Validation of the rheumatic disease comorbidity index

Incidence and Prevalence of Idiopathic Inflammatory Myopathies in Korea: a Nationwide Population-based Study

BACKGROUND

This study aimed to estimate the incidence and prevalence of idiopathic inflammatory myopathies (IIM) and associated comorbidities in Korea from 2006 to 2015.

METHODS

IIM between 2004 to 2015 were identified using the Korean National Health Insurance Service medical claim database. The case definition required more than one visit based on diagnostic codes including juvenile dermatomyositis (JDM), dermatomyositis (DM), or polymyositis (PM) and registration in the Individual Copayment Beneficiaries Program (ICBP) for rare and intractable diseases. IIM patients with a disease-free period of 24 months before the index date were defined as incident cases. The Elixhauser comorbidity score was calculated.

RESULTS

Using the base case definition, 1,150 prevalent patients with IIM (117 JDM, 521 DM, 512 PM) were recorded in 2006 and 2,210 (130 JDM, 1,101 DM, 869 PM) in 2015. The prevalence was estimated at 2.3-4.0 (0.9-1.2 for JDM, 1.2-2.7 for DM, 1.4-2.1 for PM)/100,000 person-year (PY). We identified 218 incident cases of IIM in 2006 (18 JDM, 98 DM, 102 PM) and 191 cases (7 JDM, 83 DM, 101 PM) in 2015. The incidence was estimated at 2.9-5.2 (0.7-1.9 for JDM, 1.8-4.0 for DM, 1.6-3.0 for PM)/1,000,000 PY. The mean age (± standard deviation) of prevalent patients with IIM was 51.2 (± 16.9) years, and the percentage of women was 72.1%. More than two-thirds of patients (70.7%) had more than two comorbidities. Twenty percent of patients had interstitial lung diseases.

CONCLUSION

In Korea, the incidence and prevalence of IIM were 2.9-5.2/1,000,000 PY and 2.3-4.0/100,000 PY, respectively.

HLA-DRB1 Haplotypes, Shared Epitope, and Disease Outcomes in US Veterans with Rheumatoid Arthritis

OBJECTIVE

To evaluate associations of HLA-DRB1 haplotypes and shared epitope (SE) with rheumatoid arthritis (RA) severity and all-cause mortality in RA.

METHODS

Patients with RA from the Veterans Affairs Rheumatoid Arthritis (VARA) registry were followed from enrollment until death or December 31, 2013. Clinical characteristics, DNA, and serum were collected at enrollment. Radiographic damage, the presence or absence of subcutaneous nodules, disease activity measures, and functional status were assessed at enrollment and updated during followup. Sixteen HLA-DRB1 haplotypes and SE status were determined from banked DNA. Associations between HLA-DRB1 haplotypes, RA disease characteristics, and mortality were assessed in multivariable regression models.

RESULTS

Within VARA, 1443 participants had genotyping and accrued 6150 patient-years of followup. Haplotypes VKA, VRA, LRA, SRA, SRE, SKR, and SEA, and SE alleles were significantly associated with seropositivity for rheumatoid factor (RF) and/or anticyclic citrullinated peptide (anti-CCP). Haplotypes VKA and SKR were associated with higher RF concentrations, while VRA, DRE, and GRQ were associated with lower RF concentrations. Haplotypes VKA, VRA, and LRA were associated with higher concentrations of anti-CCP antibody, while haplotypes SRA, SRE, LEA, SKR, and SEA were significantly associated with lower anti-CCP concentrations. Haplotype VKA (OR 1.39, 95% CI 1.08-1.80) was associated with increased frequency of radiographic damage at enrollment but none of the haplotypes were associated with the presence of subcutaneous nodules. Haplotypes SKA (HR 1.52, 95% CI 1.26-1.83) was associated with higher mortality.

CONCLUSION

HLA-DRB1 haplotypes are independently and variably associated with seropositivity, autoantibody concentrations, and outcomes in RA.

Prevalence of frailty and its associated factors in patients with rheumatoid arthritis: a cross-sectional analysis

OBJECTIVES

The aims of the present research were to assess the prevalence of frailty and its potential associated factors in a cohort of adult patients with rheumatoid arthritis (RA).

METHODS

Consecutive RA patients and healthy controls were assessed according to the Survey of Health, Ageing and Retirement in Europe Frailty Instrument (SHARE-FI), and classified as frail, pre-frail, or non-frail. Chi-square, analysis of variance (ANOVA), and multinomial logistic regression analyses were used to test the prognostic value of frailty for the outcomes of interest.

RESULTS

Two hundred and ten consecutive RA patients (65.7% female, mean age 60.4 years) and 100 healthy controls (63% female, mean age 59.1 years) were included. According to SHARE-FI criteria, 35 RA patients (16.6%) were categorized as frail, 68 (32.4%) as pre-frail, and 107 (51%) as non-frail, while 8 control subjects were categorized as frail, (8%), 17 as pre-frail (17%), and 75 as non-frail (75%) (chi-squared 12.8; P = 0.0016). The results from logistic regression analysis revealed that age (odds ratio [OR] = 1.12, 95% confidence interval [CI] = 1.07-1.17; P < 0.0001), comorbidities (OR = 1.51, 95% CI = 1.01-2.27; P = 0.0446), and high disease activity (OR = 1.10, 95% CI = 1.04-1.16; P = 0.0006) were independently associated with frailty in RA.

CONCLUSIONS

Frailty or pre-frailty are common in RA. The SHARE-FI may be a useful tool for the screening of frailty in RA and may summarize the results of a comprehensive RA assessment providing a marker of deficits accumulation.

The Use of Rheumatic Disease Comorbidity Index for Predicting Clinical Response and Retention Rate in a Cohort of Rheumatoid Arthritis Patients Receiving Tumor Necrosis Factor Alpha Inhibitors

Introduction

To retrospectively evaluate the impact of comorbidities on treatment choice, 12-month clinical response, and 24-month retention rate in a cohort of patients with rheumatoid arthritis (RA) treated with a first-line tumor necrosis factor alpha inhibitor (TNFi), by using for the first time the Rheumatic Disease Comorbidity Index (RDCI).

Methods

The study population was extracted from a local registry of RA patients receiving adalimumab or etanercept as first-line biologics between January 2001 and December 2013. The prevalence of comorbidities was computed, and patients were stratified according to RDCI for evaluating the role of comorbidities on TNFi choice, concomitant methotrexate, clinical response (1-year DAS28-ESR remission and low disease activity [LDA] and EULAR good-moderate response), and the 24-month retention rate.

