The time-dependent changes in serum immunoglobulin after kidney transplantation and its association with infection.

Introduction: Kidney transplant recipients often experience significant alterations in their immune system, which can lead to increased susceptibility to infections. This study aimed to analyze time-dependent changes in serum immunoglobulin and complement levels and determine the risk factors associated with infection. Methods: A retrospective analysis of serum samples from 192 kidney transplant recipients who received transplantations between August 2016 and December 2019 was conducted. The serum samples were obtained at preoperative baseline (T0), postoperative 2 weeks (T1), 3 months (T2), and 1 year (T3). The levels of serum C3, C4, IgG, IgA, and IgM were measured to evaluate immune status over time. Results: The analysis revealed significant decreases in IgG and IgA levels at T1. This period was associated with the highest occurrence of hypogammaglobulinemia (HGG) and hypocomplementemia (HCC), as well as an increased incidence of severe infection requiring hospitalization and graft-related viral infections. Using a time-dependent Cox proportional hazards model adjusted for time-varying confounders, HGG was significantly associated with an increased risk of infection requiring hospitalization (HR, 1.895; 95% CI: 1.871-1.920, P-value<0.001) and graft-related viral infection (HR, 1.152; 95% CI: 1.144-1.160, P-value<0.001). Discussion: The findings suggest that monitoring serum immunoglobulin levels post-transplant provides valuable insights into the degree of immunosuppression. Hypogammaglobulinemia during the early post-transplant period emerges as a critical risk factor for infection, indicating that serum immunoglobulins could serve as feasible biomarkers for assessing infection risk in kidney transplant recipients.

Outcomes and risk factors for infection after endovascular treatment in patients with acute ischemic stroke.

AIMS: Infection is a common complication following acute ischemic stroke (AIS) and significantly contributes to poor functional outcomes after stroke. This study aimed to investigate the effects of infection after endovascular treatment (post-EVT infection) on clinical outcomes and risk factors in patients with AIS. METHODS: We retrospectively analyzed AIS patients treated with endovascular treatment (EVT) between January 2016 and December 2022. A post-EVT infection was defined as any infection diagnosed within 7 days after EVT. The primary outcome was functional independence, defined as a modified Rankin scale (mRS) score of 0-2 at 90 days. A multivariable logistic regression analysis was conducted to determine independent predictors of post-EVT infection and the associations between post-EVT infection and clinical outcomes. RESULTS: A total of 675 patients were included in the analysis; 306 (45.3%) of them had post-EVT infections. Patients with post-EVT infection had a lower rate of functional independence than patients without infection (31% vs 65%, p = 0.006). In addition, patients with post-EVT infection achieved less early neurological improvement (ENI) after EVT (25.8% vs 47.4%, p < 0.001). For safety outcomes, the infection group had a higher incidence of any intracranial hemorrhage (23.9% vs 15.7%, p = 0.01) and symptomatic intracranial hemorrhage (10.1% vs 5.1%, p = 0.01). Unsuccessful recanalization (aOR 1.87, 95% CI 1.11-3.13; p = 0.02) and general anesthesia (aOR 2.22, 95% CI 1.25-3.95; p = 0.01) were identified as independent predictors for post-EVT infection in logistic regression analysis. CONCLUSION: AIS patients who develop post-EVT infections are more likely to experience poor clinical outcomes. Unsuccessful recanalization and general anesthesia were independent risk factors for the development of post-EVT infection.

Comparison of infectious complications with BCMA-directed therapies in multiple myeloma.

B-cell-maturation-antigen (BCMA)-directed therapies are highly active for multiple myeloma, but infections are emerging as a major challenge. In this retrospective, single-center analysis we evaluated infectious complications after BCMA-targeted chimeric-antigen-receptor T-cell therapy (CAR-T), bispecific-antibodies (BsAb) and antibody-drug-conjugates (ADC). The primary endpoint was severe (grade ≥3) infection incidence. Amongst 256 patients, 92 received CAR-T, 55 BsAb and 109 ADC. The incidence of severe infections was higher with BsAb (40%) than CAR-T (26%) or ADC (8%), including grade 5 infections (7% vs 0% vs 0%, respectively). Comparing T-cell redirecting therapies, the incidence rate of severe infections was significantly lower with CAR-T compared to BsAb at 1-year (incidence-rate-ratio [IRR] = 0.43, 95%CI 0.25-0.76, P = 0.004). During periods of treatment-emergent hypogammaglobulinemia, BsAb recipients had higher infection rates (IRR:2.27, 1.31-3.98, P = 0.004) and time to severe infection (HR 2.04, 1.05-3.96, P = 0.036) than their CAR-T counterparts. During periods of non-neutropenia, CAR-T recipients had a lower risk (HR 0.44, 95%CI 0.21-0.93, P = 0.032) and incidence rate (IRR:0.32, 95% 0.17-0.59, P < 0.001) of severe infections than BsAb. In conclusion, we observed an overall higher and more persistent risk of severe infections with BsAb. Our results also suggest a higher infection risk during periods of hypogammaglobulinemia with BsAb, and with neutropenia in CAR-T recipients.

