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.

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.

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.

Associations of the MUC5B promoter variant with timing of interstitial lung disease and rheumatoid arthritis onset.

OBJECTIVES: To investigate the associations of the common MUC5B promoter variant with timing of RA-associated interstitial lung disease (RA-ILD) and RA onset. METHODS: We identified patients with RA meeting 2010 ACR/EULAR criteria and available genotype information in the Mass General Brigham Biobank, a multihospital biospecimen and clinical data collection research study. We determined RA-ILD presence by reviewing all RA patients who had CT imaging, lung biopsy or autopsy results. We determined the dates of RA and RA-ILD diagnoses by manual records review. We examined the associations of the MUC5B promoter variant (G>T at rs35705950) with RA-ILD, RA-ILD occurring before or within 2 years of RA diagnosis and RA diagnosis at age >55 years. We used multivariable logistic regression to estimate odds ratios (ORs) for each outcome by MUC5B promoter variant status, adjusting for potential confounders including genetic ancestry and smoking. RESULTS: We identified 1005 RA patients with available genotype data for rs35705950 (mean age 45 years, 79% female, 81% European ancestry). The MUC5B promoter variant was present in 155 (15.4%) and was associated with RA-ILD [multivariable OR 3.34 (95% CI 1.97, 5.60)], RA-ILD before or within 2 years of RA diagnosis [OR 4.01 (95% CI 1.78, 8.80)] and RA onset after age 55 years [OR 1.52 (95% CI 1.08, 2.12)]. CONCLUSIONS: The common MUC5B promoter variant was associated with RA-ILD onset earlier in the RA disease course and older age of RA onset. These findings suggest that the MUC5B promoter variant may impact RA-ILD risk early in the RA disease course, particularly in patients with older-onset RA.

Associations of baseline use of biologic or targeted synthetic DMARDs with COVID-19 severity in rheumatoid arthritis: Results from the COVID-19 Global Rheumatology Alliance physician registry.

OBJECTIVE: To investigate baseline use of biologic or targeted synthetic (b/ts) disease-modifying antirheumatic drugs (DMARDs) and COVID-19 outcomes in rheumatoid arthritis (RA). METHODS: We analysed the COVID-19 Global Rheumatology Alliance physician registry (from 24 March 2020 to 12 April 2021). We investigated b/tsDMARD use for RA at the clinical onset of COVID-19 (baseline): abatacept (ABA), rituximab (RTX), Janus kinase inhibitors (JAKi), interleukin 6 inhibitors (IL-6i) or tumour necrosis factor inhibitors (TNFi, reference group). The ordinal COVID-19 severity outcome was (1) no hospitalisation, (2) hospitalisation without oxygen, (3) hospitalisation with oxygen/ventilation or (4) death. We used ordinal logistic regression to estimate the OR (odds of being one level higher on the ordinal outcome) for each drug class compared with TNFi, adjusting for potential baseline confounders. RESULTS: Of 2869 people with RA (mean age 56.7 years, 80.8% female) on b/tsDMARD at the onset of COVID-19, there were 237 on ABA, 364 on RTX, 317 on IL-6i, 563 on JAKi and 1388 on TNFi. Overall, 613 (21%) were hospitalised and 157 (5.5%) died. RTX (OR 4.15, 95% CI 3.16 to 5.44) and JAKi (OR 2.06, 95% CI 1.60 to 2.65) were each associated with worse COVID-19 severity compared with TNFi. There were no associations between ABA or IL6i and COVID-19 severity. CONCLUSIONS: People with RA treated with RTX or JAKi had worse COVID-19 severity than those on TNFi. The strong association of RTX and JAKi use with poor COVID-19 outcomes highlights prioritisation of risk mitigation strategies for these people.

Effect of Resident Gender and Surname Origin on Clinical Load: Observational Cohort Study in an Internal Medicine Continuity Clinic.

