Current and emerging therapies for rheumatoid arthritis, with a focus on infliximab: clinical impact on joint damage and cost of care in canada.

BACKGROUND: Rheumatoid arthritis (RA) is a physically debilitating disease that places an enormous burden not only on individuals and their families but also on the economy. Affecting -1% of the Canadian population, RA is characterized by pain and swelling of joints. Without effective treatment, RA results in joint destruction that often requires surgery. OBJECTIVE: This review summarizes the effect of current and new RA treatments on joint damage, with a focus on infliximab. The health-economic repercussions and potential impact of arresting the joint destruction of RA are discussed. METHODS: Information for inclusion in this review was identified through searches of the MEDLINE and HealthStar databases from 1995 to 2000. Search terms included rheumatoid arthritis, treatment guidelines, economics, and individual drug names. RESULTS: Standard initial RA drug therapy has been aimed at reducing pain and inflammation, whereas use of the more potent disease-modifying antirheumatic drugs (DMARDs) has been reserved for later stages of disease. More aggressive RA treatment involves introducing DMARDs at the earliest stage. The largest single direct cost of RA involves hospital admissions for the correction of joint deformities. Among newer therapies, the anti-tumor necrosis factor-alpha agent infliximab has been shown to arrest radiographic measures of disease progression. CONCLUSIONS: With early and aggressive treatment involving new drugs and drug combinations, it may be possible to ameliorate the physical, social, and economic effects of RA.     

Etanercept in psoriatic arthritis

Psoriatic arthritis (PsA), an inflammatory arthritis associated with psoriasis, can lead to disability from progressive joint destruction and bony fusion. To date, conventional disease modifying antirheumatic drugs (DMARDS) have not convincingly lessened joint pain and inflammation in PsA and there is very little data on the limitation of radiographic progression with these agents. The biological agent etanercept (Enbrel^TM, Amgen, Inc, Thousand Oaks, California, USA) is a soluble TNF receptor fusion protein with proven efficacy in the treatment of rheumatoid arthritis (RA). In a Phase II and Phase III trial, conducted in moderate-to-severe PsA, etanercept significantly reduced joint pain and swelling and lowered the erythrocyte sedimentation rate (ESR) and C-reactive protein (CRP) level. A significant decline in structural damage was observed as early as 6 months after starting the drug. Etanercept also improved quality of life measures (Health Assesment Questionnaire [HAQ] and global assessment scores). Up to a third of patients experienced transient injection-site reactions. Rare cases of opportunistic infection, demyelinating disorders and aplastic anaemia have been reported, but a causal link has not been established. In summary, etanercept is a safe and effective agent for the treatment of PsA and represents a major advance in the therapy of this potentially crippling disease.     

Etanercept in psoriatic arthritis

Psoriatic arthritis (PsA), an inflammatory arthritis associated with psoriasis, can lead to disability from progressive joint destruction and bony fusion. To date, conventional disease modifying antirheumatic drugs (DMARDS) have not convincingly lessened joint pain and inflammation in PsA and there is very little data on the limitation of radiographic progression with these agents. The biological agent etanercept (Enbrel, Amgen, Inc, Thousand Oaks, California, USA) is a soluble TNF receptor fusion protein with proven efficacy in the treatment of rheumatoid arthritis (RA). In a Phase II and Phase III trial, conducted in moderate-to-severe PsA, etanercept significantly reduced joint pain and swelling and lowered the erythrocyte sedimentation rate (ESR) and C-reactive protein (CRP) level. A significant decline in structural damage was observed as early as 6 months after starting the drug. Etanercept also improved quality of life measures (Health Assesment Questionnaire [HAQ] and global assessment scores). Up to a third of patients experienced transient injection-site reactions. Rare cases of opportunistic infection, demyelinating disorders and aplastic anaemia have been reported, but a causal link has not been established. In summary, etanercept is a safe and effective agent for the treatment of PsA and represents a major advance in the therapy of this potentially crippling disease.     

Somatosensory perception and function of diffuse noxious inhibitory controls (DNIC) in patients suffering from rheumatoid arthritis.

