Mortality and causes of death across the systemic connective tissue diseases and the primary systemic vasculitides.

Objectives: Studies assessing relative mortality risks across the spectrum of systemic inflammatory rheumatic diseases are largely missing. In this study, we wanted to estimate standard mortality ratios (SMRs) and causes of death in an ethnically homogeneous cohort covering all major CTDs and primary systemic vasculitides (PSVs). Methods: We prospectively followed all incident CTD and PSV cases included in the Norwegian CTD and vasculitis registry (NOSVAR) between 1999 and 2015. Fifteen controls for each patient matched for sex and age were randomly drawn from the Norwegian National Population Registry. Causes of death were obtained from the National Cause of Death Register, death certificates and hospital charts. Results: The cohort included 2140 patients (1534 with CTD, 606 with PSV). During a mean follow-up time of 9 years, 279 of the patients (13%) died, compared with 2864 of 32 086 (9%) controls (P < 0.001). Ten years after diagnosis, the lowest survival was 60% in dcSSc, 73% in anti-synthetase syndrome (ASS) and 75% in lcSSc. In the CTD group, the highest SMRs were observed in dcSSc (SMR 5.8) and ASS (SMR 4.1). In the PSV group, Takayasu arteritis (SMR 2.5) and ANCA-associated vasculitis (SMR 1.5) had the highest SMRs. Major causes of death were cardiovascular disease (CTD 27%, PSV 28%), neoplasms (CTD 25%, PSV 27%), chronic respiratory disease (CTD 20%, PSV10%) and infections (CTD 9%, PSV 16%). Conclusion: We observed premature deaths across the spectrum of CTDs and PSVs, with highest SMRs in dcSSc and ASS. The overall mortality was highest in the CTD group.

Survival and cancer risk in an unselected and complete Norwegian idiopathic inflammatory myopathy cohort.

OBJECTIVE: To utilise an exposed/unexposed cohort strategy for mortality and cancer analyses across unselected and complete cohorts of patients with idiopathic inflammatory myopathy (IIM) resident in south-east Norway (denominator population 2.6 million), between 2003 and 2012. METHOD: IIM cases were identified by comprehensive searches through patient administrative databases followed by manual chart review. Polymyositis (PM) and dermatomyositis (DM) cases were classified by the Peter and Bohan and/or Targoff diagnostic criteria and sporadic inclusion body myositis (sIBM) by the European NeuroMuscular Centre (ENMC) criteria from 1997 and/or 2011. Every patient was matched for sex, age and residential area with 15 unexposed/non-IIM individuals drawn from the national population registry. RESULTS: Total mortality in the IIM cohort was 27% (87/326). Standardized mortality rate (SMR) was higher in DM (2.6) than PM (2.4) and sIBM (1.7). IIM-related causes of death were frequent (64%) and included cancer (all IIM subsets), aspiration (sIBM), pulmonary complications (PM/DM) and infections (PM/DM). Multivariate analyses identified age at diagnosis (PM and sIBM), positive anti-SSA (PM), cancer (DM), and DLCO < 60% (DM) as independent mortality risk factors. Cancer risk was increased in DM (standard incidence rate 2.0) and PM (SIR = 1.3), but not in sIBM (SIR = 0.9). Ovarian cancer was more prevalent in DM than in the general population (8.3% vs 1.1%). CONCLUSION: Our results suggest that mortality rates and cancer risk remain elevated in DM, and to a lesser degree also in PM. Mortality rate was also increased in sIBM, but some deaths appeared to be due to potentially preventable causes.

Predictive value of serial high-resolution computed tomography analyses and concurrent lung function tests in systemic sclerosis.