Results

346 patients (172 adalimumab and 174 etanercept) were included. A significantly higher EULAR good/moderate response (P = 0.020) and DAS28-ESR remission (P = 0.003) were obtained according to RDCI (0, 1, 2, or ≥3). Lower RDCI (P = 0.022), male sex (P = 0.006), higher baseline DAS28-ESR (P = 0.001), ETN (P < 0.001), and concomitant methotrexate (P = 0.016) were predictors of EULAR good/moderate response. Elevated RDCI was a predictor of discontinuation of biologics (P = 0.036), whereas treatment with etanercept (P < 0.001) and methotrexate (P = 0.007) was associated with a lower risk of TNFi withdrawal.

Conclusions

Multimorbidity, measured by RDCI, is a negative predictor of TNFi persistence on treatment and of achieving a good clinical response. The use of RDCI may be very useful for identifying patients with RA carrying those comorbid conditions associated with poor prognostic outcomes and for defining new treatment targets in multimorbid RA patients.

Chronic lung disease in U.S. Veterans with rheumatoid arthritis and the impact on survival

Assess the impact of chronic lung diseases (CLD) on survival in rheumatoid arthritis (RA). Among participants in the Veterans Affairs Rheumatoid Arthritis (VARA) Registry, a prospective cohort of U.S. Veterans with RA, we identified CLD and cardiovascular disease (CVD) using administrative and registry data. Demographics, smoking status, RA characteristics including Disease Activity Score in 28 joints (DAS28), and disease-modifying anti-rheumatic drug (DMARD) use were obtained from registry data, which were linked to the National Death Index to obtain vital status. We evaluated associations of CLD with survival using the multivariable Cox regression models. Among a large (n = 2053), male-predominant (91%) RA cohort, 554 (27%) had CLD at enrollment. Mortality risk was increased 1.51-fold (95% CI 1.26-1.81) in RA patients with CLD after multivariable adjustment, a risk that was similar to that observed with CVD (HR CLD alone 1.46 [1.03-2.06]; CVD alone 1.62 [1.35-1.94]). Survival was significantly reduced in those with interstitial lung disease (ILD) as well as other forms of CLD. Mortality risk with methotrexate and biologic use was not different in those with CLD compared to those without (p interaction ≥ 0.15) using multiple exposure definitions and propensity score adjustment. Mortality risk is significantly increased in RA patients with CLD. This risk is attributable not only to ILD but also to other chronic lung conditions and does not appear to be substantially greater in those receiving methotrexate or biologic therapies. Comorbid lung disease should be targeted as a means of improving long-term outcomes in RA.

A Mobile App With Optical Imaging for the Self-Management of Hand Rheumatoid Arthritis: Pilot Study

Background

Patient outcomes are improved and the burden to the health care system is reduced when individuals are active self-managers of their own health. There is a need for technology that facilitates self-management of rheumatoid arthritis (RA) and can reduce the number of patient visits, promptly identify treatment needs, and reduce the costs associated with poor RA management. A mobile app named LiveWith Arthritis (eTreatMD, Vancouver, BC) has been developed that allows patients with RA to use their mobile device to regularly collect self-management data and to take objective measurements of the impact of RA on their finger joints using optical imaging technology.

Objective

The objectives of this pilot study were to (1) gather preliminary data as to whether a mobile app with hand optical imaging capabilities improves self-management behaviors (self-efficacy in managing symptoms and patient activation), (2) determine if app use shows promise in improving health outcomes (Pain, Health Assessment Questionnaire-II [HAQ-II]), and (3) determine barriers to using the mobile app in adults with RA.

Methods

This pilot study used a mixed-methods design. The quantitative portion was a traditional 2-group experimental design, and the qualitative portion was a follow-up telephone interview for intervention participants who did not complete the study. Measures of self-management included the Patient-Reported Outcomes Measurement Information System (PROMIS) self-efficacy in managing symptoms (P-SEMS) and Patient Activation Measure (PAM). Health outcomes included pain by Visual Analog Scale and disability by HAQ-II.

Results

The final sample consisted of 21 intervention participants and 15 controls. There was a statistically significant improvement in P-SEMS and promising trends for improvement in PAM, HAQ-II, and pain scores for participants who used the app. Of the intervention participants who did not complete the study, 12 completed the qualitative interview on barriers to use. Qualitative content analysis revealed 3 themes for barriers to using the app, including (1) frustration with technology, (2) RA made the app difficult to use, and (3) satisfaction with current self-management system.

Conclusions

The LiveWith Arthritis app shows promise for improving self-management behaviors and health outcomes in adults with RA. Future study with a larger sample size is required to confirm findings. Initial app experience is important for adoption and continual use of the app. Individuals with significant disability to the hand would benefit from voice-activated app features. Participants who already have a system of managing their RA may not feel compelled to switch methods, even when a novel optical imaging feature is available.

Disease-related outcomes influence prevalence of falls in people with rheumatoid arthritis

BACKGROUND

Patients with rheumatoid arthritis (RA) are at increased risk of falls, with potential adverse outcomes. There is a considerable variation across studies regarding the prevalence of falls and its correlation with clinical data, disease-related outcomes and physical performance tests.

OBJECTIVE

The aim of this study was to evaluate the prevalence of falls and its association with clinical data, disease-related outcomes and physical performance tests.

METHODS

In this cross-sectional study, 113 RA patients were divided into 3 groups - "non-fallers", "sporadic fallers" and "recurrent fallers" - and compared in terms of clinical data, Clinical Disease Activity Index (CDAI), lower-limb tender and swollen joint count, disability (Health Assessment Questionnaire-Disability Index [HAQ-DI]), Foot Function Index (FFI), Berg Balance Scale (BBS), Timed-up-and-go Test (TUG) and 5-Time Sit Down-To-Stand Up Test (SST5). Logistic regression analysis was performed to analyze the associations between the studied variables and the occurrence of falls, estimating odds ratios (ORs). We also analyzed the correlation between disease outcome measures (HAQ-DI and CDAI) and physical tests (BBS, TUG, SST5).

