Prevalence, risk factors, and impact of knee pain suggesting osteoarthritis in Spain

OBJECTIVE

To estimate the point prevalence of knee pain suggesting osteoarthritis (OA) in the adult Spanish population. Secondary objectives were to examine the distribution of associated factors, as well as to assess the impact of knee pain on quality of life and function in the general population.

METHODS

A population survey was conducted in year 2000 for which 2,192 subjects over 20 years of age were selected by stratified polystage cluster sampling from the censuses of 20 towns. Trained rheumatologists administered structured interviews that permitted them to rule out the presence of rheumatic symptoms, and which included validated instruments to measure function and quality of life. We used the definition of clinical symptomatic knee OA of the American College of Rheumatology.

RESULTS

The estimated prevalence of knee pain suggesting OA in the general adult population is 10.2% (95% confidence interval: 7.9-12.5). Elderly women with fewer studies and from the lower social class, as well as those subjects involved in physically demanding jobs are more frequently affected. Obesity is also an important determinant for knee pain suggesting OA. Knee pain is associated to a significant decrease in functional ability and quality of life, even after adjustment for age, sex, and comorbidity.

CONCLUSION

The prevalence of knee pain suggesting OA in the general Spanish population is higher than expected, mainly related to a high rate of knee pain in women over 55. The proportion of very old persons and of those obese are important factors to take into account when comparing the rate of knee OA between populations.

Ultrasonographic assessment of inflammatory activity in rheumatoid arthritis: comparison of extended versus reduced joint evaluation

OBJECTIVE

To investigate the validity of reduced joint counts for ultrasonographic (US) assessment of joint inflammatory activity in patients with rheumatoid arthritis (RA).

METHODS

Ninety-four patients with RA were included. C-reactive protein (CRP) and erythrocyte sedimentation rate (ESR) levels were recorded for each patient. The presence of tenderness, swelling and a subjective swelling score from 0 to 3 were assessed by two rheumatologists who reached consensus in 60 joints examined in each patient. All patients underwent an US examination by a third blinded rheumatologist, using power Doppler (PD). US joint effusion, synovitis and PD signal were graded from 0 to 3 in the 60 joints. A 60-joint count and index for effusion, synovitis and PD signal were recorded. A 6-, 10-, 16-, 18-, and two 12-joint counts and indices for US parameters that included the most frequently US involved joints were calculated for each patient.

RESULTS

A 12-joint assessment for effusion, synovitis and PD signal, including bilateral wrist, second and third MCP, second and third PIP of hands and knee joints highly correlated with corresponding 60-joint US counts and indices. This reduced-joint US evaluation showed a similar correlation with clinical and laboratory parameters of disease activity to corresponding 60-joint assessment.

CONCLUSION

We propose that a 12-joint evaluation may be a useful tool for US assessment of overall joint inflammatory activity in RA.

Assessment of inflammatory activity in rheumatoid arthritis: a comparative study of clinical evaluation with grey scale and power Doppler ultrasonography

OBJECTIVE

To compare the clinical assessment of overall inflammatory activity in patients with rheumatoid arthritis (RA) with grey scale and power Doppler (PD) ultrasonography (US).

METHODS

Ninety four consecutive patients with RA were included. Demographic and clinical data, C reactive protein (CRP) level, and erythrocyte sedimentation rate (ESR) were recorded for each patient. The presence of tenderness, swelling, and a subjective swelling score from 1 to 3 were independently assessed by two rheumatologists, who reached a consensus in 60 joints examined in each patient. All patients underwent a US examination by a third blinded rheumatologist, using PD. US joint effusion, synovitis, and PD signal were graded from 1 to 3 in the 60 joints. Joint count and joint index for effusion, synovitis, and PD signal were recorded. A 28 joint count for clinical and US variables was calculated. Interobserver reliability of the US examination was evaluated by a fourth blinded rheumatologist.