The purpose was to investigate the influence of ongoing pain from an inflammatory nociceptive pain with two different disease durations on somatosensory functions and the effect of heterotopic noxious conditioning stimulation (HNCS) on 'diffuse noxious inhibitory controls' (DNIC) related mechanisms. Eleven patients with rheumatoid arthritis of a short duration (<1 year) (RA1), and 10 patients with rheumatoid arthritis of longer duration (>5 years) (RA5) as well as 21 age- and sex-matched healthy controls participated. Pressure pain sensitivity, low threshold mechanoreceptive function and thermal sensitivity, including thermal pain, were assessed over a painful and inflamed joint as well as in a pain-free area, i.e. the right thigh before HNCS (cold-pressor test) and repeated at the thigh only during and following HNCS. In RA1 and RA5 allodynia to pressure was seen over the joint (p<0.02 and p<0.001 respectively) in conjunction with hypoaesthesia to light touch (p<0.02) and hyperaesthesia to innocuous cold (p<0.05) in RA5. At the thigh, allodynia to pressure was found in RA5 (p<0.002). During HNCS, the sensitivity to pressure pain decreased in patients and controls alike (p<0.001). In conclusion, over an inflamed joint allodynia to pressure was found in both RA groups, with additional sensory abnormalities in RA5. In a non-painful area, allodynia to pressure was found in RA5, suggesting altered central processing of somatosensory functions in RA5 patients. The response to HNCS was similar in both RA groups and controls, indicating preserved function of DNIC-related mechanisms.     

Increased expression of blood mononuclear cell nitric oxide synthase type 2 in rheumatoid arthritis patients

Nitric oxide (NO) is an important inflammatory mediator in nonhuman animal models of rheumatoid arthritis (RA). The purpose of the present study was to determine whether blood mononuclear cells from patients with active RA (as compared to control subjects) have higher levels of NO synthase type 2 (NOS2) and produce more NO in vitro. Leukocytes from 25 RA patients and 20 normal subjects were examined. Arthritis activity was assessed by tender and swollen joint counts, duration of morning stiffness, patient assessment of pain, physician and patient global assessment of disease activity, the modified Stanford Health Assessment Questionnaire, and by blood levels of acute phase reactants. Blood mononuclear cell NOS enzyme activity/antigen content and nitrite/nitrate formation in vitro were measured. Blood mononuclear cells from RA patients had increased NOS activity and increased NOS2 antigen content as compared to those from normal subjects, and responded to interferon-gamma with increased NOS expression and nitrite/nitrate production in vitro. NOS activity of freshly isolated blood mononuclear cells correlated significantly with disease activity, as assessed by render and swollen joint counts. Our results demonstrate that patients with RA have systemic activation for NOS2 expression, and that the degree of activation correlates with disease activity. Increased NOS2 expression and NO generation may be important in the pathogenesis of RA.     

Advancement in contemporary diagnostic and therapeutic approaches for rheumatoid arthritis

This review is intended to provide a summary of the pathogenesis, diagnosis and therapies for rheumatoid arthritis. Rheumatoid arthritis (RA) is a common form of inflammatory autoimmune disease with unknown aetiology. Bone degradation, cartilage and synovial destruction are three major pathways of RA pathology. Sentinel cells includes dendritic cells, macrophages and mast cells bound with the auto antigens and initiate the inflammation of the joints. Those cells further activates the immune cells on synovial membrane by releasing inflammatory cytokines Interleukin 1, 6, 17, etc., Diagnosis of this disease is a combinational approach comprises radiological imaging, blood and serology markers assessment. The treatment of RA still remain inadequate due to the lack of knowledge in disease development. Non-steroidal anti-inflammatory drugs, disease modifying anti rheumatic drugs and corticosteroid are the commercial drugs to reduce pain, swelling and suppressing several disease factors. Arthroscopy will be an useful method while severe degradation of joint tissues. Gene therapy is a major advancement in RA. Suppressor gene locus of inflammatory mediators and matrix degrading enzymes were inserted into the affected area to reduce the disease progression. To overcome the issues aroused from those therapies like side effects and expenses, phytocompounds have been investigated and certain compounds are proved for their anti-arthritic potential. Furthermore certain complementary alternative therapies like yoga, acupuncture, massage therapy and tai chi have also been proved for their capability in RA treatment.     