Infectious complications in pediatric patients undergoing CD19+CD22+ chimeric antigen receptor T-cell therapy for relapsed/refractory B-lymphoblastic leukemia.

Chimeric antigen receptor T-cell (CAR-T) therapy is effective in the treatment of relapsed/refractory acute B-lymphoblastic leukemia (R/R B-ALL); however, patients who receive CAR-T therapy are predisposed to infections, with considerable detrimental effects on long-term survival rates and the quality of life of patients. This study retrospectively analyzed infectious complications in 79 pediatric patients with R/R B-ALL treated with CAR-T cells at our institution. Overall, 53 patients developed 88 infections. Nine patients experienced nine infections during lymphodepletion chemotherapy, 35 experienced 41 infections during the early phase (days 0-+ 30 after infusion), and 29 experienced 38 infections during the late phase (day + 31-+ 90 after infusion). Pathogens were identified in 31 infections, including 23 bacteria, seven viruses, and one fungus. Four patients were admitted to the intensive care unit for infection and one died. In a univariate analysis, there were ten factors associated with infection, including tumor load, lymphodepleting chemotherapy, neutrophil deficiency and lymphocyte reduction, cytokine release syndrome (CRS) and immune effector cell-associated neurotoxicity syndrome (ICANS), etc. In a multivariate analysis, CRS ≥ grade 3 was identified as a risk factor for infection (hazard ratio = 2.41, 95% confidence interval: 1.08-5.36, P = 0.031). Therefore, actively reducing the CRS grade may decrease the risk of infection and improve the long-term quality of life of these patients.

Risk stratification for infection during immunosuppressive therapy in patients with lupus nephritis: A nested case-control study.

BACKGROUND: The current prediction models for the risk of infection during immunosuppressive treatment for lupus nephritis (LN) lack a prediction time window and have poor pertinence. This study aimed to develop a risk stratification to predict infection during immunosuppressive therapy in patients with LN. METHODS: This retrospective nested case-control study collected patients with LN treated with immunosuppressive therapy between 2014 and 2022 in the Nephrology ward in Huashan Hospital affiliated to Fudan University and Huashan Hospital Baoshan Branch. Cases were defined as patients who experienced infection during the follow-up period; patients were eligible as controls if they did not have infection during the follow-up period. RESULTS: There were 53 patients with infection by CTCAE V5.0 grade ≥2. According to the 1:3 nested matching, the 53 patients with infection were matched with 159 controls. In the multivariable logistic regression model, the change rate of fibrinogen (OR = 0.97, 95% CI: 0.94-0.99, p = 0.008), leukopenia (OR = 8.68, 95% CI: 1.16-301.72, p = 0.039), and reduced albumin (OR = 6.25, 95% CI: 1.38-28.24, p = 0.017) were independently associated with infection. The AUC of the ROC curve in the validation set of the multivariable logistic regression model in the internal random sampling was 0.864. The scores range from -2 to 10. The infection risk stratification ranges from 2.8% at score -2 to 97.5% at score 10. CONCLUSION: A risk stratification was built to predict the risk of infection in patients with LN undergoing immunosuppressive therapy.

Diabetic Foot Infections and Amputations Are All Too Common-Here's What Could Move the Needle.

This Medical News article discusses how multidisciplinary care teams, new drugs and devices, and practical solutions to socioeconomic factors could reduce diabetic foot infections and amputations.

Characteristics and incidence of infections in patients with multiple myeloma treated by bispecific antibodies: a national retrospective study.

