Race, Ethnicity, and Other Patient and Clinical Encounter Characteristics Associated with Patient Experiences of Access to Care.

The Press Ganey (PG) Outpatient Medical Practice Survey measures patients' experiences of healthcare access in the U.S. We aimed to identify differences in experiences of access to care by patient race, ethnicity, and other sociodemographic characteristics, an important first step in informing health policy and ensuring equitable healthcare delivery. We performed a cross-sectional analysis of PG surveys for adult outpatient visits within the University of Pennsylvania Health System from 2014-2017, including 119,373 unique patients. Compared with White patients, Black (odds ratio [OR] 0.84; 95% confidence interval [CI] 0.80-0.87), Asian (OR 0.62; 95% CI 0.58-0.66), and other/unknown race patients (OR 0.83; 95% CI 0.72-0.94) were each less likely to report the maximum score for timely access to care. Patients of all minoritized groups, as well as those whose primary language was not English, reported lower scores in secondary access measures related to communication and respect, compared to White and primarily English-speaking patients, respectively. Efforts to improve the experience of access to care among racial and ethnic minoritized patients are imperative to achieve equity in healthcare delivery.

Patient-Reported Outcomes and Mortality in Cutaneous Chronic Graft-vs-Host Disease.

Importance: Chronic graft-vs-host disease (GVHD) is associated with impaired quality of life and symptom burden. The independent association of skin involvement with patient-reported outcomes (PROs) and their utility as a clinical prognostic marker remain unknown. Identification of patients with cutaneous chronic GVHD and impaired PROs could assist in initial risk stratification and treatment selection. Objective: To compare the association of sclerotic and epidermal-type chronic GVHD with longitudinal PROs and to evaluate whether PROs can identify patients with cutaneous chronic GVHD at high risk for death. Design, Setting, and Participants: This multicenter prospective cohort study involved patients from the Chronic GVHD Consortium of 9 US medical centers, enrolled between August 2007 and April 2012, and followed up until December 2020. Participants included adults 18 years and older with a diagnosis of chronic GVHD requiring systemic immunosuppression and with skin involvement during the study period. Main Outcomes and Measures: Patient-reported symptom burden was assessed using the Lee Symptom Scale (LSS) skin subscale with higher scores indicating worse outcomes. Quality of life was measured using the Functional Assessment of Cancer Therapy-Bone Marrow Transplantation (FACT-BMT) instrument with lower scores indicating worse outcomes. Nonrelapse mortality, overall survival, and their association with PROs at diagnosis were also assessed. Results: Among 436 patients with cutaneous chronic GVHD (median [IQR] age at transplant, 51 [41.5-56.6] years; 261 [59.9%] male), 229 patients had epidermal-type chronic GVHD (52.5%), followed by 131 with sclerotic chronic GVHD (30.0%), and 76 with combination disease (17.4%). After adjusting for confounders, patients with sclerotic chronic GVHD had mean FACT-BMT scores 6.1 points worse than those with epidermal disease (95% CI, 11.7-0.4; P = .04). Patients with combination disease had mean LSS skin subscale scores 9.0 points worse than those with epidermal disease (95% CI, 4.2-13.8; P < .001). Clinically meaningful differences were defined as at least 7 points lower for FACT-BMT and 11 points higher for LSS skin subscale. At diagnosis, clinically meaningful worsening in FACT-BMT score was associated with an adjusted odds of nonrelapse mortality increased by 9.1% (95% CI, 2.0%-16.7%; P = .01). Similarly, for clinically meaningful worsening in LSS skin subscale score, adjusted odds of nonrelapse mortality increased by 16.4% (95% CI, 5.4%-28.5%; P = .003). These associations held true after adjusting for clinical severity by the National Institutes of Health Skin Score. Conclusions and Relevance: The results of this cohort study demonstrated that skin chronic GVHD was independently associated with long-term PRO impairment, with sclerotic and combination disease carrying the highest morbidity. The degree of impairment at skin chronic GVHD diagnosis was a prognostic marker for mortality. Therefore, PROs could be useful for risk stratification and treatment selection in clinical practice and clinical trials.

Incident Asthma, Asthma Exacerbations, and Asthma-Related Hospitalizations in Patients With Atopic Dermatitis.

