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Dive into the research topics where Marek Zak is active.

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Featured researches published by Marek Zak.


Arthritis & Rheumatism | 2011

Ongoing disease activity and changing categories in a long‐term nordic cohort study of juvenile idiopathic arthritis

Ellen Nordal; Marek Zak; Kristiina Aalto; Lillemor Berntson; Anders Fasth; Troels Herlin; Pekka Lahdenne; Susan Nielsen; Bjørn Straume; Marite Rygg

OBJECTIVE To describe the disease characteristics, long-term course, and outcome of patients with juvenile idiopathic arthritis (JIA) in a population-based setting. METHODS Consecutive cases of JIA from defined geographic areas of Denmark, Finland, Sweden, and Norway in whom disease onset occurred in 1997-2000 were included in a prospective, multicenter cohort study. The study was designed to be as close to a population-based study as possible, with centers participating only if they were able to include in their catchment area all children in whom JIA was diagnosed. RESULTS Of 500 children included, 440 (88.0%) had repeated visits, with the last visit occurring at least 7 years after disease onset (median 98 months, range 84-147 months). Changes in the International League of Associations for Rheumatology category were observed in 10.8% of the children, and, in addition, extended oligoarthritis developed in 34.7% of the group with oligoarticular JIA. During the observation period, 58.0% of the children were treated with disease-modifying antirheumatic drugs, including biologic medications. Ongoing disease activity was mostly mild, but some JIA-related damage developed in 22.9% of the children. At the last followup visit, remission off medication was observed in 42.4% of the children, 8.9% were in remission on medication, and 48.7% were not in remission. The highest rates of remission were observed in patients with persistent oligoarticular JIA and in those with systemic JIA. CONCLUSION In this long-term prospective study of JIA in a population-based Nordic setting, ongoing disease was evident in a majority of the children. The present results underline the need to identify early predictors of outcome, to further improve therapy, and to continue long-term followup of patients with JIA.


Scandinavian Journal of Rheumatology | 2012

Long-term outcome in patients with juvenile dermatomyositis: a cross-sectional follow-up study

P Mathiesen; H Hegaard; Troels Herlin; Marek Zak; Fk Pedersen; Susan Nielsen

Objective: To evaluate a group of 53 patients with juvenile dermatomyositis (JDM), on average 13.9 years after disease onset, in order to describe the long-term disease outcome and to identify disease-related parameters associated with poor disease outcome. Methods: Baseline information at disease onset was obtained from medical records. Disease status at follow-up was evaluated by physical examination. The Myositis Damage Index (MDI) and the Myositis Disease Damage by Visual Analogue Scale (MYODAM-VAS) were used to describe disease damage. Results: Disease damage was seen in 60.4% of patients. The most common damage was cutaneous scarring (39.6%) and muscle dysfunction (34%). Calcinosis was found in 20%, lipodystrophy in 13%, and severe damage affecting more than two organ systems in 24.5% of patients. A disease duration > 4 years increased the risk of damage based on: MDI score [adjusted odds ratio (AOR) 8.3, 95% confidence interval (CI) 1.7–41.7], MYODAM-VAS score (AOR 26.2, 95% CI 3.1–223.7), and number of affected organs (AOR 16.3, 95% CI 1.1–232.4). Disease onset age ≥ 7.4 years increased the risk of more than two affected organs (AOR 15.8, 95% CI 1.9–129.4). Disease duration ≥ 4 years increased the risk of calcinosis (OR 4.8, 95% CI 1.1–20.9) and continuous muscle dysfunction (OR 4.2, 95% CI 1.1–17.3). Conclusion: In a long-term follow-up study, 60% of JDM patients had disease damage at a mean of 14 years after disease onset. Longer disease duration was the most important predictor of damage, calcinosis, and impaired muscle function, and higher age at disease onset predicted more organs involved at follow-up.


Annals of the Rheumatic Diseases | 2012

Validity and predictive ability of the juvenile arthritis disease activity score based on CRP versus ESR in a Nordic population-based setting

Ellen Nordal; Marek Zak; Kristiina Aalto; Lillemor Berntson; Anders Fasth; Troels Herlin; Pekka Lahdenne; Susan Nielsen; Suvi Peltoniemi; Bjørn Straume; Marite Rygg

