The validity of rheumatoid arthritis diagnoses in Finnish biobanks

OBJECTIVE

The aim of this study was to determine the validity of rheumatoid arthritis (RA) diagnoses in patients participating in Finnish biobanks.

METHOD

We reviewed the electronic medical records of 500 Finnish biobank participants: 125 patients with at least one visit with a diagnosis of seropositive RA, 125 patients with at least one visit with a diagnosis of seronegative RA, and 250 age- and gender-matched controls. The patients were chosen from five different biobank hospitals in Finland. A rheumatologist reviewed the medical records to assess whether each patients' diagnosis was correct. The diagnosis was compared with the diagnostic codes in the Finnish Care Register for Health Care (CRHC) and special reimbursement data of the Social Insurance Institution of Finland.

RESULTS

The positive predictive value (PPV) of CRHC diagnosis of RA (for seropositive and seronegative RA combined) was 0.82. For patients with a special reimbursement for anti-rheumatic medications for RA, the PPV was 0.89. The PPV was higher in patients with more than one visit. For one, two, five, and 10 visits, the PPV was 0.82, 0.85, 0.89, and 0.90, respectively, and for patients who also had the special reimbursement, the PPV was 0.89, 0.91, 0.93, and 0.94 for one, two, five, and 10 visits, respectively. In patients positive for anti-citrullinated protein antibodies, the PPV was 0.98.

CONCLUSION

These results demonstrate that the validity of RA diagnoses in Finnish biobanks was good and can be further improved by including data on special reimbursement for medication, number of visits, and serological data.

Immunogenicity of subcutaneous TNF inhibitors and its clinical significance in real-life setting in patients with spondyloarthritis

Key messages

Considerable proportion of patients with SpA have been immunized to the subcutaneous anti-TNF drug they are using. Concomitant use of MTX protects from immunization, whereas SASP does not. Patients with SpA using subcutaneous anti-TNF drugs can benefit from monitoring of the drug trough levels.

Abstract

Immunization to biological drugs can lead to decreased efficacy and increased risk of adverse effects. The objective of this cross-sectional study was to assess the extent and significance of immunization to subcutaneous tumor necrosis factor (TNF) inhibitors in axial spondyloarthritis (axSpA) patients in real-life setting. A serum sample was taken 1–2 days before the next drug injection. Drug trough concentrations, anti-drug antibodies (ADAb) and TNF-blocking capacity were measured in 273 patients with axSpA using subcutaneous anti-TNF drugs. The clinical activity of SpA was assessed using the Bath AS Disease Activity Index (BASDAI) and the Maastricht AS Entheses Score (MASES). ADAb were found in 11% of the 273 patients: in 21/99 (21%) of patients who used adalimumab, in 0/83 (0%) of those who used etanercept, in 2/79 (3%) of those who used golimumab and in 6/12 (50%) of those who used certolizumab pegol. Use of methotrexate reduced the risk of formation of ADAb, whereas sulfasalazine did not. Presence of ADAb resulted in decreased drug concentration and reduced TNF-blocking capacity. However, low levels of ADAb had no effect on TNF-blocking capacity and did not correlate with disease activity. The drug trough levels were below the consensus target level in 36% of the patients. High BMI correlated with low drug trough concentration. Patients with low drug trough levels had higher disease activity. The presence of anti-drug antibodies was associated with reduced drug trough levels, and the patients with low drug trough levels had higher disease activity. The drug trough levels were below target level in significant proportion of patients and, thus, measuring the drug concentration and ADAb could help to optimize the treatment in SpA patients.

Supplementary Information

The online version contains supplementary material available at 10.1007/s00296-021-04955-8.

Antibodies to malondialdehyde-acetaldehyde modified low-density lipoprotein in patients with newly diagnosed inflammatory joint disease