BACKGROUND: Atopic dermatitis (AD) is thought to induce asthma via the "atopic march," but the effects of AD on incident asthma and asthma severity have not been fully characterized. OBJECTIVE: To determine risk of asthma, asthma exacerbations, and asthma-related hospitalizations among patients fwith AD. METHODS: A cohort study was conducted using electronic health records data from UK general practices from 1994 to 2015. Children (<18 years old) and adults (≥18 years) with AD were matched on age, practice, and index date to patients without AD. AD severity was categorized using treatments and dermatologist referrals. Outcomes were incident asthma among all patients and asthma exacerbation or hospitalization among patients with asthma. RESULTS: On comparing 409,341 children with AD (93.2% mild, 5.5% moderate, 1.3% severe) with 1,809,029 unaffected children, those with AD were found to be associated with a 2-fold greater risk of asthma compared with those without AD (hazard ratio, 1.96; 95% CI, 1.93-1.98). On comparing 625,083 adults with AD (65.7% mild, 31.4% moderate, and 2.9% severe) with 2,678,888 unaffected adults, AD was found to be associated with a 38% higher risk of asthma (hazard ratio, 1.38; 95% CI, 1.36-1.40). Asthmatic patients with AD also had a 21% to 63% greater risk of asthma exacerbations and a 20% to 64% greater risk of asthma-related hospitalizations compared with asthmatic patients without AD. Risk of asthma, asthma exacerbation, or asthma-related hospitalization increased with AD severity in a dose-dependent manner in both the pediatric and adult cohorts. CONCLUSIONS: AD, especially in children and when more severe, is associated with greater risk of asthma as well as greater risk of asthma exacerbations and hospitalizations among asthmatic patients.

Neuropsychiatric disorders in adults with atopic dermatitis: A population-based cohort study.

BACKGROUND: Atopic dermatitis (AD) may be associated with an increased burden of neuropsychiatric outcomes such as anxiety and depression, but longitudinal data on the impact of AD severity is lacking, and a comprehensive assessment of neuropsychiatric disease in adults with AD is needed. OBJECTIVES: Determine risk of incident neuropsychiatric disease among adults with AD by severity. METHODS: A cohort study using electronic health records data from UK general practices from 1994 to 2015. Adults (≥18 years) with AD were matched on age, practice and index date to patients without AD. AD severity was categorized using treatments and dermatology referrals. Outcomes were incident anxiety, depression, bipolar disorder, schizophrenia, attention-deficit/hyperactivity disorder (ADHD), autism, obsessive-compulsive disorder (OCD), suicidality and completed suicide. RESULTS: Comparing 625,083 adults with AD to 2,678,888 adults without AD, AD was associated with higher risk of anxiety [HR 1.14 (1.13-1.15)], depression [1.14 (1.13-1.15)] and OCD [1.48 (1.38-1.58)] across all severities. Mild or moderate AD was also associated with higher risk of autism, ADHD, bipolar disorder and suicidality. CONCLUSIONS: Atopic dermatitis is associated with a higher risk of multiple neuropsychiatric conditions, but these risks differ by specific condition and AD severity. Clinicians should inquire about mental health in patients with AD.

Risk of atopic dermatitis and the atopic march paradigm in children of mothers with atopic illnesses: A birth cohort study from the United Kingdom.

BACKGROUND: Atopic dermatitis (AD) is thought to precede the onset of other allergic illness (OAI) in a temporal progression (ie, atopic march), yet the timing and progression has been questioned. It is also unclear how parental allergic illness impacts the development of these illnesses in offspring. OBJECTIVE: (1) Explore risk of incident AD and (2) timing of allergic disease onset in children of mothers with AD compared with mothers without AD from the United Kingdom. METHODS: We created a birth cohort of mother-child pairs using IQVIA Medical Research Data database and developed Cox proportional models to examine the above associations (hazard ratio, HR [95% confidence interval, CI]). RESULTS: Among 1,224,243 child-mother pairs, mean child (standard deviation) follow-up time was 10.8 (8.3) years and 50.1% were males (N = 600,905). Children were 59% (HR = 1.59 [1.57, 1.60]) more likely to have AD if their mothers had AD compared with no AD with mean age of first AD diagnosis at 3.3 (4.8) years. Most children with any diagnosis of AD present with AD first (91.0%); however, in those with asthma, only 67.8% developed AD first. CONCLUSION: Children born to mothers with AD are more prone to develop AD and some develop OAI first, suggesting that not all follow the same sequential pathway.

In utero or early in life exposure to antibiotics and the risk of childhood atopic dermatitis, a population-based cohort study.