Objective To compare the juvenile arthritis disease activity score (JADAS) based on C reactive protein (CRP) (JADAS-CRP) with JADAS based on erythrocyte sedimentation rate (ESR) (JADAS-ESR) and to validate JADAS in a population-based setting. Methods The CRP and ESR values and the corresponding JADAS scores (JADAS10/27/71) were compared in a longitudinal cohort study of 389 children newly diagnosed with juvenile idiopathic arthritis (JIA) in the Nordic JIA study. The construct validity and the discriminative and predictive ability of JADAS were assessed during a median disease course of 8 years by comparing JADAS with other measures of disease activity and outcome. Results At the first study visit the correlation between JADAS27-CRP and JADAS27-ESR was r=0.99 whereas the correlation between CRP and ESR was r=0.57. Children with higher JADAS scores had an increased risk of concomitant pain, physical disability and use of disease-modifying antirheumatic drugs (DMARDs). A higher JADAS score at the first study visit also significantly predicted physical disability, damage and no remission off medication at the final study visit, and also use of DMARDs during the disease course. Sensitivity to change, demonstrated as change in JADAS score compared with the American College of Rheumatology paediatric measures of improvement criteria, mostly showed excellent classification ability. Conclusion The JADAS-CRP and JADAS-ESR correlate closely, show similar test characteristics and are feasible and valid tools for assessing disease activity in JIA.


Rheumatology | 2011

3D analysis of facial asymmetry in subjects with juvenile idiopathic arthritis

Sune Demant; Nuno V. Hermann; Tron A. Darvann; Marek Zak; Helena Schatz; Per Larsen; Sven Kreiborg

OBJECTIVE To investigate and compare facial asymmetry in subjects with JIA with unilateral, bilateral or no TM joint (TMJ) involvement. METHODS Eighty-one subjects with JIA: 22 with unilateral TMJ involvement (Group 1), 15 with bilateral TMJ involvement (Group 2) and 44 with no TMJ involvement (Group 3). Panoramic X-rays and three-dimensional (3D) photographs (surface scans) were obtained for all subjects. Panoramic X-rays were rated for severity of TMJ involvement. For each individual, a spatially detailed facial asymmetry map was created from the 3D photograph. Mean and variability of asymmetry were calculated for each of the three groups and compared. RESULTS Distinct patterns of asymmetry were found in Groups 1 and 2. With mean asymmetry values up to 3.5 mm, Group 1 exhibited a significantly greater amount of asymmetry in a broad band along the lower jaw extending from the region of the condyle to the chin than Group 2. The mean facial asymmetry (1 S.D.) for each JIA group was 2.3 (0.9), 2.0 (0.7), 1.7 (0.5) mm for Groups 1, 2 and 3, respectively. CONCLUSION JIA subjects with TMJ involvement displayed patterns of facial asymmetry consistent with the destruction of the condylar growth centre, leading to mandibular asymmetry with displacement of the bony chin. Facial asymmetry quantification was found to be an effective method for assessing both the amount and the localization and spatial extent of asymmetry in all 3Ds.


Pediatric Rheumatology | 2014

Anti-type II collagen antibodies, anti-CCP, IgA RF and IgM RF are associated with joint damage, assessed eight years after onset of juvenile idiopathic arthritis (JIA).

Lillemor Berntson; Ellen Nordal; Anders Fasth; Kristiina Aalto; Troels Herlin; Susan Nielsen; Marite Rygg; Marek Zak; Johan Rönnelid

BackgroundEarly appearance of antibodies specific for native human type II collagen (anti-CII) characterizes an early inflammatory and destructive phenotype in adults with rheumatoid arthritis (RA). The objective of this study was to investigate the occurrence of anti-CII, IgM RF, IgA RF and anti-CCP in serum samples obtained early after diagnosis, and to relate the occurrence of autoantibodies to outcome after eight years of disease in children with juvenile idiopathic arthritis (JIA).MethodsThe Nordic JIA database prospectively included JIA patients followed for eight years with data on remission and joint damage. From this database, serum samples collected from 192 patients, at a median of four months after disease onset, were analysed for IgG anti-CII, IgM RF, IgA RF and IgG anti-CCP. Joint damage was assessed based on Juvenile Arthritis Damage Index for Articular damage (JADI-A), a validated clinical instrument for joint damage.ResultsElevated serum levels of anti-CII occurred in 3.1%, IgM RF in 3.6%, IgA RF in 3.1% and anti-CCP in 2.6% of the patients. Occurrence of RF and anti-CCP did to some extent overlap, but rarely with anti-CII. The polyarticular and oligoarticular extended categories were overrepresented in patients with two or more autoantibodies. Anti-CII occurred in younger children, usually without overlap with the other autoantibodies and was associated with high levels of C-reactive protein (CRP) early in the disease course. All four autoantibodies were significantly associated with joint damage, but not with active disease at the eight-year follow up.ConclusionsAnti-CII, anti-CCP, IgA RF and IgM RF detected early in the disease course predicted joint damage when assessed after eight years of disease. The role of anti-CII in JIA should be further studied.


