Haematological abnormalities in new-onset rheumatoid arthritis and risk of common infections: a population-based study

Mean Platelet Volume in a Series of 315 Patients with Rheumatoid Arthritis: Relationship with Disease Characteristics, including Subclinical Atherosclerosis and Cardiovascular Comorbidity

Mean platelet volume (MPV) refers to the average platelet size in femtoliters. Increased or decreased MPV has been associated with several disorders, including inflammatory and cardiovascular diseases. In the present study, our objective was to analyze the relationship of MPV with disease activity in a large and well-characterized series of patients with rheumatoid arthritis (RA). This is a cross-sectional study that included 315 patients with RA and 208 controls matched by sex and age. Complete blood count, including MPV, was assessed. Multivariable analysis was performed to examine the relationship of MPV with RA disease characteristics, carotid atherosclerosis, and traditional cardiovascular factors, including a comprehensive profile of lipid molecules and insulin resistance or beta cell function indices. The multivariable analysis, which includes other hematological modifications produced by the disease and platelet values, showed that MPV levels were significantly lower in RA patients than in controls. Erythrocyte sedimentation rate and interleukin-6, but not C-reactive protein, were negatively correlated with MPV after adjustment for covariates. Similarly, disease activity and MPV had a significant and independent negative correlation. No relationships were found between MPV and cardiovascular risk factors, lipid profile or insulin resistance indices or subclinical atherosclerosis. In conclusion, patients with RA have lower levels of MPV than controls. MPV is negatively related to acute phase reactants and disease activity in RA.

Red Cell Distribution Width Association with Subclinical Cardiovascular Disease in Patients with Rheumatoid Arthritis

Red cell distribution width (RDW) is a measure of the variation in mean corpuscular volume that reflects the degree of anisocytosis on the peripheral blood smear. RDW value variation has been implicated in several disorders including chronic inflammatory processes and cardiovascular (CV) diseases. In the present work, our objective was to study the relationship that RDW has with the characteristics of the disease in patients with rheumatoid arthritis (RA), focusing on CV risk factors and subclinical atherosclerosis. A cross-sectional study was conducted that included 430 patients with RA and 208 controls matched by sex and age. Complete blood count, including RDW, was assessed. Multivariable analysis was performed to analyze the relationship of RDW with RA disease characteristics, subclinical carotid atherosclerosis, and traditional CV factors, including a comprehensive profile of lipid molecules and insulin resistance and beta cell function indices. After multivariable adjustment, the RDW was significantly higher in RA patients compared with controls (beta coefficient 1.0 [95% confidence interval 0.2 to 1.8] %, p = 0.020). Furthermore, although the erythrocyte sedimentation rate showed a positive and significant relationship with RDW, this association was not found with C-reactive protein and interleukin-6. A positive and independent relationship was observed between DAS28-ESR disease activity score and RDW. However, no association was found between the RDW and other disease activity scores that do not include erythrocyte sedimentation rate in their formula. The SCORE2 CV risk algorithm was positively and significantly associated with higher RDW values. Likewise, a negative relationship was found between RDW with total cholesterol and low-density lipoprotein cholesterol, and a positive relationship was found between RDW and insulin resistance indices. In conclusion, RDW values are higher in RA patients compared to matched controls. Although the relationship of RDW with disease activity was not consistent, RDW shows associations with subclinical CV disease risk factors, including dyslipidemia and insulin resistance, and with the SCORE2 CV disease-risk prediction algorithm.

The Ratio of Monocytes to HDL-Cholesterol Is Associated with Cardiovascular Risk and Insulin Resistance in Patients with Rheumatoid Arthritis

The monocytes to high-density lipoprotein (HDL)-cholesterol ratio (MHR) indicates inflammation based on the anti-inflammatory properties of HDL-cholesterol as well as the pro-inflammatory effect of monocytes. Several studies have investigated MHR in various disorders, specifically in cardiovascular diseases. Consequently, MHR has been significantly associated with cardiovascular and all-cause mortality in the general population, regardless of established risk factors. However, its role in the augmented risk of cardiovascular disease found in rheumatoid arthritis (RA) has not been studied to date. This is a cross-sectional study that encompassed 430 patients with RA and 208 controls matched by sex and age. Complete blood cell count and complete lipid profile were evaluated. Multivariable analysis was made to analyze the relationship between MHR and RA disease and features subclinical carotid atherosclerosis, and traditional CV factors including insulin resistance and beta cell function indices. MHR values did not differ between controls and patients after multivariable adjustment (12 ± 6 vs. 11 ± 6, p = 0.18). No relationship between this ratio and the characteristics of the disease was found excluding ESR, which showed a significant and positive association with MHR after adjustment for covariates. MHR significantly correlated with Systematic Coronary Risk Evaluation-2 (SCORE2) cardiovascular risk algorithm, and insulin resistance and beta cell function parameters after adjustment. In conclusion, MHR does not differ between patients with RA and controls. The relationship of this biomarker with disease-related data is poor. However, MHR is highly and positively related to cardiovascular risk and insulin resistance in RA.

