Updates on interstitial lung disease and other selected extra-articular manifestations of rheumatoid arthritis.

PURPOSE OF REVIEW: To discuss changes in epidemiology, recent advances in understanding of the pathogenesis and management of selected extraarticular manifestations of rheumatoid arthritis (ExRA). RECENT FINDINGS: The incidence of ExRA overall and subcutaneous rheumatoid nodules in particular is declining after 2000. These trends reflect improved RA disease activity with early effective immunosuppressive treatments; changing environmental risk factors can be contributing. ExRA continues to carry a two-fold increased mortality risk. RA-associated interstitial lung disease (RA-ILD) is a major contributor to mortality, with no decline in incidence and scant therapeutic options. Individualized risk stratification for RA-ILD based on patient-level risk factors and biomarker profile is evolving with MUC5B as a major genetic risk factor. Clinical trials are underway to evaluate the benefits of novel antifibrotic therapies and targeted therapies for RA-ILD. The risk of cardiovascular disease in RA is generally amendable to treatment with disease-modifying antirheumatic drugs, although cardiovascular risk associated with JAK inhibition is not fully understood. SUMMARY: Despite reduction in incidence of ExRA overall, the incidence of RA-ILD shows no significant decline and remains a major therapeutic challenge. The use of novel antifibrotics and immunosuppressive drugs shows promise in slowing the progression of RA-ILD.

Comorbidity clusters in patients with rheumatoid arthritis identify a patient phenotype with a favourable prognosis.

OBJECTIVES: We aimed to cluster patients with rheumatoid arthritis (RA) based on comorbidities and then examine the association between these clusters and RA disease activity and mortality. METHODS: In this population-based study, residents of an eight-county region with prevalent RA on 1 January 2015 were identified. Patients were followed for vital status until death, last contact or 31 December 2021. Diagnostic codes for 5 years before the prevalence date were used to define 55 comorbidities. Latent class analysis was used to cluster patients based on comorbidity patterns. Standardised mortality ratios were used to assess mortality. RESULTS: A total of 1643 patients with prevalent RA (72% female; 94% white; median age 64 years, median RA duration 7 years) were studied. Four clusters were identified. Cluster 1 (n=686) included patients with few comorbidities, and cluster 4 (n=134) included older patients with 10 or more comorbidities. Cluster 2 (n=200) included patients with five or more comorbidities and high prevalences of depression and obesity, while cluster 3 (n=623) included the remainder. RA disease activity and survival differed across the clusters, with cluster 1 demonstrating more remission and mortality comparable to the general population. CONCLUSIONS: More than 40% of patients with prevalent RA did not experience worse mortality than their peers without RA. The cluster with the worst prognosis (<10% of patients with prevalent RA) was older, had more comorbidities and had less disease-modifying antirheumatic drug and biological use compared with the other clusters. Comorbidity patterns may hold the key to moving beyond a one-size-fits-all perspective of RA prognosis.

Association between sinusitis and incident rheumatic diseases: a population-based study.

OBJECTIVES: To determine whether antecedent sinusitis is associated with incident rheumatic disease. METHODS: This population-based case-control study included all individuals meeting classification criteria for rheumatic diseases between 1995 and 2014. We matched three controls to each case on age, sex and length of prior electronic health record history. The primary exposure was presence of sinusitis, ascertained by diagnosis codes (positive predictive value 96%). We fit logistic regression models to estimate ORs for incident rheumatic diseases and disease groups, adjusted for confounders. RESULTS: We identified 1729 incident rheumatic disease cases and 5187 matched controls (mean age 63, 67% women, median 14 years electronic health record history). After adjustment, preceding sinusitis was associated with increased risk of several rheumatic diseases, including antiphospholipid syndrome (OR 7.0, 95% CI 1.8 to 27), Sjögren's disease (OR 2.4, 95% CI 1.1 to 5.3), vasculitis (OR 1.4, 95% CI 1.1 to 1.9) and polymyalgia rheumatica (OR 1.4, 95% CI 1.0 to 2.0). Acute sinusitis was also associated with increased risk of seronegative rheumatoid arthritis (OR 1.8, 95% CI 1.1 to 3.1). Sinusitis was most associated with any rheumatic disease in the 5-10 years before disease onset (OR 1.7, 95% CI 1.3 to 2.3). Individuals with seven or more codes for sinusitis had the highest risk for rheumatic disease (OR 1.7, 95% CI 1.3 to 2.4). In addition, the association between sinusitis and incident rheumatic diseases showed the highest point estimates for never smokers (OR 1.7, 95% CI 1.3 to 2.2). CONCLUSIONS: Preceding sinusitis is associated with increased incidence of rheumatic diseases, suggesting a possible role for sinus inflammation in their pathogenesis.

