Association study of candidate genes for the progression of hand osteoarthritis

OBJECTIVE

Although a few consistent osteoarthritis (OA) susceptibility genes have been identified, little is known on OA progression. Since OA progression is clinically the most relevant phenotype, we investigate the association between asporin (ASPN), bone morphogenetic protein 5 (BMP5) and growth differentiation factor 5 (GDF5) polymorphisms and progression of hand OA.

METHODS

Single-nucleotide polymorphisms (SNPs) ASPN rs13301537, BMP5 rs373444 and GDF5 rs143383 were genotyped in 251 hand OA patients from the Genetics osteoARthritis and Progression (GARP) study and 725 controls. In a case-control comparison we assessed the association between these SNPs and radiographic progression of hand OA over 6 years, which was based on change in osteophytes or joint space narrowing (JSN), above the smallest detectable change. SNPs with suggestive evidence for association were further analysed for their effect on progression over 2 years, and for the mean change in osteophytes and JSN.

RESULTS

The minor allele of ASPN SNP rs13301537 was associated with hand OA progression over 6 years (odds ratio (OR) (95% CI) 1.49 (1.06-2.07); P = 0.020). The mean change in osteophytes and JSN was higher in carriers of the minor allele compared to homozygous carriers of the common allele with mean difference of 0.73 (95% CI - 0.07-1.56; P = 0.073) and 0.82 (95% CI 0.12-1.52; P = 0.022), respectively. An association with similar effect size was found between ASPN SNP rs13301537 and 2-year progression, and the mean change in osteophytes and JSN was significantly higher in homozygotes.

CONCLUSION

ASPN is associated with hand OA progression. This gives insight in the pathogenesis of hand OA progression and identified a potential target for therapeutic approaches.

Concentration-controlled treatment of lupus nephritis with mycophenolate mofetil

Background:

Mycophenolate mofetil (MMF) has recently been established as a potent drug in maintenance treatment for lupus nephritis. However, there is no consensus on the optimal dosing regimen because of a high inter-individual variability of mycophenolic acid (MPA), the active metabolite of MMF. This retrospective study aimed to investigate the effect of an individualized dosing regimen through concentration-controlled treatment on MPA exposure and renal outcome in patients with lupus nephritis.

Methods:

Sixteen patients with lupus nephritis and treatment with low-dose intravenous cyclophosphamide followed by MMF were included. MPA area under the plasma concentration-time curve from 0 to 12 hours (MPA-AUC0–12) was assessed within a month after MMF initiation. After determination of MPA-AUC0–12, MMF doses were titrated to achieve a target MPA-AUC0–12 of 60–90 mg*h/l. After on average six months, MPA-AUC0–12 measures were repeated to assess the effect of dose adjustment.

Results:

One month after introducing MMF, MPA-AUC0–12 was low and showed a high inter-individual variability. Dose adjustment with a target MPA-AUC0–12 of 60–90 mg*h/l resulted in individualized MMF dosing, significantly higher MPA-AUC0–12 levels, and a non-significant reduction in variability of MPA-AUC0–12. Adverse effects were reported by 37.5% of patients, which resulted in a switch to azathioprine in two patients. There was no significant relationship between the occurrence of adverse effects and MPA-AUC0–12. At 12 months of follow-up 87.5% of patients had achieved either partial (18.7%) or complete (68.8%) remission.

Conclusion:

Concentration-controlled dose adjustments with a target MPA-AUC0–12 of 60–90 mg*h/l was associated with optimized MPA exposure and an excellent renal outcome at 12 months of follow-up in a small sample of SLE patients with lupus nephritis.

Risk of alanine transferase (ALT) elevation in patients with rheumatoid arthritis treated with methotrexate in a DAS-steered strategy

OBJECTIVE

To determine incidence of increased levels of alanine transferase (ALT) >2× upper limit of normal (ULN) in patients receiving methotrexate (MTX), treated according to a dynamic strategy, and to identify predictors of ALT of >2× ULN.

METHODS

Data of 508 recent-onset rheumatoid arthritis (RA) patients from the BeSt study, randomized to initial monotherapy or combination therapy, were used. Treatment was dynamic, aiming at a disease activity score = ≤ 2.4. ALT was measured every three months. With logistic regression analyses, baseline variables predictive of first ALT of >2× ULN were identified and the association between use of concomitant antirheumatic drugs, the actual and cumulative dose of MTX and ALT of >2× ULN was determined.