Objective:To assess antibodies to malondialdehyde-acetaldehyde-modified low-density lipoprotein (MAA-LDL) in patients with newly diagnosed inflammatory joint disease.Method: Patients with rheumatoid arthritis (RA), spondyloarthritis (SpA), and undifferentiated arthritis (UA), participating in the Northern Savo 2010 Study, were evaluated for metabolic syndrome (MetS), metabolic and inflammatory markers, antibodies to MAA-LDL, Aggregatibacter actinomycetemcomitans, and Porphyromonas gingivalis.Results: Among 135 newly diagnosed untreated patients, of whom 53 (39%) were diagnosed to have RA, 44 (33%) SpA, and 38 (28%) UA, 49%, 30%, and 47%, respectively, had MetS. After adjusting for age and gender, anti-MAA-LDL immunoglobulin (Ig)A (p = 0.009), IgG (p = 0.031), and IgM (p = 0.001) levels differed between the diagnostic categories, but not in patients with MetS present or absent. All antibody classes to MAA-LDL correlated with erythrocyte sedimentation rate (ESR), and IgA and IgG antibodies with high-sensitivity C-reactive protein (hs-CRP). IgA antibodies to MAA-LDL correlated with rheumatoid factor (RF), anti-citrullinated protein antibodies (ACPAs), fasting plasma glucose, IgA antibodies to A. actinomycetemcomitans, and in IgA and IgG antibodies to P. gingivalis.Conclusion: Among various arthritis groups, antibodies to MAA-LDL were most common in RA. Antibodies to modified lipoproteins were associated with inflammation measured by ESR and hs-CRP. IgA antibodies to MAA-LDL correlated with age, antibodies to periodontal bacteria, RF, ACPA, and fasting glucose. Associations between antibodies to MAA-LDL and antibodies to periodontal bacteria, RA-associated antibodies, inflammatory parameters, and plasma glucose already reflect cardiovascular burden in inflammatory joint diseases at diagnosis.

AB1251 VALIDITY OF RHEUMATOID ARTHRITIS DIAGNOSES IN FINNISH BIOBANK PATIENTS

Background:

Finnish healthcare registers are used in medical research, but there is little data about the validity of these registers in rheumatology.

Objectives:

The aim of our study was to determine the validity of rheumatoid arthritis (RA) diagnoses in patients participating in the Finnish Biobanks.

Methods:

We reviewed the electronic patient charts of 125 patients with at least one visit with a diagnosis of seropositive RA, 125 patients with at least one visit with a diagnosis of seronegative RA and 250 age-and-sex matched controls. Patients were randomly selected from Finnish biobank participants. We evaluated whether the patients’ diagnosis of RA recorded in the hospital discharge registry at the participating hospital was correct according to chart review and expert opinion. In the control group it was investigated whether the diagnosis of RA was written in the patients’ chart, but the diagnosis code was not recorded.

Results:

The positive predictive value (PPV) of a single hospital registry diagnosis of seropositive RA was 0.74 but rose to 0.98 in patients with a special reimbursement for seropositive RA and 0.98 in anti-citrullinated protein antibody positive patients. For seronegative RA, the PPV of a diagnosis was 0.72 and in patients with a special reimbursement for seronegative RA 0.89. The PPV was higher in patients with more than one visit with the diagnosis: 0.92 if the patients had at least 5 visits with seropositive RA and 0.88 with at least 5 visits with seronegative RA. Negative predictive value for RA diagnosis was 0.99.

Conclusion:

These results demonstrate that the validity of RA diagnoses in healthcare registers can be markedly improved with data about special reimbursement for medication, number of visits and serological data.

Disclosure of Interests:

Antti Palomäki Consultant of: Pfizer, Speakers bureau: Pfizer, Sanofi, MSD, Johanna Paltta Consultant of: Lilly, Abbvie, Laura Pirilä Consultant of: Novartis, MSD Finland, Roche, Bristol-Myers-Squibb, Pfizer, Sanofi, Abbvie, Oy Eli LIlly Finland Ab, UCB Pharma Oy Finland, Jansen-Cilag, Mylan, Sandoz, Boehringer-Ingelheim, Paid instructor for: Boehringer -Ingelheim, MSD Finland, Speakers bureau: Boehringer-Ingelheim, Pfizer Finland, Hanna-Kaisa Heikkilä: None declared, Pia Isomäki Consultant of: Abbvie, BMS, Eli Lilly, MSD, Novartis, Pfizer, Roche, Sanofi, Johanna Huhtakangas Consultant of: Boehringer Ingelheim, Tuulikki Sokka-Isler: None declared, Oili Kaipiainen-Seppänen Speakers bureau: Boehringer Ingelheim, Kari Eklund Consultant of: Celgene, Lilly, Speakers bureau: Pfizer, Roche

Drugs used in incident systemic lupus erythematosus – results from the Finnish nationwide register 2000–2007