Multiple morbidities are associated with serious infections in patients with rheumatoid arthritis.

OBJECTIVE: To assess the association between a comprehensive list of morbidities and serious infection (SI) in patients with rheumatoid arthritis (RA). METHODS: This study evaluated SI risk associated with 55 comorbidities using a population-based inception cohort including all adult patients with incident RA from 1999 through 2014 with follow up through 2021. Morbidities and SI were ascertained using previously validated international classification of disease (ICD)-9 and ICD-10 codes. Conditional frailty models were utilized to analyze the association between each morbidity and SI: Model 1 adjusted for age, sex, and calendar year; Model 2 adjusted for factors in Model 1 and the Rheumatoid Arthritis Observation of Biologic Therapy (RABBIT) Risk Score of Infections; and Model 3 adjusted for factors in Model 1 and the Mayo SI Risk Score. RESULTS: 911 patients (70 % female, mean age 56 years, 66 % seropositive) were included. There were 293 SI among 155 patients (17 %), corresponding to an incidence of 3.9 SI per 100 person-years. Eighteen SI were fatal. Risk of SI was significantly increased in 27 of 55 morbidities in Model 1, 11 morbidities in Model 2, and 23 morbidities in Model 3. Additionally, several morbidities included in the RABBIT and Mayo risk scores continued to have large effect sizes despite adjustment. Serious infection risk increased by 11-16 % per morbidity in the three models. CONCLUSIONS: Several morbidities are associated with an increased risk for SI. Future risk scores may include morbidities identified in this study for improved SI risk assessment.

Decline in Incidence of Extra-Articular Manifestations of Rheumatoid Arthritis: A Population-Based Cohort Study.

OBJECTIVE: The focus of this study was to assess changes in the cumulative incidence of extra-articular manifestations of rheumatoid arthritis (ExRAs) and associated mortality risk. METHODS: This study evaluated trends in occurrence of ExRAs using a population-based inception cohort that included all adult patients with incident rheumatoid arthritis (RA) from 1985 through 2014 meeting the 1987 American College of Rheumatology criteria. Patients were divided into two cohorts based on the incidence date of RA, 1985 to 1999 and 2000 to 2014. The occurrence of ExRAs was determined by manual chart review, and the 10-year cumulative incidence was estimated for each ExRA in both cohorts. Cox proportional hazard models were used to determine associations between specific demographic and RA disease characteristics and ExRAs and between ExRAs and mortality. RESULTS: There were 907 patients included, 296 in the 1985 to 1999 cohort and 611 in the 2000 to 2014 cohort. The 10-year cumulative incidence of any ExRA decreased significantly between the earlier and later cohorts (45.1% vs 31.6%, P < 0.001). This was largely driven by significant declines in subcutaneous rheumatoid nodules (30.9% vs 15.8%, P < 0.001) and nonsevere ExRAs (41.4% vs 28.8%, P = 0.001). Identified risk factors for the development of any ExRAs include rheumatoid factor positivity (hazard ratio [HR] 2.02, 95% confidence interval [CI] 1.43-2.86) and current smoking (HR 1.61, 95% CI 1.10-2.34). Mortality was increased in patients with either nonsevere (HR 1.83, 95% CI 1.18-2.85) or severe ExRAs (HR 3.05, 95% CI 1.44-6.49). CONCLUSIONS: The incidence of ExRAs has decreased over time. Mortality remains increased in patients with ExRAs.