Anti-citrulline antibodies in the diagnosis and prognosis of rheumatoid arthritis: evolving concepts

Citrulline is a non-standard amino acid that can be incorporated into proteins only by post-translational modification of arginine by peptidylarginine deiminase (PAD) enzymes during a variety of biologic processes, including inflammation. Rheumatoid arthritis (RA) is an inflammatory autoimmune disease, with a prevalence of 0.3 to 1% worldwide, which leads to progressive joint erosion and substantial disability if not treated early. A reliable and specific test for a marker present early in the disease would be useful to identify RA patients prior to the occurrence of joint damage. A new group of autoantibodies, the anti-cyclic citrullinated peptide antibodies (anti-CCP), can be detected in up to 80% of patients with RA, are highly specific for the disease, and may be of value for both the diagnosis and the prognosis of RA. The fact that these antibodies may appear before the onset of the disease suggests a potential role in primary prevention. Interestingly, they may also play a role in the pathophysiology of this disabling disease. The process of citrullination, its physiologic role, and citrullination-related pathologies, as well as the use of anti-citrullinated protein antibody tests (ACPA) for the early diagnosis and prognosis of RA and their potential role in the pathophysiology of the disease, are discussed.     

Rheumatoid arthritis and osteoporosis: trends in their treatments

Rheumatoid arthritis (RA) is a systemic autoimmune disease characterized by chronic synovitis and bone damages, which consist of joint destruction and systemic osteoporosis. During the pathological process, pro-inflammatory cytokines such as TNF-alpha are largely produced from inflamed synovium and cause activation of osteoclasts deviated from bone remodeling cycle, resulting in joint destruction. On the other side, systemic osteoporosis, mainly caused by glucocorticoid (GC) is often complicated in RA, in which GC decreases number of osteoblasts, reduces synthesis of bone matrix proteins from them and enhances bone resorption, resulting in impairment of bone remodeling. Thus, joint destruction and systemic osteoporosis are brought about by different mechanisms. However, recent treatment strategies have improved managements of RA-related joint destruction as well as GC-induced osteoporosis. Treatments using biologics including infliximab and etanercept, effective for treating RA disease activity, also reduce joint destruction. Also, bisphosphonate is well known to be effective for not only treatment but also prevention of GC-induced osteoporosis. Thus, it is a clinical trend that physicians treat joint destruction as an inflammatory disease and osteoporosis as a metabolic disease.     

Infliximab for the treatment of early rheumatoid arthritis

Rheumatoid arthritis (RA) is a systemic, chronic inflammatory disease characterised predominately by polyarthritis with frequent progression to permanent joint damage and disability. Evidence shows that starting treatment with disease-modifying antirheumatic drug (DMARD) therapy early in the course of disease can slow radiographic progression of RA compared with a more delayed approach. Moreover, in the early stages of RA, treatment with a combination of methotrexate (MTX), a traditional DMARD, and a biologic with tumour necrosis factor (TNF)-alpha blocking activity has proven to be more effective than using MTX alone. Among the approved TNF-alpha inhibitors, infliximab is a chimeric monoclonal antibody with high affinity and specificity for its target cytokine. It binds to soluble TNF monomers and trimers, as well as membrane-bound TNF-alpha, forming a stable complex which prevents TNF-alpha from binding to its receptor and triggering a biological response. The combination of MTX and infliximab therapy has shown superior clinical outcomes compared with MTX monotherapy in early RA, as well as greater protection against joint damage and physical disability. Although infliximab therapy has been associated with side effects, including serious infections, this drug can be administered with an acceptable margin of safety for several years by appropriate selection of patients, screening for latent and active tuberculosis, and monitoring of patients for infection and other toxicities. The knowledge of the benefits of infliximab therapy for early RA affords groundwork for developing more effective treatment strategies that can minimise disease progression over the long term.     

Anakinra: review of recombinant human interleukin-I receptor antagonist in the treatment of rheumatoid arthritis

BACKGROUND: Interleukin-1 (IL-1) plays an important role in the pathophysiology and progression of rheumatoid arthritis (RA) by contributing to destruction of cartilage, bone, and periarticular tissues. Inhibiting IL-1 synthesis or activity with the use of recombinant human IL-1 receptor antagonist (anakinra) may prove to be an effective approach to the treatment of RA. OBJECTIVE: The purpose of this article is to review the effects of anakinra in the treatment of RA. METHODS: A MEDLINE search from 1982 to 2003 was used to identify animal studies and randomized clinical trials of anakinra and other therapies that target IL-1. RESULTS: Clinical trials of anakinra have shown that it reduces the signs and symptoms of active disease and slows the rate of radiographic destruction in adults with RA. With anakinra 150 mg/d, 43% of patients achieved an American College of Rheumatology (ACR) 20% response, compared with 27% with placebo (P = 0.014). The ACR20 score indicates at least 20% improvement in the ACR composite score, which includes assessment of tender and swollen joint count, and other clinical end points such as pain and disability assessment. Patients treated with anakinra also experienced a 59% reduction in new bony erosion compared with controls (P < 0.001) and a 65% reduction in joint space narrowing as measured by the modified Sharp score (P = 0.020). Injection-site reactions were the most commonly reported adverse event, occurring in 50%, 73%, and 81% of patients receiving anakinra 30, 75, and 150 mg/d, respectively, compared with 25% of patients receiving placebo. Few serious adverse events were reported, and they typically occurred in patients receiving the highest daily dosage. CONCLUSIONS: IL-1 is an important cytokine in promoting the damage associated with RA. Anakinra is mildly to moderately effective and well tolerated in patients with active RA when used as monotherapy or in combination with methotrexate.     