OBJECTIVES: Bispecific antibodies (BsAbs) are an effective treatment used in relapsed or refractory multiple myeloma. Despite a well-tolerated safety profile, infectious events appear to be frequent in clinical trials. Real-world data on epidemiology, characteristics, risk factors, and outcomes of infections in patients treated with BsAb are still needed. METHODS: A retrospective, multicentre study in BsAb-treated patients with multiple myeloma was performed in 14 French centres from December 2020 to February 2023. The primary objective was to describe the incidence of infections that required hospitalization, specific treatment, or adaptation in BsAb administration. RESULTS: Among 229 patients with multiple myeloma treated with BsAb, 153 (67%) received teclistamab, 47 (20%) received elranatamab, and 29 (13%) talquetamab. We reported a total of 234 infections, including 123 (53%) of grade of ≥3. Predominant infections affected the respiratory tract (n = 116, 50%) followed by bacteraemias (n = 36, 15%). The hospitalization rate was 56% (n = 131), and 20 (9%) infections resulted in death. Global cumulative incidence of the first infection was 70% in all patients, 73% in patients treated with B-cell maturation antigen-targeting, and 51% with GPRC5D-targeting BsAb. In univariate analyses, corticosteroids for cytokine release syndrome (CRS)/immune effector cell-associated neurotoxicity syndrome (ICANS) were associated with a higher risk of first infection (HR = 2.13; 95% CI, 1.38-3.28), whereas GPRC5D-targeting BsAb and anti-bacterial prophylaxis were associated with a lower risk (HR = 0.53; 95% CI, 0.3-0.94 and HR = 0.65; 95% CI, 0.46-0.9). Fine and Gray multivariate model found that only corticosteroids for CRS/ICANS were correlated with a higher risk of first infection (HR = 2.01; 95% CI, 1.27-3.19). DISCUSSIONS: The implementation of preventive measures that aim to mitigate the risk of infection under BsAb is pivotal, notably in patients who received corticosteroids for CRS/ICANS.

Defining and Grading Infections in Clinical Trials Involving Hematopoietic Cell Transplantation: A Report From the BMT CTN Infectious Disease Technical Committee.

The Blood and Marrow Transplant Clinical Trials Network (BMT-CTN) was established in 2001 to conduct large multi-institutional clinical trials addressing important issues towards improving the outcomes of HCT and other cellular therapies. Trials conducted by the network investigating new advances in HCT and cellular therapy not only assess efficacy but require careful capturing and severity assessment of adverse events and toxicities. Adverse infectious events in cancer clinical trials are typically graded according to the National Cancer Institute's Common Terminology Criteria for Adverse Events (CTCAE). However, there are limitations to this framework as it relates to HCT given the associated immunodeficiency and delayed immune reconstitution. The BMT-CTN Infection Grading System is a monitoring tool developed by the BMT CTN to capture and monitor infectious complications and differs from the CTCAE by its classification of infections based on their potential impact on morbidity and mortality for HCT recipients. Here we offer a report from the BMT CTN Infectious Disease Technical Committee regarding the rationale, development, and revising of BMT-CTN Infection Grading System and future directions as it applies to future clinical trials involving HCT and cellular therapy recipients.

CD19 CAR T-Cell Therapy in Autoimmune Disease - A Case Series with Follow-up.

BACKGROUND: Treatment for autoimmune diseases such as systemic lupus erythematosus (SLE), idiopathic inflammatory myositis, and systemic sclerosis often involves long-term immune suppression. Resetting aberrant autoimmunity in these diseases through deep depletion of B cells is a potential strategy for achieving sustained drug-free remission. METHODS: We evaluated 15 patients with severe SLE (8 patients), idiopathic inflammatory myositis (3 patients), or systemic sclerosis (4 patients) who received a single infusion of CD19 chimeric antigen receptor (CAR) T cells after preconditioning with fludarabine and cyclophosphamide. Efficacy up to 2 years after CAR T-cell infusion was assessed by means of Definition of Remission in SLE (DORIS) remission criteria, American College of Rheumatology-European League against Rheumatism (ACR-EULAR) major clinical response, and the score on the European Scleroderma Trials and Research Group (EUSTAR) activity index (with higher scores indicating greater disease activity), among others. Safety variables, including cytokine release syndrome and infections, were recorded. RESULTS: The median follow-up was 15 months (range, 4 to 29). The mean (±SD) duration of B-cell aplasia was 112±47 days. All the patients with SLE had DORIS remission, all the patients with idiopathic inflammatory myositis had an ACR-EULAR major clinical response, and all the patients with systemic sclerosis had a decrease in the score on the EUSTAR activity index. Immunosuppressive therapy was completely stopped in all the patients. Grade 1 cytokine release syndrome occurred in 10 patients. One patient each had grade 2 cytokine release syndrome, grade 1 immune effector cell-associated neurotoxicity syndrome, and pneumonia that resulted in hospitalization. CONCLUSIONS: In this case series, CD19 CAR T-cell transfer appeared to be feasible, safe, and efficacious in three different autoimmune diseases, providing rationale for further controlled clinical trials. (Funded by Deutsche Forschungsgemeinschaft and others.).