The objectives of the study were to examine the initial, first-year anti-rheumatic outpatient therapy in patients with incident SLE, as well as the concomitant use of drugs for certain comorbidities, compared to the use in the general population. The Finnish nationwide register data on special reimbursements for medication costs was screened to identify the inception cohort of 566 adult SLE patients (87% females, mean age 46.5 ± 15.9 years) over the years 2000–2007. The patients were linked to the national Drug Purchase Register. Of those, 90% had purchased at least once some disease-modifying anti-rheumatic drugs (DMARDs) during the first year. Hydroxychloroquine was the most common (76%), followed by azathioprine (15%) and methotrexate (13%). With the exception of increase in mycophenolate mofetil, the proportions remained stable over the whole study period 2000–2007. Drugs for cardiovascular diseases, dyslipidemia, diabetes mellitus, hypothyroidism and obstructive pulmonary disease were more frequently purchased than in the sex- and age-adjusted population, with rate ratios ranging from 1.6 to 7.8. Over the years 2000–2007, almost all the patients with incident SLE in Finland started with a DMARD. Higher percentages of SLE patients were on medication for several common chronic diseases than in the population as a whole.

Mortality and causes of death among incident cases of systemic lupus erythematosus in Finland 2000-2008

The objectives of the study were to investigate mortality and causes of death in patients with recent-onset systemic lupus erythematosus (SLE) in Finland. Data for patients with SLE for the study were collected (2000-2007) from the nationwide register on decisions of special reimbursements for drugs, maintained by the Social Insurance Institution (SII) in Finland. Data on deaths of the patients were obtained from the official death certificate statistics of Statistics Finland until the end of 2008. Of the 566 incident SLE patients, median follow-up time was 5.4 (IQR 3.3, 7.1) years, and 30 patients (23 females, seven males) died in the years 2000 through 2008. Mean age at death was 67.8 ± 17.2 years for females and 62.3 ± 15.2 years for males. The 5-year survival rates were 94.8% (95%CI 92.0-96.6%) and 88.2% (95%CI 76.5-94.3%), respectively. The age- and sex-adjusted standardized mortality ratio was 1.48 (95%CI 1.01-2.12). Primary causes of death were cardiovascular diseases, malignancy and SLE itself. In conclusion, survival of the patients with SLE was inferior to that of the general population. Cardiovascular diseases were responsible for 37% of deaths.

Prevalence of antibodies against Chlamydia trachomatis and incidence of C. trachomatis-induced reactive arthritis in an early arthritis series in Finland in 2000

OBJECTIVE

To study the prevalence of different serotypes of Chlamydia trachomatis antibodies and the incidence of C. trachomatis-induced reactive arthritis (ReA) among patients with early arthritis in a defined population.

METHODS

Serum samples were collected from a cohort of 122 adult patients in the age group 18-65 years included in the Kuopio 2000 Arthritis Survey. Antibodies against C. trachomatis serotypes C, E, and G were studied using enzyme immunoassay (EIA) tests among patients and in a control cohort of 78 adults without any joint symptoms. The incidence assessment for Chlamydia-induced ReA was based on a ligase chain reaction (LCR) test in urine and clinical symptoms and signs appropriate for ReA.

RESULTS

Of 122 patients, with the baseline diagnosis of rheumatoid arthritis (RA) in 11, spondyloarthropathy (SpA) in 28, and undifferentiated arthritis (UA) in 83 cases, 42 (34%) showed immunoglobulin (Ig)G or IgA antibodies against at least one serotype C, E, or G. Among the patients with UA the prevalence was significantly increased compared with the controls (p = 0.010). C. trachomatis-induced ReA arthritis was diagnosed in only three patients with the LCR test. On this basis the incidence of C. trachomatis-induced arthritis was 5.4/100 000 [95% confidence interval (CI) 1.1-15.7] in the age group 18-65 years.

CONCLUSION

Antibodies against C. trachomatis were most common in patients with UA reflecting the fact that cases with chlamydia-induced ReA are included in this subgroup.

Serum soluble CD30 in early arthritis: a sign of inflammation but not a predictor of outcome

OBJECTIVE

To evaluate serum soluble CD30 levels (sCD30) in an early arthritis series and assess their ability to predict the outcome in patients with rheumatoid arthritis (RA) and undifferentiated arthritis (UA) at one year follow-up.

METHODS

Serum sCD30 levels were measured by ELISA from 92 adult patients with RA and UA at baseline and from 60 adult controls. The patients were followed up for one year in the Kuopio 2000 Arthritis Survey. Receiver operating characteristic (ROC) curves were constructed to determine cut off points of sCD30 in RA and UA that select the inflammatory disease from controls. Sensitivity, specificity and positive likelihood ratio, and their 95 % CIs were calculated for sCD30 levels in RA and UA.