BACKGROUND: Atopic dermatitis (AD) is a common inflammatory disease of the skin that begins early in life and can be lifelong. The purpose of our study was to evaluate whether fetal exposure and/or early life exposure of a child to antibiotics increases the risk of early onset AD. OBJECTIVE: We hypothesize that antibiotic exposure in utero or early in life (e.g., first 90 days) increases the likelihood that children develop AD. METHODS: Utilizing a large prospectively collected electronic medical records database, we studied the association of antibiotic exposure received in utero or very early in life and the relative risk of onset of AD in a population-based cohort study. Associations were estimated using proportional hazards models as hazard ratios (HR) with 95% confidence intervals (CI). RESULTS: The risk of AD in childhood was increased after in utero or early life antibiotic exposure. For any in utero AB exposure the HR was 1.38 (1.36,1.39). However, penicillin demonstrated the strongest association with AD for both in utero exposure, 1.43 (1.41,1.44), and for childhood exposure, 1.81(1.79,1.82). HRs were higher in children born to mothers without AD than those with AD pointing to effect modification by maternal AD status. CONCLUSION: Children born to mothers exposed to antibiotics while in utero had, depending on the mother's history of AD, approximately a 20 to 40% increased risk of developing AD. Depending on the antibiotic, children who received antibiotics early-in-life had a 40 to 80% increased risk of developing AD. Our study, supports and refines the association between incident AD and antibiotic administration. It also adds population-based support to therapeutic attempts to treat AD by modifying skin microbiome.

Incidence of Cardiovascular Disease and Venous Thromboembolism in Patients With Atopic Dermatitis.

BACKGROUND: Atopic dermatitis (AD) may increase risk for atherothrombotic and cardiovascular (CV) disease. OBJECTIVE: Determine CV disease and venous thromboembolism risk among patients with AD. METHODS: Cohort study using electronic health data from U.K. general practices in 1994 to 2015. Children (<18 y) and adults (≥18 y) with AD were matched to patients without AD on age, same practice, and encounter date. Treatments and specialist referrals served as proxies of AD severity. Outcomes were incident myocardial infarction, cerebrovascular accident (CVA), diabetes, hypertension, dyslipidemia, deep vein thrombosis (DVT), and pulmonary embolism. Cox regression analysis was used to compare outcomes in AD versus non-AD patients. RESULTS: Comparing 409,341 children with AD (93.2% mild, 5.5% moderate, and 1.3% severe) to 1,809,029 unaffected children, AD was associated with higher risk of DVT (hazard ratio [HR] 1.23; 95% confidence interval [95% CI] 1.02-1.48) and severe AD was associated with higher risk of CVA (HR 2.43; 95% CI 1.13-5.22) and diabetes (HR 1.46; 95% CI 1.06-2.01). Comparing 625,083 adults with AD (65.7% mild, 31.4% moderate, and 2.9% severe) to 2,678,888 unaffected adults, AD, especially when severe, was associated with higher risk of DVT (HR 1.14; 95% CI 1.11-1.18; and HR 1.64; 95% CI 1.49-1.82, respectively) and small but increased risks of CVA, diabetes, and dyslipidemia. Adults with severe AD had higher risk of myocardial infarction (HR 1.27; 95% CI 1.15-1.39), CVA (HR 1.21; 95% CI 1.13-1.30), diabetes (HR 1.15; 95% CI 1.09-1.22), dyslipidemia (HR 1.11; 95% CI 1.06-1.17), and pulmonary embolism (HR 1.39; 95% CI 1.21-1.60) compared with adults without AD. CONCLUSIONS: Atopic dermatitis, particularly when severe, is associated with small but increased risks of CV risk factors and events and significantly increased risk of venous thromboembolism.

Risk of Inflammatory Bowel Disease in Patients With Atopic Dermatitis.