RESULTS

Falls and fear of falling were reported by 59 (52.21%) and 71 (64.5%) patients, respectively. Significant associations were found between "recurrent fallers" and vertigo (OR=3.42; P=0.03), fear of falling (OR=3.44; P=0.01), low income (OR=2.02; P=0.04), CDAI (OR=1.08; P<0.01), HAQ-DI (OR=3.66; P<0.01), Lower-limb HAQ (OR=3.48; P<0.01), FFI-pain (OR=1.24; P=0.03), FFI-total (OR=1.23; P=0.04), lower-limb tender joint count (OR=1.22; P<0.01), BBS score (OR=1.14; P<0.01), TUG score (OR=1.13; P=0.03) and SST5 score (OR=1.06; P=0.02). On multivariate analysis, CDAI was the only significant predictor of recurrent falls (OR=1.08; P<0.01). Physical performance test scores (BBS, TUG, SST5) were correlated with the CDAI and HAQ-DI.

CONCLUSION

The prevalence of falls in RA is high, most influenced by disease-related outcomes and linked to worse performance on physical tests (BBS, TUG and SST5).

Work participation in spondyloarthritis across countries: analysis from the ASAS-COMOSPA study

OBJECTIVES

To explore the role of individual and country level socioeconomic (SE) factors on employment, absenteeism and presenteeism in patients with spondyloarthritis (SpA) across 22 countries worldwide.

METHODS

Patients with a clinical diagnosis of SpA fulfilling the ASAS classification criteria and in working age (≤65 years) from COMOSPA were included. Outcomes of interest were employment status, absenteeism and presenteeism, assessed by the Work Productivity and Activity Impairment Specific General Health questionnaire. Three multivariable models were built (one per outcome) using mixed-effects binomial (for work status) or ordinal regressions (for absenteeism and presenteeism), with country as random effect. The contribution of SE factors at the individual-level (eg, gender, education, marital status) and country-level (healthcare expenditure (HCE) per capita, Human Development Index (HDI) and gross domestic product per capita) SE factors, independent of clinical factors, was assessed.

RESULTS

In total, 3114 patients with SpA were included of which 1943 (62%) were employed. Physical function and comorbidities were related to all work outcomes in expected directions and disease activity also with absenteeism and presenteeism. Higher education (OR 4.2 (95% CI 3.1 to 5.6)) or living in a country with higher HCE (OR 2.3 (1.5 to 3.6)) or HDI (OR 1.9 (1.2 to 3.3)) was positively associated with being employed. Higher disease activity was associated with higher odds for absenteeism (OR 1.5 (1.3 to 1.7)) and presenteeism (OR 2.1 (1.8 to 2.4)). No significant association between individual-level and country-level SE factors and absenteeism or presenteeism was found.

CONCLUSIONS

Higher education level and higher country SE welfare are associated with a higher likelihood of keeping patients with SpA employed. Absenteeism and presenteeism are only associated with clinical but not with individual-level or country-level SE factors.

Allopurinol Dose Escalation and Mortality Among Patients With Gout: A National Propensity-Matched Cohort Study

OBJECTIVE

Observational data suggest that hyperuricemia and gout are associated with increased mortality, while allopurinol use is associated with reduced mortality. In addition, the protective effect of allopurinol may be dose dependent. The aim of the current study was to determine whether allopurinol dose escalation is associated with cause-specific mortality in patients with gout.

METHODS

In this 10-year observational, active-comparator study of US Veterans with gout who initiated treatment with allopurinol, propensity score matching, Cox proportional hazards models, and competing risks regression analyses were used to assess differences in cause-specific mortality between patients whose allopurinol dose was escalated (dose escalators) and those whose allopurinol dose was not escalated or was reduced (non-escalators) over a 2-year period.

RESULTS

Among the 6,428 dose escalators and 6,428 matched non-escalators, there were 2,867 deaths during the observation period (40.4 deaths per 1,000 person-years). Dose escalators experienced an increase in all-cause mortality (hazard ratio [HR] 1.08, 95% confidence interval [95% CI] 1.01-1.17), with the effect sizes being similar for incidence of cardiovascular-related deaths (HR 1.08, 95% CI 0.97-1.21) and cancer-related deaths (HR 1.06, 95% CI 0.88-1.27), although neither reached statistical significance. Dose escalation to achieve the goal of lowering the serum urate (SU) level to <6.0 mg/dl was infrequent. At 2 years, 10% of dose escalators were receiving a final daily dose of >300 mg and 31% had achieved the SU goal. In a sensitivity analysis limited to dose escalators achieving the SU goal, there was a nonsignificant reduction of 7% in the hazard of cardiovascular-related mortality (HR 0.93, 95% CI 0.76-1.14).

CONCLUSION

This is the largest study to date to investigate the effects of allopurinol use on mortality and is the first to use a rigorous active-comparator design. Dose escalation was associated with a small (<10%) increase in all-cause mortality, thus showing that a strategy of allopurinol dose escalation, which in current real-life practice is characterized by limited dose increases, is unlikely to improve the survival of patients with gout.

Disease and management beliefs of elderly patients with rheumatoid arthritis and comorbidity: a qualitative study

To explore in elderly patients with rheumatoid arthritis (RA) and comorbidity (1) in which order and why patients prioritize their morbidities with regard to functioning and health, (2) their beliefs about common (age-related) musculoskeletal complaints, and (3) experiences about the influence of comorbidity on medication treatment of RA. Patients between 50 and 85 years with RA and ≥ 1 comorbidity or lifestyle risk factor were invited for a semi-structured interview. Two readers coded the transcripts of the interviews, by using NVivo11 software. Fifteen patients (14 women; mean age 67 years (range 51-83 years); mean disease duration 14 years (range 1-39 years)) were interviewed. Only 3 (20%) out of 15 patients prioritized RA over their comorbidity; these patients often experienced severe functional limitations. The level of current or (perceived) future disability, risk of dependency, and the perceived lethality of a condition were considered by participants when prioritizing morbidities. Most participants had misconceptions about common age-related musculoskeletal complaints. Consequently, these participants attributed all joint complaints or even all physical complaints to RA, disregarding degenerative joint disease and physiological aging as alternative diagnoses. Half of the participants ever had to change RA medication because of comorbidity. Most of these patients had prioritized the comorbidity, sometimes even over treatment of RA disease activity. Most elderly RA patients with comorbidity prioritize the importance and treatment of comorbidity over RA. Better understanding of patients' beliefs on RA and comorbidity is essential when managing chronic conditions in elderly patients.

Deriving common comorbidity indices from the MedDRA classification and exploring their performance on key outcomes in patients with rheumatoid arthritis

Objective

To develop algorithms for calculating the Rheumatic Diseases Comorbidity Index (RDCI), Charlson-Deyo Index (CDI) and Functional Comorbidity Index (FCI) from the Medical Dictionary for Regulatory Activities (MedDRA), and to assess how these MedDRA-derived indices predict clinical outcomes, utility and health resource utilization (HRU).