Future Biomarkers for Infection and Inflammation in Rheumatoid Arthritis

Rheumatoid arthritis (RA) increases the susceptibility to a variety of infections that are often difficult to diagnose and can be asymptomatic or symptoms are atypical. Usually, this is a great challenge for rheumatologists, because it is difficult to distinguish infection and aseptic inflammation at an early stage. Prompt diagnosis and treatment of bacterial infections in immunosuppressed individuals is critical for clinicians, and early exclusion of infection allows for specific treatment of inflammatory diseases and avoids the unnecessary use of antibiotics. However, for patients with clinically suspected infection, traditional laboratory markers are not specific for bacterial infection and cannot be used to distinguish outbreaks from infections. Therefore, new infection markers that can distinguish infection from underlying disease are urgently needed for clinical practice. Here, we review the novel biomarkers in RA patients with infection. These biomarkers include presepsin, serology and haematology, as well as neutrophils, T cells, and natural killer cells. Meanwhile, we discuss meaningful biomarkers that distinguish infection from inflammation and develop novel biomarkers for clinical applications, allowing clinicians to make better decisions when diagnosing and treating RA.

The association between atopic eczema and lymphopenia: Results from a UK cohort study with replication in US survey data

BACKGROUND

Lymphocyte skin homing in atopic eczema (AE) may induce lymphopenia.

OBJECTIVE

To determine if AE is associated with lymphopenia.

METHODS

We used UK primary care electronic health records (Clinical Practice Research Datalink GOLD) for a matched cohort study in adults (18 years+) (1997-2015) with at least one recorded lymphocyte count. We matched people with AE to up to five people without. We used multivariable logistic regression to estimate the association between AE and lymphopenia (two low lymphocyte counts within 3 months) and linear mixed effects regression to estimate the association with absolute lymphocyte counts using all available counts. Cox proportional hazard models were used to investigate the effect of lymphopenia on common infections. We replicated the study using US survey data (National Health and Nutrition Examination Survey [NHANES]).

RESULTS

Among 71,731 adults with AE and 126,349 adults without AE, we found an adjusted odds ratio (OR) for lymphopenia of 1.16 (95% CI: 1.09-1.23); the strength of association increased with increasing eczema severity. When comparing all recorded lymphocyte counts from adults with AE (n = 1,497,306) to those of people without AE (n = 4,035,870) we saw a lower mean lymphocyte (adjusted mean difference -0.047 × 109 /L [95% CI: -0.051 to -0.043]) in those with AE. The difference was larger for men, with increasing age, and with increasing AE severity and was present among people with AE not treated with immunosuppressive drugs. In NHANES (n = 22,624), the adjusted OR for lymphopenia in adults with AE was 1.30 (95% CI: 0.80-2.11), and the adjusted mean lymphocyte count difference was -0.03 × 109 /L (95% CI: -0.07 to 0.02). Despite having a lower lymphocyte count, adjusting for time with lymphopenia, did not alter risk estimates of infections.

CONCLUSION

Atopic eczema, including increasing AE severity, is associated with a decreased lymphocyte count, regardless of immunosuppressive drug use. Whether the lower lymphocyte count has wider health implications for people with severe eczema warrants further investigation.

Association of hemoglobin levels with radiographic progression in patients with rheumatoid arthritis: an analysis from the BRASS registry

BACKGROUND

To evaluate baseline hemoglobin (Hb) and radiographic progression over time in patients enrolled in the Brigham and Women's Rheumatoid Arthritis Sequential Study (BRASS) registry.

METHODS

The BRASS is a prospective observational registry of patients with rheumatoid arthritis. BRASS Hb data and total sharp score data were matched with the main BRASS patients. Hb at baseline was categorized per the World Health Organization guidelines. Mean Hb, mean total sharp score, and mean changes over time from baseline to month 120 were summarized (overall, by low/normal Hb, and by current medication at baseline). All analyses were descriptive.