Importance: Data on the association between atopic dermatitis (AD) and inflammatory bowel disease (IBD) are inconsistent. Few studies have examined the association of AD or AD severity with risk of ulcerative colitis (UC) and Crohn disease (CD) separately. Objectives: To examine the risk of new-onset IBD, UC, and CD in children and adults with AD. Design, Setting, and Participants: This population-based cohort study assessed patients with AD matched with up to 5 controls on age, practice, and index date. Treatment exposure was used as a proxy for AD severity. Data were retrieved from The Health Improvement Network, a UK electronic medical record database, for January 1, 1994, to February 28, 2015. Data analysis was performed from January 8, 2020, to June 30, 2023. Main Outcomes and Measures: Outcomes of interest were incident IBD, UC, and CD. Logistic regression was used to examine the risk for each outcome in children and adults with AD compared with controls. Results: A total of 1 809 029 pediatric controls were matched to 409 431 children with AD (93.2% mild, 5.5% moderate, and 1.3% severe). The pediatric cohort ranged in median age from 4 to 5 years (overall range, 1-10 years), was predominantly male (936 750 [51.8%] controls, 196 996 [51.6%] with mild AD, 11 379 [50.7%] with moderate AD, and 2985 [56.1%] with severe AD), and with similar socioeconomic status. A total of 2 678 888 adult controls were matched to 625 083 adults with AD (65.7% mild, 31.4% moderate, and 2.9% severe). The adult cohort ranged in median age from 45 to 50 years (overall range, 30-68 years) and was predominantly female (1 445 589 [54.0%] controls, 256 071 [62.3%] with mild AD, 109 404 [55.8%] with moderate AD, and 10 736 [59.3%] with severe AD). In fully adjusted models, children with AD had a 44% increased risk of IBD (hazard ratio [HR], 1.44; 95% CI, 1.31-1.58) and a 74% increased risk of CD (HR, 1.74; 95% CI, 1.54-1.97), which increased with worsening AD; however, they did not have increased risk of UC (HR, 1.09; 95% CI, 0.94-1.27) except for those with severe AD (HR, 1.65; 95% CI, 1.02-2.67). Adults with AD had a 34% (HR, 1.34; 95% CI, 1.27-1.40) increased risk of IBD, a 36% (HR, 1.36; 95% CI, 1.26-1.47) increased risk of CB, and a 32% (HR, 1.32; 95% CI, 1.24-1.41) increased risk of UC, with risk increasing with worsening AD. Conclusion and Relevance: In this cohort study, children and adults with AD had an increased risk of IBD, with risk varying by age, AD severity, and IBD subtype. These findings provide new insights into the association between AD and IBD. Clinicians should be aware of these risks, particularly when selecting systemic treatments for AD in patients who may have coincident gastrointestinal symptoms.

Malignancy risk in patients with atopic dermatitis: a population-based cohort study.

BACKGROUND: Atopic dermatitis (AD) is associated with immunological dysfunction, which may influence cancer development. Previous studies of AD and cancer demonstrate inconsistent results and few of these studies examined children or AD severity and treatment. OBJECTIVES: To determine malignancy risk among children and adults with AD. METHODS: We conducted a cohort study using electronic health records data from UK general practices in The Health Improvement Network between 1994 and 2015. Children (< 18 years old) and adults (≥ 18 years old) with AD were matched on age, practice and index date to patients without AD. AD was categorized as mild, moderate or severe using treatments and dermatology referrals as proxies. The primary outcome was any incident malignancy, including in situ malignancy, identified using diagnosis codes and categorized into haematological, skin and solid organ malignancies. Secondary outcomes included specific malignancies: leukaemia, lymphoma, melanoma, nonmelanoma skin cancer (NMSC) and common solid-organ cancers. RESULTS: Among 409 431 children with AD (93.2% mild, 5.5% moderate, 1.3% severe) and 1 809 029 children without AD who had median follow-up of 5-7 years, the incidence rates of malignancy were 1.9-3.4 and 2.0 per 10 000 person-years (PY), respectively. The adjusted risk of malignancy overall did not differ with respect to AD [hazard ratio (HR) 1.02 (95% confidence interval 0.92-1.12)]. Severe AD was associated with increased lymphoma risk [HR 3.18 (1.41-7.16), excluding cutaneous T-cell lymphoma (CTCL)], and mild AD was associated with increased NMSC risk [1.55 (1.06-2.27)]. Among 625 083 adults with AD (65.7% mild, 31.4% moderate, 2.9% severe) and 2 678 888 adults without AD who had median follow-up of 5 years, incidence rates of malignancy were 97.4-125.3 per 10 000 PY and 103.7 per 10 000 PY, respectively. The adjusted risk of any malignancy did not differ with respect to AD [HR 1.00 (0.99-1.02)]. However, adults with severe AD had a twofold higher risk of non-CTCL lymphoma. AD was also associated with slightly higher skin cancer risk [HR 1.06 (1.04-1.08)] and slightly lower solid cancer risk [0.97 (0.96-0.98)] but results varied by specific cancers and AD severity. CONCLUSIONS: Epidemiological evidence does not support a strong overall malignancy risk in AD but lymphoma risk may be increased with severe AD.