BACKGROUND: Studies show patients may have gender or racial preferences for physicians. OBJECTIVE: To determine the degree to which physicians' gender and name characteristics influenced physician clinical load in medical practice, including patient panel size and percent of slots filled. DESIGN: Observational cohort study of a continuity clinic site in Rochester, MN, from July 1, 2015 to June 30, 2017 ("historical" period) and July 1, 2018 to January 30, 2020 ("contemporary" period). PARTICIPANTS: Internal medicine resident physicians. MAIN MEASURES: Resident gender, name, and race came from residency management system data. Panel size, percent of appointment slots filled ("slot fill"), panel percent female, and panel percent non-White came from the electronic health record. Multivariable linear regression models calculated beta estimates with 95% confidence intervals and R2 for the impact of physician gender, surname origin, name character length, and name consonant-to-vowel ratio on each outcome, adjusting for race and year of residency. KEY RESULTS: Of the 307 internal medicine residents, 122 (40%) were female and 197 (64%) were White. Their patient panels were 51% female (SD 16) and 74% White (SD 6). Female gender was associated with a 5.3 (95% CI 2.7-7.9) patient increase in panel size and a 1.5% (95% CI -0.6 to 3.7) increase in slot fill. European, non-Hispanic surname was associated with a 5.3 (95% CI 2.6-7.9) patient increase in panel size and a 4.3 percent (95% CI 2.1-6.4) increase in slot fill. Race and other name characteristics were not associated with physician clinical load. From the historical to contemporary period, the influence of name characteristics decreased from 9 to 4% for panel size and from 15 to 5% for slot fill. CONCLUSIONS: Female gender and European, non-Hispanic surname origin are associated with increased physician clinical load-even more than race. While these disparities may have serious consequences, they are also addressable.

Etiologies of Rheumatoid Arthritis: Update on Mucosal, Genetic, and Cellular Pathogenesis.

PURPOSE OF REVIEW: Over the last few years, the scientific community has made significant progress in understanding the etiology of rheumatoid arthritis (RA). In this review, we summarize those key findings and trends. RECENT FINDINGS: New data strongly implicates respiratory exposures, obesity, diet and microbiome, genetics, and their interactions in the etiology of RA. Furthermore, anti-posttranslationally modified protein antibodies (AMPAs) and abnormal glycosylation may be additional biomarkers for RA. Finally, functional genomics techniques implicate loss of certain macrophage populations and proliferation of synovial fibroblasts in RA. These findings support the notion that RA originates at mucosal sites, augmented by genetic predisposition, and mediated by certain cell types including macrophages and fibroblasts. Weight loss, physical activity, and diet are additional modifiable factors beyond smoking cessation that can reduce risk of RA. Future epidemiologic and translational studies leveraging multi-omics approaches will help map the precise sequence of events in RA pathogenesis.

Occurrence and aetiology of gastrointestinal perforation in patients with vasculitis.

OBJECTIVES: This study aimed to characterise the presenting features and outcomes of patients with vasculitis and gastrointestinal perforation. METHODS: Using a retrospective cohort design, this study included 20 cases with verified vasculitis and gastrointestinal perforation at Mayo Clinic, Rochester, USA, between 1998 and 2017. RESULTS: Four of the twenty cases experienced vasculitis-induced perforation. Cases with perforations due to vasculitic involvement had more small bowel involvement, longer duration of abdominal pain prior to perforation (41 days vs. 0 days, p=0.005), and a higher proportion of active tobacco use (75% vs. 7%, p=0.01) compared to the cases with non-vasculitis perforation. A majority (88%) of the non-vasculitis perforations were associated with glucocorticoid use. The median cumulative glucocorticoid dose prior to perforation in patients with additional, non-vasculitic risk factors for perforation was 4,320 mg prednisone and was 22,170 mg for those without additional risk factors. Mortality rates for the whole cohort were higher than the general population (standardised mortality ratio: 2.19, 95% confidence interval 1.05 to 4.02). The cases with vasculitis-induced perforation tended to have increased number of surgeries and length of stay compared to the non-vasculitis cases; however, those differences failed to reach statistical significance. CONCLUSIONS: Small bowel location and longer abdominal pain duration may help distinguish vasculitis-induced bowel perforation from other etiologies. Overall mortality in patients with vasculitis and bowel perforation is increased, highlighting the importance of prompt diagnosis and management.

Frailty Phenotypes and Relations With Surgical Outcomes: A Latent Class Analysis.