OBJECTIVE: Systemic sclerosis (SSc) carries a high risk of progressive interstitial lung disease (ILD), but tools for stratifying individual risk are scarce. The purpose of this study was to assess detailed data from serial lung fibrosis measurements and paired pulmonary function tests (PFTs) as outcome prediction tools in a prospective cohort of SSc patients. METHODS: Paired PFTs and high-resolution computed tomography (HRCT) scans were obtained at baseline and at followup in 305 SSc patients who met the American College of Rheumatology/European League Against Rheumatism 2013 classification criteria. The extent of fibrosis was scored on 10 sections from every HRCT scan and expressed as the percentage of the total lung volume. RESULTS: Baseline HRCT analyses revealed 3 SSc subgroups: those with >20% lung fibrosis (n = 40), those with 1-20% fibrosis (n = 157), and those with no fibrosis (n = 108). At followup HRCT (mean of 3.1 years later), all 108 group 3 patients were still free of fibrosis. In group 2 patients, 146 continued to have 1-20% fibrosis (group 2a), whereas 11 (marked by short disease duration of 1.3 years) had experienced progression to >20% fibrosis (group 2b). The annual fibrosis progression rate differed across the 4 groups: 0.9% in group 1, 0.7% in group 2a, 5.9% in group 2b, and 0% in group 3. The annual fibrosis progression rate correlated with the total decline in the forced vital capacity (FVC) (7.1%, 5.7%, 8.7%, and 2.9% in groups 1, 2a, 2b, and 3, respectively), but not the diffusing capacity for carbon monoxide (DLco) (8.4%, 7.7%, 7.7%, and 8.6%, respectively). Multivariate analyses identified anticentromere antibodies (odds ratio [OR] 4.7) and baseline DLco (OR 1.04) as predictors of no fibrosis at followup and baseline fibrosis (OR 1.3) and FVC (OR 0.96) as predictors of >20% fibrosis at followup. CONCLUSION: These prospective cohort data suggest that HRCT performed at baseline predicts the development of fibrosis, the rate of progression of fibrosis, and the decline in pulmonary function in SSc.

Prevalence and clinical characteristics of adult polymyositis and dermatomyositis; data from a large and unselected Norwegian cohort.

OBJECTIVES: The occurrence of polymyositis (PM) and dermatomyositis (DM) in the general population is largely unknown and unbiased data on clinical and laboratory features in PM/DM are missing. Here, we aim to identify and characterise every PM/DM patient living in southeast Norway (denominator population 2.64 million), 2003-2012. METHOD: Due to the structure of the Norwegian health system, all patients with PM/DM are followed at public hospitals. Hence, all public hospital databases in southeast Norway were screened for patients having ICD-10 codes compatible with myositis. Manual chart review was then performed to identify all cases meeting the Peter & Bohan and/or Targoff classification criteria for PM/DM. RESULTS: The ICD-10 search identified 3160 potential myositis patients, but only 208/3160 patients met the Peter & Bohan criteria and 230 the Targoff criteria (100 PM, 130 DM). With 56 deaths during the observation period, point prevalence of PM/DM was calculated to 8.7/100 000. Estimated annual incidences ranged from 6 to 10 /1 000 000, with peak incidences at 50-59 (DM) and 60-69 years (PM). Myositis specific antibodies (Jo-1, PL-7, PL-12, signal recognition particle (SRP) and Mi-2) were present in 53% (109/204), while 137/163 (87%) had pathological muscle MRI. Frequent clinical features included myalgia (75%), arthritis (41%) dyspnoea (62%) and dysphagia (58%). Positive anti-Jo-1, present in 39% of DM and 22% of PM cases, was associated with dyspnoea, arthritis and mechanic hands. CONCLUSIONS: Our data indicate that the population prevalence of PM/DM in Caucasians is quite low, but underscores the complexity and severity of the disorders.

[A man in his forties with swelling in both orbits]. / En mann i 40-årene med hevelse i begge øyehuler.