Atopic dermatitis and risk of major neuropsychiatric disorders in children: A population-based cohort study.

BACKGROUND: Paediatric atopic dermatitis (AD) has been linked to neuropsychiatric comorbidities such as depression, anxiety and attention-deficit/hyperactivity disorder (ADHD). However, longitudinal data are limited, and the effect of AD severity on neuropsychiatric outcomes requires further characterization. OBJECTIVES: To determine the risk of several major neuropsychiatric conditions in children with AD. METHODS: We analysed UK health records data in a population-based cohort study. Each patient <18 years old with AD was matched to up to five unaffected patients on age, practice and index date. Treatments served as proxies for AD severity, which was analysed in a time-updated manner. Outcomes were incident anxiety, depression, bipolar disorder, schizophrenia, ADHD, autism, obsessive-compulsive disorder (OCD), suicidal ideation or attempt, and completed suicide. RESULTS: A total of 409,431 children with AD (93.2% mild, 5.5% moderate, 1.3% severe) were compared to 1,809,029 children without AD. In Cox regression models adjusted for age, sex, socioeconomic status and other atopic comorbidities, no statistically significant relationships were observed between AD and incident anxiety (HR 1.01, 95% CI 0.99-1.03), ADHD (1.02, 0.97-1.06), autism (1.02, 0.98-1.06), bipolar disorder (1.08, 0.85-1.36), suicidal ideation/attempt (0.98, 0.95-1.01) or completed suicide (0.85, 0.64-1.14). Children with AD were less likely to develop depression (0.93, 0.91-0.95) or schizophrenia (0.72, 0.54-0.95) but more likely to develop OCD (1.26, 1.16-1.37). However, there was substantial variation by AD severity and age in both the direction and magnitude of effect for many of the neuropsychiatric conditions examined. CONCLUSIONS: The was no substantial impact of AD on the overall risk of many neuropsychiatric conditions in children, but disease severity and age may be important modifying factors. Additional research is needed to further dissect the complex relationship between paediatric AD and neuropsychiatric comorbidities.

Association of Apremilast With Vascular Inflammation and Cardiometabolic Function in Patients With Psoriasis: The VIP-A Phase 4, Open-label, Nonrandomized Clinical Trial.

Importance: Psoriasis is an inflammatory condition associated with metabolic and cardiovascular disease. Apremilast, a phosphodiesterase 4 inhibitor, is commonly used for psoriasis and can cause weight loss. Objective: To determine the association between apremilast and aortic vascular inflammation as assessed by 18F-fluorodeoxyglucose positron emission tomography/computed tomography (FDG-PET/CT), cardiometabolic markers (primary outcomes at week 16), and abdominal fat composition. Design, Setting, and Participants: A single-arm, open-label, interventional, nonrandomized clinical trial in which the imaging and laboratory outcomes were measured by an investigator who was blinded to time was conducted between April 11, 2017, and August 17, 2021, at 7 dermatology sites in the United States. A total of 101 patients with moderate to severe psoriasis were screened, 70 enrolled, 60 completed week 16, and 39 completed week 52. Intervention: Apremilast, 30 mg, twice daily. Main Outcomes and Measures: Aortic vascular inflammation (measured by FDG-PET/CT), 68 cardiometabolic biomarkers, and abdominal fat composition (measured by CT) at week 16 and week 52 compared with baseline. Results: The mean (SD) age of the 70 patients was 47.5 (14.6) years, 54 were male (77.1%), 4 were Black (5.7%), and 58 were White (82.9%). There was no change in aortic vascular inflammation at week 16 (target to background ratio, -0.02; 95% CI, -0.08 to 0.05; P = .61) or week 52 (target to background ratio, -0.07; 95% CI, -0.15 to 0.01; P = .09) compared with baseline. At week 16, potentially beneficial decreases in interleukin 1b, valine, leucine, isoleucine, fetuin A, and branched-chain amino acids were observed. At week 52 compared with baseline, potentially beneficial decreases in ferritin, ß-hydroxybutyrate, acetone, and ketone bodies, with an increase in apolipoprotein A-1, were observed, but there was a reduction in cholesterol efflux. There was an approximately 5% to 6% reduction in subcutaneous and visceral adiposity at week 16 that was maintained at week 52. Conclusions and Relevance: The findings of this nonrandomized clinical trial suggest that apremilast has a neutral association with aortic vascular inflammation, variable but generally beneficial associations with a subset of cardiometabolic biomarkers, and associations with reductions in visceral and subcutaneous fat, indicating that the drug may have an overall benefit for patients with cardiometabolic disease and psoriasis. Trial Registration: ClinicalTrials.gov Identifier: NCT03082729.