RESULTS

US showed significantly more joints with effusion (mean 15.2) and synovitis (mean 14.6) than clinical examination (mean 11.5, p<0.05). A significant correlation was found between joint count and joint index for swelling, US effusion, synovitis, and PD signal. The 28 joint count for effusion, synovitis, and PD signal correlated highly with the corresponding 60 joint counts. US findings correlated better with CRP and ESR than clinical measures. Interobserver reliability was better for US findings than for clinical assessment.

CONCLUSION

US is a sensitive method for assessing joint inflammatory activity in RA, complementary to clinical evaluation.

Increased serum levels of interleukin-15 in rheumatoid arthritis with long- term disease

OBJECTIVE

To study the serum levels of IL-15 in patients with rheumatoid arthritis (RA), systemic lupus erythematosus (SLE), seronegative spondyloarthropathies (SSd) and healthy donors.

METHODS

The IL-15 serum levels were measured by ELISA in sera from 50 RA patients, 30 patients with SLE, 30 patients with SSd and 30 healthy donors. In RA patients, several clinical and demographic parameters were also obtained at the time of sample collection. IL-15 levels were compared in different RA subpopulations (positive or negative rheumatoid factor [RF], long term or recent onset disease, high or low disease activity). In addition, the possible association with other demographic and clinical parameters (gender, age, disease duration, etc) was also analysed.

RESULTS

RA patients had significantly higher serum levels of IL-15 (102.4 +/- 150 pg/ml; p = 0.0001) than SLE patients (9.8 +/- 15.3 pg/ml), SSd patients (7.9 +/- 14.6 pg/ml) and healthy donors' (5.2 +/- 11.6 pg/ml). RA patients with a disease evolution less than 2 years showed lower IL-15 levels (33.7 +/- 62.2 pg/ml) than those with long-term disease (152.4 +/- 64.6 pg/ml; p = 0.004). In addition, a significant correlation between IL15 in serum and the number of disease-modifying antirheumatic drugs (DMARDs) prescribed was detected in RA patients (r = 0.42; p = 0.002). No association between IL-15 levels and age, gender, RF or disease activity was observed in this group.

CONCLUSION

IL-15 is elevated in RA patients, specially in those with long term disease, compared to other rheumatic disorders. This finding supports that IL-15 is involved in the perpetuation of RA synovitis.

The prevalence of rheumatoid arthritis in the general population of Spain

OBJECTIVE

To estimate the prevalence of rheumatoid arthritis (RA) in the adult Spanish population and to assess its distribution by basic sociodemographic characteristics.

METHODS

Two thousand nine hundred and ninety-eight adults were selected randomly from the censuses of 20 municipalities. Trained rheumatologists administered a structured interview that included a screening questionnaire for RA. Subjects with a positive screening result were examined according to a standardized protocol. Cases were defined by the 1987 American College of Rheumatology (ACR) criteria adapted to epidemiological surveys.

RESULTS

One hundred and eighty-six persons (8.5%) had a positive screening result for RA and 11 of these fulfilled the ACR criteria for RA. The estimated prevalence was 0.5% (95% confidence interval 0.25-0.85). The ratios of women to men and of urban to rural were both 4:1. Function and health perception of the cases were significantly impaired, even after controlling for age and sex.

CONCLUSION

The prevalence of RA in Spain is comparable to that in other Mediterranean countries. RA may be less frequent in rural settings, a finding that merits further research. A significant proportion of RA cases in the community remain undiagnosed despite impaired functional status.

The burden of musculoskeletal diseases in the general population of Spain: results from a national survey

OBJECTIVE

The objective of the EPISER study was to estimate the prevalence of rheumatoid arthritis (RA), low back pain, hand and knee osteoarthritis (OA), and fibromyalgia in the adult Spanish population, and to assess the impact of these diseases on function and quality of life, and use of health and social resources.

METHODS

2998 subjects aged 20 years or above were randomly selected by stratified multistage cluster sampling from the censuses of 20 municipalities. Trained rheumatologists carried out structured visits at which subjects were asked about rheumatic symptoms and sociodemographic characteristics, completed validated instruments for measuring function (HAQ) and quality of life (SF-12), and underwent a standardised physical examination. Cases were defined by previously validated criteria.