UNLABELLED: Erdheim-Chester disease. A multi-disiplinary challenge. The histiocytoses are a diverse, but rare group of disorders with symptoms affecting many organs, varying from self-limiting, localised lesions to disseminated multi-organ disease. The diagnostic challenges are illustrated and discussed in the following case. CASE REPORT: A man in his forties was admitted to hospital due to pain in his right eye and visual disturbances. MRI imaging detected a mass in his right orbit and a minor mass in his left orbit. The histological results of the mass in his right orbit revealed an inflammatory process with lymphocytes and macrophages and no sign of vasculitis, infection or malignancy. The diagnosis pseudotumor orbita was made and treatment with corticosteroids was initiated. He did not respond to corticosteroids or radiotherapy and increasing symptoms necessitated rehospitalisation. Further tests disclosed a multisystem disease which affected the aorta, skeleton, lung, heart and kidney. The biopsy was reconsidered and the disease was classified as a histiocytosis with CD68 positive and CD1a negative cells. The diagnosis Erdheim-Chester was given, about 14 months after the initial hospitalisation. Treatment with interferon α was started.

Survival and causes of death in an unselected and complete cohort of Norwegian patients with systemic sclerosis.

OBJECTIVE: To determine survival and causes of death in an unselected and complete cohort of Norwegian patients with systemic sclerosis (SSc) compared to the background population. METHODS: Multiple methods were used to identify every patient with SSc living in southeast Norway, with a denominator population of 2,707,012, between 1999 and 2009. All patients who met either the American College of Rheumatology criteria or the Medsger and LeRoy criteria for SSc were included. Every patient was matched for sex and age with 15 healthy controls drawn from the national population registry. Vital status at January 1, 2010, was provided for patients and controls by the national population registry. Causes of death were obtained from death certificates and by chart review. RESULTS: Forty-three (14%) of 312 patients with SSc died during the study period. The standardized mortality rate (SMR) was estimated to be 2.03 for the entire cohort and 5.33 for the subgroup with diffuse cutaneous (dc) SSc. The 5- and 10-year survival rates were 91% and 70%, respectively, for dcSSc and 98% and 93% for limited cutaneous (lc) SSc. Causes of death were related to SSc in 24/43 (56%) patients, mostly cardiopulmonary diseases (n = 13), including pulmonary hypertension (n = 8). Factors associated with fatal outcome included male sex, dcSSc, pulmonary hypertension, and interstitial lung disease. CONCLUSION: Compared to the Norwegian background population, our cohort of 312 unselected patients with SSc had decreased survival. The survival rates observed were, however, better than those previously reported from SSc referral centers.

Prevalence of pulmonary hypertension in an unselected, mixed connective tissue disease cohort: results of a nationwide, Norwegian cross-sectional multicentre study and review of current literature.

OBJECTIVES: The aim of this study was to assess the overall prevalence of pulmonary hypertension (PH) in an unselected MCTD cohort and review the current knowledge with a systematic database search. METHODS: A nationwide multicentre cohort of 147 adult MCTD patients were initially screened for PH by echocardiography, high-resolution computed tomography (HRCT), pulmonary function tests and N-terminal pro-brain natriuretic peptide (NT-proBNP) and then followed up for a mean of 5.6 years. Right-sided heart catheterization was performed when estimated pulmonary artery systolic pressure was >40 mmHg on echocardiography. PH was diagnosed according to the 2009 European Society of Cardiology and European Respiratory Society guidelines. RESULTS: At inclusion, 2.0% (3/147) had established PH. Two additional PH patients were identified during follow-up, giving a total PH frequency in the cohort of 3.4% (5/147). All five had elevated serum NT-proBNP. Two had isolated pulmonary arterial hypertension (PAH) and three PH associated with interstitial lung disease (PH-ILD). Three PH patients died during follow-up. Nine other patients in the cohort also died, but none of them had echocardiographic signs of PH prior to death. CONCLUSION: The data from the current unselected MCTD cohort suggest that the prevalence of PH is much lower than expected from previous studies but confirm the seriousness of the disease complication.

Clinical pulmonary involvement in primary Sjogren's syndrome: prevalence, quality of life and mortality--a retrospective study based on registry data.

