteopenia in the femoral neck and Ward's triangle compared with anti-CCP-negative patients (p = 0.016 and 0.003, respectively). This difference was found in men at any anti-CCP titer, but in women, osteopenia in these hip locations was found only in those with high anti-CCP titers (> 500 IU/ml). Anti-CCP was not associated with osteopenia in the lumbar spine or the metacarpal bones. In multiple logistic regression analyses, anti-CCP was independently associated with osteopenia in the femoral neck and/or Ward's triangle but not with unacceptable pain. Instead, inflammatory variables were independently associated with unacceptable pain.

CONCLUSION

These data show that in patients with early RA, anti-CCP positivity was independently associated with osteopenia in the femoral neck and/or Ward, but not in the lumbar spine. In our patients, we could not confirm a recently suggested association between anti-CCP antibodies and pain. Further studies are necessary to explore the possible clinical relevance of interactions between ACPA, bone, and pain found in vitro and in animal models.

Association of high titers of anti-carbamylated protein antibodies with decreased bone mineral density in early arthritis patients

Rheumatoid arthritis (RA) has a negative impact on bone that is partly mediated by anti-citrullinated proteins antibodies (ACPA). These antibodies are associated with erosions, and with juxta-articular and systemic bone loss. Other RA autoantibodies, the anti-carbamylated protein antibodies (anti-CarPA), are independently associated with erosions. However, we do not know if they are also associated with juxta-articular and systemic bone loss. Here, we have addressed this question with data from 548 early arthritis (EA) patients. Bone mineral density (BMD) was assessed by dual-energy x-ray absorptiometry at the lumbar spine (LS), total hip (TH) and metacarpophalangeal joints (MCP). The 25.9% anti-CarPA positive patients did not show significant differences in BMD Z-scores with the negative patients. Nevertheless, this result was due to the similarity between negative and low-positive (below the median of the positive) patients, whereas the high-positive patients showed significant decrease of BMD at LS (β = -0.39, p = 0.01) and TH (β = -0.30, p = 0.02); but not at the juxta-articular bone of MCP. Given the overlap between anti-CarPA and ACPA, we included the two autoantibodies in an analysis that showed significantly lower BMD Z-scores at LS and TH (p< 0.01) only in the ACPA positive/anti-CarPA high-positive subgroup. However, the similar coefficients of regression between the ACPA positive/anti-CarPA high-positive and the ACPA negative/anti-CarPA high-positive subgroups (β = -0.50 vs. -0.52 at LS, and β = -0.37 vs. -0.30 at TH) suggested an independent association. Overall, these results support a contribution of anti-CarPA to systemic bone loss in EA patients.

Anti-CCP-positive patients with RA have a higher 10-year probability of fracture evaluated by FRAX®: a registry study of RA with osteoporosis/fracture

Background

Positive anticyclic citrullinated peptide (anti-CCP+) is associated with bone loss in patients with rheumatoid arthritis (RA). However, whether overall positivity or specific levels of anti-CCP are associated with prevalent fracture or a 10-year probability of fracture remains unclear.

Methods

This interim analysis of an RA registry was conducted at Chang Gung Memorial Hospital in Kaohsiung (CGMHK) for RA-related osteoporosis/fracture. Consecutive patients with RA who had visited the rheumatology clinic at CGMHK since September 1, 2014, and fulfilled the classification criteria of RA were enrolled. The demographics, disease duration, Disease activity in 28 joints based on erythrocyte sedimentation rate (DAS28-ESR), lifestyle, evidence of previous fracture, risk factors of fracture in the Fracture Risk Assessment Tool (FRAX®), and FRAX® score of each participant were collected. Anti-CCP, rheumatoid factor (RF), erythrocyte sedimentation rate (ESR), C-reactive protein (CRP), and bone mineral density (BMD) were measured at enrollment. The patients were grouped by positivity or quartiles of anti-CCP level (I–IV).

Results

Five hundred twenty-one patients with RA were enrolled through May 31, 2016. In total, 359 (68.9%) patients were anti-CCP+. Compared with anti-CCP− patients, anti-CCP+ patients had a significantly higher DAS28-ESR (p = 0.0001) and 10-year probability of major (15.0 [18.9] vs. 12.0 [15.3], p = 0.0461) or hip (5.0 [9.2] vs. 3.6 [8.2], p = 0.0118) fracture, but a significantly lower BMD of the FN (p = 0.0196). The rates of osteoporosis and previous fracture were comparable. There were 130, 127, 132, and 132 patients in groups I–IV, respectively. The DAS28-ESR was significantly different (p = 0.0001) among the groups and correlated to anti-CCP levels. The BMD and 10-year probability of major (p = 0.0067) and hip (p = 0.0013) fracture among the groups were also different.

Conclusions

Anti-CCP+ RA patients had a higher 10-year probability of major or hip fracture, independent of anti-CCP levels, and a lower BMD of the FN than anti-CCP− patients.