Utilisation of cardiovascular preventive services in a rheumatoid arthritis population-based cohort.

OBJECTIVES: The objective is to examine utilisation of cardiovascular preventive services in patients with rheumatoid arthritis (RA), compared with a non-RA population, and to examine cardiovascular disease (CVD) screening rates among RA patients without diabetes mellitus (DM), hypertension or hyperlipidaemia to non-RA patients with one of these diagnoses. METHODS: All ≥18-year-old patients with an RA diagnosis living in one of eight Minnesota counties on 1 January 2015 were included and matched (1:1) by sex, age and county to non-RA comparators. Rates of screening for CVD risk factors, including DM (ie, glucose), hypertension (ie, blood pressure) and hyperlipidaemia (ie, lipids), were compared between groups using Cox models. RESULTS: The study included 1614 patients with RA and 1599 non-RA comparators. DM screening was more common among patients with RA (HR: 1.10, 95% CI: 1.01 to 1.19), as was hypertension screening (HR: 1.37, 95% CI: 1.24 to 1.52). Hyperlipidaemia screening in RA was similar to comparators (HR: 0.99, 95% CI: 0.89 to 1.10). Conversely, patients with RA and no CVD risk factors had a lower probability of undergoing diabetes (HR: 0.67, 95% CI: 0.57 to 0.78) and hyperlipidaemia screening (HR: 0.65, 95% CI: 0.54 to 0.79) than non-RA patients with only one CVD risk factor diagnosis. Hypertension screening was similar between both groups. CONCLUSIONS: RA patients undergo CVD preventive screening at rates at least comparable to the general population. However, patients with RA as their sole CVD risk factor were less likely to undergo screenings, despite an equivalent-to-higher risk as the traditional CVD risk factors. These findings demonstrate opportunities for improvement of RA patient care.

Neuropathologic evaluation of cerebrovascular disease in patients with rheumatoid arthritis.

OBJECTIVES: Active RA has been associated with an increased risk of both cardiovascular and peripheral vascular disease. We aimed to compare cerebrovascular changes in patients with and without RA, both with and without a neuropathologic diagnosis of neurodegenerative disease. METHODS: Patients with RA (n = 32) who died and underwent autopsy between 1994 and 2021 were matched to non-RA controls (n = 32) on age, sex and level of neurodegenerative proteinopathy. Routine neuropathologic examination was performed at the time of autopsy. Cerebrovascular disease severity was evaluated using modified Kalaria and Strozyk scales. Clinical dementia diagnoses were manually collected from patients' medical records. RESULTS: Prior to death, 15 (47%) RA patients and 14 (44%) controls were diagnosed with dementia; 9 patients in each group (60% and 64%, respectively) had Alzheimer's disease. The prevalence of cerebral amyloid angiopathy, microinfarcts, infarcts or strokes was found to be similar between groups. Patients with RA were more likely to have more severe vascular changes in the basal ganglia by Kalaria scale (P = 0.04), but not in other brain areas. There were no significant differences in the presence of large infarcts, lacunar infarcts or leukoencephalopathy by Strozyk scale. Among patients with RA and no clinical diagnosis of dementia, the majority had mild-moderate cerebrovascular abnormalities, and a subset of patients had Alzheimer's disease neuropathologic changes. CONCLUSION: In this small series of autopsies, patients with and without RA had largely similar cerebrovascular pathology when controlling for neurodegenerative proteinopathies, although patients with RA exhibited more pronounced cerebrovascular disease in the basal ganglia.

Clinical Response to Tumor Necrosis Factor-α Inhibitor Therapy in the Management of Cardiac Sarcoidosis.