OBJECTIVE: The aim of the present study was to describe the prevalence of clinical pulmonary manifestations in primary SS (pSS), and based on registry data, to assess quality of life (QoL) and mortality in these patients. METHODS: Patients with pSS consecutively included in the Norwegian systemic CTD and vasculitis registry (NOSVAR) were investigated for pulmonary manifestations when presenting with clinical pulmonary symptoms. Pulmonary involvement was defined as typical abnormalities identified with high-resolution CT (HRCT) and/or pulmonary function tests (PFTs). RESULTS: Among patients referred from our primary area, Oslo (n = 117), lung involvement was found in 26 patients (22%). In our total cohort (n = 216), 59 patients (27%) were affected. A higher rate of pulmonary complications and trends towards longer disease duration and higher age indicated a selection of more complicated cases referred from outside our primary area. Abnormal HRCTs were found in 50 patients (23%) and PFTs in 34 patients (16%). The Medical Outcomes Study 36-Item Short-Form Health Survey Physical Functioning subscore, was significantly reduced in patients with lung involvement (P = 0.03). Furthermore, a 4-fold increased risk of dying after 10 years of disease among patients with lung involvement (n = 10, 17%) compared with those without lung involvement (n = 7, 4.5%) (P = 0.002) was found. CONCLUSION: We found a high population-based prevalence of clinical pulmonary involvement (22%) among patients with pSS. Moreover, patients with lung involvement had reduced QoL represented by the subscale Physical Functioning, and mortality was increased.

Long-term follow-up of sporadic inclusion body myositis treated with intravenous immunoglobulin: a retrospective study of 16 patients.

OBJECTIVES: Previous studies of intravenous immunoglobulin (IVIG) treatment in sporadic inclusion body myositis (sIBM) have yielded conflicting results. Here, we have undertaken a retrospective assessment of the long-term effects of IVIG in our sIBM cohort. METHODS: Sixteen sIBM patients, treated with a mean of 10 IVIG infusions and followed up for a mean period of 23 months, were identified. Six sIBM patients treated with other drugs were used as an internal control group. Serial data on manual muscle testing (MMT), laboratory parameters and patients' subjective assessment were collected. RESULTS: Serial MMT scores were available in 14 IVIG treated patients. Two of these patients improved more than 20% in MMT from baseline up to the third IVIG infusion. One of six patients in the control group showed a similar MMT improvement during the first six months. Improved swallowing function was reported by three IVIG-treated patients, but none of the controls. The serum levels of creatine kinase fell more than 20 % after the first IVIG infusion in 7/16 IVIG-treated patients, but this improvement was not sustained during the follow-up period. CONCLUSIONS: IVIG treatment appears to have short-term beneficial effects on muscle strength and dysphagia in some few sIBM patients, but these effects are not sustained over time.

Prevalence and severity of interstitial lung disease in mixed connective tissue disease: a nationwide, cross-sectional study.

BACKGROUND: Mixed connective tissue disease (MCTD) is an immune-mediated, systemic disorder of unknown cause. OBJECTIVE: To assess the prevalence, pattern and severity of interstitial lung disease (ILD) in a cross-sectional study of the nationwide, Norwegian MCTD cohort. METHODS: 126 patients with MCTD were systematically examined for ILD by high-resolution CT (HRCT), pulmonary function tests (PFT), 6 min walk test (6MWT) and by the New York Heart Association (NYHA) functional classification of dyspnoea. The extent and type of HRCT lung abnormalities were scored according to the CT criteria of ILD recommended by the Fleischner Society. RESULTS: All 126 patients were Caucasian, 75% women. At the time of the cross-sectional ILD study, the patients had a mean disease duration of 9.0 years. 52% of the patients had abnormal HRCT findings, most commonly reticular patterns consistent with lung fibrosis (35%). Lung fibrosis was quantified as minor in 7%, moderate in 9% and severe in 19% of the patients. Fibrosis was uniformly concentrated in the lower parts of the lungs and was not associated with smoking. Patients with severe lung fibrosis had lower PFT values, shorter 6MWT and a higher mean NYHA functional class. After a mean 4.2 years' follow-up, overall mortality was 7.9%. Mortality in patients with normal HRCT was 3.3%, as compared with 20.8% in patients with severe lung fibrosis (p<0.01). CONCLUSIONS: Severe lung fibrosis is common in MCTD, has an impact on pulmonary function and overall physical capacity and is associated with increased mortality.