European Journal of Pediatrics | 2013

Multicentric osteolysis with nodulosis and arthropathy (MONA) with cardiac malformation, mimicking polyarticular juvenile idiopathic arthritis: case report and literature review

Filip Christian Castberg; Susanne Kjaergaard; Rebecca A. Mosig; Mollie Lobl; Chiara R. Martignetti; John A. Martignetti; Charlotte Myrup; Marek Zak

The ‘vanishing bone’ syndrome multicentric osteolysis with nodulosis and arthropathy (MONA) is a rare chronic skeleton disorder caused by matrix metalloproteinase 2 (MMP2) deficiency, mimicking erosive polyarticular juvenile idiopathic arthritis. MONA is characterised by facial dysmorphism, subcutaneous fibrocollagenous nodules, carpal and tarsal osteolysis and interphalangeal joint erosions. We present the case of a 5-year-old boy with double outlet right ventricle, ventricular septal defect, coarctation of the aorta and MONA. Previously, a total of 24 cases of MONA have been reported of which six also had congenital cardiac malformations. Despite treatment attempts of our patient with methotrexate, eternacept and prednisolone, serial X-ray studies documented continuous severe bone degeneration. Conclusion: The case documents the natural history of MONA and establishes a link between MMP2 deficiency and heart development, and given the recurring cardiac association, we suggest that all MONA patients be examined for possible cardiac defects.


Pediatric Rheumatology | 2012

Juvenile systemic lupus erythematosus onset patterns in Vietnamese children: a descriptive study of 45 children

Nguyen Thi Ngoc Dung; Huynh Thoai Loan; Susan Nielsen; Marek Zak; Freddy K Petersen

BackgroundIncidence and disease pattern of childhood-onset SLE is reported to differ among ethnic groups.MethodsTo describe disease pattern and 6 month follow-up in a referral based cohort of 45 Vietnamese children with SLE. Forty-five children who were subsequently diagnosed to have systemic lupus erythematosus (f/m = 4/1) were referred to the Ho Chi Minh City Children’s Hospital No.1 during a 12-month period in 2009.ResultsThe mean age at diagnosis was 12.8 years (SD = 2.5). Thirty-seven (82%) fulfilled criteria for lupus nephritis (LN). At diagnosis, impressively high SLEDAI and ECLAM scores were recorded (mean and SD), 23.8 (11.6) and 6 (2.3), respectively. The mean renal SLEDAI score was 8.2. The mean haemoglobin (g/dL, SD) was 8.5 (2.1). The Coombs test was positive in 30 of 36 children (83%). The mean plasma creatinine was 0.98 (SD 1.2) and mean Westergren sedimentation rate was 83.6 (SD 37.4). The patient age at diagnosis was positively correlated to the SLEDAI (p = 0.034) and ECLAM (p = 0.022). At 6 month follow-up of the 45 children, 15 patients were in complete remission, 5 were in partial remission, 6 had stable disease, 3 had relapsed, 3 had evolving disease, 2 had ongoing resistant disease and 4 had died. Seven patients were lost to follow-up. A second renal biopsy showed an improved ISN class in 13 of 15; in 2 cases the ISN class remained unchanged.ConclusionsForty-five Vietnamese children with SLE were referred to Ho Chi Minh Children’s Hospital No. 1 during a16 month period from 2008–2009. These patients had a strikingly high prevalence of Coombs positive anaemia, a high prevalence of lupus nephritis, and very high SLEDAI and ECLAM scores at the time of diagnosis. While there may be referral biases, our Vietnamese SLE patients appear to have severe disease upon presentation but do reasonably well in the short-term.


The Journal of Rheumatology | 2009

Cartilage Oligomeric Matrix Protein in Patients with Juvenile Idiopathic Arthritis: Relation to Growth and Disease Activity

Birgitte Bjørnhart; Anders Juul; Susan Nielsen; Marek Zak; Pernille Svenningsen; Klaus Müller