Evidence that tumor necrosis factor-α (TNF-α) inhibitors may benefit patients with cardiac sarcoidosis (CS) is limited to small case series and both imaging and clinical outcomes in this population are not well known. This study aimed to evaluate the disease course of patients with CS treated with either infliximab or adalimumab therapy based on serial 18F-fluorodeoxyglucose positron emission tomography (FDG-PET) imaging and clinical outcomes. An institutional CS research database was queried for patients treated with TNF-α inhibitors between 2016 and 2021. Outcomes included (1) change in mean prednisone dose, (2) FDG-PET improvement, and (3) unplanned hospitalizations, advanced heart failure therapies, or death. Our query yielded 31 patients with CS. A total of 13 patients were on infliximab, 15 patients were on adalimumab, and 3 patients were on adalimumab before transitioning to infliximab. Mean prednisone dose decreased between FDG-PET immediately preceding TNF-α and second after TNF-α FDG-PET (18.6 ± 15.7 mg to 7.7 ± 12.4 mg, p = 0.018). A significant decrease was seen in the mean number of segments demonstrating FDG uptake between most recent pre-TNF-α and first after TNF-α inhibitor FDG-PET (mean segments = 4.2 vs 3.1, p = 0.048). Between earliest pre-TNF-α and first after TNF-α FDG-PET there was a numerical decrease in average myocardial maximum standard uptake values (SUVmax) (4.4 vs 3.1, p = 0.18), and the ratio of SUVmax myocardium:SUVmax blood pool (1.9 vs 1.5, p = 0.26). Within 36 months of initiating TNF-α inhibitor, 4 patients (13%) experienced unplanned cardiovascular hospitalization (median time to hospitalization = 12.1 months). In conclusion, in patients with CS, TNF-α inhibitor therapy is associated with decreased glucocorticoid use, numerical decrease in cardiac FDG uptake, and minimal cardiac morbidity.

Disparities in multimorbidity and comorbidities in rheumatoid arthritis by sex acrossthe lifespan.

OBJECTIVES: Multimorbidity is burdensome for people with rheumatoid arthritis (RA). We investigated differences in multimorbidity and comorbidities by sex and age in the RA population. METHODS: This cross-sectional analysis used national administrative claims (OptumLabs® Data Warehouse) from people with RA and non-RA comparators (matched on age, sex, race, census region, index year, and length of baseline insurance coverage) from 2010-2019. RA was determined using a validated algorithm. Multimorbidity was defined as ≥ 2 (MM2+) or ≥ 5 (MM5+) comorbidities from a validated set of 44 chronic conditions. We used logistic regression to assess associations between characteristics and multimorbidity. RESULTS: The sample included 154,391 RA patients and 154,391 non-RA comparators. For people aged 18-50 years, RA women (vs RA men) had 7.5 and 4.4 (vs 3.2 and 0.9 in non-RA women vs non-RA men) percentage point increases for MM2+ and MM5+, respectively. For people aged 51+ years, RA women (vs RA men) had 2.1 and 2.5 (vs 1.2 and 0.3 in non-RA women vs non-RA men) percentage point increases for MM2+ and MM5+, respectively. Interactions revealed that differences in multimorbidity between women and men were exacerbated by RA (vs non-RA) (p < 0.05), with more pronounced effects in people aged 18-50. Men had more cardiovascular-related conditions, whereas RA women had more psychological, neurological, and general musculoskeletal conditions. Other comorbidities varied by sex and age. CONCLUSION: Multimorbidity disproportionately impacts women with RA. Research, clinical, and policy agendas for rheumatic diseases should acknowledge and support the variation in care needs by sex and gender across the lifespan.

Validating the Fracture Risk Assessment Tool Score in a US Population-Based Study of Patients With Rheumatoid Arthritis.

