ObjectivesClinically suspect arthralgia (CSA) is an at-risk stage of rheumatoid arthritis (RA), in which patients experience symptoms and physical limitations. Perceptions of CSA-patients have... Show moreObjectivesClinically suspect arthralgia (CSA) is an at-risk stage of rheumatoid arthritis (RA), in which patients experience symptoms and physical limitations. Perceptions of CSA-patients have remained largely unknown. Therefore, we aimed to map perceptions of CSA-patients and compare these to RA-patients. Additionally, we studied changes in perceptions in CSA over time.MethodsThree hundred and ninety-nine consecutively included CSA-patients from the Leiden and Rotterdam CSA-cohorts and 100 recently diagnosed RA-patients from the Leiden Early Arthritis Clinic were included. Patients’ illness perceptions (IP) were assessed using the Brief Illness Perception Questionnaire (BIPQ), consisting of 8 questions (scale 0–10; higher score indicating more negative IP) covering cognitive, emotional and comprehensibility domains, and one open question about causes of disease. IP were measured at baseline in both populations and during 2 years follow-up in the CSA-cohorts.ResultsTotal BIPQ-scores were comparable at CSA-presentation and RA-diagnosis (40 ± 11 and 40 ± 10; range 0–80). Comparing dimensions separately revealed that CSA-patients were less worried about physical complaints compared to RA-patients. However, CSA-patients were more negative about expected treatment-effect on symptoms. IP over time in CSA improved in patients without development of clinical arthritis (from 38 ± 11 to 34 ± 14; P = 0.005) but remained similar in CSA-patients who progressed to arthritis/RA (mean 40 at both timepoints). CSA-patients mainly perceived physical strain and heredity as causes of their complaints.ConclusionsAlthough CSA-patients have not developed clinical arthritis, illness perceptions at CSA-presentation and RA-diagnosis are equally severe. Knowledge on worries and expectations may contribute to improving patient-contact and care in patients at risk of RA. Show less
Dijk, B.T. van; Boeren, A.M.P.; Khidir, S.J.H.; Hollander, N.K. den; Helm-van Mil, A.H.M. van der 2024
Objectives Rheumatoid arthritis (RA) mainly affects small joints. Despite the mechanical function of joints, the role of mechanical stress in the development of arthritis is insufficiently... Show moreObjectives Rheumatoid arthritis (RA) mainly affects small joints. Despite the mechanical function of joints, the role of mechanical stress in the development of arthritis is insufficiently understood. We hypothesised that mechanical stress/physical strain is a risk factor for joint inflammation in RA. Therefore, we studied work-related physical strain in subjects with clinically suspected arthralgia (CSA) as a risk factor for the presence of imaging-detected subclinical joint inflammation and the development of clinical arthritis/RA. Methods In 501 CSA patients and 155 symptom-free persons’ occupation-related physical strain was quantified using the International Standard Classification of Occupations. Contrastenhanced hand-MRIs were made and evaluated for joint inflammation (sum of synovitis/tenosynovitis/osteitis). CSA patients were followed on RA development. Age relationship was studied using an interaction term of physical strain with age. Results The degree of physical strain in CSA is associated with the severity of joint inflammation, independent of educational-level/BMI/smoking (interaction physical strain-age p=0.007; indicating a stronger association with increasing age). Physical strain is associated with higher tenosynovitis scores, in particular. In symptom-free persons, physical strain was not associated with imaging-detected joint inflammation. Higher degrees of physical strain also associated with higher risks for RA development in an age-dependent manner (HR=1.20 (1.06–1.37)/10-year increase in age), independent of educational-level/BMI/smoking. This association was partly mediated by an effect via subclinical joint inflammation. Conclusions Work-related physical strain increases the risk of subclinical joint inflammation and of developing RA. The age relationship suggests an effect of long-term stress or that tenosynovium is more sensitive to stress at older age. Together, the data indicate that mechanical stress contributes to the development of arthritis in RA. Show less