RESULTS

Median serum sCD30 levels were higher in RA 25.1 (IQ range 16.3-38.6) IU/ml (p<0.001) and in UA 23.4 (15.4-35.6) IU/ml (p<0.001) than in controls 15.1 (10.7-20.8) IU/ml. No differences were recorded between RA and UA (p=0.840). Serum sCD30 levels at baseline did not predict remission at one year follow-up.

CONCLUSION

Serum sCD30 levels were higher in RA and UA than in controls at baseline but they did not predict remission at one year follow-up in this series.

Change of diagnoses and outcome of patients with early inflammatory joint diseases during a mean 13-month follow-up

OBJECTIVE

To assess the state of the disease and verify the diagnoses during a 7-24-month follow-up of adult patients with newly diagnosed inflammatory joint diseases in a defined population.

METHODS

Patients with previously undiagnosed synovitis in at least one peripheral joint or signs of inflammation in sacroiliac, glenohumeral or hip joints were enrolled on their first hospital visit in 2000 and followed-up for up to 24 months in Kuopio.

RESULTS

A total of 138/173 adult patients completed a mean 13-month follow-up. During the follow-up the diagnosis was specified for 15/81 (19%) patients previously classified as undifferentiated arthritis (UA). Eight patients developed rheumatoid arthritis (RA). Of 28 patients with RA, 92% were on disease-modifying anti-rheumatic drugs (DMARDs) and 75% had a combination treatment with two or more DMARDs. According to the diagnosis at baseline, 75% of cases with RA, 38% with spondyloarthropathies (SpAs) and 42% with UA had active synovitis or arthralgia at follow-up. In multivariate analysis, older patients at disease onset were less likely to be in remission (p = 0.011).

CONCLUSION

The diagnosis could be specified for 19% of patients with UA. Fifteen of 20 patients with RA had an active disease despite treatment with DMARDs. Patients with SpAs and UA had a better short-term outcome. Patients with active disease need aggressive therapy in all age groups.

Classic disease modifying anti-rheumatic drugs (DMARDs) in combination with infliximab. The Finnish experience

To assess the performance of infliximab in a clinical setting, 364 rheumatoid arthritis (RA) patients from the National Register of Biological Treatment in Finland (ROB-FIN) were analysed. Corticosteroid usage and dose diminished (p<0.05 and 0.001, respectively) in patients on infliximab, of whom 51% also used one, 28% two and 16% three other concomitant DMARDs. A 34% of the RA patients used methotrexate+/-corticosteroids without any other DMARD. Methotrexate was most frequently used with sulphasalazine and/or hydroxychloroquine. Non-methotrexate patients most frequently used leflunomide or azathioprine combined with corticosteroids. The clinical effect of these combinations was similar to that of infliximab with methotrexate alone. The results indicate that infliximab can be used together with other DMARDs than methotrexate alone, quite according to the philosophy of the combination drug therapy, as the effectiveness is as good as or even slightly better than that of methotrexate and infliximab.

Regional differences in Finland in the prevalence of rheumatoid factor in the presence and absence of arthritis

OBJECTIVES

To look for possible regional differences in the prevalence of rheumatoid factor (RF) in the presence and absence of arthritis.

METHODS

The study covered a representative sample of the Finnish population aged 30 years or over, primarily comprising 8000 people, of whom 7217 participated in the field survey carried out in 1978-80. RF from serum samples from 7116 subjects was determined by the Waaler-Rose (sensitised sheep cell agglutination) test. Titres >or=32 were regarded as positive and titres >or=128 as strongly positive. Arthritis was diagnosed by a thorough clinical examination.

RESULTS

In the absence of arthritis the prevalence of positive and strongly positive RF reactions was 2.1% and 1.0%, respectively. The lowest prevalence of strongly "false positive" RF occurred in south western Finland. After adjustment for age, sex, smoking, and coffee consumption the odds ratio of having a strongly "false positive" RF reaction in eastern Finland was 3.16 (95% confidence interval 1.29 to 7.72) and in northern Finland 2.94 (1.13 to 7.64) compared with south western Finland. The corresponding odds ratio of strongly RF positive arthritis in eastern Finland was 5.08 (1.41 to 18.27).

CONCLUSION

Regional differences are found in the prevalence of a strongly positive RF reaction in the Finnish population. The findings are in accordance with recent results from another study concerning regional differences in the incidence of rheumatoid arthritis in Finland.