RESULTS

Out of the total (N = 1114) rheumatoid arthritis patients included in the analysis, patients with low Hb at baseline (n = 224 [20%]) had longer disease duration and higher disease activity and reported more pain compared with patients with normal Hb at baseline (n = 890 [80%]). Patients with low Hb at baseline continued to have lower Hb than patients with normal Hb throughout 10 years; although, on average, patients in the low Hb subgroup exhibited a steady increase in Hb levels. A larger increase in total sharp score over time was observed for patients with low Hb than for patients with normal Hb. No meaningful differences potentially attributable to medication at baseline were detected.

CONCLUSIONS

Patients with low Hb levels at baseline tended to have increased radiographic progression as measured by total sharp score compared with patients with rheumatoid arthritis having normal Hb levels. Patients with low Hb experienced sustained improvements in Hb levels over time, regardless of the class of medication used.

TRIAL REGISTRATION

ClinicalTrials.gov NCT01793103.

Alopecia areata and risk of common infections: a population-based cohort study

BACKGROUND

It is not known whether alopecia areata (AA) is associated with a greater or reduced risk for infection.

AIM

We undertook a population-based study exploring associations between AA and common infections.

METHODS

We extracted primary care records from the UK Oxford-Royal College of General Practitioners Research and Surveillance Centre database (trial registration: NCT04239521). The incidence of common and viral infection composite outcomes, and individual respiratory, gastrointestinal (GI), skin, urinary tract, genital and herpes infections, were compared in people with AA (AA group, n = 10 391) and a propensity-matched control group (n = 41 564). Adjusted hazard ratios (aHRs), controlling for sociodemographic and clinical covariates, and comorbidities were used to estimate the association between AA and each infection over 5 years.

RESULTS

The incidence (per 100 person-years) of common infections was slightly higher in the AA group [14.2, 95% confidence interval (CI) 13.8-14.6] than the control group (11.7, 95% CI 11.5-11.9). In adjusted analysis, positive associations were observed for composite outcomes (common infections aHR 1.13, 95% CI 1.09-1.17; viral infections aHR 1.11, 95% CI 1.07-1.16) and with respiratory tract, GI, skin and herpes simplex infections (aHR range 1.09-1.32). Excluding people in the control group without a recent consultation with their general practitioner showed no association between AA and infection (common infections aHR 1.01, 95% CI 0.98-1.05, viral infections aHR 0.99, 95% CI 0.95-1.03).

CONCLUSIONS

The association between AA and common infection may represent a higher propensity of people with AA to engage with healthcare services (and thereby to have infections recorded), rather than a true association between AA and infection. Overall our findings suggest that AA is not associated with a clinically significantly increased or decreased incidence of common infections.

Association between low hemoglobin, clinical measures, and patient-reported outcomes in patients with rheumatoid arthritis: results from post hoc analyses of three phase III trials of sarilumab

Background

Anemia is common in patients with rheumatoid arthritis (RA). Higher hemoglobin (Hb) levels may be associated with better clinical outcomes and patient-reported outcomes (PROs). To assess this hypothesis, we conducted two post hoc analyses in three sarilumab phase III studies: TARGET, MOBILITY, and MONARCH.

Methods

Pooled data from combination therapy from placebo-controlled MOBILITY (sarilumab + methotrexate) and TARGET (sarilumab + conventional synthetic disease-modifying antirheumatic drugs [csDMARDs]) and monotherapy data from active-controlled MONARCH (sarilumab vs. adalimumab) studies were included. Associations between Hb levels and clinical measures and PROs were assessed over 24 weeks. The mean changes from baseline in clinical outcomes and PROs (to week 24) and radiographic outcomes (to week 52) were evaluated between low and normal Hb levels (based on the World Health Organization [WHO] criteria).

Results

From TARGET, MOBILITY, and MONARCH, 546, 1197, and 369 patients, respectively, were stratified according to Hb levels (low vs. normal). Over 24 weeks, higher Hb levels were found to be consistently associated with better clinical outcomes and PROs in combination therapy and monotherapy groups and were more pronounced among the patients treated with sarilumab than those treated with placebo and adalimumab. The mean change from baseline to week 24 in clinical efficacy measures and PROs was similar in patients with low vs. normal Hb at baseline. Differences between sarilumab and/or adalimumab, for all outcomes, were larger for low Hb subgroups. In MOBILITY, by week 52, the inhibition of progression of structural damage (assessed via Modified Total Sharp Score [mTSS]) was 84% (sarilumab 200 mg) and 68% (sarilumab 150 mg) vs. placebo in patients with low Hb and 97% (sarilumab 200 mg) and 68% (sarilumab 150 mg) vs. placebo in patients with normal Hb. Similar results were observed for other radiographic outcomes.