Methods

Two independent researchers linked the preferred terms of the MedDRA classification into the conditions included in the RDCI, the CDI and the FCI. Next, using data from the Norwegian Register-DMARD study (a register of patients with inflammatory joint diseases treated with DMARDs), the explanatory value of these indices was studied in models adjusted for age, gender and DAS28. Model fit statistics were compared in generalized estimating equation (prediction of outcome over time) models using as outcomes: modified HAQ, HAQ, physical and mental component summary of SF-36, SF6D and non-RA related HRU.

Results

Among 4126 patients with RA [72% female, mean (s.d.) age 56 (14) years], median (interquartile range) of RDCI at baseline was 0.0 (1.0) [range 0-6], CDI 0.0 (0.0) [0-7] and FCI 0.0 (1.0) [0-6]. All the comorbidity indices were associated with each outcome, and differences in their performance were moderate. The RDCI and FCI performed better on clinical outcomes: modified HAQ and HAQ, hospitalization, physical and mental component summary, and SF6D. Any non-RA related HRU was best predicted by RDCI followed by CDI.

Conclusion

An algorithm is now available to compute three commonly used comorbidity indices from MedDRA classification. Indices performed comparably well in predicting a variety of outcomes, with the CDI performing slightly worse when predicting outcomes reflecting functioning and health.

Allopurinol Medication Adherence as a Mediator of Optimal Outcomes in Gout Management

BACKGROUND

Patient and provider factors, including allopurinol medication adherence, affect gout treatment outcomes.

OBJECTIVES

The aim of this study was to examine associations of patient and provider factors with optimal gout management.

METHODS

Linking longitudinal health and pharmacy dispensing records to questionnaire data, we assessed patient and provider factors among 612 patients with gout receiving allopurinol during a recent 1-year period. Associations of patient (medication adherence and patient activation) and provider factors (dose escalation, low-dose initiation, and anti-inflammatory prophylaxis) with serum urate (SU) goal achievement of less than 6.0 mg/dL were examined using multivariable logistic regression. Medication adherence was assessed as a mediator of these factors with goal achievement.

RESULTS

A majority of patients (63%) were adherent, whereas a minority received dose escalation (31%). Medication adherence was associated with initiation of daily allopurinol doses of 100 mg/d or less (odds ratio [OR], 1.82; 95% confidence interval [CI], 1.20-2.76). In adjusted models, adherence (OR, 2.35; 95% CI, 1.50-3.68) and dose escalation (OR, 2.48; 95% CI, 2.48-4.25) were strongly associated with SU goal attainment. Low starting allopurinol dose was positively associated with SU goal attainment (OR, 1.11; 95% CI, 1.02-1.20) indirectly through early adherence, but also had a negative direct association with SU goal attainment (OR, 0.21; 95% CI, 0.12-0.37).

CONCLUSIONS

Medication adherence and low starting dose combined with dose escalation represent promising targets for future gout quality improvement efforts. Low starting dose is associated with better SU goal attainment through increased medication adherence, but may be beneficial only in settings where appropriate dose escalation is implemented.

Mortality and its predictors in patients with rheumatoid arthritis: a Danish population-based inception cohort study

OBJECTIVES

To investigate mortality and its predictors in a retrospectively defined population-based rheumatoid arthritis (RA) inception cohort Method: We included patients ascertained with incident RA from a region in the southern part of Denmark from 1995 to 2002. All patients fulfilled the 1987 American College of Rheumatology criteria for RA. The patients were followed from RA classification until death, emigration, or end of follow-up on 31 December 2013. We used personal record linkage with national public registers to obtain information on education, employment, cohabitation, comorbidity, and vital status.

RESULTS

The cohort comprised 509 patients, of whom 200 (39%) died during 6079 person-years. The most frequent underlying causes of death were cardiovascular disease (34%), neoplasms (26%), and respiratory disease (12%). In rheumatoid factor (RF)-positive males, the standardized mortality ratio (95% confidence interval) from all causes was 1.47 (1.15-1.88), from cardiovascular disease 1.63 (1.09-2.46), from respiratory disease 2.03 (1.06-3.90), and from neoplasms 2.26 (1.02-5.03) in the age group < 70 years, and 2.45 (1.23-4.90) in the age group > 79 years. On applying Cox models after multiple imputations by chained equations, we found that RF modified the effect of age. Employment status, comorbidity, and gender were independent baseline predictors of subsequent mortality.

CONCLUSION

In this cohort, significant excess mortality was confined to RF-positive males. The effect of age was modified by RF, and employment status and comorbidity were independent predictors of mortality.

Inequity in biological DMARD prescription for spondyloarthritis across the globe: results from the ASAS-COMOSPA study

OBJECTIVES

The value of biological disease-modifying antirheumatic drugs (bDMARDs) in spondyloarthritis (SpA) is well recognised, but global access to these treatments can be limited due to high costs and other factors. This study explores country variation in the use of bDMARDs in SpA in relation to country-level socioeconomic factors.

METHODS

Patients fulfilling the Assessment in SpondyloArthritis International Society (ASAS) SpA criteria in the multinational, cross-sectional ASAS Comorbidities in Spondyloarthritis study were studied. Current use of bDMARDs or conventional synthetic DMARDs (csDMARDs) was investigated in separate models, with multilevel logistic regression analysis, taking the country level into account. Contribution of socioeconomic factors, including country health expenditures, gross domestic product and human development index as independent country-level factors, was explored individually, in models adjusted for sociodemographic as well as clinical variables.

RESULTS

In total, 3370 patients from 22 countries were included (mean (SD) age 43 (14) years; 66% male; 88% axial disease). Across countries, 1275 (38%) patients were bDMARD users. Crude mean bDMARD use varied between 5% (China) to 74% (Belgium). After adjustment for relevant sociodemographic and clinical variables, important variation in bDMARD use across countries remained (P<0.001). Country-level socioeconomic factors, specifically higher health expenditures, were related to higher bDMARD uptake, though not meeting statistical significance (OR 1.96; 95% CI 0.94 to 4.10). csDMARD uptake was significantly lower in countries with higher health expenditures (OR 0.32; 95% CI 0.15 to 0.65). Similar trends were seen with the other socioeconomic variables.

CONCLUSIONS

There remains important residual variation across countries in bDMARD uptake of patients with SpA followed in specialised SpA centres. This is independent of well-known factors for bDMARD use such as clinical and country-level socioeconomic factors.