Khidir, S.J.H.; Toes, R.E.M.; Mulligen, E. van; Helm-van Mil, A.H.M. van der 2024
Objectives ACPA-positive and ACPA-negative RA differ in underlying risk factors but have a similar clinical presentation at RA diagnosis. It is unknown what the ACPA-associated differences or... Show moreObjectives ACPA-positive and ACPA-negative RA differ in underlying risk factors but have a similar clinical presentation at RA diagnosis. It is unknown what the ACPA-associated differences or similarities are during the symptomatic at-risk stage of RA, i.e. clinically suspect arthralgia (CSA). To deepen insights into these differences/similarities, we compared the course of symptoms/impairments and subclinical joint inflammation in the CSA phase during progression to inflammatory arthritis (IA) or to CSA resolution.Methods A total of 845 CSA patients were followed for a median of 24 months; 136 patients developed IA and an additional 355/505 patients had resolution of CSA according to rheumatologists. Patient burden (pain, morning stiffness, fatigue, functional disabilities, presenteeism) was assessed at baseline and 4, 12 and 24 months and at IA development. Subclinical joint inflammation in the hands and feet was assessed over time with 1.5T MRI. Linear and Poisson mixed models were used.Results In both ACPA-positive and ACPA-negative patients, patient burden increased towards IA development and decreased towards CSA resolution. However, patient burden was lower in ACPA-positive vs ACPA-negative disease at all timepoints. Conversely, subclinical joint inflammation tended to increase more rapidly during development of ACPA-positive IA [incidence rate ratio (IRR) 1.52 (95% CI 0.94, 2.47), P = 0.089] and remained higher over time in ACPA-positive CSA patients achieving resolution compared with ACPA-negative patients [IRR 1.52 (95% CI 1.07, 2.15), P = 0.018]. Although correlation coefficients between changes in patient burden and subclinical joint inflammation during progression to IA were weak, they were consistently higher in ACPA-positive than ACPA-negative disease, e.g. rho = 0.29 vs 0.12 for functional disabilities.Conclusion During RA development and CSA resolution, ACPA-positive CSA patients have lower patient burden but more subclinical joint inflammation than ACPA-negative CSA patients. These data strengthen the notion that the development of ACPA-positive and ACPA-negative RA is pathophysiologically different and encourage further research on these differences. Show less
Boeren, A.M.P.; Khidir, S.J.H.; Jong, P.H.P. de; Helm-van Mil, A.H.M. van der; Mulligen, E. van 2023
ObjectivePatients with clinically suspect arthralgia (CSA) are at risk for developing rheumatoid arthritis (RA). These patients often report joint swelling while this is not objectified by physical... Show moreObjectivePatients with clinically suspect arthralgia (CSA) are at risk for developing rheumatoid arthritis (RA). These patients often report joint swelling while this is not objectified by physical examination. To explore the value of patient-reported swelling in CSA, we aimed to determine its association with subclinical joint inflammation on imaging and RA development.MethodsIn two independent, similarly designed CSA cohorts from the Netherlands, symptomatic patients at risk for RA were studied. At baseline, patients indicated whether they had experienced swelling in hand joints. Subclinical joint inflammation was assessed with MRI or US. Patients were followed for inflammatory arthritis development.ResultsIn total, 534 CSA patients from two independent cohorts were studied, and patient-reported swelling was present in 57% in cohort 1 and in 43% in cohort 2. In both cohorts patient-reported swelling was associated with subclinical joint inflammation. Using MRI, it associated specifically with tenosynovitis (odds ratio [OR] 3.7 [95% CI: 2.0, 6.9]) and when using US with synovitis (OR 2.3 [95% CI: 1.04, 5.3]). CSA patients with self-reported swelling at baseline developed arthritis more often, with hazard ratios of 3.7 (95% CI: 2.0, 6.9) and 3.4 (95% CI: 1.4, 8.4) in cohort 1 and 2, respectively. This was independent of clinical predictors (e.g. morning stiffness), autoantibody positivity and US-detected subclinical joint inflammation. However, when corrected for MRI-detected subclinical joint inflammation, self-reported swelling was no longer an independent predictor.ConclusionPatient-reported joint swelling in CSA relates to subclinical joint inflammation and is an independent risk factor for RA development, but it is less predictive than the presence of MRI-detected subclinical joint inflammation. Show less
