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.

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.

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.

Vasculitis in Patients With Sarcoidosis: A Single-Institution Case Series of 17 Patients.

OBJECTIVES: Vasculitis in patients with sarcoidosis is rare and can affect any sized blood vessel. Limited information describing this association is available. METHODS: A single-institution medical records review study was performed reviewing all patients with a diagnosis code for sarcoidosis and vasculitis between January 1, 1998, and December 31, 2019. Data were abstracted regarding diagnosis, treatment, and outcomes from medical records. Patients were diagnosed with vasculitis based on biopsy and/or arterial imaging. Comparison between patients presenting with large and/or medium vessel vasculitis (L/MVV) versus patients with only small vessel vasculitis (SVV) was performed. RESULTS: Seventeen patients were identified during the study period. Nine patients (56% female) had L/MVV, and 8 (50% female) had SVV. Sarcoidosis preceded vasculitis in 4 (44%) L/MVV and 3 (38%) SVV. The mean ± SD age at sarcoidosis diagnosis was 53.2 ± 17.8 and 51.9 ± 11.4 years, and the mean ± SD age at vasculitis diagnosis was 57.4 ± 19.6 and 59.0 ± 13.4 years in L/MVV and SVV, respectively. Number of organ systems involved by sarcoidosis was similar (median [interquartile range], 3 [1-4] L/MVV vs 2.5 [1.75-3.25] SVV). The mean length of follow-up was 11.5 ± 12.8 in L/MVV and 13.1 ± 14.3 years in SVV. Complete response to therapy for vasculitis was observed in 8 of 9 with L/MVV and 7 of 8 with SVV. Four patients with SVV were able to stop all immunosuppression as compared with only 1 patient with L/MVV at the last follow-up. CONCLUSIONS: This series observed a comparable number of patients with L/MVV and SVV. Although a variety of treatments were used, most patients achieved remission regardless of vessel size affected. Clinicians should be aware of the overlap between sarcoidosis and vasculitis.

Interstitial Lung Disease in Giant Cell Arteritis: Review of 23 Patients.

BACKGROUND/OBJECTIVE: Giant cell arteritis (GCA) is a large-vessel vasculitis with systemic manifestations. A few case reports have described a possible association of GCA with interstitial lung disease (ILD). The primary aim of the present study was to describe the pattern, severity, and course of ILD in patients with GCA. METHODS: This medical records review study evaluated adult patients presenting to Mayo Clinic in Rochester, MN, from January 1, 1997, through December 31, 2018, who had the diagnoses of GCA and ILD. Clinical, laboratory, and radiologic data were analyzed. RESULTS: In total, 23 patients were in the study. Median (range) age was 78 (58-93) years, and 14 (61%) were women. Six patients (26%) had a cough at GCA diagnosis. At ILD diagnosis, 15 patients had respiratory symptoms, including dyspnea (n = 12, 52%), dry cough (n = 6, 26%), wheezing (n = 1, 4%), and chest pain (n = 1, 4%). On initial chest computed tomography, the most common pattern of ILD was probable usual interstitial pneumonia (n = 7, 30%), indeterminate for usual interstitial pneumonia (n = 5, 22%), and combined pulmonary fibrosis and emphysema (n = 3, 13%). Airway abnormalities were present in 10 patients: 6 with bronchial wall thickening, 2 with bronchiectasis, and 2 with both. At follow-up computed tomography, 8 patients had ILD progression. Three patients with cough improved after initiation of glucocorticoid therapy. CONCLUSIONS: Interstitial lung disease and airway abnormalities may be associated with GCA. Although cough may improve, ILD in some patients with GCA may progress despite immunosuppressive therapy.

Use of the electrosurgical unit in a carbon dioxide atmosphere.

The electrosurgical unit (ESU) utilizes an electrical discharge to cut and coagulate tissue and is often held above the surgical site, causing a spark to form. The voltage at which the spark is created, termed the breakdown voltage, is governed by the surrounding gaseous environment. Surgeons are now utilizing the ESU laparoscopically with carbon dioxide insufflation, potentially altering ESU operating characteristics. This study examines the clinical implications of altering gas composition by measuring the spark gap distance as a marker of breakdown voltage and use of the ESU on a biologic model, both in room air and carbon dioxide. Paschen's Law predicted a 35% decrease in gap distance in carbon dioxide, while testing revealed an average drop of 37-47% as compared to air. However, surgical model testing revealed no perceivable clinical difference. Electrosurgery can be performed in carbon dioxide environments, although surgeons should be aware of potentially altered ESU performance.

Operating room fire prevention: creating an electrosurgical unit fire safety device.