The prevalence, complications, and risk factors for infantile hemangioma: a systematic review and meta-analysis.

The epidemiological landscape of infantile hemangioma (IH) has been extensively explored through diverse data sources; however, a scarcity of systematically pooled and quantified evidence from comprehensive global studies persists. In this meta-analysis, we systematically review available literature to elucidate the prevalence, distribution of lesions, complications, and risk factors associated with IH. A meticulous search encompassing the Cochrane Library, PubMed, Embase, and Web of Science identified 3206 records, of which 55 studies met the inclusion criteria. We found that the overall prevalence of IH is 2.8% [95% confidence interval (CI): 1.5-4.4%] (31,274,396 infants), and IH was located more frequently in the head and neck with a prevalence of 47.4% (95% CI: 39.5-55.4%). The overall prevalence of complications of IH is 24.3% (95% CI: 18.6-30.5%), ulceration is 16.0% (95% CI: 10.4-21.2%), bleeding is 5.6% (95% CI: 3.3-8.5%), visual impairment is 5.6% (95% CI: 3.0-8.9%), infection is 2.8% (95% CI: 1.5-4.8%), subglottic obstruction is 1.5% (95% CI: 0.5-3.0%), respectively. Through 27 studies, we have evaluated 35 factors encompassing perinatal factors, socioeconomic factors, maternal complications, drug factors, and antepartum procedures, and identified 18 risk factors that increase the prevalence of IH. These findings can greatly assist clinicians and family members in effectively evaluating the risk of IH, and determining whether pregnant women should undergo intensified monitoring or preventive measures.

Granulocyte transfusions in life-threatening infections of children with hemato-oncological diseases.

Granulocytes are the most important cells for host defense during infections. Granulocyte suspension transfusions (GTx) may be given as additional treatment in severely neutropenic patients with life-threatening infections when antimicrobial therapy is inadequate. The aim of this study was to evaluate the effectiveness and safety of GTx for the treatment of children with hemato-oncological disease, febrile neutropenia and serious life-threatening infections. Patients who underwent GTx between July 2020 and September 2022 were evaluated retrospectively. Hematologic and clinical response rates, adverse effects, characteristics of infection episodes and survival data of the patients were analyzed. During the study period, 60 patients received a total of 313 GTx for 81 infection episodes with a median number of GTx/infection episode of 3 (range 1-29). The median neutrophil count per bag was 20.8 (range 7.9-68.3) × 109 and the median neutrophil count per kg body weight was 0.82 (range 0.17-9.2) × 109. Clinical response was 85 %. Clinical response decreased significantly as the duration of neutropenia increased (p = 0.002). Hematologic response was calculated in 198 GTx (GTx given with pre-transfusion neutrophil count ≤ 0.5 × 109/L); hematologic response rate was 34 %. The infection-related mortality was 15 % and overall survival rate was 87 % and 70 % on days 30 and 90, respectively. No serious side effects were observed in any patient. Granulocyte transfusions appear to be safe and effective supportive treatment in neutropenic children with hematologic/oncologic diseases and severe infections.

Smoking changes adaptive immunity with persistent effects.