Recurrent myopericarditis in association with Crohn's disease

Myopericarditis is a rare extraintestinal complication of inflammatory bowel disease (IBD). It has also been described as a side-effect of the treatment of IBD. We report a 37-year-old-woman with Crohn's disease who had several mild episodes of myopericarditis, two of which were associated with a pleural effusion, and two with conduction abnormalities in the atrioventricular node. During the last episode, a nodal rhythm was followed by a third-degree atrioventricular block and a prolonged pause, resulting in loss of consciousness and convulsions. A permanent pacemaker was implanted. Our patient is also human lymphocyte antigen (HLA) B27-positive. HLA B27 is known to be associated with conduction disturbances in the AV node. Recurrent myopericarditis can be a sign of IBD.

Carriers of the aspartylglucosaminuria genetic mutation and chronic arthritis

OBJECTIVE

To ascertain whether being a carrier of an autosomal recessive disease, aspartylglucosaminuria (AGU), predisposes to chronic arthritis, as does AGU disease.

METHODS

A group of 173 unrelated patients with rheumatoid arthritis (RA) but with no family members with AGU each gave a blood sample for AGUFin major mutation DNA analysis. A group of 131 AGU carriers who were parents of patients with AGU completed a questionnaire on joint symptoms and gave a blood sample for rheumatoid factor (RF) analysis. Eight RF positive parents with prolonged joint symptoms had a rheumatological evaluation.

RESULTS

Six patients (1/28) with RA were carriers of the AGUFin major mutation, whereas the carrier frequency among Finns in general is 1/50 to 1/85. Three AGU carriers had chronic arthritis (2.3%), and 17 (13%) were RF positive; the respective percentages among Finns in general are 1.4% and 5%.

CONCLUSION

As for AGU disease, carrier status may also predispose to chronic arthritis.

Changes in the incidence of juvenile rheumatoid arthritis in Finland

OBJECTIVE

To study trends in the incidence of juvenile rheumatoid arthritis (JRA).

METHODS

The study covered subjects who were entitled under the nation-wide sickness insurance scheme to receive specially reimbursed medication for juvenile rheumatic diseases in 11 of 21 central hospital districts in Finland (the base population comprised about 445,000 children <16 yr of age) in 1995. Data from the years 1980, 1985 and 1990 were compared with data from 1995 concerning the central part of the area, which had been included in a previous study by us.

RESULTS

A total of 87 incident cases (58 girls and 29 boys) satisfied criteria for JRA in 1995 in the study area. The incidence of JRA was 19.5 per 100 000 [95% confidence interval (CI) 15.6-24.1] of the population <16 yr of age for the whole area. It was 22.7 per 100,000 (95% CI 17.3-29.2) for the area that had been covered by the earlier study (five districts) and 14.9 per 100,000 (95% CI 9.8-21.7) for the new area (six additional districts). The incidence of JRA was significantly higher than in the earlier years (1980, 1985 and 1990) in the same district (trend, P=0.024). The highest incidence, 60.3 per 100,000 (95% CI 35.8-95.4), was noted in 1995 among girls in the age group 10-15 yr in the southernmost part of the study area.

CONCLUSIONS

There was both temporal and regional variation in the incidence of JRA. Results of the present study suggest that environmental factors may influence the frequency of JRA.

Intensive treatment of rheumatoid arthritis reduces need for dialysis due to secondary amyloidosis

We have analysed changes in the intensity of treatment of patients with rheumatoid arthritis (RA) and its influence on the number of patients with RA and secondary amyloidosis (SA) admitted to dialysis due to end-stage renal disease. The number of visits and patients at the rheumatological outpatient clinic because of RA, the type of medication used in 1988-1997, and the number of patients with RA and SA on dialysis from 1989 to 1999 were extracted from the data set of Kuopio University Hospital. The intensity of treatment could be evaluated as the treated number of patients with RA and the number of visits at the outpatient clinic. Both the numbers increased from 1988 to 1996, patients under treatment from 201 to 550 and visits from 1091 to 2198, respectively. In 1997, the number of patients still increased (n=637), although the number of visits started to decline (n=2054), partly due to better collaboration of health centres. A marked shift from use of only symptomatic treatment or one disease-modifying antirheumatic drug (DMARD) to more common use of immunosuppressants and/or combinations of at least two DMARDs occurred in the five years from 1992 to 1997. In 1988, the figures for only nonsteroidal anti-inflammatory drugs or only glucocorticoids or one immunosuppressive drug were 24%, 8%, and 9%, and in 1997, 4%, 3%, and 22%, respectively. In 1997, 43% of the patients were treated with combinations of two or more DMARDs. The number of patients with RA on dialysis treatment and the number of new admissions each year due to SA decreased from 11 to 2 and from 5 to none, respectively. At the beginning of year 2000 there was only one patient with RA and SA on dialysis.