OBJECTIVE: The World Health Organization fracture risk assessment tool (FRAX) algorithm for risk prediction of major osteoporotic and hip fractures accounts for several risk factors, including rheumatoid arthritis (RA), since individuals with RA have an excess burden of fractures. FRAX has not been validated in population-based RA cohorts in the US. We aimed to determine the accuracy of FRAX predictions for individuals with RA in the US. METHODS: This retrospective population-based cohort study included residents of Olmsted County, Minnesota, who were followed until death, migration, or last medical record review. Each patient with RA (1987 American College of Rheumatology criteria met in 1980-2007, age 40-89 years) was matched 1:1 on age and sex to an individual without RA from the same underlying population. Ten-year predictions for major osteoporotic and hip fractures were estimated using the FRAX tool. Fractures were ascertained through follow-up, truncated at 10 years. Standardized incidence ratios (SIRs) and 95% CI were calculated to compare observed and predicted fractures. RESULTS: The study included 662 patients with RA and 658 non-RA comparators (66.8% vs 66.9% female and a mean age of 60.6 vs 60.5 years, respectively). Among patients with RA, 76 major osteoporotic fractures and 21 hip fractures were observed during follow-up (median follow-up: 9.0 years) compared to 67.0 predicted major osteoporotic fractures (SIR 1.13, 95% CI 0.91-1.42) and 23.3 predicted hip fractures (SIR 0.90, 95% CI 0.59-1.38). The observed and predicted major osteoporotic and hip fracture risks were similar for patients with RA and non-RA comparators. CONCLUSION: The FRAX tool is an accurate method for estimating major osteoporotic and hip fracture risk in patients with RA.

Time Trends in Glucocorticoid Use in Rheumatoid Arthritis During the Biologics Era: 1999-2018.

OBJECTIVES: To examine time trends in glucocorticoid (GC) use among patients diagnosed with rheumatoid arthritis (RA) during the biologic era. METHODS: A population-based inception cohort of RA patients diagnosed during 1999 - 2018 was followed longitudinally through their medical records until death, migration or 12/31/2020. All patients fulfilled 1987 American College of Rheumatology classification criteria for RA. GC start and stop dates were collected along with dosages in prednisone equivalents. The cumulative incidence of GC initiation and discontinuation adjusted for the competing risk of death was estimated. Cox models adjusted for age and sex were used to compare trends between time periods. RESULTS: The study population included 399 patients (71% female) diagnosed in 1999 - 2008 and 430 patients (67% female) diagnosed in 2009 - 2018. GC use was initiated within 6 months of meeting RA criteria in 67% of patients in 1999-2008 and 71% of patients in 2009-2018, corresponding to a 29% increase in hazard for initiation of GC in 2009-2018 (adjusted hazard ratio [HR]: 1.29; 95% confidence interval [CI]: 1.09-1.53). Among GC users, similar rates of GC discontinuation within 6 months after GC initiation were observed in patients with RA incidence in 1999 - 2008 and 2009 - 2018 (39.1% versus 42.9%, respectively), with no significant association in adjusted Cox models (HR: 1.11; 95% CI: 0.93-1.31). CONCLUSION: More patients are initiating GCs early in their disease course now compared to previously. The rates of GC discontinuation were similar, despite the availability of biologics.

Patients with ACPA-positive and ACPA-negative rheumatoid arthritis show different serological autoantibody repertoires and autoantibody associations with disease activity.