Tools for the Assessment of Comorbidity Burden in Rheumatoid Arthritis

Introduction

Comorbidities influence the prognosis, clinical outcomes, disease activity, and treatment response in rheumatoid arthritis (RA). RA patients have a high-comorbidity burden necessitating their study. Comorbidity indices are used to measure comorbidities and to study their impacts on different outcomes. A large number of such indices are used in clinical research. Some indices have been specifically developed in RA patients.

Aim

This review aims to provide an overview of generic and specific comorbidity indices commonly used in RA research.

Methods

We performed a critical literature review of comorbidity indices in RA using the PubMed database.

Results/discussion

This non-systematic literature review provides an overview of generic and specific comorbidity indices commonly used in RA studies. Some of the older but commonly used comorbidity indices like the Charlson comorbidity index and the Elixhauser comorbidity measure were primarily developed to estimate mortality risk from comorbid diseases. They were not specifically developed for RA patients but have been widely used in rheumatology comorbidity measurement. Of the many comorbidity indices available, only the rheumatic disease comorbidity index (RDCI) and the multimorbidity index have been specifically developed in RA patients. The functional comorbidity index was developed to look at functional disability and has been used in RA patients considering that morbidity is more important than mortality in such patients. While there is limited data comparing these indices, available evidence seems to favor the use of RDCI as it predicts mortality, hospitalization, disability, and healthcare utilization. The choice of the index, however, depends on several factors such as the population under study, outcome of interest, and sources of data. More research is needed to study the RA-specific comorbidity measures to make evidence-based recommendations for the choice of a comorbidity measure.

Blood glucose changes surrounding initiation of tumor-necrosis factor inhibitors and conventional disease-modifying anti-rheumatic drugs in veterans with rheumatoid arthritis

AIM

To determine the scope of acute hypoglycemic effects for certain anti-rheumatic medications in a large retrospective observational study.

METHODS

Patients enrolled in the Veterans Affairs Rheumatoid Arthritis (VARA) registry were selected who, during follow-up, initiated treatment with tumor necrosis factor inhibitors (TNFi’s, including etanercept, adalimumab, infliximab, golimumab, or certolizumab), prednisone, or conventional disease-modifying anti-rheumatic drugs (DMARDs), and for whom proximate random blood glucose (RBG) measurements were available within a window 2-wk prior to, and 6 mo following, medication initiation. Similar data were obtained for patients with proximate values available for glycosylated hemoglobin A1C values within a window 2 mo preceding, and 12 mo following, medication initiation. RBG and A1C measurements were compared before and after initiation events using paired t-tests, and multivariate regression analysis was performed including established comorbidities and demographics.

RESULTS

Two thousands one hundred and eleven patients contributed at least one proximate measurement surrounding the initiation of any examined medication. A significant decrease in RBG was noted surrounding 653 individual hydroxychloroquine-initiation events (-3.68 mg/dL, P = 0.04), while an increase was noted for RBG surrounding 665 prednisone-initiation events (+5.85 mg/dL, P < 0.01). A statistically significant decrease in A1C was noted for sulfasalazine initiation, as measured by 49 individual initiation events (-0.70%, P < 0.01). Multivariate regression analyses, using methotrexate as the referent, suggest sulfasalazine (β = -0.58, P = 0.01) and hydroxychloroquine (β = -5.78, P = 0.01) use as predictors of lower post-medication-initiation RBG and A1C values, respectively. Analysis by drug class suggested prednisone (or glucocorticoids) as predictive of higher medication-initiation event RBG among all start events as compared to DMARDs, while this analysis did not show any drug class-level effect for TNFi. A diagnosis of congestive heart failure (β = 4.69, P = 0.03) was predictive for higher post-initiation RBG values among all medication-initiation events.

CONCLUSION

No statistically significant hypoglycemic effects surrounding TNFi initiation were observed in this large cohort. Sulfasalazine and hydroxychloroquine may have epidemiologically significant acute hypoglycemic effects.

Large country differences in work outcomes in patients with RA - an analysis in the multinational study COMORA

Background

We aimed to explore whether country of residence or specific country characteristics are associated with work outcomes in rheumatoid arthritis (RA).

Methods

Data from the 17 countries participating in the Comorbidities in RA (COMORA) study were used. Work outcomes were measured by the Work Productivity and Activity Impairment Questionnaire, addressing employment (yes/no), absenteeism (percentage of time; 3 categories) and presenteeism (percentage of at-work productivity restrictions; 4 categories). Contribution of country of residence, gross domestic product (GDP), Human Development Index (HDI), unemployment rate, social protection expenditures (SPE) or world region to work outcomes was investigated in adjusted (ordered) logistic regressions.

Results

The patients (n = 2395) were younger than 60 years; mean age 48 (SD 9.2) years, 1972 (84%) female and 1065 (45%) employed. Large country differences were found. Taking the country with the best work outcome as reference, Moroccan patients had the lowest odds of being employed (OR 0.2 (95% CI 0.1; 0.3) vs. Germany) and highest odds of absenteeism (OR 13.2 (3.6; 48.3) vs. Japan). Patients in Taiwan had the highest odds of presenteeism (OR 13.0 (5.5; 30.9) vs. Venezuela). All country indices except SPE were associated with work outcomes. For example, patients in low-GDP countries had lower odds of employment (OR 0.6 (0.5; 0.8)), higher odds of absenteeism (OR 2.8 (2.0; 4.1)), but lower odds of presenteeism (OR 0.5 (0.4; 0.7)) compared to higher-GDP countries.

Conclusion

Substantial differences in work outcomes among patients with RA were observed between countries. Lower economic wealth and human development of countries were associated with worse employment and higher absenteeism, but lower presenteeism.

Electronic supplementary material

The online version of this article (doi:10.1186/s13075-017-1421-y) contains supplementary material, which is available to authorized users.

Performance of the Patient-Reported Outcomes Measurement Information System 29-Item Profile in Rheumatoid Arthritis, Osteoarthritis, Fibromyalgia, and Systemic Lupus Erythematosus

OBJECTIVE

The Patient-Reported Outcomes Measurement Information System (PROMIS) was developed to improve measurement of patient-reported outcomes. We examined performance of the 29-item PROMIS Profile (PROMIS-29) in persons with rheumatoid arthritis (RA), osteoarthritis (OA), fibromyalgia (FM), and systemic lupus erythematosus (SLE).