Individuals differ widely in their immune responses, with age, sex and genetic factors having major roles in this inherent variability1-6. However, the variables that drive such differences in cytokine secretion-a crucial component of the host response to immune challenges-remain poorly defined. Here we investigated 136 variables and identified smoking, cytomegalovirus latent infection and body mass index as major contributors to variability in cytokine response, with effects of comparable magnitudes with age, sex and genetics. We find that smoking influences both innate and adaptive immune responses. Notably, its effect on innate responses is quickly lost after smoking cessation and is specifically associated with plasma levels of CEACAM6, whereas its effect on adaptive responses persists long after individuals quit smoking and is associated with epigenetic memory. This is supported by the association of the past smoking effect on cytokine responses with DNA methylation at specific signal trans-activators and regulators of metabolism. Our findings identify three novel variables associated with cytokine secretion variability and reveal roles for smoking in the short- and long-term regulation of immune responses. These results have potential clinical implications for the risk of developing infections, cancers or autoimmune diseases.

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.

Impact of preoperative infection on the outcomes of liver transplant recipients: a national propensity score-matched retrospective cohort study in China.

BACKGROUND: Impact of preoperative infection on liver transplantation (LT) needs further investigation. MATERIALS AND METHODS: From 1 January 2015 to 31 December 2022, 24 122 eligible patients receiving LT were enrolled from the China Liver Transplant Registry database. The outcomes of LT were compared after using the propensity score-matched analysis. RESULTS: Compared to the noninfection group, patients in the infection group were more likely to have postoperative effusion, infection, abdominal bleeding, and biliary complications (all P <0.01), and they had shorter 30-day, 90-day survival, and overall survival (all P <0.01). Cox proportional hazards regression analysis revealed that MELD score and cold ischemia time were risk factors for the overall survival in the infection group (both P <0.05). Besides, compared to the nonpulmonary group, patients in the pulmonary group were more likely to have postoperative effusion and infection (both P <0.0001), and less likely to have postoperative abscess and early allograft dysfunction (both P <0.05). Patients in the nonabdominal group also had a higher proportion of postoperative infection than those in the abdominal group ( P <0.05). Furthermore, compared to the number=1 group, patients in the number ≥2 group were more prone to postoperative effusion and infection (both P <0.01), and they also had shorter 30-day and 90-day survival (both P <0.05). CONCLUSION: Preoperative infection can result in a higher incidence of early postoperative complications and shorter survival in liver transplant recipients. The types and number of infection sites will also influence the prognosis of liver transplant recipients.

SOHO State of the Art Updates and Next Questions | CTLs for Infections Following Stem Cell Transplantation.

Allogeneic hematopoietic stem cell transplantation (AHSCT) is an important modality in the treatment of acute leukemia and other hematologic disorders. The post-transplant period is associated with prolonged periods of impaired immune function. Delayed T-cell immune reconstitution is correlated with increased risk of viral, bacterial, and fungal infections. This risk increases with high intensity inductions regimens often required for alternative donor sources. Current therapies for prophylaxis and treatment of these infections are limited by poor efficacy and significant toxicity. Adoptive cell therapy with cytotoxic T lymphocytes (CTL) has proven to be both efficacious and safe in the management of post-transplant viral infections. Recent advances have led to faster production of CTLs and broadened applications for their use. In particular, the generation of third party CTLs has helped ameliorate the problems related to donor availability and product generation time. In this review we aim to describe both the history of CTL use and current advances in the field.

Does Temporary Externalization of Electrodes After Deep Brain Stimulation Surgery Result in a Higher Risk of Infection?

OBJECTIVES: Deep brain stimulation (DBS) is a well-established surgical therapy for movement disorders that comprises implantation of stimulation electrodes and a pacemaker. These procedures can be performed separately, leaving the possibility of externalizing the electrodes for local field potential recording or testing multiple targets for therapeutic efficacy. It is still debated whether the temporary externalization of DBS electrodes leads to an increased risk of infection. We therefore aimed to assess the risk of infection during and after lead externalization in DBS surgery. MATERIALS AND METHODS: In this retrospective study, we analyzed a consecutive series of 624 DBS surgeries, including 266 instances with temporary externalization of DBS electrodes for a mean of 6.1 days. Patients were available for follow-up of at least one year, except in 15 instances. In 14 patients with negative test stimulation, electrodes were removed. All kinds of infections related to implantation of the neurostimulation system were accounted for. RESULTS: Overall, infections occurred in 22 of 624 surgeries (3.5%). Without externalization of electrodes, infections were noted after 7 of 358 surgeries (2.0%), whereas with externalization, 15 of 252 infections were found (6.0%). This difference was significant (p = 0.01), but it did not reach statistical significance when comparing groups within different diagnoses. The rate of infection with externalized electrodes was highest in psychiatric disorders (9.1%), followed by Parkinson's disease (7.3%), pain (5.7%), and dystonia (5.5%). The duration of the externalization of the DBS electrodes was comparable in patients who developed an infection (6.1 ± 3.1 days) with duration in those who did not (6.0 ± 3.5 days). CONCLUSIONS: Although infection rates were relatively low in our study, there was a slightly higher infection rate when DBS electrodes were externalized. On the basis of our results, the indication for electrode externalization should be carefully considered, and patients should be informed about the possibility of a higher infection risk when externalization of DBS electrodes is planned.