Patients with rheumatoid arthritis (RA) can test either positive or negative for circulating anti-citrullinated protein antibodies (ACPA) and are thereby categorized as ACPA-positive (ACPA+) or ACPA-negative (ACPA-), respectively. In this study, we aimed to elucidate a broader range of serological autoantibodies that could further explain immunological differences between patients with ACPA+ RA and ACPA- RA. On serum collected from adult patients with ACPA+ RA (n = 32), ACPA- RA (n = 30), and matched healthy controls (n = 30), we used a highly multiplex autoantibody profiling assay to screen for over 1600 IgG autoantibodies that target full-length, correctly folded, native human proteins. We identified differences in serum autoantibodies between patients with ACPA+ RA and ACPA- RA compared with healthy controls. Specifically, we found 22 and 19 autoantibodies with significantly higher abundances in ACPA+ RA patients and ACPA- RA patients, respectively. Among these two sets of autoantibodies, only one autoantibody (anti-GTF2A2) was common in both comparisons; this provides further evidence of immunological differences between these two RA subgroups despite sharing similar symptoms. On the other hand, we identified 30 and 25 autoantibodies with lower abundances in ACPA+ RA and ACPA- RA, respectively, of which 8 autoantibodies were common in both comparisons; we report for the first time that the depletion of certain autoantibodies may be linked to this autoimmune disease. Functional enrichment analysis of the protein antigens targeted by these autoantibodies showed an over-representation of a range of essential biological processes, including programmed cell death, metabolism, and signal transduction. Lastly, we found that autoantibodies correlate with Clinical Disease Activity Index, but associate differently depending on patients' ACPA status. In all, we present candidate autoantibody biomarker signatures associated with ACPA status and disease activity in RA, providing a promising avenue for patient stratification and diagnostics.

Trends in Incidence of Chronic Heart Failure in Patients With Rheumatoid Arthritis: A Population-Based Study Validating Different Heart Failure Definitions.

OBJECTIVE: To assess trends in the incidence of heart failure (HF) in patients with incident rheumatoid arthritis (RA) from 1980 to 2009 and to compare different HF definitions in RA. METHODS: The study population comprised Olmsted County, Minnesota residents with incident RA (age ≥ 18 yrs, 1987 American College of Rheumatology criteria met in 1980-2009). All subjects were followed until death, migration, or April 30, 2019. Incident HF events were defined as follows: (1) meeting the Framingham criteria for HF, (2) diagnosis of HF (outpatient or inpatient) by a physician, or (3) International Classification of Diseases, 9th revision (ICD-9), or ICD, 10th revision (ICD-10), codes for HF. Patients with HF prior to the RA incidence/index date were excluded. Cox proportional hazards models were used to compare incident HF events by decade, adjusting for age, sex, and cardiovascular risk factors. HF definitions 2 and 3 were compared to the Framingham criteria. RESULTS: The study included 905 patients with RA (mean age 55.9 years; 68.6% female; median follow-up 13.4 years). The 10-year cumulative incidence of HF events by any chart-reviewed method in the RA cohort in the 1980s was 11.66% (95% CI 7.86-17.29), in the 1990s it was 12.64% (95% CI 9.31-17.17), and in the 2000s it was 7.67% (95% CI 5.36-10.97). The incidence of HF did not change across the decades of RA incidence using any of the HF definitions. Physician diagnosis of HF and ICD-9/10 code-based definitions of HF performed well compared to the Framingham criteria, showing moderate to high sensitivity and specificity. CONCLUSION: The incidence of HF in patients with incident RA in the 2000s vs the 1980s was not statistically significantly different. Physician diagnosis of HF and ICD-9/10 codes for HF performed well against the Framingham criteria.

Risk Factors for Dementia in Patients With Incident Rheumatoid Arthritis: A Population-Based Cohort Study.