A cross-cultural study of pain intensity in Egyptian and Dutch women with rheumatoid arthritis.

It has been suggested that patients from Mediterranean cultures tend to report more intense pain than their Northern or Western European counterparts in comparable medical conditions. However, empirical data to support this hypothesis are limited. The goals of the present study were to examine differences in pain intensity reports between Dutch and Egyptian women with rheumatoid arthritis (RA) and to examine the influence of possible confounding variables using multivariate analyses. We performed a cross-sectional study in 30 Dutch and 42 Egyptian women with comparable RA, matched for age and disease duration. Pain intensity was measured on a 100-mm graphic rating scale. Additionally, we assessed physical function, radiographic joint damage, progression of RA, disease activity, number of swollen and tender joints, medication, rheumatoid factor, and socioeconomic variables. The progression of RA and radiographic damage were not significantly different between Egyptian and Dutch patients. However, the Egyptian population reported significantly worse pain and physical function and demonstrated higher disease activity. Multiple linear regression analysis showed that the country of residence and the number of tender and swollen joints were significant independent determinants of pain reports. The results provide some support for the idea that there are ethnocultural differences in pain reports between Egyptian and Dutch women with RA, although the mechanisms underlying these differences remain unclear. PERSPECTIVE: This article shows that after controlling for differences in demographic, socioeconomic, and clinical variables, Egyptian women with RA reported more pain than Dutch women with RA. Clinicians and investigators should recognize that cultural or ethnic factors may play an important role in patients' pain reports.     

Prolactin promotes cartilage survival and attenuates inflammation in inflammatory arthritis

Chondrocytes are the only cells in cartilage, and their death by apoptosis contributes to cartilage loss in inflammatory joint diseases, such as rheumatoid arthritis (RA). A putative therapeutic intervention for RA is the inhibition of apoptosis-mediated cartilage degradation. The hormone prolactin (PRL) frequently increases in the circulation of patients with RA, but the role of hyperprolactinemia in disease activity is unclear. Here, we demonstrate that PRL inhibits the apoptosis of cultured chondrocytes in response to a mixture of proinflammatory cytokines (TNF-α, IL-1β, and IFN-γ) by preventing the induction of p53 and decreasing the BAX/BCL-2 ratio through a NO-independent, JAK2/STAT3–dependent pathway. Local treatment with PRL or increasing PRL circulating levels also prevented chondrocyte apoptosis evoked by injecting cytokines into the knee joints of rats, whereas the proapoptotic effect of cytokines was enhanced in PRL receptor–null (Prlr^–/–) mice. Moreover, eliciting hyperprolactinemia in rats before or after inducing the adjuvant model of inflammatory arthritis reduced chondrocyte apoptosis, proinflammatory cytokine expression, pannus formation, bone erosion, joint swelling, and pain. These results reveal the protective effect of PRL against inflammation-induced chondrocyte apoptosis and the therapeutic potential of hyperprolactinemia to reduce permanent joint damage and inflammation in RA.     