METHODS

Participants in the National Data Bank for Rheumatic Diseases completed the PROMIS-29, which includes 4-item forms for 7 PROMIS domains. Scales were scored and converted to T scores. Distributions of scale scores were examined, convergent and known-groups validity was tested, and differences in scores from online versus paper questionnaires were examined.

RESULTS

Sample sizes were 4,346 for RA, 727 for OA, 241 for FM, and 240 for SLE. Participants were predominantly female, with a mean disease duration ≥20 years, and were ages ∼60 years. Large ceiling effects occurred for some PROMIS-29 scales. Correlations of PROMIS-29 scores with scales measuring similar constructs ranged from high to moderate for RA, OA, and SLE; correlations for FM were markedly lower for some scales. Consistent patterns of worsening PROMIS-29 scores with increasing disease severity or declining health status were observed. Differences in scores obtained by online versus paper questionnaires ranged from 0.3 to 2.2 points.

CONCLUSION

Results provide guarded support for using the PROMIS-29 in these conditions. The PROMIS-29 4-item static forms appear to identify differences among levels of health and to measure constructs similar to those measured by legacy questionnaires. However, large ceiling effects suggest that measurement may be more precise at the "bad" ends of the scales, which may limit responsiveness, and differences by mode of administration appear to exist.

Persistence With Conventional Triple Therapy Versus a Tumor Necrosis Factor Inhibitor and Methotrexate in US Veterans With Rheumatoid Arthritis

OBJECTIVE

To compare persistence and adherence to triple therapy with the nonbiologic disease-modifying antirheumatic drugs (DMARDs) methotrexate (MTX), hydroxychloroquine, and sulfasalazine, versus a tumor necrosis factor inhibitor (TNFi) plus MTX in patients with rheumatoid arthritis (RA).

METHODS

Administrative and laboratory data were analyzed for US Veterans with RA initiating triple therapy or TNFi + MTX between January 2006 and December 2012. Treatment persistence 365 days postindex was calculated using 3 definitions. Definition 1 required no gap in therapy of ≥90 days for any drug in the original combination. Definition 2 required no added or switched DMARD, no decrease to nonbiologic DMARD monotherapy, and no termination of all DMARD therapies. Definition 3 was similar to definition 2 but allowed a switch to another drug within the same class. Adherence used a proportion of days covered of ≥80%. Propensity-weighted analysis with matched weights was used to balance covariates.

RESULTS

The analysis included 4,364 RA patients (TNFi + MTX, n = 3,204; triple therapy, n = 1,160). In propensity-weighted analysis, patients in the TNFi + MTX group were significantly more likely than patients in the triple therapy group to satisfy all persistence criteria in definition 1 (risk difference [RD] 13.1% [95% confidence interval (95% CI) 9.2-17.0]), definition 2 (RD 6.4% [95% CI 2.3-10.5]), and definition 3 (RD 9.5% [95% CI 5.5-13.6]). Patients in the TNFi + MTX group also exhibited higher adherence during the first year (RD 7.2% [95% CI 3.8-10.5]).

CONCLUSION

US Veterans with RA were significantly more likely to be persistent and adherent to combination therapy with TNFi + MTX than triple therapy with nonbiologic DMARDs.

Associations of Circulating Cytokines and Chemokines With Cancer Mortality in Men With Rheumatoid Arthritis

OBJECTIVE

To examine the potential of circulating cytokines and chemokines as biomarkers of cancer mortality risk in patients with rheumatoid arthritis (RA).

METHODS

Male participants in the Veterans Affairs RA registry were followed up from the time of enrollment until death or December 2013. Cytokines and chemokines were measured in banked serum obtained at the time of enrollment, using a bead-based multiplex assay, and a previously developed cytokine score was calculated. Vital status and cause of death were determined through the National Death Index. Associations of cytokines with cancer mortality were examined using multivariable competing-risks regression.

RESULTS

Among 1,190 men with RA, 60 cancer deaths (30 of which were attributable to lung cancer) occurred over 5,307 patient-years of follow-up. The patients had a mean age of 64.5 years, had established disease (median duration 8.7 years), were seropositive for rheumatoid factor (81%) or anti-cyclic citrullinated peptide antibody (77%), and frequently had a history of smoking (82% current or former). Seven of 17 analytes examined were individually associated with cancer mortality. The cytokine score was associated with overall cancer (subhazard ratio [SHR] 1.42, 95% confidence interval [95% CI] 1.08-1.85) and lung cancer (SHR 1.86, 95% CI 1.57-2.19) mortality in multivariable analyses. Those in the highest quartile of cytokine scores had a >2-fold increased risk of overall cancer mortality (P = 0.039) and a 6-fold increased risk of lung cancer mortality (P = 0.028) relative to the lowest quartile. A synergistic interaction between current smoking and high cytokine score was observed.

CONCLUSION

Serum cytokines and chemokines are associated with cancer and lung cancer mortality in men with RA, independent of multiple factors including age, smoking status, and prevalent cancer.

Changes in Body Mass Related to the Initiation of Disease-Modifying Therapies in Rheumatoid Arthritis

OBJECTIVE

Unintentional weight loss is important and can be predictive of long-term outcomes in patients with rheumatoid arthritis (RA). This study was undertaken to assess how primary therapies for RA may influence changes in body mass index (BMI) in RA patients from a large administrative database.

METHODS

Unique dispensing episodes of methotrexate, prednisone, leflunomide, and tumor necrosis factor inhibitors (TNFi) administered to RA patients were identified from the US Department of Veterans Affairs pharmacy databases. Values for C-reactive protein (CRP) level and BMI closest to the time point within 30 days of the treatment course start date and at follow-up time points were linked. Missing laboratory values were imputed. Weight loss was defined as a decrease in BMI of >1 kg/m(2) . Regression models were used to evaluate changes in BMI during each drug treatment as compared to treatment with methotrexate. To assess the impact of confounding by indication, propensity scores for use of each drug were incorporated in analyses using matched-weighting techniques.

RESULTS

In total, 52,662 treatment courses in 32,859 RA patients were identified. At 6 months from the date of prescription fill, weight gain was seen among patients taking methotrexate, those taking prednisone, and those taking TNFi. On average, compared to methotrexate-treated patients, prednisone-treated patients had significantly more weight gain, while leflunomide-treated patients demonstrated weight loss. In multivariable models, more weight loss (β = -0.41 kg/m(2) , 95% confidence interval [95% CI] -0.46, -0.36; P < 0.001) and a greater risk of weight loss (odds ratio 1.73, 95% CI 1.55, 1.79; P < 0.001) were evident among those receiving leflunomide compared to those receiving methotrexate. Treatment with prednisone was associated with greater weight gain (β = 0.072 kg/m(2) , 95% CI 0.042, 0.10; P < 0.001). These associations persisted in analyses adjusted for propensity scores and in sensitivity analyses.