OBJECTIVE: Growing evidence suggests that patients with rheumatoid arthritis (RA) have increased risk for dementia. We assessed risk factors for incident dementia in an inception cohort of patients with RA. METHODS: This retrospective population-based cohort study included residents of 8 counties in Minnesota who were ≥ 50 years of age when they met 1987 American College of Rheumatology criteria for incident RA between 1980 and 2014 and were followed until death/migration or December 31, 2019. Patients with dementia before RA incidence were excluded. Incident dementia was defined as 2 relevant International Classification of Diseases, 9th or 10th revision codes at least 30 days apart. Data on sociodemographics, disease characteristics, cardiovascular/cerebrovascular disease (CVD) risk factors, and comorbidities were abstracted from medical records. RESULTS: The study included 886 patients with RA (mean age 65.1 yrs, 65.2% female). During the follow-up period (median 8.5 yrs), 103 patients developed dementia. After adjusting for age, sex, and calendar year of RA incidence, older age at RA incidence (HR 1.14 per 1 year increase, 95% CI 1.12-1.17), rheumatoid nodules (HR 1.76, 95% CI 1.05-2.95), hypertension (HR 1.84, 95% CI 1.19-2.85), presence of large joint swelling (HR 2.03, 95% CI 1.14-3.60), any CVD (HR 2.25, 95% CI 1.38-3.66), particularly ischemic stroke (HR 3.16, 95% CI 1.84-5.43) and heart failure (HR 1.82, 95% CI 1.10-3.00), anxiety (HR 1.86, 95% CI 1.16-2.97), and depression (HR 2.63, 95% CI 1.76-3.93) were associated with increased risk of dementia. After adjusting for CVD risk factors and any CVD, all covariates listed above were still significantly associated with risk of dementia. CONCLUSION: Apart from age, hypertension, depression, and anxiety, all of which are universally recognized risk factors for dementia, clinically active RA and presence of CVD were associated with an elevated risk of dementia incidence among patients with RA.

Racial Differences in Multimorbidity and Comorbidities in Rheumatoid Arthritis.

OBJECTIVE: To identify differences in multimorbidity and individual comorbidities among individuals with rheumatoid arthritis (RA), separated by race and ethnicity. METHODS: This case-control study within OptumLabs Data Warehouse from 2010 to 2019 matched RA cases (defined by 2 codes plus prescription of an RA drug) to non-RA controls 1:1 on age, sex, race and ethnicity, region, index date of RA, and insurance coverage duration. We defined multimorbidity as the presence of ≥2 or ≥5 validated comorbidities. Logistic regression models calculated adjusted odds of multimorbidity with 95% confidence intervals (95% CIs) within each race and ethnicity. RESULTS: We identified 154,391 RA cases and 154,391 controls (mean age 59.6, 76% female). Black enrollees had the most multimorbidity ≥2/≥5 (73.1%, 34.3%); Asian enrollees had the least (52.4%, 17.3%). Adjusted odds of multimorbidity ≥2 and ≥5 in RA cases versus controls was 2.19 (95% CI 2.16-2.23) and 2.06 (95% CI 2.02-2.09), respectively. This increase was similar across race and ethnicity. However, we observed elevated occurrence of certain comorbidities by race and ethnicity versus controls (P < 0.001), including renal disease in White enrollees (4.7% versus 3.2%) and valvular heart disease in Black and White enrollees (3.2% and 2.8% versus 2.6% and 2.2%). CONCLUSION: Multimorbidity is a problem for all RA patients. Targeted identification of certain comorbidities by race and ethnicity may be a helpful approach to mitigate multimorbidity.

Using Unsupervised Machine Learning Methods to Cluster Comorbidities in a Population-Based Cohort of Patients With Rheumatoid Arthritis.

OBJECTIVE: To identify clusters of comorbidities in patients with rheumatoid arthritis (RA) using 4 methods and to compare to patients without RA. METHODS: In this retrospective, population-based study, residents of 8 Minnesota counties with prevalent RA as of January 1, 2015 were identified. Age-, sex-, and county-matched non-RA comparators were selected from the same underlying population. Diagnostic codes were retrieved for 5 years before January 1, 2015. Using 2 codes ≥30 days apart, 44 previously defined morbidities and 11 nonoverlapping chronic disease categories based on Clinical Classifications Software were defined. Unsupervised machine learning methods of interest included hierarchical clustering, factor analysis, K-means clustering, and network analysis. RESULTS: Two groups of 1,643 patients with and without RA (72% female; mean age 63.1 years in both groups) were studied. Clustering of comorbidities revealed strong associations among mental/behavioral comorbidities and among cardiovascular risk factors and diseases. The clusters were associated with age and sex. Differences between the 4 clustering methods were driven by comorbidities that are rare and those that were weakly associated with other comorbidities. Common comorbidities tended to group together consistently across approaches. The instability of clusters when using different random seeds or bootstrap sampling impugns the usefulness and reliability of these methods. Clusters of common comorbidities between RA and non-RA cohorts were similar. CONCLUSION: Despite the higher comorbidity burden in patients with RA compared to the general population, clustering comorbidities did not identify substantial differences in comorbidity patterns between the RA and non-RA cohorts. The instability of clustering methods suggests caution when interpreting clustering using 1 method.