RESULTS

The estimated prevalences with 95% confidence intervals were as follows: RA lifetime cumulative: 0.5% (0.3 to 0.9); low back pain: 14.8% (12.2 to 17.4); symptomatic knee OA: 10.2% (8.5 to 11.9); hand OA: 6.2% (5.9 to 6.5); fibromyalgia: 2.4% (1.5 to 3.2). Most conditions significantly impaired function and quality of life.

CONCLUSIONS

The EPISER study has internal and external validity for application of the results to the adult Spanish population. The diseases studied affect a significant proportion of the population, with various degrees of impact on disability and quality of life resulting in a significant number of physician visits, work disability, and medication use.

Cyclosporin A inhibits CD69 expression induced on synovial fluid and peripheral blood lymphocytes by interleukin 15

OBJECTIVE

To study the modulation of CD69 expression on peripheral blood (PB) and synovial fluid (SF) lymphocytes by interleukin 15 (IL-15) and several other cytokines and chemokines widely detected in the rheumatoid microenvironment. The effect of cyclosporin A (CSA) or methotrexate (MTX) in the cytokine mediated regulation of CD69 was analyzed.

METHODS

CD69 expression on lymphocytes was assessed by flow cytometry after incubation with different cytokines, chemokines, phorbol myristate acetate, or calcium ionophore in the presence or absence of CSA, MTX, or both. The effect of IL-15 and SF supernatants in maintaining CD69 expression on SF lymphocytes was also assessed. IL-15 levels in SF supernatants were measured by ELISA.

RESULTS

IL-15 induced the greatest upregulation of CD69 expression on PB lymphocytes in a time and dose dependent manner. IL-15 was able to maintain a high CD69 expression on SF lymphocytes. SF supernatants from rheumatoid arthritis (RA), which contain significant amounts of IL-15, also reversed the CD69 downregulation of SF lymphocytes in culture. CSA, but not MTX, inhibited the CD69 upregulation mediated by IL-15 both in PB and SF lymphocytes.

CONCLUSION

IL-15 appears to be responsible, at least in part, for the high CD69 expression on lymphocytes from the rheumatoid microenvironment. Consistent with the virtual absence of lymphocyte derived cytokines in RA synovium, the prevention of IL-15 mediated CD69 upregulation on lymphocytes may explain the effect of CSA in the treatment of RA.

Nontropical pyomyositis in adults

Pyomyositis (PMS) is a primary infection of striated muscle. Recent scanty reports suggest that non-tropical PMS may differ from classical tropical PMS. To address this question, 12 cases of nontropical PMS seen at two hospitals between 1976 and 1992 were reviewed and an English-literature search of similar cases was conducted. Both the series and reported cases are pooled together and herein reported. The age distribution of the 97 patients showed 30-50 and 60-70-year peaks, with a 3:1 (male-female) ratio. Fever, high erythrocyte sedimentation rate, and muscle stiffness or inflammation were present in more than 75% of patients. Muscles of the thigh (54%), back (13%), buttock (11%), arm (9%), or chest wall (4%) were involved. Staphylococci (61%), gram-negative bacilli (16%), streptococci (12%), and fungi (2%) were isolated from muscle specimens. Human immunodeficiency virus infection, diabetes mellitus, hemopoietic disorders, and other conditions with defective neutrophil function were present in 64 patients (66%). Drainage of pus and antibiotic therapy were the standard treatments. The mortality rate reached 10%. Analysis of patients classified by the comorbid condition showed differences in age, causative microorganisms, clinical features, and death rate. It is concluded that several clinical presentations of nontropical PMS are at variance with that of tropical PMS.

