Objective. To determine whether patients with rheumatoid arthritis (RA) have an increased risk of fracture, and to estimate their long-term absolute fracture risk.Methods. We studied patients with RA ages >40 years in the British General Practice Research Database, each matched by age, sex, calendar time, and practice to 3 control patients. Incident fractures, as recorded in the computerized medical records, were ascertained over a median followup of 7.6 years. The fracture rate in RA patients compared with controls was adjusted for smoking, body mass index (BMI), and several clinical risk factors, and Cox proportional hazards models were used to calculate the relative risk (RR) of fracture in RA. A risk score was then developed to provide an estimate of the 5-and 10-year fracture risk among RA patients.Results. There were 30,262 patients with RA, of whom 2,460 experienced a fracture during followup. Compared with controls, patients with RA had an increased risk of fracture, which was most marked at the hip (RR 2.0, 95% confidence interval [95% CI] 1.8-2.3) and spine (RR 2.4, 95% CI 2.0-2.8). Indicators of a substantially elevated risk of fracture (at the hip) included >10 years' duration of RA (RR 3.4, 95% CI 3.0-3.9), low BMI (RR 3.9, 95% CI 3.1-4.9), and use of oral glucocorticoids (RR 3.4, 95% CI 3.0-4.0). Modeling of the long-term risk profiles revealed that, for example, in a woman age 65 years with longstanding RA whose risk factors also included low BMI, a history of fracture, and frequent use of oral glucocorticoids, the 5-year risk of hip fracture was 5.7% (95% CI 5.3-6.1%).Conclusion. Patients with RA are at increased risk of osteoporotic fractures. This increased risk is attributable to a combination of disease activity and use of oral glucocorticoids.

Patients with AS have an increased risk of clinical vertebral fracture but not of non-vertebral fractures, while the risk of any clinical fracture is increased in patients with concomitant inflammatory bowel disease. The mechanism by which non-steroidal anti-inflammatory drugs reduce the risk of any clinical fracture warrants further research.

Objective. The known risk factors for radiologic progression in rheumatoid arthritis (RA) are not optimally discriminative in patients with early disease who do not have evidence of radiologic damage. We sought to determine whether urinary C-terminal crosslinking telopeptide of type I (CTX-I) and type II (CTX-II) collagen (markers of bone and cartilage destruction, respectively) are associated with long-term radiologic progression in patients with early RA.Methods. This was a prospective study of 110 patients with early RA who were participating in the COBRA (Combinatietherapie Bij Reumatoïde Artritis) clinical trial and followup study, a randomized controlled trial comparing the efficacy of oral pulse prednisolone, methotrexate, plus sulfasalazine with sulfasalazine alone. We investigated the relationship between baseline levels of urinary CTX-I and CTX-II and the mean annual progression of joint destruction over a median of 4 years, as measured by changes in the modified Sharp score (average of 2 independent readers).Results. In multivariate logistic regression analysis, baseline urinary CTX-I and CTX-II levels in the highest tertile were the strongest predictors of radiologic progression (Sharp score increase >2 units/year; odds ratio 7.9 and 11.2, respectively), independently of treatment group, erythrocyte sedimentation rate (ESR), Disease Activity Score in 28 joints, rheumatoid factor (RF), and baseline joint damage (Sharp score). The likelihood ratios for a positive test were 3.8 and 8.0 for CTX-I and CTX-II, respectively, which compared favorably with the likelihood ratios for the ESR (3.0), baseline joint damage (1.6), and RF (1.8). When patients were grouped according to the presence (Sharp score >4, n ‫؍‬ 49) and absence (Sharp score <4, n ‫؍‬ 61) of joint damage at baseline, CTX-I and CTX-II levels were predictive only in those without baseline joint damage (odds ratio 14.9 and 25.7, respectively).Conclusion. High baseline levels of urinary CTX-I and CTX-II independently predict an increased risk of radiologic progression over 4 years in patients with early RA, especially those without radiologic joint damage. Urinary CTX-I and CTX-II may be useful for identifying individual RA patients at high risk of progression very early in the disease, before erosions can be detected radiographically. Such patients may be in special need of treatments that inhibit bone and cartilage degradation.