Conclusions

In these post hoc analyses, a consistent relationship was observed between higher Hb levels and better clinical outcomes and PROs in patients with RA. Irrespective of the baseline Hb levels, sarilumab treatment was associated with improvements in clinical measures and PROs over 24 weeks (improvements were more pronounced than those with adalimumab treatment) and mitigation of joint damage progression over 52 weeks.

Trial registration

ClinTrials.gov NCT01061736, NCT01709578, and NCT02332590

Supplementary Information

The online version contains supplementary material available at 10.1186/s13075-022-02891-x.

Metabolic Enzyme Triosephosphate Isomerase 1 and Nicotinamide Phosphoribosyltransferase, Two Independent Inflammatory Indicators in Rheumatoid Arthritis: Evidences From Collagen-Induced Arthritis and Clinical Samples

Metabolic intervention is a novel anti-rheumatic approach. The glycolytic regulator NAMPT has been identified as a therapeutic target of rheumatoid arthritis (RA), while other metabolic regulators coordinating NAMPT to perpetuate inflammation are yet to be investigated. We continuously monitored and validated expression changes of Nampt and inflammatory indicators in peripheral while blood cells from rats with collagen-induced arthritis (CIA). Gene transcriptional profiles of Nampt+ and Nampt++ samples from identical CIA rats were compared by RNA-sequencing. Observed gene expression changes were validated in another batch of CIA rats, and typical metabolic regulators with persistent changes during inflammatory courses were further investigated in human subjects. According to expression differences of identified genes, RA patients were assigned into different subsets. Clinical manifestation and cytokine profiles among them were compared afterwards. Nampt overexpression typically occurred in CIA rats during early stages, when iNos and Il-1β started to be up-regulated. Among differentially expressed genes between Nampt+ and Nampt++ CIA rat samples, changes of Tpi1, the only glycolytic enzyme identified were sustained in the aftermath of acute inflammation. Similar to NAMPT, TPI1 expression in RA patients was higher than general population, which was synchronized with increase in RFn as well as inflammatory monocytes-related cytokines like Eotaxin. Meanwhile, RANTES levels were relatively low when NAMPT and TPI1 were overexpressed. Reciprocal interactions between TPI1 and HIF-1α were observed. HIF-1α promoted TPI1 expression, while TPI1 co-localized with HIF-1α in nucleus of inflammatory monocytes. In short, although NAMPT and TPI1 dominate different stages of CIA, they similarly provoke monocyte-mediated inflammation.

Epidemiology, management and the associated burden of mental health illness, atopic and autoimmune conditions, and common infections in alopecia areata: protocol for an observational study series

INTRODUCTION

Alopecia areata (AA) is a common cause of immune-mediated non-scarring hair loss. Links between AA and common mental health, autoimmune and atopic conditions, and common infections have previously been described but remain incompletely elucidated and contemporary descriptions of the epidemiology of AA in the UK are lacking.

METHODS AND ANALYSIS

Retrospective study series using a large population-based cohort (5.2 million) from the Oxford Royal College of General Practitioners (RCGP) Research and Surveillance Centre (RSC) database, exploring four themes: AA epidemiology, mental health comorbidities, autoimmune/atopic associations and common infections.In the epidemiology theme, we will describe the incidence and point prevalence of AA overall and by age, sex and sociodemographic factors. Healthcare utilisation (primary care visits and secondary care referrals) and treatments for AA will also be assessed. In the mental health theme, we will explore the prevalence and incidence of mental health conditions (anxiety, depressive episodes, recurrent depressive disorder, adjustment disorder, agoraphobia, self-harm and parasuicide) in people with AA compared with matched controls. We will also explore the mental health treatment patterns (medication and psychological interventions), time off work and unemployment rates. Within the autoimmune/atopic associations theme, we will examine the prevalence of atopic (atopic dermatitis, allergic rhinitis, asthma) and autoimmune conditions (Crohn's disease, ulcerative colitis, coeliac disease, type 1 diabetes, Hashimoto's thyroiditis, Graves' disease, rheumatoid arthritis, psoriatic arthritis, ankylosing spondylitis, systemic lupus erythematosus (SLE), polymyalgia rheumatica, Sjögren's syndrome, psoriasis, vitiligo, multiple sclerosis, pernicious anaemia) in people with AA compared with matched controls. We will also estimate the incidence of new-onset atopic and autoimmune conditions after AA diagnosis. Within the common infections theme, we will examine the incidence of common infections (respiratory tract infection, pneumonia, acute bronchitis, influenza, skin infection, urinary tract infection, genital infections, gastrointestinal infection, herpes simplex, herpes zoster, meningitis, COVID-19) in people with AA compared with matched controls.