BACKGROUND: Frailty is an important concept in the care of older adults although controversy remains regarding its defining features and clinical utility. Both the Fried phenotype and the Rockwood deficit accumulation approaches cast frailty as a "burden" without exploring the relative salience of its cardinal markers and their relevance to the patient. New multifactorial perspectives require a reliable assessment of frailty that can validly predict postoperative health outcomes. METHODS: In a retrospective study of 2828 unselected surgical patients, we used item response theory to examine the ability of 32 heterogeneous markers capturing limitations in physical, functional, emotional, and social activity domains to indicate severity of frailty as a latent continuum. Eighteen markers efficiently indicated frailty severity and were then subject to latent class analysis to derive discrete phenotypes. Next, we validated the obtained frailty phenotypes against patient-reported 30-day postoperative outcomes using multivariable logistic regression. Models were adjusted for demographics, comorbidity, type and duration of surgery, and cigarette and alcohol consumption. RESULTS: The 18 markers provided psychometric evidence of a single reliable continuum of frailty severity. Latent class analyses produced 3 distinct subtypes, based on patients' endorsement probabilities of the frailty indicators: not frail (49.7%), moderately frail (33.5%), and severely frail (16.7%). Unlike the moderate class, severely frail endorsed emotional health problems in addition to physical burdens and functional limitations. Models adjusting for age, sex, type of anesthesia, and intraoperative factors indicated that severely frail (odds ratio, 1.89; 95% confidence interval, 1.42-2.50) and moderately frail patients (odds ratio, 1.31; 95% confidence interval, 1.03-1.67) both had higher odds of experiencing postoperative complications compared to not frail patients. In a 3-way comparison, a higher proportion of severely frail patients (10.7%) reported poorer quality of life after surgery compared to moderately frail (9.2%) and not frail (8.3%) patients (P < .001). There was no significant difference among these groups in proportions reporting hospital readmission (5.6%, 5.1%, and 3.8%, respectively; P = .067). CONCLUSIONS: Self-report frailty items can accurately discern 3 distinct phenotypes differing in composition and their relations with surgical outcomes. Systematically assessing a wider set of domains including limitations in functional, emotional, and social activities can inform clinicians on what precipitates loss of physiological reserve and profoundly influences patients' lives. This information can help guide the current discussion on frailty and add meaningful clinical tools to the surgical practice.

Changes in quality of life after elective surgery: an observational study comparing two measures.

PURPOSE: Our main objective was to compare the change in a validated quality of life measure to a global assessment measure. The secondary objectives were to estimate the minimum clinically important difference (MCID) and to describe the change in quality of life by surgical specialty. METHODS: This prospective cohort study included 7902 adult patients undergoing elective surgery. Changes in the Veterans RAND 12-Item Health Survey (VR-12), composed of a physical component summary (PCS) and a mental component summary (MCS), were calculated using preoperative and postoperative questionnaires. The latter also contained a global assessment question for quality of life. We compared PCS and MCS to the global assessment using descriptive statistics and weighted kappa. MCID was calculated using an anchor-based approach. Analyses were pre-specified and registered (NCT02771964). RESULTS: By the change in VR-12 scores, an equal proportion of patients experienced improvement and deterioration in quality of life (28% for PCS, 25% for MCS). In contrast, by the global assessment measure, 61% reported improvement, while only 10% reported deterioration. Agreement with the global assessment was slight for both PCS (kappa = 0.20, 57% matched) and MCS (kappa = 0.10, 54% matched). The MCID for the overall VR-12 score was approximately 2.5 points. Patients undergoing orthopedic surgery showed the most improvement in quality of life measures, while patients undergoing gastrointestinal/hepatobiliary or urologic surgery showed the most deterioration. CONCLUSIONS: Subjective global quality of life report does not agree well with a validated quality of life instrument, perhaps due to patient over-optimism.

Preoperative Falls and Their Association with Functional Dependence and Quality of Life.

BACKGROUND: No study has rigorously explored the characteristics of surgical patients with recent preoperative falls. Our objective was to describe the essential features of preoperative falls and determine whether they are associated with preoperative functional dependence and poor quality of life. METHODS: This was an observational study involving 15,060 surveys from adult patients undergoing elective surgery. The surveys were collected between January 2014 and August 2015, with a response rate of 92%. RESULTS: In the 6 months before surgery, 26% (99% CI, 25 to 27%) of patients fell at least once, and 12% (99% CI, 11 to 13%) fell at least twice. The proportion of patients who fell was highest among patients presenting for neurosurgery (41%; 99% CI, 36 to 45%). At least one fall-related injury occurred in 58% (99% CI, 56 to 60%) of those who fell. Falls were common in all age groups, but surprisingly, they did not increase monotonically with age. Middle-aged patients (45 to 64 yr) had the highest proportion of fallers (28%), recurrent fallers (13%), and severe fall-related injuries (27%) compared to younger (18 to 44 yr) and older (65+ yr) patients (P < 0.001 for each). A fall within 6 months was independently associated with preoperative functional dependence (odds ratio, 1.94; 99% CI, 1.68 to 2.24) and poor physical quality of life (odds ratio, 2.18; 99% CI, 1.88 to 2.52). CONCLUSIONS: Preoperative falls might be common and are possibly often injurious in the presurgical population, across all ages. A history of falls could enhance the assessment of preoperative functional dependence and quality of life.