Krijbolder, D.I.; Khidir, S.J.H.; Helm-van Mil, A.H.M. van der 2023
Objectives While awaiting therapies accomplishing rheumatoid arthritis (RA)-prevention in individuals at-risk, recent evidence supports that a 1-year methotrexate treatment may lead to sustained... Show moreObjectives While awaiting therapies accomplishing rheumatoid arthritis (RA)-prevention in individuals at-risk, recent evidence supports that a 1-year methotrexate treatment may lead to sustained reduction in disease burden and subclinical joint inflammation in patients with clinically suspect arthralgia (CSA). We aimed to study the previously unexplored attitudes of CSA patients and rheumatologists on 1-year DMARD treatment in the arthralgia phase to reduce the disease burden, while not preventing RA.Methods CSA patients who participated in the TREAT EARLIER trial, thus being expert by experience, were informed on the trial results. Thereafter they completed an anonymous questionnaire about their attitudes on treatment in the CSA phase. We used the same approach for Dutch healthcare professionals in rheumatology.Results The majority of trial participants (85%) considered the effects of the 1-year treatment as found in the TREAT EARLIER trial, beneficial in the symptomatic at-risk stage. 79% would recommend a 1-year methotrexate course to others with comparable joint complaints. Two-thirds indicated RA prevention and improving disease burden to be equally important treatment goals in the CSA phase. Most healthcare professionals (88%) were inclined to prescribe 1-year treatment to CSA patients aimed at long-term improvement of symptoms and functioning, while not preventing RA development. 59% believed the profits of a 1-year methotrexate course to outweigh disadvantages, for example, side effects.Conclusions A considerable willingness exists among CSA patients and rheumatologists to start a 1-year treatment resulting in long-term improvement of symptoms and functioning, while not preventing RA. This emphasises the need for more research optimising treatment regimens and disease monitoring in individuals at-risk to facilitate such treatment decisions in the future, while avoiding an intervention, either limited or for a prolonged period, which may have harms that outweigh benefits. Show less
Background Inflammation around the tendons of interosseous muscles of the hand (interosseous tendon inflammation) was recently observed with MRI for the first time in patients with rheumatoid... Show moreBackground Inflammation around the tendons of interosseous muscles of the hand (interosseous tendon inflammation) was recently observed with MRI for the first time in patients with rheumatoid arthritis and in at-risk individuals with detectable anti-citrullinated protein antibodies, generating the hypothesis that interosseous tendon inflammation precedes clinical arthritis. To better understand the role of interosseous tendon inflammation during the development of rheumatoid arthritis, we studied the frequency of interosseous tendon inflammation in healthy individuals and in those with arthralgia that was suspected of progressing to rheumatoid arthritis (ie, clinically suspect arthralgia) and the association of interosseous tendon inflammation with other symptoms of inflamed joint tissues and with clinical arthritis development.Methods Adult (age >= 18 years) patients who presented with clinically suspect arthralgia and symptom-free (control) individuals underwent contrast-enhanced hand MRI. MRIs were evaluated for interosseous tendon inflammation on the radial and ulnar sides of the second to fifth metacarpophalangeal joints, and for synovitis, tenosynovitis, and osteitis using the rheumatoid arthritis MRI scoring system. Patients with clinically suspect arthralgia were followed up for clinical arthritis development. The