Autologous peripheral blood stem cell transplantation in a patient with severe mixed connective tissue disease

A 65-year old man with mixed connective tissue disease (MCTD) and severe therapy resistant polymyositis was considered for high-dose cyclophosphamide (200 mg/kg) supported by autologous stem cell transplantation (ASCT). During a 21 months follow-up there has been a significant subjective, but objectively only a slight improvement in muscle strength. Initially the levels of serum creatine kinase and serum aldolase normalised, but are at 21 months at about the same level as before ASCT. Based on histopathological examination there is still active myositis. Our case would suggests that this treatment may have some efficacy in MCTD with severe polymyositis although longer follow-up is needed.

Regional differences in the incidence of rheumatoid arthritis in Finland in 1995

OBJECTIVE

To investigate regional differences in the incidence of rheumatoid arthritis (RA).

METHODS

Those subjects entitled to receive drug reimbursement for chronic inflammatory joint diseases in 11/21 central hospital districts (population base about 1.8 million adults) in Finland during 1995 were studied. The incidence rates from these central hospital districts were compared.

RESULTS

A total of 1213 subjects were entitled to drug reimbursement for chronic inflammatory joint disease which had started at the age of 16 or over. Of these, 598 subjects satisfied the American Rheumatism Association 1987 criteria for RA. The age adjusted incidence of RA was 31.7/100 000 (95% CI 29.2 to 34.4) and varied significantly (p<0.001) among the central hospital districts, ranging from 16.3 to 44.8/100 000.

CONCLUSION

There are regional differences in the incidence of RA. The reasons for these are probably environmental rather than genetic.

Evaluation of iron status in anemic patients with rheumatoid arthritis using an automated immunoturbidimetric assay for transferrin receptor

We have evaluated a newly introduced immunoturbidimetric transferrin receptor assay (IdeA TfR-IT, Orion Diagnostica, Finland) in healthy subjects and in a study population consisting of patients with rheumatoid arthritis and juvenile chronic arthritis. The IdeA TfR-IT assay was found to provide reproducible results which were in good agreement with the ELISA assays from Orion Diagnostica (IDeA-ELISA, correlation R2=0.8, n=102) and R&D systems (Quantikine TfR ELISA assay, correlation R2=0.95, n=39). The analysis of the patient samples suggested that, on the basis of serum transferrin receptor and ferritin concentrations, in approximately one third of patients with rheumatoid arthritis anemia is due to the depletion of iron stores. Apparently, in all patients with rheumatoid arthritis iron deficiency must be considered as a potential cause of the anemia. Now, that assays which are suitable for automated analyzers have become available for the measurement of serum transferrin receptor, this analyte has the potential to become a part of the routine evaluation of iron status.

Incidence of chronic inflammatory joint diseases in Finland in 1995

OBJECTIVE

To investigate trends in the incidence of chronic inflammatory joint diseases.

METHODS

Subjects entitled to receive drug reimbursement for chronic inflammatory joint diseases in 5/21 central hospital districts (population base about 1 million adults) in Finland during 1995 were studied. The mean age at disease onset was compared with figures from 1975, 1980, 1985, and 1990. Incidence rates were compared with those from 1980, 1985, and 1990.

RESULTS

A total of 710 subjects were entitled to drug reimbursement for chronic inflammatory joint disease that had started at the age of 16 or over. The total incidence was 65/100,000 (95% confidence interval 60.7-70.4); the figures for rheumatoid arthritis (RA), ankylosing spondylitis, psoriatic arthritis, and undifferentiated chronic poly/oligoarthritis were 34, 6, 7, and 13/100,000, respectively. In RA, the mean age at diagnosis was 59.0 years and was the same in rheumatoid factor (RF) positive and RF negative disease. The mean age at diagnosis had increased by 8.8 years from 1975 to 1995 (p<0.001). A 14% decline was evident in the incidence of RA in 1990 and 1995 compared with the earlier years (p = 0.013). In the younger age groups (35-54 years), the incidence declined by 50% compared with the year 1980. The incidence of spondyloarthropathies remained similar during 1980-95.

CONCLUSION

Continuous monitoring of sickness insurance data provides information on the epidemiology of inflammatory joint diseases that will be useful in assessing demand for and supply of health services.