RESULTS

In total, 498 patients ever initiated MTX, with a total duration on MTX of 1,416 patient-years. In 89 patients, a first incidence of ALT of >2× ULN occurred. Incidence rate was 6.3 per 100 patient-years and cumulative incidence 18 %. ACPA positivity and baseline ALT of >1× ULN were independent predictors of later ALT of >2× ULN (OR 1.8 (95 % CI, 1.1-3.1) and OR 3.1 (95 % CI, 1.6-6.2), respectively). Smoking showed a trend (OR 1.6 (95 % CI, 0.98-2.7)). Mean MTX dosage over time was higher in patients with an ALT of >2× ULN. Patients who did not have an ALT of >2× ULN used more concomitant disease-modifying antirheumatic drugs and longer.

CONCLUSIONS

In RA patients treated with MTX according to a dynamic strategy resembling daily clinical practice, incidence of increased ALT of >2× ULN was lower than previously reported, and also without treatment adjustments, persistence was rare. The recommendations for ALT monitoring may be reevaluated.

New biomarkers in rheumatoid arthritis

Rheumatoid arthritis (RA) is a common autoimmune disease affecting around 1% of the population. Although major advances have been made in the treatment of RA, still relatively little is known on disease pathogenesis and aetiology. From treatment studies it has become clear that treating patients early in their disease course will provide the best results. However, especially in the early phase of arthritis, in particular when the patients do not yet fulfil the criteria for RA, it is difficult to decide which patients would benefit most from an early and aggressive intervention. Good biomarkers are important to guide decisions in the clinical management of RA. Next to the well-known rheumatoid factor (RF) and the anti-citrullinated protein antibodies (ACPA), several new markers are now likely to become available with interesting potential. Besides antibody responses directed against citrullinated proteins, also antibodies against carbamylated proteins (anti-CarP) have recently been shown to be present in RA. Interestingly these anti-CarP antibodies are also present in around 20% of the ACPA-negative RA patients and are associated with more severe joint damage in this group. Apart from the antibodies that help in establishing the diagnosis and prognosis, also novel biomarkers that reflect clinical disease activity scores are being discovered. The development of biomarker-based disease activity scores might allow easy and frequent monitoring of patients to rapidly adjust treatment.

Genetic variants in IL15 associate with progression of joint destruction in rheumatoid arthritis: a multicohort study

BACKGROUND

Interleukin (IL)-15 levels are increased in serum, synovium and bone marrow of patients with rheumatoid arthritis (RA). IL-15 influences both the innate and the adaptive immune response; its major role is activation and proliferation of T cells. There are also emerging data that IL-15 affects osteoclastogenesis. The authors investigated the association of genetic variants in IL15 with the rate of joint destruction in RA.

METHOD

1418 patients with 4885 x-ray sets of both hands and feet of four independent data sets were studied. First, explorative analyses were performed on 600 patients with early RA enrolled in the Leiden Early Arthritis Clinic. Twenty-five single-nucleotide polymorphisms (SNPs) tagging IL-15 were tested. Second, SNPs with significant associations in the explorative phase were genotyped in data sets from Groningen, Sheffield and Lund. In each data set, the relative increase of the progression rate per year in the presence of a genotype was assessed. Subsequently, data were summarised in an inverse weighting meta-analysis.

RESULTS

Five SNPs were significantly associated with rate of joint destruction in phase 1 and typed in the other data sets. Patients homozygous for rs7667746, rs7665842, rs2322182, rs6821171 and rs4371699 had respectively 0.94-, 1.04-, 1.09-, 1.09- and 1.09-fold rate of joint destruction compared to other patients (p=4.0×10(-6), p=3.8×10(-4), p=5.0×10(-3), p=5.0×10(-3) and p=9.4×10(-3)).

DISCUSSION

Independent replication was not obtained, possibly due to insufficient power. Meta-analyses of all data sets combined resulted in significant results for four SNPs (rs7667746, p<0.001; rs7665842, p<0.001; rs4371699, p=0.01; rs6821171, p=0.01). These SNPs were also significant after correction for multiple testing.