CONCLUSION

Leflunomide is associated with significantly more, but modest, weight loss, while prednisone is associated with greater weight gain compared to other therapies for RA.

Association of Early Outpatient Rehabilitation With Health Service Utilization in Managing Medicare Beneficiaries With Nontraumatic Knee Pain: Retrospective Cohort Study

BACKGROUND

Nontraumatic knee pain (NTKP) is highly prevalent in adults 65 years of age and older. Evidence-based guidelines recommend early use of rehabilitation; however, there is limited information comparing differences in health care utilization when rehabilitation is included in the management of NTKP.

OBJECTIVES

To describe the overall health care utilization associated with the management of NTKP; estimate the proportion of people who receive outpatient rehabilitation services; and evaluate the timing of outpatient rehabilitation and its association with other health care utilization.

DESIGN

Rretrospective cohort study was conducted using a random 10% sample of 2009-2010 Medicare claims. The sample included 52,504 beneficiaries presenting within the ambulatory setting for management of NTKP.

METHODS

Exposure to outpatient rehabilitative services following the NTKP index ambulatory visit was defined as 1) no rehabilitation; 2) early rehabilitation (1-15 days); 3) intermediate rehabilitation (16-120 days); and 4) late rehabilitation (>120 days). Logistic regression models were fit to analyze the association of rehabilitation timing with narcotic analgesic use, utilization of nonsurgical invasive procedure, and knee surgery during a 12-month follow-up period.

RESULTS

Only 11.1% of beneficiaries were exposed to outpatient rehabilitation services. The likelihood of using narcotics, nonsurgical invasive procedures, or surgery was significantly less (adjusted odds ratios; 0.67, 0.50, 0.58, respectively) for those who received early rehabilitation when compared to no rehabilitation. The exposure-outcome relationships were reversed in the intermediate and late rehabilitation cohorts.

LIMITATIONS

This was an observational study, and residual confounding could affect the observed relationships. Therefore, definitive conclusions regarding the causal effect of rehabilitation exposure and reduced utilization of more aggressive interventions cannot be determined at this time.

CONCLUSIONS

Early referral for outpatient rehabilitation may reduce the utilization of health services that carry greater risks or costs in those with NTKP.

Models solely using claims-based administrative data are poor predictors of rheumatoid arthritis disease activity

BACKGROUND

This study developed and validated a claims-based statistical model to predict rheumatoid arthritis (RA) disease activity, measured by the 28-joint count Disease Activity Score (DAS28).

METHOD

Veterans enrolled in the Veterans Affairs Rheumatoid Arthritis (VARA) registry with one year of data available for review before being assessed by the DAS28, were studied. Three models were developed based on initial selection of variables for analyses. The first model was based on clinically defined variables, the second leveraged grouping systems for high dimensional data and the third approach prescreened all possible predictors based on a significant bivariate association with the DAS28. The least absolute shrinkage and selection operator (LASSO) with fivefold cross-validation was used for variable selection and model development. Models were also compared for patients with <5 years to those ≥5 years of RA disease. Classification accuracy was examined for remission (DAS28 < 2.6) and for low (2.6-3.1), moderate (3.2-5.1) and high (>5.1) activity.

RESULTS

There were 1582 Veterans who fulfilled inclusion criteria. The adjusted r-square for the three models tested ranged from 0.221 to 0.223. The models performed slightly better for patients with <5 years of RA disease than for patients with ≥5 years of RA disease. Correct classification of DAS28 categories ranged from 39.9% to 40.5% for the three models.

CONCLUSION

The multiple models tested showed weak overall predictive accuracy in measuring DAS28. The models performed poorly at predicting patients with remission and high disease activity. Future research should investigate components of disease activity measures directly from medical records and incorporate additional laboratory and other clinical data.

The clinical status and economic savings associated with remission among patients with rheumatoid arthritis: leveraging linked registry and claims data for synergistic insights

INTRODUCTION

Treat to target guidelines recommend achieving remission or low disease activity in rheumatoid arthritis (RA). However, the reduction in adverse events and costs associated with lower disease activity is unclear.

METHODS

We used Corrona linked to Medicare data to identify RA patients. Time varying disease activity was measured using Clinical Disease Activity Index (CDAI); outcomes included all-cause hospitalization, a composite of hospitalization or emergency department (ED) visits, mortality, and medical costs. Outcome-specific Cox proportional models evaluated the adjusted hazard ratios between disease activity and outcomes, controlling for potential confounders including comorbidities grouped into four patient phenotypes. Costs were analyzed with mixed models using a Gaussian distribution with log transformation.

RESULTS

Depending on outcome, 4593 RA patients contributed up to 12 001 person years. Median age was 71 years, 75% women. At baseline, approximately 50-60% of patients were in remission or low disease activity. There was a dose-response relationship between RA disease activity (remission, low, moderate, and high) and the incidence of hospitalizations (13.1, 17.8, 21.2, 27.5 per 100 py, respectively); all adjusted hazard ratios were significant: 0.68 (remission), 0.87 (low), and 1.24 (high) compared with moderate disease activity. Similar trends were observed for ED visits and mortality. The crude difference in annual medical costs between remission ($11 145) and moderate disease activity ($17 646) was $-6 500; the adjusted difference (95%CI) was $-3133 (-4737.72, -1528.43).

CONCLUSION

Leveraging the benefits of linking registry and administrative data together, lower disease activity in RA was associated with incrementally reduced risks of all-cause hospitalization, ED visits, mortality, and medical costs in a dose-dependent fashion. Copyright © 2016 John Wiley & Sons, Ltd.

Generalizability of Patients With Rheumatoid Arthritis in Biologic Agent Clinical Trials

OBJECTIVE

Randomized controlled trials (RCTs) have consistently demonstrated the efficacy of biologic agents in treating patients with rheumatoid arthritis (RA) who satisfy strict eligibility criteria, yet studies report that a majority of RA patients in the US have had biologic treatment exposure. We identified the proportion of RA patients in clinical practice satisfying entry criteria for biologic agent RCTs.