Patient Factors Associated With Teledermatology Visit Type and Submission of Photographs During the COVID-19 Pandemic: Cross-sectional Analysis.

BACKGROUND: The COVID-19 pandemic necessitated the widespread adoption of teledermatology, and this continues to account for a significant proportion of dermatology visits after clinics have reopened for in-person care. Delivery of high-quality teledermatology care requires adequate visualization of the patient's skin, with photographs being preferred over live video for remote skin examination. It remains unknown which patients face the greatest barriers to participating in a teledermatology visit with photographs. OBJECTIVE: The aim of this study was to identify patient characteristics associated with type of telemedicine visit and the factors associated with participating in teledermatology visits with digital photographs versus those without photographs. METHODS: We performed a cross-sectional analysis of the University of Pennsylvania Health System electronic health record data for adult patients who participated in at least 1 teledermatology appointment between March 1, 2020, and June 30, 2020. The primary outcomes were participation in a live-interactive video visit versus a telephone visit and participation in any teledermatology visit with photographs versus one without photographs. Multivariable logistic regression was performed to evaluate the associations between patient characteristics and the primary outcomes. RESULTS: In total, 5717 unique patients completed at least 1 teledermatology visit during the study period; 68.25% (n=3902) of patients participated in a video visit, and 31.75% (n=1815) participated in a telephone visit. A minority of patients (n=1815, 31.75%) submitted photographs for their video or telephone appointment. Patients who submitted photographs for their teledermatology visit were more likely to be White, have commercial insurance, and live in areas with higher income, better education, and greater access to a computer and high-speed internet (P<.001 for all). In adjusted analysis, older age (age group >75 years: odds ratio [OR] 0.60, 95% CI 0.44-0.82), male sex (OR 0.85, 95% CI 0.75-0.97), Black race (OR 0.79, 95% CI 0.65-0.96), and Medicaid insurance (OR 0.81, 95% CI 0.66-0.99) were each associated with lower odds of a patient submitting photographs for their video or telephone visit. Older age (age group >75 years: OR 0.37, 95% CI 0.27-0.50) and Black race (OR 0.82, 95% CI 0.68-0.98) were also associated with lower odds of a patient participating in a video visit versus telephone visit. CONCLUSIONS: Patients who were older, male, or Black, or who had Medicaid insurance were less likely to participate in teledermatology visits with photographs and may be particularly vulnerable to disparities in teledermatology care. Further research is necessary to identify the barriers to patients providing photographs for remote dermatology visits and to develop targeted interventions to facilitate equitable participation in teledermatology care.

Body surface area affected by psoriasis and the risk for psoriatic arthritis: a prospective population-based cohort study.

OBJECTIVE: Increasing psoriasis severity has been associated with comorbidities including cardiovascular disease. The objective of this study was to examine the association of psoriasis severity with the development of PsA. METHODS: A prospective population-based cohort study was performed within The Health Improvement Network, a UK medical record database. Patients aged 25-60 years with a code for psoriasis were randomly selected between 2008 and 2011. Questionnaires were sent to their general practitioners to confirm the diagnosis of psoriasis and provide the patient's approximate body surface area (BSA). Incidence of PsA was calculated by BSA, and Cox proportional hazard ratios were used to examine the risk of developing PsA by BSA category after adjusting for other covariates. RESULTS: Among 10 474 questionnaires sent, 9987 (95%) were returned, 9069 (91%) had confirmed psoriasis, and BSA was provided for 8881 patients: 52% had mild psoriasis, 36% moderate psoriasis and 12% severe psoriasis. The mean age was 46, and 49% were female. Mean follow-up time was 4.2 years (s.d. 2.1); the incidence of PsA was 5.4 cases per 1000 person-years. After adjusting for age and sex, BSA >10% [hazard ratio (HR) 2.01, 95% CI: 1.29, 3.13], BSA 3-10% (HR 1.44, 95% CI: 1.02, 2.03), obesity (HR 1.64, 95% CI: 1.19, 2.26) and depression (HR 1.68, 95% CI: 1.21, 2.33) were associated with incident PsA. CONCLUSIONS: In this large prospective cohort study, BSA assessed by general practitioners was a strong predictor of developing PsA, and obesity and depression were additive risk factors.