OBJECTIVE: To reduce the incidence of surgical fires. BACKGROUND: Operating room fires represent a potentially life-threatening hazard and are triggered by the electrosurgical unit (ESU) pencil. Carbon dioxide is a fire suppressant and is a routinely used medical gas. We hypothesize that a shroud of protective carbon dioxide covering the tip of the ESU pencil displaces oxygen, thereby preventing fire ignition. METHODS: Using 3-dimensional modeling techniques, a polymer sleeve was created and attached to an ESU pencil. This sleeve was connected to a carbon dioxide source and directed the gas through multiple precisely angled ports, generating a cone of fire-suppressive carbon dioxide surrounding the active pencil tip. This device was evaluated in a flammability test chamber containing 21%, 50%, and 100% oxygen with sustained ESU activation. The sleeve was tested with and without carbon dioxide (control) until a fuel was ignited or 30 seconds elapsed. Time to ignition was measured by high-speed videography. RESULTS: Fires were ignited with each control trial (15/15 trials). The control group median ± SD ignition time in 21% oxygen was 3.0 ± 2.4 seconds, in 50% oxygen was 0.1 ± 1.8 seconds, and in 100% oxygen was 0.03 ± 0.1 seconds. No fire was observed when the fire safety device was used in all concentrations of oxygen (0/15 trials; P < 0.0001). The exact 95% confidence interval for absolute risk reduction of fire ignition was 76% to 100%. CONCLUSIONS: A sleeve creating a cone of protective carbon dioxide gas enshrouding the sparks from an ESU pencil effectively prevents fire in a high-flammability model. Clinical application of this device may reduce the incidence of operating room fires.

Mitigating operating room fires: development of a carbon dioxide fire prevention device.

Operating room fires are sentinel events that present a real danger to surgical patients and occur at least as frequently as wrong-sided surgery. For fire to occur, the 3 points of the fire triad must be present: an oxidizer, an ignition source, and fuel source. The electrosurgical unit (ESU) pencil triggers most operating room fires. Carbon dioxide (CO2) is a gas that prevents ignition and suppresses fire by displacing oxygen. We hypothesize that a device can be created to reduce operating room fires by generating a cone of CO2 around the ESU pencil tip. One such device was created by fabricating a divergent nozzle and connecting it to a CO2 source. This device was then placed over the ESU pencil, allowing the tip to be encased in a cone of CO2 gas. The device was then tested in 21%, 50%, and 100% oxygen environments. The ESU was activated at 50 W cut mode while placing the ESU pencil tip on a laparotomy sponge resting on an aluminum test plate for up to 30 seconds or until the sponge ignited. High-speed videography was used to identify time of ignition. Each test was performed in each oxygen environment 5 times with the device activated (CO2 flow 8 L/min) and with the device deactivated (no CO2 flow-control). In addition, 3-dimensional spatial mapping of CO2 concentrations was performed with a CO2 sampling device. The median ± SD [range] ignition time of the control group in 21% oxygen was 2.9 s ± 0.44 [2.3-3.0], in 50% oxygen 0.58 s ± 0.12 [0.47-0.73], and in 100% oxygen 0.48 s ± 0.50 [0.03-1.27]. Fires were ignited with each control trial (15/15); no fires ignited when the device was used (0/15, P < 0.0001). The CO2 concentration at the end of the ESU pencil tip was 95%, while the average CO2 concentration 1 to 1.4 cm away from the pencil tip on the bottom plane was 64%. In conclusion, an operating room fire prevention device can be created by using a divergent nozzle design through which CO2 passes, creating a cone of fire suppressant. This device as demonstrated in a flammability model effectively reduced the risk of fire. CO2 3-dimensional spatial mapping suggests effective fire reduction at least 1 cm away from the tip of the ESU pencil at 8 L/min CO2 flow. Future testing should determine optimum CO2 flow rates and ideal nozzle shapes. Use of this device may substantially reduce the risk of patient injury due to operating room fires.

Flammability of surgical drapes and materials in varying concentrations of oxygen.

BACKGROUND: Over 600 operating room fires occur annually although many cases go unreported. Over 81% of operating room fires involve surgical drapes, yet limited data exist on the differing degrees of flammability of drapes and other surgical fuel sources in varying oxygen concentrations. The purpose of this study is to assess the flammability characteristics of fuels in the operating room under varying oxygen concentrations. METHODS: Five fuel sources were analyzed in three levels of oxygen: 21%, 50%, and 100%. Three test samples of each material were burned in a manner similar to that established by the Consumer Product Safety Commission. Time to sample ignition and time to complete burn were measured with video analysis. RESULTS: The median [minimum, maximum] ignition time in 21% oxygen was 0.9 s [0.3, 1.9], in 50% oxygen 0.4 s [0.1, 1.2], and in 100% oxygen 0.2 s [0.0, 0.4]. The median burn time in 21% oxygen was 20.4 s [7.8, 33.5], in 50% oxygen 3.1 s [1.4, 8.1], and in 100% oxygen 1.7 s [0.6, 2.7]. Time to ignite and total burn times decreased as oxygen concentration increased (P < 0.001). Flammability characteristics differed by material and oxygen concentration. Utility drapes and surgical gowns did not support combustion in room air, whereas other materials quickly ignited. Flash fires were detected on woven cotton materials in oxygen-enriched environments. CONCLUSIONS: Operating room personnel should be aware that common materials in the operating room support rapid combustion in oxygen-enriched environments. The risk of ignition and speed of fire propagation increase as oxygen exposure increases. Advances in material science may reduce perioperative fire risk.