METHODS

Eligibility criteria of 30 RCTs of 10 Food and Drug Administration-approved biologic agents to treat RA were reviewed, summarized, and applied to 2 observational clinical cohorts: the Veterans Affairs Rheumatoid Arthritis registry (VARA; n = 1,523) and the Rheumatology and Arthritis Investigational Network Database (RAIN-DB; n = 1,548). Patients at a single clinical encounter were assessed for overall trial eligibility as well as eligibility across 3 domains: demographics, disease activity, and medication exposure.

RESULTS

The mean percentage of patients that satisfied eligibility criteria was 3.7% (interquartile range [IQR] 1.5-3.1) in VARA and 7.1% (IQR 4.4-7.7) in RAIN-DB. Ineligibility was most often due to low disease activity, specifically low joint counts. The mean Disease Activity Score in 28 joints at enrollment was 6.59 (range 6.1-7.1) across RCTs versus 3.87 (0.07-8.69) in VARA and 3.65 (0.49-7.21) in RAIN-DB. RCTs for non-tumor necrosis factor (TNF) inhibitor biologic agents were more restrictive than RCTs for TNF inhibitors. There was no trend in eligibility by RCT study publication or drug approval date.

CONCLUSION

The vast majority of RA patients from our clinical cohorts did not satisfy criteria for participation in biologic agent RCTs. These findings underscore the need for caution in extrapolating trial results to day-to-day management of RA patients and may provide insight into the differential responses to biologic agents reported in prior observational studies.

Cause-Specific Mortality in Male US Veterans With Rheumatoid Arthritis

OBJECTIVE

There has been limited investigation into cause-specific mortality and the associated risk factors in men with rheumatoid arthritis (RA). We investigated all-cause and cause-specific mortality in men with RA, examining determinants of survival.

METHODS

Men from a longitudinal RA registry were followed from enrollment until death or through 2013. Vital status and cause of death were determined using the National Death Index. Crude mortality rates and standardized mortality ratios (SMRs) were calculated for all-cause, cardiovascular disease (CVD), cancer, and respiratory mortality. Associations with all-cause and cause-specific mortality were examined using multivariable Cox proportional hazards and competing-risks regression.

RESULTS

There were 1,652 men with RA and 332 deaths. The leading causes of death were CVD (31.6%; SMR 1.77 [95% confidence interval (95% CI) 1.46-2.14]), cancer (22.9%; SMR 1.50 [95% CI 1.20-1.89]), and respiratory disease (15.1%; SMR 2.90 [95% CI 2.20-3.83]). Factors associated with all-cause mortality included older age, white race, smoking, low body weight, comorbidity, disease activity, and prednisone use. Rheumatoid factor concentration and nodules were associated with CVD mortality. There were no associations of methotrexate or biologic agent use with all-cause or cause-specific mortality.

CONCLUSION

Men in this RA cohort experienced increased all-cause and cause-specific mortality, with a 3-fold risk of respiratory-related deaths compared to age-matched men in the general population. Further studies are needed in order to examine whether interventions targeting potentially modifiable correlates of mortality might lead to improved long-term survival in men with RA.

In wealthier countries, patients perceive worse impact of the disease although they have lower objectively assessed disease activity: results from the cross-sectional COMORA study

OBJECTIVES

To investigate patterns in patient-reported and physician-reported disease outcomes in patients with rheumatoid arthritis (RA) from countries with different level of socioeconomic development.

METHODS

Data from a cross-sectional multinational study (COMOrbidities in RA) were used. Contribution of socioeconomic welfare (gross domestic product (GDP); low vs high) of country of residence to physician-reported (tender joint count, swollen joint count (SJC), erythrocyte sedimentation rate, disease activity score based on 28 joints assessment (DAS28)-3v based on these three components and physician global assessment) and patient-reported (modified Health Assessment Questionnaire (mHAQ), patient global assessment and fatigue) disease outcomes was explored in linear regressions, adjusting for relevant confounders.

RESULTS

In total, 3920 patients with RA from 17 countries (30 to 411 patients per country) were included, with mean age of 56 years (SD13) and 82% women. Mean SJC varied between 6.7 (Morocco) and 0.9 (The Netherlands), mean mHAQ ranged between 0.7 (Taiwan) and 1.5 (The Netherlands). Venezuela had the lowest (1.7) and the Netherlands the highest score on fatigue (5.0). In fully adjusted models, lower GDP was associated with worse physician-reported outcomes (1.85 and 2.84 more swollen and tender joints, respectively, and 1.0 point higher DAS28-3v), but only slightly worse performance-based patient-reported outcome (0.15 higher mHAQ), and with better evaluation-based patient-reported outcomes (0.43 and 0.97 points lower on patient global assessment and fatigue, respectively).

CONCLUSIONS

In patients with RA, important differences in physician-reported and patient-reported outcomes across countries were seen, with overall a paradox of worse physician-reported outcomes but better patient-reported outcomes in low-income countries, while results indicate that these outcomes in multinational studies should be interpreted with caution. Research on explanatory factors of this paradox should include non-disease driven cultural factors influencing health.

Less educated and older patients have reduced access to biologic DMARDs even in a country with highly developed social welfare (Norway): results from Norwegian cohort study NOR-DMARD

OBJECTIVE

To explore whether age, gender or education influence the time until initiation of the first bDMARD in patients with RA.

METHODS

Data from the Norwegian Register of DMARDs collected between 2000 and 2012 were used. Only DMARD-naïve patients with RA starting their first conventional synthetic DMARD were included in the analyses. The start of the first bDMARD was the main outcome of interest. Cox regression analyses were used to explore the impact of education, age and gender on the start of a first bDMARD, adjusting for confounders, either at baseline or varying over time (time-varying model).

RESULTS

Of 1946 eligible patients [mean (s.d.) age: 55 (14) years, 68% females], 368 (19%) received a bDMARD during follow-up (mean 2.6 years). In the baseline prediction model, older age [Hazard Ratio (HR) 0.97, 95% CI: 0.96, 0.98], lower education [HR = 0.76 and 0.68 for low and intermediate education levels vs college/university education, respectively (P = 0.01)] and female gender [only in the period 2000-03, HR = 0.61 (95% CI: 0.41, 0.91)] were associated with a lower hazard ratio to start a bDMARD. The time-varying model provided overall consistent results, but the effect of education was only relevant for older patients (>57 years) and became more pronounced by the end of the decade.

CONCLUSIONS

Less educated and older patients have disadvantages with regard to access to costly treatments, even in a country with highly developed welfare like Norway. Females had lower access in the beginning of the 2000s, but access had improved by the end of the decade.