Characterization of the acute and persistent pain state present in K/BxN serum transfer arthritis

Rheumatoid arthritis (RA) is a chronic autoimmune arthritis that affects approximately 1% of the population. Synovial inflammation cannot fully explain the level of pain reported by patients and facilitation of pain processing at the spinal level has been implicated. We characterized the K/BxN serum transfer arthritis model as a model of joint inflammation-induced pain and examined pharmacologic responsiveness and spinal glia activation. Mechanical allodynia developed congruently with joint swelling. Surprisingly, allodynia persisted after resolution of inflammation. At the peak of joint inflammation (days 4-10), hypersensitivity was attenuated with i.p. etanercept, gabapentin, and ketorolac. Following resolution of synovial inflammation (days 19-23), only gabapentin relieved allodynia. The superficial dorsal horn of arthritic mice displayed increased staining of microglia at early and late time points, but astrocyte staining increased only during the inflammatory phase. ATF3, a marker of nerve injury, was significantly increased in the lumbar dorsal root ganglia during the late phase (day 28). Hence, serum transfer in the K/BxN serum transfer arthritis model produces a persistent pain state, where the allodynia during the inflammatory state is attenuated by TNF and prostaglandin inhibitors, and the pharmacology and histochemistry data suggest a transition from an inflammatory state to a state that resembles a neuropathic condition over time. Therefore, the K/BxN serum transfer model represents a multifaceted model for studies exploring pain mechanisms in conditions of joint inflammation and may serve as a platform for exploring novel treatment strategies for pain in human arthritic conditions.     

Window of opportunity for treatment of rheumatoid arthritis

Rheumatoid arthritis (RA) is an autoimmune disorder of unknown etiology characterized by symmetric, erosive synovitis. Joints become eroded in the first 2 years of early RA. But the subsequent course of radiological progression is highly variable and cannot be easily explained. Their disability correlates with signs and symptoms of inflammation and it correlates more closely with articular damage. TNF blockers (infliximab and etanercept) affect signs and symptoms as well as radiographic progression of RA. They are among the most effective therapies for RA. Early diagnosis and early appropriate treatment of RA are thought to be key to controlling progress of disease and preventing further joint and tissue damage. The concept of "window of opportunity" exists from the notion that early institution of therapy for RA is more effective in preventing joint damage, decreasing functional disability, and inducing clinical remission.     

Arthroscopic synovectomy in rheumatoid arthritis of wrist

The wrist is the most commonly involved region of the upper extremity in rheumatoid arthritis (RA). Because the wrist joint becomes involved early during the disease course and its involvement rapidly progresses, and because the disabilities associated with progressive RA are significant, early and adequate treatment must be introduced to prevent disease progression. Various treatment methods can be employed to treat RA wrists based on radiological and clinical findings. Arthroscopic synovectomy is recommended for pain relief and functional recovery in early stage RA, and is also helpful in advanced staged RA with Larsen stage III. However, arthroscopic synovectomy is not recommended as an effective method of treatment for all patients with advanced radiographic changes. Nevertheless, arthroscopic synovectomy may delay the need for complex surgery, such as wrist arthrodesis or total wrist arthroplasty in selective cases. Although arthroscopic synovectomy of the wrist cannot improve grip strength or range of motion, it can reduce wrist pain and improve function, and thus facilitate return to work.     

Direct, quantitative clinical assessment of hand function: usefulness and reproducibility

Methods of assessing functional impairment in arthritic hands include pain assessments and disability scoring scales which are subjective, variable over time and fail to take account of the patients' need to adapt to deformities. The aim of this study was to evaluate measures of functional strength and joint motion in the assessment of the rheumatoid (RA) and osteoarthritic (OA) hand. Ten control subjects, ten RA and ten OA patients were recruited for the study. All underwent pain and disability scoring and functional assessment of the hand using measures of pinch/grip strength and range of joint motion (ROM). Functional assessments including ROM analyses at interphalangeal (IP), metacarpophalangeal (MCP) and wrist joints along with pinch/grip strength clearly discriminated between patient groups (RA vs. OA MCP ROM P<0.0001), pain and disability scales were unable to. In the RA there were demonstrable relationships between ROM measurements and disability (R2=0.31) as well as disease duration (R2=0.37). Intra-patient measures of strength were robust whereas inter-patient comparisons showed variability. In conclusion, pinch/grip strength and ROM are clinically reproducible assessments that may more accurately reflect functional impairment associated with arthritis.     