Prevalence of systemic sclerosis in south-east Norway.

OBJECTIVE: To assess the prevalence of SSc in south-east Norway. METHODS: The survey was conducted in south-east Norway with a denominator population of 2,707,012, 56% of the total Norwegian population. All SSc patients living in the study area between 1 January 1999 and 31 December 2009 were included. Patients were identified by five overlapping acquisition routes, including all the rheumatology departments, private rheumatologists and the dermatology department in the study area. Only cases meeting the 1980 ACR and/or the Medsger and LeRoy classification criteria were included. The patients were assigned to three clinical subsets: limited SSc, lcSSc or dcSSc. RESULTS: At the end of the study period, a total of 269 patients fulfilled the ACR and/or the Medsger and LeRoy SSc criteria, giving a point prevalence of 9.9/100,000 (95% CI 8.8, 11.2). The estimated prevalences of lSSc, lcSSc and dcSSc were 1.3/100,000, 6.9/100,000 and 1.8/100,000 (95% CIs 0.9, 1.8; 5.8, 7.8; 1.4, 2.5), respectively. The mean age at onset was 47 years and the female:male ratio was 3.8:1. The prevalence estimates of SSc in the 10 different counties in south-east Norway varied between 5.2 and 14.4/100,000 (95% CIs 2.8, 8.8; 10.3, 19.6). CONCLUSION: This study establishes baseline estimates of the occurrence and disease characteristics in a large, unselected group of Norwegian SSc patients. Our data suggest that the prevalence of SSc in Norway is comparable with other northern European countries, supporting the notion of a north-south gradient of SSc in Europe with the lowest prevalence in northern Europe.

Differences between rheumatologists and other internists regarding diagnosis and treatment of systemic lupus erythematosus.

OBJECTIVES: To compare the diagnostics and treatment of SLE patients in the care of rheumatologists with patients in the care of other specialities within a geographically complete cohort. METHODS: Nine different sources were used to identify SLE patients resident in Oslo between 1999 and 2008. Only SLE patients fulfilling four or more of the updated 1997 ACR criteria were included. Data were extracted from medical records. The patients were classified into three groups according to each patient's responsible doctor's speciality. RESULTS: A total of 325 SLE patients were included in the study. Of these, 227 had solely been in the care of rheumatologists (rheumatology group), 34 had solely been in the care of nephrologists, haematologists or infectious disease specialists (non-rheumatology group) and 64 had been in the care of both rheumatologists and other specialists (multidisciplinary group). Even though patients in the non-rheumatology group and multidisciplinary group showed similar disease characteristics, patients in the non-rheumatology group were less often tested for aPLs (68 vs 94%; P = 0.001) and less often treated with HCQ (12 vs 78%; P < 0.001). CONCLUSIONS: In contrast to rheumatologists, non-rheumatologists do not routinely test all SLE patients for aPLs, and rarely prescribe HCQ. These findings indicate that more communication between different specialists caring for SLE is needed, and highlights an area in need of agreement.

Increased mortality in ankylosing spondylitis is related to disease activity.