ETHICS AND DISSEMINATION

The Health Research Authority decision tool classed this a study of usual practice, ethics approval was not required. Study approval was granted by the RCGP RSC Study Approval Committee. Results will be disseminated through peer-reviewed publications.

OBSERVATIONAL STUDY REGISTRATION NUMBER

NCT04239521.

Systemic effects of IL-6 blockade in rheumatoid arthritis beyond the joints

Interleukin (IL)-6 is produced locally in response to an inflammatory stimulus, and is able to induce systemic manifestations at distance from the site of inflammation. Its unique signaling mechanism, including classical and trans-signaling pathways, leads to a major expansion in the number of cell types responding to IL-6. This pleiotropic cytokine is a key factor in the pathogenesis of rheumatoid arthritis (RA) and is involved in many extra-articular manifestations that accompany the disease. Thus, IL-6 blockade is associated with various biological effects beyond the joints. In this review, the systemic effects of IL-6 in RA comorbidities and the consequences of its blockade will be discussed, including anemia of chronic disease, cardiovascular risks, bone and muscle functions, and neuro-psychological manifestations.

Risk of venous thromboembolism in immune-mediated inflammatory diseases: a UK matched cohort study

Objectives

To describe the risk of venous thromboembolism (VTE), and risk factors for VTE, in people with immune-mediated inflammatory diseases (IMID) (ulcerative colitis, Crohn’s disease (CD), rheumatoid arthritis (RA) and psoriatic arthritis (PsA)), compared with a matched control population.

Methods

A total of 53 378 people with an IMID were identified over 1999–2019 in the UK Royal College of General Practitioners (RCGP) Research and Surveillance Centre (RSC) primary care database and were matched to 213 512 people without an IMID. The association between the presence of any IMID, and each IMID separately, and risk of VTE was estimated using unadjusted and multivariable-adjusted Cox proportional hazards models. The prevalence of VTE risk factors, and associations between VTE risk factors and risk of VTE, were estimated in people with and without an IMID.

Results

People with an IMID were at increased risk of VTE (adjusted HR [aHR] 1.46, 95% CI 1.36,1.56), compared with matched controls. When assessing individual diseases, risk was increased for CD (aHR 1.74, 95% CI 1.45 to 2.08), ulcerative colitis (aHR 1.27, 95% CI 1.10 to 1.45) and RA (aHR 1.54, 95% CI 1.40 to 1.70) but there was no evidence of an association for PsA (aHR 1.21, 95% CI 0.96 to 1.52). In people with an IMID, independent risk factors for VTE included male sex, overweight/obese body mass index, current smoking, history of fracture, and, across study follow-up, abnormal platelet count.

Conclusions

VTE risk is increased in people with IMIDs. Routinely available clinical information may be helpful to identify individuals with an IMID at increased future risk of VTE.

Observational study registration number

Clinicaltrials.gov (NCT03835780).

Ginsenoside compound K- a potential drug for rheumatoid arthritis

Rheumatoid arthritis (RA) is a chronic inflammatory and autoimmune disease, if prescription of effective delayed, the articular disturbances may lead to disability. Ginsenoside compound K (GCK) is the main degradation product of oral ginsenosides in the human intestine. Numerous researches in vitro and in vivo have recorded the anti-arthritic effect of GCK, we discuss the mechanisms from the following three aspects, including anti-inflammatory, immune-regulatory, and bone-protective, respectively, in this review, and the anti-arthritic mechanism of GCK may be related to the effect on TNF-α-TNFR2, glucocorticoid receptor (GR) and β-arrestin1/2. We also describe the anti-anemia effect of GCK to open the possibility that GCK can be used as an effective disease-modifying anti-rheumatic drug (DMARD).