CONCLUSION

Genetic variants in IL-15 are associated with progression of joint destruction in RA.

Prevalence of vertebral fractures in a disease activity steered cohort of patients with early active rheumatoid arthritis

Objective

To determine the prevalence of vertebral fractures (VFs) after 5 years of disease activity score (DAS)-steered treatment in patients with early rheumatoid arthritis (RA) and to investigate the association of VFs with disease activity, functional ability and bone mineral density (BMD) over time.

Methods

Five-year radiographs of the spine of 275 patients in the BeSt study, a randomized trial comparing four treatment strategies, were used. Treatment was DAS-steered (DAS ≤ 2.4). A height reduction >20% in one vertebra was defined a vertebral fracture. With linear mixed models, DAS and Health Assessment Questionnaire (HAQ) scores over 5 years were compared for patients with and without VFs. With generalized estimating equations the association between BMD and VFs was determined.

Results

VFs were observed in 41/275 patients (15%). No difference in prevalence was found when stratified for gender, prednisone use and menopausal status. Disease activity over time was higher in patients with VFs, mean difference 0.20 (95% CI: 0.05-0.36), and also HAQ scores were higher, independent of disease activity, with a mean difference of 0.12 (95% CI: 0.02-0.2). Age was associated with VFs (OR 1.06, 95% CI: 1.02-1.09), mean BMD in spine and hip over time were not (OR 95% CI, 0.99: 0.78-1.25 and 0.94: 0.65-1.36, respectively).

Conclusion

After 5 years of DAS-steered treatment, 15% of these RA patients had VFs. Higher age was associated with the presence of VFs, mean BMD in hip and spine were not. Patients with VFs have greater functional disability over time and a higher disease activity, suggesting that VFs may be prevented by optimal disease activity suppression.

'Insights in the relationship of joint space narrowing versus erosive joint damage and physical functioning of patients with RA'

OBJECTIVE

To evaluate the contribution of joint space narrowing (JSN) and erosions in general and in four different joint groups in relation to physical disability in rheumatoid arthritis (RA).

METHODS

5-year follow-up data from the Behandel Strategieën (BeSt) trial were used, where 508 patients with recent onset RA were treated aiming at a disease activity score≤2.4. Joint damage was assessed annually and scored according to the Sharp-van der Heijde method. Physical disability was measured 3-monthly with the Health Assessment Questionnaire (HAQ). Generalised Estimating Equations analyses were performed to assess the relationship between the HAQ and JSN scores and erosions scores, separately and in joint groups.

RESULTS

Overall, damage scores were low, and neither total JSN nor erosions showed a significant effect on HAQ (β=0.001 95% CI -0.003 to 0.004 and β=0.002 95% CI -0.001 to 0.006, respectively). Of the total damage scores per joint group, damage in the wrist shows a trend for association with physical disability displaying the largest effect size (β=0.005 95% CI 0.000 to 0.011). Also in the analysis with erosions per joint group, the wrist was most strongly related with physical functioning (β=0.016 95% CI 0.003 to 0.029); in the analysis with JSN per joint group no joint group was significantly related to the HAQ. Analysis of all erosion and narrowing scores per joint group in one model reveals only erosions in the wrist to be independently associated with impaired physical functioning (β=0.017 95% CI 0.003 to 0.030).

CONCLUSIONS

Joint damage in the wrist, erosions more than JSN, is associated with impaired physical functioning even in patients with early RA with limited overall damage after 5 years tightly controlled treatment.

Evaluating joint destruction in rheumatoid arthritis: is it necessary to radiograph both hands and feet?

BACKGROUND

Radiological damage is an important outcome measure in rheumatoid arthritis (RA), both for research and clinical purposes. Depending on the setting, both hands and feet are radiographed, or only a part of these. It is unknown whether radiographing part of the four extremities gives comparable information to radiographing both hands and feet. This study therefore aimed to compare the radiological information obtained both when evaluating single time point radiographs and progression over time, in early and advanced RA.

METHODS

6261 sets of hands and feet x-rays of 2193 RA patients from Leiden, Groningen (both from The Netherlands) and North America were studied. Correlations between joint damage at different regions were compared (unilateral vs bilateral and hands vs feet). Analyses were done at single time points (cross-sectional) and for progression over time (longitudinal), both for continuous severity measures (Sharp/van der Heijde score; SHS) and binomial measures of erosiveness.