BACKGROUND: The onset of disease in ankylosing spondylitis (AS) is generally earlier than in other joint diseases, exposing patients to a prolonged burden of disease. Whether this is associated with excess mortality is still uncertain. Radiation therapy for AS has previously been shown to increase mortality. The present study investigated standardised mortality ratios, causes of death and survival predictors in a large regional cohort of patients with AS. METHOD: A total of 677 patients with AS followed at our hospital since 1977 were matched by gender, age and postal area to three controls from the general population and standardised mortality rates (SMRs) were calculated. Cause of death was established using patients' hospital records. In a subset of 360 patients, clinical and demographic data collected during an earlier research visit (1998-2000) were used in a prospective multivariate analysis of predictors for mortality in AS. RESULTS: The crude mortality among patients with AS in this study was 14.5% (98 patients); SMR was only significantly increased among male patients compared with female patients (1.63 vs 1.38, p<0.001). Circulatory disease was the most frequent cause of death (40.0%), followed by malignant (26.8%) and infectious (23.2%) diseases. Factors independently associated with reduced survival were diagnostic delay (OR 1.05), increasing levels of C-reactive protein (OR 2.68), work disability (OR 3.65) and not using any non-steroidal anti-inflammatory drugs (OR 4.35). CONCLUSIONS: Mortality is increased in patients with AS and circulatory disease is the most frequent cause of death. Parameters reflecting the duration and intensity of inflammation are associated with reduced survival. These results indicate that, to improve long-term survival in AS, there is a need for early detection and anti-inflammatory treatment as well as a vigilant approach for cardiovascular risk factors.

The prevalence and incidence of mixed connective tissue disease: a national multicentre survey of Norwegian patients.

OBJECTIVES: Mixed connective tissue disease (MCTD) is an immune-mediated, systemic disorder of unknown aetiology. As the epidemiology of the disease is largely unknown, the authors performed a nationwide cross-sectional retrospective study to assess the prevalence and incidence of MCTD in Norway. METHODS: Every adult patient (≥ 18 years) with MCTD seen at one of the departments of rheumatology was reviewed for inclusion. Only patients who satisfied the following four criteria were included: clinical diagnosis of MCTD verified by a rheumatologist; positive serum anti-ribonucleoprotein antibody test; fulfilment of at least one of three of following criteria sets: the modified Sharp's criteria, the criteria of Alarcón-Segovia and Villareal and those of Kasukawa; and exclusion of other connective tissue diseases. RESULTS: The four inclusion criteria were fulfilled by 147 adult Caucasian patients. The female to male ratio was 3.3 and the mean age at diagnosis of adult-onset MCTD was 37.9 years (95% CI 35.3 to 40.4 years). At the end of 2008, the point prevalence of living adult MCTD patients in Norway was 3.8 (95% CI 3.2 to 4.4) per 100,000 adults. The incidence of adult-onset MCTD in Norway during the period from 1996 to 2005 was 2.1 (95% CI 1.7 to 2.5) per million per year. CONCLUSIONS: MCTD has a female predominance and the incidence and prevalence of MCTD is low, and lower than reported figures for polymyositis, dermatomyositis, systemic sclerosis and systemic lupus erythematosus. The prevalence estimates were similar across the three criteria sets of MCTD.

[A woman with recurrent urticaria, joint pain and fever]. / En kvinne med tilbakevendende urticaria, leddsmerter og feber.

A middle-aged woman suffered from chronic recurrent urticarial rash and fever. After 13 years of skin disease, she developed monoclonal IgM gammopathy, myalgia and joint pain. She was diagnosed with Schnitzler's syndrome and successfully treated with the IL-1 receptor antagonist anakinra.

Pulmonary outcome in juvenile dermatomyositis: a case-control study.

OBJECTIVES: To compare pulmonary function in patients with juvenile dermatomyositis (JDM) with that of matched controls; and to examine associations between pulmonary function impairment, high-resolution CT (HRCT) abnormalities and other disease variables in patients with JDM. METHODS: A total of 59 patients with JDM clinically examined a median 16.8 years (range 2-38 years) after disease onset were compared with 59 age-matched and sex-matched controls. Pulmonary function tests included spirometry, diffusing capacity for carbon monoxide (DLCO) and body plethysmography. In patients with JDM, HRCT scans were performed and cumulative organ damage and patient-reported health status assessed. RESULTS: Patients with JDM had lower total lung capacity (TLC) and DLCO compared to controls (p=0.003 and <0.001, respectively). A low TLC was found in 26% of patients versus 9% of controls (p=0.026), and a low DLCO in 49% of patients versus 9% of controls (p<0.001). HRCT abnormalities were found in 37% of patients, and included interstitial lung disease (ILD) (14%), chest wall calcinosis (14%) and airway disease (15%). Three patients were diagnosed as having ILD prior to the follow-up visit. A low TLC was more often found in patients with than without abnormal HRCT (50% vs 12%, p=0.002). HRCT abnormality correlated with cumulative organ damage (r(s)=0.346, p=0.008) and patient-reported health status at follow-up (p<0.005). CONCLUSIONS: Patients with JDM had smaller lung volumes than controls; a restrictive ventilatory defect was found in 26% and HRCT abnormality in 37% of the patients, and these findings were associated. Although mostly subclinical, the relatively high frequency of pulmonary involvement highlights the systemic nature of JDM.