presence of local tenosynovium was examined using immunohistochemistry for anti-CD55 and anti-CD68 on tissue from the hands of three embalmed bodies donated for scientific research. The primary outcome for the cross-sectional part of the study was the presence of interosseous tendon inflammation on MRI. The primary outcome for the longitudinal part of the study was development of clinical arthritis.Findings Between April 3, 2012, and May 20, 2020, 667 patients with clinically suspect arthralgia (mean age 44 years [SD 13], 504 [76%] were women and 163 [24%] were men) underwent contrast-enhanced hand MRI. Between Nov 1, 2013, and Nov 30, 2014, 193 symptom-free controls were recruited (mean age 50 years [SD 16], 136 [70%] were women and 57 [30%] were men). Two (1%) of 193 symptom-free controls had interosseous tendon inflammation. Immunohistochemistry of cadaveric hand tissues showed no tenosynovium surrounding interosseous tendons. At inclusion, 67 (10%) of 667 patients with clinically suspect arthralgia had interosseous tendon inflammation (p<00001 vs symptom-free controls). Interosseous tendon inflammation occurred more frequently if synovitis (odds ratio [OR] 22 [95% CI 12-42]), or tenosynovitis (OR 97 [55-170]), was present at metacarpophalangeal joints. A three-dimensional MRI reconstruction suggested confluency of interosseous tendon inflammation with metacarpophalangeal-flexor-tenosynovitis. 91 (16%) of 558 patients with clinically suspect arthralgia developed clinical arthritis during follow-up (median total follow-up 253 months [95% CI 251-255]). Patients with clinically suspect arthralgia with interosseous tendon inflammation had a higher risk of developing clinical arthritis (hazard ratio [HR] 45 [28-72]), which was attenuated but still significant after adjusting for concomitant synovitis, tenosynovitis, or osteitis (HR 17 [102-28]).Interpretation Interosseous tendon inflammation is almost absent in symptom-free individuals but occurs in people with clinically suspect arthralgia, in whom it correlates with symptoms and is associated with the development of clinical arthritis. The absence of local tenosynovium suggests that interosseous tendon inflammation arises from expanding local subclinical inflammation in the pre-arthritis phase of rheumatoid arthritis. Show less
Khidir, S.J.H.; Dijk, B.T. van; Krijbolder, D.I.; Verstappen, M.; Mulligen, E. van; Helm-van Mil, A.H.M. van der 2023
Objectives: It is unknown whether rheumatoid arthritis (RA) starts in hands or feet. To investigate this, we performed functional, clinical and imaging studies during progression from clinically... Show moreObjectives: It is unknown whether rheumatoid arthritis (RA) starts in hands or feet. To investigate this, we performed functional, clinical and imaging studies during progression from clinically suspect arthralgia (CSA) to RA. Additionally, we studied whether functional disabilities of hands/feet at CSA onset contribute to predicting RA development. Methods: 600 patients with CSA were followed for clinical inflammatory arthritis (IA) during median follow-up of 25 months, during which 99 developed IA. Functional disabilities were measured at baseline/4/12/24 months with the Health Assessment Questionnaire Disability Index (HAQ); HAQ items assessing hand disabilities and foot disabilities were selected. The course of disabilities towards IA development (here considered as t=0) was depicted by increasing incidences and analysed using linear mixed models. To evaluate robustness of findings, tender hand/foot joints and subclinical joint inflammation (measured with CE-1.5TMRI) of hand/foot were additionally studied. Associations between disabilities at CSA presentation (here t=0) and future IA development were studied using Cox regression in the total CSA population.Results: During IA development, hand disabilities occurred earlier and more frequently than foot disabilities. Despite both hand disabilities and foot disabilities rose significantly towards IA development, hand disabilities were more severe during this course (mean difference over time: 0.41 units, 95% CI 0.28 to 0.55, p<0.001, on a range 0-3). Similar to functional disabilities, tender joints and subclinical joint inflammation occurred earlier in the hands than feet. In the total CSA population, a single HAQ question on difficulties with dressing (hand functioning) was independently predictive for IA development: HR=2.2, 95% CI 1.4 to 3.5, p=0.001.Conclusion: Evaluation of functional disabilities, supported by clinical and imaging findings, revealed that joint involvement starts predominantly in the hands during RA development. Additionally, a single question on dressing difficulties adds value to risk stratification in patients with CSA. Show less