Risk of common infections in people with inflammatory bowel disease in primary care: a population-based cohort study

OBJECTIVE

To evaluate the risk of common infections in individuals with inflammatory bowel disease (IBD) [ulcerative colitis and Crohn's disease] compared with matched controls in a contemporary UK primary care population.

DESIGN

Matched cohort analysis (2014-2019) using the Royal College of General Practitioners Research and Surveillance Centre primary care database. Risk of common infections, viral infections and gastrointestinal infections (including a subset of culture-confirmed infections), and predictors of common infections, were evaluated using multivariable Cox proportional hazards models.

RESULTS

18 829 people with IBD were matched to 73 316 controls. People with IBD were more likely to present to primary care with a common infection over the study period (46% vs 37% of controls). Risks of common infections, viral infections and gastrointestinal infections (including stool culture-confirmed infections) were increased for people with ulcerative colitis and Crohn's disease compared with matched controls (HR range 1.12-1.83, all p<0.001). Treatment with oral glucocorticoid therapy, immunotherapies and biologic therapy, but not with aminosalicylates, was associated with increased infection risk in people with IBD. Despite mild lymphopenia and neutropenia being more common in people with IBD (18.4% and 1.9%, respectively) than in controls (6.5% and 1.5%, respectively), these factors were not associated with significantly increased infection risk in people with IBD.

CONCLUSION

People with IBD are more likely to present with a wide range of common infections. Health professionals and people with IBD should remain vigilant for infections, particularly when using systemic corticosteroids, immunotherapies or biologic agents.

TRIAL REGISTRATION NUMBER

Clinicaltrials.gov (NCT03835780).

Elevation of cytomegalovirus antigenemia predicts serious infection and death in patients receiving immunosuppressive therapies for autoimmune diseases

AIM

We examined the relationship between cytomegalovirus (CMV) reactivation and serious infections.

METHOD

We conducted a single-center retrospective chart review study with 43 autoimmune disease patients experiencing CMV reactivation. We investigated the risk factors for serious infections among the patients using logistic regression analysis.

RESULTS

We identified that the maximum count of CMV antigenemia during the course of infection (CMV Ag MAX) was significantly associated with serious infection by multivariate analysis (adjusted odds ratio: 1.509; 95% confidence interval: 1.071-2.125). The receiver operating characteristic curve of CMV Ag MAX count showed a predictive value for serious infections (76.9% in sensitivity and 93.3% in specificity) and death (83.3% in sensitivity and 91.9% in specificity), and the cut-off count of serious infections and death was 6 and 10 per 10⁵ white blood cell count, respectively.

CONCLUSION

We suggest that the counts of CMV Ag MAX can reflect the extent of compromise in the immune system, and can be a predictive marker for serious infections and death.

Common infections, mental health problems and healthcare use in people with inflammatory bowel disease: a cohort study protocol

Introduction

People with inflammatory bowel disease (IBD) are at increased risk of pneumonia and herpes zoster, yet other common infection types have not been explored. Anxiety and depression are more prevalent in IBD; however, the impact of these conditions on primary care healthcare use in IBD is not known.

Methods and analysis

We will perform two retrospective studies using a large English population-based primary care cohort to compare the following outcomes in people with IBD and matched controls: incident infections (Study 1) and prevalent mental health problems and healthcare use, overall and in those with and without mental health problems (Study 2). All adults registered with general practices contributing to Royal College of General Practitioners Research and Surveillance Centre database between 1 January 2014 and 1 January 2019 are eligible. Infection outcomes comprise the incidence of common infections (upper respiratory tract infections, pneumonia, acute bronchitis, influenza and influenza-like illnesses, skin infections, herpes simplex and herpes zoster infections, genital infections, urinary tract infections and gastrointestinal infections) and any viral infection. Mental health and healthcare use outcomes are: prevalence of depressive episodes; anxiety episodes; recurrent depression; rates of primary care and emergency secondary care visits; primary-care issued sick notes (reflecting time off work). Analyses will be adjusted for sociodemographic factors recorded in the primary care record.

Discussion

These studies will quantify the infection risk in IBD, the excess burden of anxiety and depression in a population-based IBD cohort, and the impact of mental health conditions on healthcare use and time off work. Greater understanding and awareness of infection risk and common mental health issues will benefit people with IBD and healthcare practitioners and will guide policy makers as allocation of resource may be guided by the real-world information produced by these studies.

Trial registration number

NCT03836612.