Low-frequency and rare genetic variants associated with rheumatoid arthritis risk.

Rheumatoid arthritis (RA) has an estimated heritability of nearly 50%, which is particularly high in seropositive RA. HLA alleles account for a large proportion of this heritability, in addition to many common single-nucleotide polymorphisms with smaller individual effects. Low-frequency and rare variants, such as those captured by next-generation sequencing, can also have a large role in heritability in some individuals. Rare variant discovery has informed the development of drugs such as inhibitors of PCSK9 and Janus kinases. Some 34 low-frequency and rare variants are currently associated with RA risk. One variant (19:10352442G>C in TYK2) was identified in five separate studies, and might therefore represent a promising therapeutic target. Following a set of best practices in future studies, including studying diverse populations, using large sample sizes, validating RA and serostatus, replicating findings, adjusting for other variants and performing functional assessment, could help to ensure the relevance of identified variants. Exciting opportunities are now on the horizon for genetics in RA, including larger datasets and consortia, whole-genome sequencing and direct applications of findings in the management, and especially treatment, of RA.

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.

Incidence, Prevalence, and Mortality of Dermatomyositis: A Population-Based Cohort Study.

OBJECTIVE: We aimed to determine the population-based incidence, prevalence, and mortality of dermatomyositis (DM) using European Alliance of Associations for Rheumatology (EULAR)/American College of Rheumatology (ACR) criteria. METHODS: This population-based cohort study included incident DM from January 1, 1995 to December 31, 2019. We manually reviewed all individuals with at least 1 code for DM or polymyositis to determine if they met EULAR/ACR criteria, subspecialty physician diagnosis, and/or Bohan and Peter criteria. We age- and sex-adjusted incidence and prevalence estimates to the US non-Hispanic White year 2000 population and estimated prevalence on January 1, 2015. Standardized mortality ratios (SMRs) with 95% confidence intervals (95% CIs) compared observed to expected mortality adjusting for age, sex, and year. RESULTS: We identified 40 cases of verified DM, with 29 cases incident in Olmsted County from 1995 to 2019. The mean age was 57 years, 26 (90%) were female, and 12 (41%) had clinically amyopathic DM (CADM). The median follow-up time was 8.2 years. The overall adjusted incidence of DM was 1.1 (95% CI 0.7-1.5) per 100,000 person-years, and prevalence was 13 (95% CI 6-19) per 100,000. The SMR was significantly elevated among the myopathic DM cases (3.1 [95% CI 1.1-6.8]) but not CADM cases (1.1 [95% CI 0.2-3.3]). The positive predictive value of ≥2 DM codes was only 40 of 82 (49%). CONCLUSION: This population-based study found that DM incidence and prevalence were higher than previously reported. Mortality was significantly elevated for myopathic DM but not for CADM.

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.

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.

Gene-respiratory disease interactions for rheumatoid arthritis risk.

OBJECTIVE: We aimed to identify gene by respiratory tract disease interactions that increase RA risk. METHODS: In this case-control study using the Mass General Brigham Biobank, we matched incident RA cases, confirmed by ACR/EULAR criteria, to four controls on age, sex, and electronic health record history. Genetic exposures included a validated overall genetic risk score (GRS) for RA, a Human Leukocyte Antigen (HLA) GRS for RA, and the MUC5B promoter variant, an established risk factor for RA-associated interstitial lung disease (ILD). Preceding respiratory tract diseases came from diagnosis codes (positive predictive value 86%). We estimated attributable proportions (AP) and multiplicative odds ratios (OR) with 95% confidence intervals (CI) for RA for each genetic and respiratory exposure using conditional logistic regression models, adjusting for potential confounders. RESULTS: We identified 653 incident RA cases and 2,607 matched controls (mean 54 years, 76% female). The highest tertile of the overall GRS and the HLA GRS were both associated with increased RA risk (OR 2.28, 95% CI 1.89,2.74; OR 2.02, 95% CI 1.67-2.45). ILD and the HLA GRS exhibited a synergistic relationship for RA risk (OR for both exposures 4.30, 95% CI 1.28,14.38; AP 0.51, 95% CI-0.16,1.18). Asthma and the MUC5B promoter variant also exhibited a synergistic interaction for seropositive RA (OR for both exposures 2.58, 95% CI 1.10,6.07; AP 0.62, 95% CI 0.24,1.00). CONCLUSION: ILD-HLA GRS and asthma-MUC5B promoter variant showed synergistic interactions for RA risk. Such interactions may prove useful for RA prevention and screening.

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.