Khidir, S.J.H.; Dijk, B.T. van; Krijbolder, D.I.; Verstappen, M.; Mulligen, E. van; Helm-van Mil, A.H.M. van der 2023
Objectives It is unknown whether rheumatoid arthritis (RA) starts in hands or feet. To investigate this, we performed functional, clinical and imaging studies during progression from clinically... Show moreObjectives It is unknown whether rheumatoid arthritis (RA) starts in hands or feet. To investigate this, we performed functional, clinical and imaging studies during progression from clinically suspect arthralgia (CSA) to RA. Additionally, we studied whether functional disabilities of hands/feet at CSA onset contribute to predicting RA development.Methods 600 patients with CSA were followed for clinical inflammatory arthritis (IA) during median follow-up of 25 months, during which 99 developed IA. Functional disabilities were measured at baseline/4/12/24 months with the Health Assessment Questionnaire Disability Index (HAQ); HAQ items assessing hand disabilities and foot disabilities were selected. The course of disabilities towards IA development (here considered as t=0) was depicted by increasing incidences and analysed using linear mixed models. To evaluate robustness of findings, tender hand/foot joints and subclinical joint inflammation (measured with CE-1.5TMRI) of hand/foot were additionally studied. Associations between disabilities at CSA presentation (here t=0) and future IA development were studied using Cox regression in the total CSA population.Results During IA development, hand disabilities occurred earlier and more frequently than foot disabilities. Despite both hand disabilities and foot disabilities rose significantly towards IA development, hand disabilities were more severe during this course (mean difference over time: 0.41 units, 95% CI 0.28 to 0.55, p<0.001, on a range 0–3). Similar to functional disabilities, tender joints and subclinical joint inflammation occurred earlier in the hands than feet. In the total CSA population, a single HAQ question on difficulties with dressing (hand functioning) was independently predictive for IA development: HR=2.2, 95% CI 1.4 to 3.5, p=0.001.Conclusion Evaluation of functional disabilities, supported by clinical and imaging findings, revealed that joint involvement starts predominantly in the hands during RA development. Additionally, a single question on dressing difficulties adds value to risk stratification in patients with CSA. Show less
Background: Clinically suspect arthralgia (CSA) is characterised by arthralgia of small joints and considered a risk stage for development of rheumatoid arthritis (RA). However, it remains unknown... Show moreBackground: Clinically suspect arthralgia (CSA) is characterised by arthralgia of small joints and considered a risk stage for development of rheumatoid arthritis (RA). However, it remains unknown if the function of the hands is already affected and what mechanisms underlie impaired hand-function in CSA.Methods: We studied various measures of hand function in two CSA populations. CSA patients in the TREAT EARLIER-trial (n=236) were evaluated at baseline for: grip strength on a dynamometer (GS), patient-reported difficulties in the grip domain of the Health Assessment Questionnaire (HAQ) questionnaire and incomplete fist closure at physical examination. Findings were validated in an independent CSA cohort (n=600) where hand function was measured as: GS evaluated by squeezing the examiner's fingers, grip domain of the HAQ questionnaire and fist closure. Contrast-enhanced MRI of the hands measured synovitis, tenosynovitis and bone marrow oedema (summed as subclinical inflammation) in both cohorts. Results: GS (on a dynamometer) was reduced in 75% compared with reference values in healthy controls, 60% reported grip difficulties and 13% had