RESULTS

When studying single time points, the severity of joint damage (SHS) is highly correlated between left and right, but weakly correlated between hands and feet. Correlation coefficients were higher in advanced than early RA. These findings were comparable in the three datasets. When evaluating erosiveness using only unilateral x-rays or hands without feet, 19.3% and 24.0-40.4% are incorrectly classified as non-erosiveness. Similarly, when evaluating disease progression by imaging only unilateral x-rays or only hand x-rays, progression would have been missed in 11.6-16.2% and 21.2-31.0% of patients.

CONCLUSION

Performing x-rays of both hands and feet yields additive information compared with imaging only a part of these.

Adding tocilizumab or switching to tocilizumab monotherapy in methotrexate inadequate responders: 24-week symptomatic and structural results of a 2-year randomised controlled strategy trial in rheumatoid arthritis (ACT-RAY)

Objective

In patients with active rheumatoid arthritis (RA) despite methotrexate, to compare the efficacy of adding tocilizumab to that of switching to tocilizumab monotherapy.

Methods

Double-blind, 2-year study in which adults with active RA (DAS28 >4.4) despite methotrexate were randomly assigned either to continue methotrexate with the addition of tocilizumab (MTX+TCZ) 8 mg/kg every 4 weeks or switch to tocilizumab and placebo (TCZ+PBO). The primary endpoint was the DAS28–erythrocyte sedimentation rate (ESR) remission rate at week 24. Secondary objectives included other symptomatic outcomes, quality of life and progression of structural damage.

Results

Of 556 randomly assigned patients, 512 (92%) completed 24 weeks. DAS28–ESR remission rates were 40.4% for TCZ+MTX and 34.8% for TCZ+PBO (p=0.19); American College of Rheumatology 20/50/70/90 rates were 71.5%/45.5%/24.5%/5.8% (TCZ+MTX) and 70.3%/40.2%/25.4%/5.1% (TCZ+PBO; differences not significant). A significant difference between groups was seen for low DAS28 (61.7% vs 51.4%). Radiographic progression was small and not different between groups (Genant–Sharp score progression ≤ smallest detectable change in 91% (TCZ+MTX) and 87% (TCZ+PBO)). Rates per 100 patient-years of serious adverse events and serious infections were 21 and six, respectively, for TCZ+MTX and 18 and six, respectively, for TCZ+PBO. Alanine aminotransferase elevations greater than threefold the upper limit of normal occurred in 7.8% and 1.2% of TCZ+MTX and TCZ+PBO patients, respectively.

Conclusion

No clinically relevant superiority of the TCZ+MTX add-on strategy over the switch to tocilizumab monotherapy strategy was observed. The combination was more commonly associated with transaminase increases. Meaningful clinical and radiographic responses were achieved with both strategies, suggesting that tocilizumab monotherapy might be a valuable treatment strategy in suitable RA patients.

Rapid radiological progression in the first year of early rheumatoid arthritis is predictive of disability and joint damage progression during 8 years of follow-up

OBJECTIVE

Several prediction models for rapid radiological progression (RRP) in the first year of rheumatoid arthritis have been designed to aid rheumatologists in their choice of initial treatment. The association was assessed between RRP and disability and joint damage progression in 8 years.

METHODS

Patients from the BeSt cohort were used. RRP was defined as an increase of ≥5 points in the Sharp/van der Heijde score (SHS) in year 1. Functional ability over 8 years, measured with the health assessment questionnaire (HAQ), was compared for patients with and without RRP using linear mixed models. Joint damage progression from years 1 to 8 was compared using logistic regression analyses.

RESULTS

RRP was observed in 102/465 patients. Over 8 years, patients with RRP had worse functional ability: difference in HAQ score 0.21 (0.14 after adjustment for disease activity score (over time)). RRP was associated with joint damage progression ≥25 points in SHS in years 1-8: OR 4.6.

CONCLUSION

RRP in year 1 is a predictor of worse functional ability over 8 years, independent of baseline joint damage and disease activity. Patients with RRP have more joint damage progression in subsequent years. RRP is thus a relevant outcome on which to base the initial treatment decision.