Increased binding of synovial T lymphocytes from rheumatoid arthritis to endothelial-leukocyte adhesion molecule-1 (ELAM-1) and vascular cell adhesion molecule-1 (VCAM-1)

The infiltration of the synovial membrane (SM) by mononuclear cells, mostly T cells, is a typical histopathological feature associated with rheumatoid arthritis (RA). The entry of T lymphocytes into the SM is believed to be mediated by a number of molecules in the endothelium that are induced in response to a series of inflammatory mediators. In this study, we have investigated the adhesion of synovial T cells from RA patients to two endothelial ligands: endothelial-leukocyte adhesion molecule-1 (ELAM-1), the only selectin known to function as a vascular addressin for T cells, and vascular cell adhesion molecule-1 (VCAM-1), the cellular ligand of VLA-4. Our results clearly demonstrate that synovial T cells isolated from both SM and synovial fluid (SF), bearing an activated and memory phenotype, displayed an enhanced capacity to interact with these two endothelial molecules as compared with T cells from peripheral blood (PB) either of the same RA patients or healthy donors. A further enhancement of VLA-4-mediated T cell binding to VCAM-1 and fibronectin could be observed when already in vivo-activated synovial T cells were stimulated in vitro with phorbol esters, suggesting the existence of several cellular affinity levels for both very late activation-4 (VLA-4) ligands. Moreover, both PB and synovial T cells from RA patients exhibited strong proliferative responses when they were cultured with either fibronectin or VCAM-1 in combination with submitogenic doses of anti-CD3 mAb. This increased endothelial binding ability of synovial T lymphocytes together with their proliferation in response to the interaction with VCAM-1 and fibronectin may represent important mechanisms in the regulation of T cell penetration and persistence in the chronically inflamed SM of RA.

Very late activation antigen on synovial fluid T cells from patients with rheumatoid arthritis and other rheumatic diseases

We used flow cytometry and immunoprecipitation techniques to study the expression of the activation molecules transferrin receptor, interleukin-2 receptor, HLA-DR, and very late activation antigen 1 (VLA-1) on purified T lymphocytes from peripheral blood and synovial fluid of 9 patients with rheumatoid arthritis and 7 patients with other rheumatic diseases. We found a T cell subset bearing VLA-1 in synovial fluid from 8 rheumatoid arthritis patients and 4 patients with other rheumatic diseases. VLA-1 was not found in peripheral blood T lymphocytes from either group.

A defect in immunoregulatory synovial fluid T cells in Behçet's syndrome

Synovial fluid mononuclear cells from 5 patients with active Behçet's syndrome who were receiving no treatment were observed to have: decreased proportions of CD4+ and CD8+ cells, decreased proliferative responses of T cells in AMLR, poor capacity of non-T cells to stimulate in AMLR, decreased production of IL-2 upon PHA stimulation as compared both to their own peripheral blood mononuclear cells and to synovial fluid and peripheral blood mononuclear cells from 6 patients with RA and 6 patients with synovial effusions due to noninflammatory conditions. These findings provide further evidence of an immunoregulatory disturbance in Behçet's syndrome and indicate that synovial fluid, may be an important site where this derangement occurs in the active stage of the disease.

Defective monocyte production of, and T lymphocyte response to, interleukin-1 in the peripheral blood of patients with systemic lupus erythematosus

Interleukin-1 (IL-1) is a monocyte product with diverse amplifying effects on immune cell reactions. We have studied 16 untreated SLE patients to determine the production of IL-1 by their monocytes under the stimulus of E. Coli lipopolysaccharide (LPS) or phorbol myristate acetate (PMA) and measured by the capacity of their supernatants to augment normal autologous mixed lymphocyte cultures (AMLR) or to replace accessory cells in Con A-induced proliferation of T lymphocytes. Concurrently, we studied the response of T lymphocytes from these same patients to IL-1 by its capacity to increase the percentage of stable E rosette forming cells and by the enhancement of T cell proliferation in AMLR. Monocytes from SLE patients produced significantly less IL-1 activity than those of age matched controls, regardless of the stimulus (LPS or PMA), as well as of the indicator system. All patients with active disease and seven of the 10 patients with inactive disease had decreased production of IL-1 activity as determined by at least one method. Response of T lymphocytes from SLE patients to IL-1 produced by normal monocytes was also found decreased as compared to normals. This defect was more marked in the T cells from patients with active than in those of patients with inactive disease. These findings indicate that the immunoregulatory disturbance that SLE patients have encompasses monocytes as well as T and B lymphocytes and suggest that the defect is either multicentric or originates in the stem cell.