[Lupus-nephritis--diagnosis and treatment]. / Lupusnefritt--diagnostikk og behandling.

BACKGROUND: Systemic lupus erythematosus (SLE) is an autoimmune, multiorgan disease that usually affects young women. The kidneys are affected (lupus nephritis) in close to one fifth of the patients. Over the past decade earlier diagnosis and improved treatment of lupus nephritis has resulted in substantial improvement of renal function and patient survival. Despite these advances, 10 - 15 % of SLE patients with lupus nephritis progress to end-stage renal disease, requiring dialysis or renal transplantation. The article outlines main principles for diagnosing and treating lupus nephritis, according to current practice at Oslo University Hospital. MATERIAL AND METHODS: National and international guidelines (on treatment of lupus nephritis), literature identified through a non-systematic search in PubMed and our own clinical experience form the basis for the article. RESULTS: In lupus nephritis, low-dose cyclophosphamide and corticosteroids are topical treatment for induction therapy, and mycophenolate mofetil is an alternative treatment. We recommend maintenance treatment with azathioprine or mycophenolate mofetil for at least two years. Treatment with rituximab may be considered in patients with refractory lupus nephritis. INTERPRETATION: Subtypes and activity of the renal disease are decisive for choice of treatment.

Long-term muscular outcome and predisposing and prognostic factors in juvenile dermatomyositis: A case-control study.

OBJECTIVE: To compare muscle strength, physical health, and HLA-DRB1 allele carriage frequencies in patients with longstanding juvenile dermatomyositis (DM) with that of controls, and to determine the presence of and risk factors for muscle weakness and magnetic resonance imaging (MRI)-detected muscle damage in juvenile DM patients. METHODS: Fifty-nine patients with juvenile DM examined a median of 16.8 years (range 2.0-38.1 years) after disease onset were compared with 59 age- and sex-matched controls. Muscle strength/endurance was measured by manual muscle testing (MMT) and the Childhood Myositis Assessment Scale (CMAS); health status was measured by the Short Form 36. HLA-DRB1 alleles were determined by sequencing in patients and 898 healthy controls. In patients, disease activity/damage was measured by the Disease Activity Score (DAS), Myositis Damage Index (MDI), Health Assessment Questionnaire/Childhood Health Assessment Questionnaire, and MRI scans of the thigh muscles. Early disease characteristics were obtained by chart review. RESULTS: Patients had lower muscle strength/endurance (P < 0.001 for both) and physical health (P = 0.014) and increased HLA-DRB1*0301 (P = 0.01) and DRB1*1401 (P = 0.003) compared with controls. In patients, persistent muscle weakness was found in 42% with MMT (score <78) and in 31% with the CMAS (score <48), whereas MRI-detected muscle damage was found in 52%. Muscle weakness and MRI-detected muscle damage were predicted by MDI muscle damage and a high DAS 1 year postdiagnosis. CONCLUSION: A median of 16.8 years after disease onset, juvenile DM patients were weaker than the controls; muscle weakness/reduced endurance was found in 31-42% of patients and MRI-detected muscular damage was found in 52% of patients. The outcomes were predicted by high disease activity and muscle damage present 1 year postdiagnosis.