incomplete fist closure. Reduced GS was associated with subclinical inflammation (-0.38 kg/point inflammation, 95% CI -0.68 to -0.08). Studying separate MRI features, GS reduction was independently associated with tenosynovitis, decreasing with -2.63 kg (95% CI -2.26 to -0.33)/point tenosynovitis (range observed tenosynovitis scores: 0-20). Similar relations with tenosynovitis were seen for patient-reported grip difficulties (OR 1.12/point, 95% CI 1.07 to 1.42) and incomplete fist closure (OR 1.36/point, 95% CI 1.03 to 1.79). In the validation cohort, 36% had decreased examiner-assessed GS, 51% reported grip difficulties and 14% incomplete fist closure: all were associated with tenosynovitis. Decreased dynamometer-measured GS was most sensitive for detecting tenosynovitis (75%), while incomplete fist closure was most specific (88%-90%). Conclusion: Hand function is already often affected before RA development. These limitations are related to subclinical inflammation and tenosynovitis in particular. Show less
Khidir, S.J.H.; Boonstra, M.; Bergstra, S.A.; Boerrigter, G.W.M.; Voog-van der Harst, E.M.; Ninaber, M.K.; ... ; Vries-Bouwstra, J.K. de 2022
Objective: Decreased maximal mouth opening is a common and disabling manifestation in systemic sclerosis patients. We aimed to study the course of maximal mouth opening, determinants of smaller... Show moreObjective: Decreased maximal mouth opening is a common and disabling manifestation in systemic sclerosis patients. We aimed to study the course of maximal mouth opening, determinants of smaller maximal mouth opening over time and the burden of smaller maximal mouth opening on mouth handicap. Methods: Consecutive systemic sclerosis patients participating in the prospective Leiden Combined Care in systemic sclerosis cohort were included. Annual clinical assessment included maximal mouth opening measurement and mouth handicap evaluation (Mouth Handicap in Systemic Sclerosis scale). Presence of microstomia (maximal mouth opening < 30 mm) was studied. Maximal mouth opening over time was assessed on group level and for all patients individually. Baseline characteristics were analysed for their association with smaller maximal mouth opening over time (linear mixed-effects models). Furthermore, cross-sectional association between maximal mouth opening with Mouth Handicap in Systemic Sclerosis scale was assessed (linear regression analysis). Results: A total of 382 systemic sclerosis patients were studied with median follow-up time of 2.0 years (interquartile range = 0.0-3.0). At baseline, mean maximal mouth opening was 42.2 +/- 8.0 mm and 7% suffered from microstomia. Annual decrease of > 5.0 mm in maximal mouth opening during follow-up occurred in 63 patients and was accompanied by increase in disease severity. Disease characteristics at baseline independently predictive for smaller maximal mouth opening over time were: more extended skin subtype; peripheral vasculopathy; pulmonary, renal and gastrointestinal involvement. Smaller maximal mouth opening was significantly associated with more reported mouth handicap. Conclusion: The course of maximal mouth opening is stable in a majority of systemic sclerosis patients. Still, maximal mouth opening over time was smaller in patients with more severe organ involvement. Although microstomia was infrequent, a smaller maximal mouth opening was significantly associated with more mouth handicap, indicating the importance to address maximal mouth opening in routine care of systemic sclerosis patients. Show less
Khidir, S.J.H.; Boonstra, M.; Bergstra, S.A.; Boerrigter, G.W.M.; Voog-van der Harst, E.M.; Ninaber, M.K.; ... ; Vries-Bouwstra, J.K. de 2022