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Systemic osteoporosis and increased fracture rates have been described in chronic inflammatory diseases such as rheumatoid arthritis, spondyloarthritis, systemic lupus erythematosus, inflammatory bowel diseases, and chronic obstructive pulmonary disease. Most of these patients receive glucocorticoids, which have their own deleterious effects on bone. However, the other main determinant of bone fragility is the inflammation itself, as shown by the interactions between the inflammatory mediators, the actors of the immune system, and the bone remodelling. The inflammatory disease activity is thus on top of the other well-known osteoporotic risk factors in these patients. Optimal control of inflammation is part of the prevention of osteoporosis, and potent anti-inflammatory drugs have positive effects on surrogate markers of bone fragility. More data are needed to assess the anti-fracture efficacy of a tight control of inflammation in patients with a chronic inflammatory disorder. This review aimed at presenting different clinical aspects of inflammatory diseases which illustrate the relationships between inflammation and bone fragility.

The concept of osteoimmunology is based on growing insight into the links between the immune system and bone at the anatomical, vascular, cellular, and molecular levels. In both rheumatoid arthritis (RA) and ankylosing spondylitis (AS), bone is a target of inflammation. Activated immune cells at sites of inflammation produce a wide spectrum of cytokines in favor of increased bone resorption in RA and AS, resulting in bone erosions, osteitis, and peri-inflammatory and systemic bone loss. Peri-inflammatory bone formation is impaired in RA, resulting in non-healing of erosions, and this allows a local vicious circle of inflammation between synovitis, osteitis, and local bone loss. In contrast, peri-inflammatory bone formation is increased in AS, resulting in healing of erosions, ossifying enthesitis, and potential ankylosis of sacroiliac joints and intervertebral connections, and this changes the biomechanical competence of the spine. These changes in bone remodeling and structure contribute to the increased risk of vertebral fractures (in RA and AS) and non-vertebral fractures (in RA), and this risk is related to severity of disease and is independent of and superimposed on background fracture risk. Identifying patients who have RA and AS and are at high fracture risk and considering fracture prevention are, therefore, advocated in guidelines. Local peri-inflammatory bone loss and osteitis occur early and precede and predict erosive bone destruction in RA and AS and syndesmophytes in AS, which can occur despite clinically detectable inflammation (the so-called 'disconnection'). With the availability of new techniques to evaluate peri-inflammatory bone loss, osteitis, and erosions, peri-inflammatory bone changes are an exciting field for further research in the context of osteoimmunology.

Objective. Rheumatoid arthritis (RA) is a chronic inflammatory disease that may result in debilitating joint deformities with destruction of bone and cartilage. Inflammation is still considered the pivotal inducer of both components of joint damage. Results of recent animal studies suggested a prominent contribution of osteoclastic bone resorption that could be dissociated from inflammation. RANKL and its natural decoy receptor, osteoprotegerin (OPG), play key roles in osteoclast activation. In a group of patients with early RA not treated with disease-modifying drugs, we tested the hypothesis that osteoclast activation, reflected by the serum OPG:RANKL ratio at baseline, is negatively associated with progression of bone damage, independent of inflammation.Methods. OPG and RANKL levels, together with a parameter of inflammation (first-year time-averaged erythrocyte sedimentation rate [tESR]), were measured in 92 patients with newly diagnosed early active RA who were participants in a randomized study. The tESR and the OPG:RANKL ratio were evaluated for the ability to predict 5-year radiographic progression of joint damage.Results. The first-year tESR and the OPG: RANKL ratio, as measured at baseline, independently predicted 5-year radiographic progression of joint damage (both P < 0.001). Progression of radiographic damage was greatest in patients with a high tESR and a low OPG:RANKL ratio and was lowest in patients with a low tESR and a high OPG:RANKL ratio.Conclusion. This study in patients with early untreated RA is the first to confirm the findings in animal models of arthritis, that radiographic progression of the bone component of joint destruction is dependent on both inflammation (tESR) and osteoclast activation (the OPG:RANKL ratio).

Patients suffering from T cell mediated autoimmune diseases (AIDs) show immune abnormalities that resemble the typical characteristics of immune dysfunction described in the elderly. In addition, the incidence of AIDs increases with advancing age. To evaluate whether rheumatoid arthritis (RA) and multiple sclerosis (MS) patients have suffered from a premature immunosenescence, we measured two indicators of aging. The number of T cell receptor excision circles (TRECs) and the percentage of CD4+CD28 null T cells were studied in peripheral blood mononuclear cells (PBMC) of 60 RA patients, 32 MS patients and 40healthy controls (HC). TREC numbers were decreased in RA and MS patients as compared to age-matched HC indicating premature thymic involution. Moreover, a subset of these patients contained age-inappropriate high frequencies of CD4+CD28 null T cells. This study provides evidence of a premature senescence of the immune system in both RA and MS patients.Premature aging could be a risk factor for developing autoimmunity in genetically prone individuals in a susceptible environment.2