Hypersensitivity to gold in gold sodium thiomalate-induced dermatosis

Gold compounds are widely used in the treatment of rheumatoid arthritis. Mucocutaneous side-effects leading to the discontinuation of medication are common with these drugs. We investigated whether allergic mechanisms are involved in dermatosis induced by gold sodium thiomalate (GSTM). Thirteen gold dermatosis patients, 15 arthritis patients without any side-effects from GSTM and 11 healthy controls participated in the study. Venous blood lymphocytes from these subjects were cultured with GSTM and gold sodium thiosulphate (GSTS) in the lymphocyte proliferation test (LPT). In some cases, interferon-gamma-producing cells were enumerated in vitro (T-cell ELISpot). The subjects were also patch-tested with GSTM and GSTS. The LPT to either GSTM, GSTS or both was positive in 12 of 13 patients with gold dermatosis. In the arthritis patient group without side-effects from gold, the LPT gave two false-positive results and in the healthy control group the LPT was falsely positive with one subject. T-cell ELISpot was positive in four of six gold dermatosis patients and negative in the arthritis and healthy control groups. Only one patient who also developed contact dermatitis from gold jewellery was positive to gold in the patch test. These results indicate that gold dermatosis is mediated, at least in part, by allergic mechanisms and that the LPT is of value in the diagnosis of gold dermatosis.

A population-based study on uveitis in juvenile rheumatoid arthritis

OBJECTIVE

To obtain information on the occurrence and characteristics of uveitis in a population-based survey of patients with juvenile rheumatoid arthritis (JRA).

METHODS

The subjects in this study were entitled, under the nationwide sickness insurance scheme, to receive specially reimbursed medication for JRA in 5 of the 21 central hospital districts in Finland (population base about 270,000 children < 16 years of age) in 1980, 1985 and 1990.

RESULTS

A total of 114 incident cases (34 boys and 80 girls) satisfied the criteria for JRA. Uveitis was diagnosed in 18 of these patients (16%). The mean age of uveitis patients at the diagnosis of JRA was 6.8 years (median 5.4 years) and the mean interval from the diagnosis of JRA to the detection of uveitis was 2.9 years. Silent (asymptomatic) anterior uveitis was found in 4 boys and 11 girls and acute anterior uveitis in 2 boys. One girl had marginal corneal ulceration with mild anterior uveitis. Uveitis was chronic (> 6 months) in 9 cases. Uveal inflammation was most severe in the 3 children whose uveitis was detected at the time of the diagnosis of JRA.

CONCLUSION

The study provides population-based information on the occurrence and characteristics of uveitis associated with JRA.

Epidemiology of rheumatoid arthritis in Finland

OBJECTIVES

To review the work pertaining to rheumatoid arthritis (RA) morbidity in Finland and to compare the data with that available from other countries.

METHODS

Extensive investigations in Finland of the epidemiology of RA, based on nationwide registers designed primarily for administrative purposes and on extensive population studies, frequently in combination.

RESULTS

According to several surveys with somewhat different study designs, the prevalence of clinically significant RA is about 0.8% of the adult Finnish population. Five national health interviews from a 30-year period have revealed figures about 50% higher, but with no clear change in prevalence. The incidence of clinically significant RA is about 40 per 100,000 of the adult population, which is in accordance with the prevalence figures. The mean age at diagnosis increased by 7.6 years from 1975 to 1990. Between 1978 and 1980, 5.8% of the severe disability in the adult Finnish population was attributable to RA. Some evidence suggests that severe disability resulting from RA diminished during the 1980s, possibly because of joint replacement surgery.

CONCLUSIONS

Monitoring sickness insurance statistics is a useful means of following the epidemiology of RA.

Incidence of psoriatic arthritis in Finland

Patients with psoriasis have an increased incidence of arthritis. Information on the incidence of psoriatic arthritis (PsA) is sparse. The present study covered those subjects who were entitled under the nationwide sickness insurance scheme to receive specially reimbursed medication for PsA in 5/21 central hospital districts in Finland (population basis approximately 1 million adults) in 1990. A total of 65 incident cases satisfied the concept of PsA. The annual incidence of PsA was 6/100,000 of the adult population (> or = 16 yr of age). The mean age at diagnosis was 46.8 yr. The peak incidence occurred in the 45-54 yr age group. The male to female ratio was 1.3:1. The incidence rate in the present study is in agreement with the sparse former figures, but age-specific incidence figures which have not been published earlier are also presented.

Incidence of rheumatoid arthritis in Finland during 1980-1990

OBJECTIVE

To obtain information on the incidence of rheumatoid arthritis and on its recent trends in Finland.

METHODS

The study covered those subjects entitled to receive specially reimbursed medication for rheumatoid arthritis under the nationwide sickness insurance scheme in five out of 21 central hospital districts in Finland (population basis about one million adults) during three years: 1980, 1985, and 1990.