Leflunomide, a novel immunomodulator for the treatment of active rheumatoid arthritis

Rheumatoid arthritis (RA) is a chronic disease affecting 0.8% of the population. Nonsteroidal anti-inflammatory drugs reduce the pain and inflammation of RA and improve mobility but do not slow the progression of joint damage. Disease-modifying antirheumatic drugs (DMARDs), which limit potentially irreversible joint damage, may influence the course of disease progression. This review describes the recently approved DMARD leflunomide, an isoxazole-based immunomodulator. Unlike other DMARDs, leflunomide arrests the growth of activated lymphocytes by inhibiting the enzyme dihydroorotate dehydrogenase, a critical link in the production of uridine monophosphate. Leflunomide is rapidly metabolized to the active major metabolite A77 1726, which is responsible for the drug's pharmacologic activity. Leflunomide has exerted inhibitory activity in animal models of RA. Its clinical efficacy has been demonstrated in a number of controlled trials. In two multinational 52-week studies and two 24-week studies, all leflunomide-treated patients received an initial loading dose of 100 mg for 3 days, followed by 20 mg/d. The effects on the signs and symptoms of RA were evaluated using the American College of Rheumatology (ACR) 20 responder index, tender and swollen joint counts and scores, patients' and physician's global assessments, and pain intensity index. Erosions and joint-space narrowing were assessed by radiography. Compared with placebo, leflunomide significantly improved the signs and symptoms of RA (41%-64% improvement) by ACR 20 responder criteria (P < 0.001). Leflunomide, methotrexate, and sulfasalazine were equally effective in terms of symptom outcomes. In terms of retarding the progression of disease, leflunomide was significantly superior to placebo, with no consistent difference from methotrexate or sulfasalazine. In a trial using a combination of leflunomide and methotrexate therapy, 53% of patients were responders by ACR 20 criteria. Adverse effects in RA patients receiving leflunomide included diarrhea, elevated liver enzymes, alopecia, and rash. Additional adverse events occurring with a frequency >5% included allergic reaction, asthenia, abdominal pain, back pain, and hypertension, among others. Thus leflunomide may be used in selected RA patients (ie, those starting RA therapy for the first time or failing earlier DMARD therapy). However, the product labeling requires monthly monitoring of liver enzymes until stable concentrations are reached. Other labeled warnings include a risk of immunosuppression and an increased risk of fetal death or teratogenic effects in pregnant women. Methotrexate, which is also hepatotoxic, is usually the initial DMARD recommended for use in patients with aggressive RA.     

Diagnosis and management of rheumatoid arthritis

Rheumatoid arthritis is the most commonly diagnosed systemic inflammatory arthritis. Women, smokers, and those with a family history of the disease are most often affected. Criteria for diagnosis include having at least one joint with definite swelling that is not explained by another disease. The likelihood of a rheumatoid arthritis diagnosis increases with the number of small joints involved. In a patient with inflammatory arthritis, the presence of a rheumatoid factor or anti-citrullinated protein antibody, or elevated C-reactive protein level or erythrocyte sedimentation rate suggests a diagnosis of rheumatoid arthritis. Initial laboratory evaluation should also include complete blood count with differential and assessment of renal and hepatic function. Patients taking biologic agents should be tested for hepatitis B, hepatitis C, and tuberculosis. Earlier diagnosis of rheumatoid arthritis allows for earlier treatment with disease-modifying antirheumatic agents. Combinations of medications are often used to control the disease. Methotrexate is typically the first-line drug for rheumatoid arthritis. Biologic agents, such as tumor necrosis factor inhibitors, are generally considered second-line agents or can be added for dual therapy. The goals of treatment include minimization of joint pain and swelling, prevention of radiographic damage and visible deformity, and continuation of work and personal activities. Joint replacement is indicated for patients with severe joint damage whose symptoms are poorly controlled by medical management.     

Predictors of functional disability in rheumatoid arthritis: results from a 13-year prospective study

Purpose. To explore the role of distress and social support as modifiers of functional disability in rheumatoid arthritis (RA). We hypothesized that: (a) higher inflammatory activity, more joint tenderness and more pain lead to more disability, and (b) that more distress and less social support lead to more disability and accelerate the disablement process by moderating the effects of inflammatory activity, joint tenderness and pain.

Methods. The study is a Dutch extension of the European Research on Incapacitating Diseases and Social Support (EURIDISS) which started with 292 patients. After five waves of data collection 129 still participated. Correlational and hierarchical regression analyses were performed.

Results. In short-term RA, 68% of the variance in disability could be explained primarily by mean disability over the prior years. Other important predictors were inflammatory activity and pain. In long-term RA, 56% of the variance in disability could be explained primarily by mean disability over the prior years. Other important predictors were joint tenderness and pain. No clear moderator effects of distress and social support were found in short-term or long-term RA.

Conclusions. The results confirm the main pathway from pathology to disability in short-term and long-term RA, but do not provide support for the influence of distress and social support on the disablement process.