Objective. Cartilage oligomeric matrix protein (COMP) has been identified as a prognostic marker of progressive joint destruction in rheumatoid arthritis. In this population based study we evaluated associations between plasma concentrations of COMP, disease activity, and growth velocity in patients with recent-onset juvenile idiopathic arthritis (JIA). COMP levels in JIA and healthy children were compared with those in healthy adults. Plasma levels of insulin-like growth factor I (IGF-1), which has been associated with COMP expression and growth velocity, were studied in parallel. Methods. 87 patients with JIA entered the study, including oligoarticular JIA (n = 34), enthesitis-related arthritis (n = 8), polyarticular rheumatoid factor (RF)-positive JIA (n = 2), polyarticular RF-negative JIA (n = 27), systemic JIA (n = 6), and undifferentiated JIA (n = 10). Plasma levels of COMP were measured by ELISA and IGF-1 by a radioimmunoassay. Results. Significantly higher COMP levels [mean 18.9 U/l (95% CI 17.3–20.5)] were found in healthy children compared with healthy adults [mean 10.7 U/l (95% CI 9.4–12.1)] (p < 0.0001). COMP levels in the JIA patients [mean 13.5 U/l (95% CI 12.4–14.7)] were significantly reduced compared to healthy children (p < 0.0001), and correlated negatively with C-reactive protein (CRP; r = −0.29, p = 0.01) and thrombocyte count (r = −0.28, p = 0.02). COMP levels in the JIA patients correlated positively with growth velocity (cm/yr) (r = 0.38, p = 0.0003) and growth velocity (SDS) (r = 0.29, p = 0.007). Conclusion. We found reduced COMP levels in children with JIA compared with healthy children. COMP levels in JIA correlated negatively with inflammatory activity as evaluated by CRP and the thrombocyte counts, and were associated with reduced growth rate.


Pediatric Rheumatology | 2017

Psoriasis and associated variables in classification and outcome of juvenile idiopathic arthritis - an eight-year follow-up study

Maria Ekelund; Kristiina Aalto; Anders Fasth; Troels Herlin; Susan T. Nielsen; Ellen Nordal; Suvi Peltoniemi; Marite Rygg; Marek Zak; Lillemor Berntson

BackgroundTo study the impact of psoriasis and features associated with psoriasis on classification and outcome in a population-based follow-up cohort of children with juvenile idiopathic arthritis (JIA).MethodsIn all, 440 children with JIA were followed for a median of 8 years in a prospective Nordic population-based cohort study. Data for remission was available for 427 of these children. The presence of psoriasis, psoriasis-like rash, dactylitis, nail pitting, enthesitis, tenosynovitis and heredity was assessed in relation to ILAR classification and remission.ResultsClinical findings associated with psoriasis developed consecutively during the 8-year period. Six of 14 children with psoriasis were not classified as juvenile psoriatic arthritis according to the ILAR criteria at 8 year follow-up. Dactylitis was more common in children with early onset of JIA. After 8 years we found a cumulative median number of eleven arthritic joints in children with psoriasis or psoriasis-like rash compared with six in the rest of the cohort (p = 0.02). Also, the chance for not being in remission after 8 years increased significantly in patients with psoriasis, psoriasis-like rash or at least two of: 1) first-degree heredity for psoriasis or psoriatic arthritis, 2) dactylitis or 3) nail pitting, compared with the rest of the group (OR 3.32, p = 0.010).ConclusionsOur results indicate a more severe disease over time in psoriasis-associated JIA, as features of psoriasis develop during the disease course. This group is a major challenge to encompass in a future JIA classification in order to facilitate early tailored treatment.


Scandinavian Journal of Rheumatology | 2000

Erythrocyte-methotrexate and disease activity in children treated with oral methotrexate for juvenile chronic arthritis.

Kim Kristensen; Susan Nielsen; Freddy Karup Pedersen; Marek Zak

The concentration of methotrexate (MTX) in erythrocytes (E-MTX) was measured twice with three months interval in 21 children suffering from juvenile chronic arthritis (JCA). At the same time joint score, visual analogue scale (VAS), and laboratory parameters (CRP, WBC, PMNs, and ALAT) were obtained. There was only a weak insignificant correlation between the dose of MTX/m2 and E-MTX (r=0.24, p=0.11). No significant relations between the clinical or laboratory parameters and E-MTX was found. However, ALAT above normal range was associated with a lower dose of MTX (p=0.02) and lower VAS (p=0.02), indicating that toxicity may be associated with less articular discomfort. At present we consider routine determination of E-MTX in children with JCA of limited value.The concentration of methotrexate (MTX) in erythrocytes (E-MTX) was measured twice with three months interval in 21 children suffering from juvenile chronic arthritis (JCA). At the same time joint score, visual analogue scale (VAS), and laboratory parameters (CRP, WBC, PMNs, and ALAT) were obtained. There was only a weak insignificant correlation between the dose of MTX/m2 and E-MTX (r=0.24, p=0.11). No significant relations between the clinical or laboratory parameters and E-MTX was found. However, ALAT above normal range was associated with a lower dose of MTX (p=0.02) and lower VAS (p=0.02), indicating that toxicity may be associated with less articular discomfort. At present we consider routine determination of E-MTX in children with JCA of limited value.

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Susan Nielsen

Copenhagen University Hospital

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Ellen Nordal

University Hospital of North Norway

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Marite Rygg

Norwegian University of Science and Technology

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Anders Fasth

University of Gothenburg

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Klaus Müller

Copenhagen University Hospital

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Pekka Lahdenne

Helsinki University Central Hospital

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