A matched cohort study evaluating the risks of infections in people with type 1 diabetes and their associations with glycated haemoglobin.

AIMS: People with type 1 diabetes (T1D) have raised infection rates compared to those without, but how these risks vary by age, sex and ethnicity, or by glycated haemoglobin (HbA1c), remain uncertain. METHODS: 33,829 patients with T1D in Clinical Practice Research Datalink on 01/01/2015 were age-sex-ethnicity matched to two non-diabetes patients. Infections were collated from primary care and linked hospitalisation records during 2015-2019, and incidence rate ratios (IRRs) were estimated versus non-diabetes. For 26,096 people with T1D, with ≥3 HbA1c measurements in 2012-2014, mean and coefficient of variation were estimated, and compared across percentiles. RESULTS: People with T1D had increased risk for infections presenting in primary care (IRR = 1.81, 95%CI 1.77-1.85) and hospitalisations (IRR = 3.37, 3.21-3.53) compared to non-diabetes, slightly attenuated after further adjustment. Younger ages and non-White ethnicities had greater relative risks, potentially explained by higher HbA1c mean and variability amongst people with T1D within these sub-groups. Both mean HbA1c and greater variability were strongly associated with infection risks, but the greatest associations were at the highest mean levels (hospitalisations IRR = 4.09, 3.64-4.59) for >97 versus ≤53 mmol/mol. CONCLUSIONS: Infections are a significant health burden in T1D. Improved glycaemic control may reduce infection risks, while prompter infection treatments may reduce hospital admissions.

Frailty and Risk of Serious Infections in Patients With Rheumatoid Arthritis Treated With Biologic or Targeted-Synthetic Disease-Modifying Antirheumatic Drugs.

OBJECTIVE: It remains unknown whether frailty status portends an increased risk of adverse outcomes in patients with rheumatoid arthritis (RA) initiating biologic or targeted-synthetic (b/ts) disease-modifying antirheumatic drugs (DMARDs). The objective of our study was to evaluate the association between frailty and serious infections in a younger population of patients (<65 years old) with RA who initiated b/tsDMARDs. METHODS: Using MarketScan data, we identified new users of tumor necrosis factor inhibitors (TNFi), non-TNFi biologic DMARDs, or Janus kinase inhibitors (JAKi) between 2008 and 2019 among those with RA. Patients' baseline frailty risk score was calculated using a Claims-Based Frailty Index (≥0.2 defined as frail) 12 months prior to drug initiation. The primary outcome was time to serious infection; secondarily, we examined time-to-any infection and all-cause hospitalizations. We used Cox proportional hazards to estimate adjusted hazard ratios and 95% confidence intervals (95% CIs) and assessed the significance of interaction terms between frailty status and drug class. RESULTS: A total of 57,980 patients, mean (±SD) age 48.1 ± 10.1 were included; 48,139 (83%) started TNFi, 8,111 (14%) non-TNFi biologics, and 1,730 (3%) JAKi. Among these, 3,560 (6%) were categorized as frail. Frailty was associated with a 50% increased risk of serious infections (adjusted hazard ratio [95% CI] 1.5, 1.2-1.9) and 40% higher risk of inpatient admissions (1.4 [1.3-1.6]) compared with nonfrail patients among those who initiated TNFi. Frailty was also associated with a higher risk of any infection relative to nonfrail patients among those on TNFi (1.2 [1.1-1.3]) or non-TNFi (1.2 [1.0-1.4]) or JAKi (1.4 [1.0-2.0]). CONCLUSION: Frailty is an important predictor for the risk of adverse outcomes among patients with RA treated with biologic or targeted-synthetic DMARDs.