Objective:Decreased maximal mouth opening is a common and disabling manifestation in systemic sclerosis patients. We aimed to study the course of maximal mouth opening, determinants of smaller... Show moreObjective:Decreased maximal mouth opening is a common and disabling manifestation in systemic sclerosis patients. We aimed to study the course of maximal mouth opening, determinants of smaller maximal mouth opening over time and the burden of smaller maximal mouth opening on mouth handicap.Methods:Consecutive systemic sclerosis patients participating in the prospective Leiden Combined Care in systemic sclerosis cohort were included. Annual clinical assessment included maximal mouth opening measurement and mouth handicap evaluation (Mouth Handicap in Systemic Sclerosis scale). Presence of microstomia (maximal mouth opening < 30 mm) was studied. Maximal mouth opening over time was assessed on group level and for all patients individually. Baseline characteristics were analysed for their association with smaller maximal mouth opening over time (linear mixed-effects models). Furthermore, cross-sectional association between maximal mouth opening with Mouth Handicap in Systemic Sclerosis scale was assessed (linear regression analysis).Results:A total of 382 systemic sclerosis patients were studied with median follow-up time of 2.0 years (interquartile range = 0.0–3.0). At baseline, mean maximal mouth opening was 42.2 ± 8.0 mm and 7% suffered from microstomia. Annual decrease of > 5.0 mm in maximal mouth opening during follow-up occurred in 63 patients and was accompanied by increase in disease severity. Disease characteristics at baseline independently predictive for smaller maximal mouth opening over time were: more extended skin subtype; peripheral vasculopathy; pulmonary, renal and gastrointestinal involvement. Smaller maximal mouth opening was significantly associated with more reported mouth handicap.Conclusion:The course of maximal mouth opening is stable in a majority of systemic sclerosis patients. Still, maximal mouth opening over time was smaller in patients with more severe organ involvement. Although microstomia was infrequent, a smaller maximal mouth opening was significantly associated with more mouth handicap, indicating the importance to address maximal mouth opening in routine care of systemic sclerosis patients. Show less
Khidir, S.J.H.; Boeren, A.M.P.; Boonen, A.; Jong, P.H.P. de; Mulligen, E. van; Helm-van Mil, A.H.M. van der 2022
Objectives: Cross-sectional studies have shown that rheumatoid arthritis is more prevalent among people with a lower educational attainment. No longitudinal data are present on educational... Show moreObjectives: Cross-sectional studies have shown that rheumatoid arthritis is more prevalent among people with a lower educational attainment. No longitudinal data are present on educational attainment in the at-risk phase of clinically suspect arthralgia (CSA). We therefore analysed the association between educational attainment and progression from CSA to inflammatory arthritis (IA), and performed mediation analysis with subclinical joint inflammation to elucidate pathways of this association. Methods: A total of 521 consecutive patients presenting with CSA were followed for IA development during median 25 months. Educational attainment was defined as low (lower secondary vocational education), intermediate or high (college/university education). Subclinical inflammation in hand and foot joints was measured at presentation with contrast enhanced 1.5 T-MRI. Cox-regression was used to analyse IA development per educational attainment. A three-step mediation analysis evaluated whether subclinical joint inflammation was intermediary in the path between educational attainment and IA development, before and after age correction. Association between educational attainment and IA development was verified in an independent CSA cohort. Results: Low educational attainment was associated with increased IA development (HR = 2.35, 95% CI = 1.27, 4.33, P = 0.006), independent of BMI and current smoking status (yes/no). Moreover, patients with a low educational attainment had higher levels of subclinical inflammation, which also was associated with IA development. Partial mediation effect of subclinical inflammation was observed in the relationship between education and IA development. Low educational attainment was also associated with increased IA development in the validation cohort (HR = 5.72, 95% CI = 1.36, 24.08, P = 0.017). Conclusion: This is the first study providing evidence that lower educational attainment is associated with a higher risk of progressing from arthralgia to IA. This effect was partially mediated by subclinical joint inflammation. Show less
Khidir, S.J.H.; Boonstra, M.; Boerrigter, G.W.M.; Voogt-van der Harst, E.M.; Bergstra, S.A.; Ninaber, M.K.; ... ; Vries-Bouwstra, J.K. de 2017