Association between work physical activity, dietary factors, and risk of rheumatoid arthritis.

OBJECTIVE: We aimed to determine the association of physical activity and dietary factors on RA risk. METHODS: This case-control study within the Mayo Clinic Biobank matched incident RA cases (two codes plus disease-modifying anti-rheumatic drug, PPV 95%) to controls 1:3 on age, sex, and recruitment year/location. A baseline questionnaire assessed activity and dietary exposures. Logistic regression models calculated adjusted odds ratios (aOR) with 95% confidence intervals (CI) of RA for each of 45 activity/dietary exposures. RESULTS: We identified 212 incident RA cases and 636 controls (mean age 64, 70% female). Active work physical activity was associated with elevated risk of RA (aOR 3.00, 95% CI 1.58-5.69 vs. sedentary); leisure activity was not (aOR 0.96, 95% CI 0.64-1.42 sedentary vs. active). Three or more servings high-fat food and 5+ servings fruits/vegetables daily showed non-significant associations with RA (aOR 1.22, 95% CI 0.74-2.00 vs. 0-1 time; aOR 0.75, 95% CI 0.51-1.11 vs. 0-3 times), especially in sensitivity analyses with at least five years between questionnaire and RA (aOR 1.80, 95% CI 0.69-4.71; aOR 0.54, 95% CI 0.27-1.08). Alcohol binging was not associated with RA risk (aOR 1.28, 95% CI 0.56-2.96). Finally, sensitivity (versus primary) analyses showed a nonsignificant increase in RA risk for most vitamins and supplements. CONCLUSION: Active work physical activity and some nutritional profiles (increased high-fat, reduced fruit/vegetable consumption) may be associated with increased risk of RA. Confirmatory studies are needed.

Rheumatoid Arthritis, Cognitive Impairment, and Neuroimaging Biomarkers: Results from the Mayo Clinic Study of Aging.

BACKGROUND: Observational studies suggested that dementia risk in patients with rheumatoid arthritis (RA) is higher than in the general population. OBJECTIVE: To examine the associations of RA with cognitive decline and dementia, and neuroimaging biomarkers of aging, Alzheimer's disease, and vascular pathology in adult participants in the Mayo Clinic Study of Aging (MCSA). METHODS: Participants with RA were matched 1:3 on age, sex, education, and baseline cognitive diagnosis to participants without RA. RA cases with MRI were also matched with non-cases with available MRI. All available imaging studies (i.e., amyloid and FDG PET, sMRI, and FLAIR) were included. The study included 104 participants with RA and 312 without RA (mean age (standard deviation, SD) 75.0 (10.4) years, 33% male and average follow-up (SD) 4.2 (3.8) years). RESULTS: Groups were similar in cognitive decline and risk of incident dementia. Among participants with neuroimaging, participants with RA (n = 33) and without RA (n = 98) had similar amyloid burden and neurodegeneration measures, including regions sensitive to aging and dementia, but greater mean white matter hyperintensity volume relative to the total intracranial volume (mean (SD)% : 1.12 (0.57)% versus 0.76 (0.69)% of TIV, p = 0.01), and had higher mean (SD) number of cortical infarctions (0.24 (0.44) versus 0.05 (0.33), p = 0.02). CONCLUSION: Although cognitive decline and dementia risk were similar in participants with and without RA, participants with RA had more abnormal cerebrovascular pathology on neuroimaging. Future studies should examine the mechanisms underlying these changes and potential implications for prognostication and prevention of cognitive decline in RA.