RESULTS

The annual incidence of rheumatoid arthritis in 1980 and 1985, satisfying the American Rheumatism Association 1987 classification criteria, was 39/100,000 of the population > or = 16 years of age. The combined incidence of rheumatoid factor (RF) positive arthritis and RF negative polyarthritis was 46/100,000. A decline of approximately 40% occurred in the number of RF negative rheumatoid arthritis cases in 1990 compared with the earlier years. The declining trend was statistically significant (P = 0.008).

CONCLUSION

The decline in incidence of RF negative rheumatoid arthritis in Finland may reflect changes in the environment specifically affecting the risk of RF negative disease.

Shift in the incidence of rheumatoid arthritis toward elderly patients in Finland during 1975-1990

OBJECTIVE

To obtain information on changes in the age distribution of new cases of rheumatoid arthritis (RA) in Finland.

METHODS

The present study covered those subjects entitled under the nationwide sickness insurance scheme to receive specially reimbursed medication for RA in 5/21 central hospital districts in Finland (population base about one million adults) in 1975, 1980, 1985, and 1990.

RESULTS

During the four study years 1321 incident cases occurred, which satisfied the American Rheumatism Association 1987 classification criteria for RA. The mean age at diagnosis increased by 7.6 years from 1975 (50.2 years) to 1990 (57.8 years). No appreciable differences occurred between men and women. The incidence rates declined in the younger age groups.

CONCLUSION

The epidemiology of RA is in a dynamic state. The trends may reflect marked changes in the host-environment relationship.

Incidence of rare systemic rheumatic and connective tissue diseases in Finland

OBJECTIVE

To obtain information on the incidence of rare systemic rheumatic and connective tissue diseases in Finland.

DESIGN

Population-based epidemiological study.

SETTING

Five out of 21 central hospital districts in Finland (population: about 1 million adults > or = 16 years of age).

SUBJECTS

Subjects entitled under the nationwide sickness insurance scheme to receive specially reimbursed medication for rare systemic rheumatic or connective tissue diseases in 1990.

MAIN OUTCOME MEASURE

Incidence.

RESULTS

A total of 30 incident cases occurred. Nine patients had mixed connective tissue disease, four had systemic sclerosis, four had dermato/polymyositis and one patient had inclusion body myositis; the corresponding annual incidence rates were 8, 4, 4 and 1/million of the adult population. Only one patient had adult Still's disease. The overall annual incidence rate of systemic vasculitides was 9/million of the adult population.

CONCLUSION

This study provides population-based figures on the incidence of rare systemic rheumatic and connective tissue diseases in Finland.

Incidence of chronic juvenile rheumatic diseases in Finland during 1980-1990

OBJECTIVE

To study trends in the incidence of juvenile rheumatoid arthritis (JRA) and to obtain information on the incidence of other juvenile rheumatic diseases in Finland.

METHODS

The present study covered those subjects entitled under the nationwide sickness insurance scheme to receive specially reimbursed medication for juvenile rheumatic diseases in 5/21 central hospital districts in Finland (population base about 270,000 children < 16 years of age) in 1980, 1985 and 1990.

RESULTS

A total of 114 incident cases (34 boys, 80 girls) satisfied the criteria for JRA during the three study years: 1980, 1985 and 1990. Seven of the patients had systemic-onset disease. The incidence of JRA remained similar (14/100,000 in the population < 16 years of age). The female: male ratio was 2.4: 1. Only one case of juvenile spondyloarthropathy was found. Seven patients had juvenile systemic lupus erythematosus and four had juvenile dermato/polymyositis. The corresponding annual incidence rates were 0.1, 0.9 and 0.5/100,000, respectively, in this population.

CONCLUSION

The present study provides population-based figures on the occurrence of various chronic arthritic syndromes in childhood using a unified data base. The incidence of JRA remained quite similar for the three study years. The incidence figures for systemic rheumatic and connective tissue diseases were slightly higher than those reported in previous studies.

Retroperitoneal fibrosis with antineutrophil cytoplasmic antibodies

A middle aged man showed retroperitoneal fibrosis with signs of vasculitis verified by biopsy of the retroperitoneal mass. Antineutrophil cytoplasmic antibodies (ANCA) with cytoplasmic staining pattern (cANCA) were strongly positive, although there were no clinical or histological signs of Wegener's granulomatosis. No cases of cANCA associated retroperitoneal fibrosis have been described except in connection with Wegener's granulomatosis. ANCA have been found to associate with any inflammatory disorders. This observation may broaden the clinical spectrum of cANCA positive vasculitides.