The association between Staphylococcus aureus colonization on cheek skin at 2†months and subsequent atopic dermatitis in a prospective birth cohort.

BACKGROUND: Staphylococcus aureus may worsen already established atopic dermatitis (AD), but its primary role in the aetiopathogenesis and severity of AD is unclear. OBJECTIVES: To compare the prevalence of S. aureus colonization in early infancy in children who developed AD during the first 2 years of life with children who did not. METHODS: In this prospective birth cohort study, which included 450 infants, we analysed bacterial swabs collected from cheek skin at 0 and 2 months of age. The development of AD, and its severity, was diagnosed by a physician and monitored prospectively for 2 years. Information on parental atopy, filaggrin gene mutation status and use of antibiotics and emollients was included in the analyses. RESULTS: At birth, the occurrence of S. aureus colonization was similar in infants who developed subsequent AD and those who did not. At 2 months of age, S. aureus colonization was more common in children who later developed AD (adjusted hazard ratio 1.97, 95% confidence interval 1.21-3.19; P = 0.006). No association was found between S. aureus colonization and AD severity or age at onset. CONCLUSIONS: It remains unknown whether colonization with S. aureus may directly increase the risk of AD, or whether it should be considered as secondary to skin barrier impairment or a skewed immune activity, but according to our findings, S. aureus colonization is more commonly increased at 2 months of age in children who later developed AD.

Development and internal validation of a diagnostic prediction model for psoriasis severity.

BACKGROUND: While administrative health records such as national registries may be useful data sources to study the epidemiology of psoriasis, they do not generally contain information on disease severity. OBJECTIVES: To develop a diagnostic model to distinguish psoriasis severity based on administrative register data. METHOD: We conducted a retrospective registry-based cohort study using the Danish Skin Cohort linked with the Danish national registries. We developed a diagnostic model using a gradient boosting machine learning technique to predict moderate-to-severe psoriasis. We performed an internal validation of the model by bootstrapping to account for any optimism. RESULTS: Among 4016 adult psoriasis patients (55.8% women, mean age 59 years) included in this study, 1212 (30.2%) patients were identified as having moderate-to-severe psoriasis. The diagnostic prediction model yielded a bootstrap-corrected discrimination performance: c-statistic equal to 0.73 [95% CI: 0.71-0.74]. The internal validation by bootstrap correction showed no substantial optimism in the results with a c-statistic of 0.72 [95% CI: 0.70-0.74]. A bootstrap-corrected slope of 1.10 [95% CI: 1.07-1.13] indicated a slight under-fitting. CONCLUSION: Based on register data, we developed a gradient boosting diagnostic model returning acceptable prediction of patients with moderate-to-severe psoriasis.

Childhood asthma is associated with development of type 1 diabetes and inflammatory bowel diseases: a Danish nationwide registry study.

Asthma and autoimmune disorders might be affected by opposing immune mechanisms, T helper cells type 2 (Th2) and T helper cells type 1 (Th1) immunity, respectively. Knowledge on comorbidity can increase understanding of the underlying etiologies. We aim to examine the association between childhood asthma and subsequent risk of type 1 diabetes (T1D) and inflammatory bowel diseases (IBD) in Danish children. Children of Danish origin born during 1991-1996 were included and childhood asthma, defined as a minimum of two collected prescriptions of inhalation corticosteroids age 5-7 years, was linked to hospitalisations with either T1D or IBD after age 8. Associations between childhood asthma and incidence of T1D and IBD were analysed using sex- and year stratified Cox regression. A total of 366,200 children were included in the study, 4.9% had asthma, which increased the risk of both T1D and IBD, hazard ratios of 1.32 (1.08-1.61) and 1.27 (1.09-1.48). In this large nationwide Danish study, we found that children with asthma have increased risk of developing immune diseases T1D and IBD. This contradicts the Th1 vs Th2 paradigm and points towards shared disease mechanisms and risk factors.

Incidence, Risk Factors, and Consequences of Human Alphaherpesvirus Infections in Patients With Psoriasis Who Initiate Methotrexate or Biologic Agents.

BACKGROUND: Immunosuppressive agents may increase the risk of infections with human alphaherpesviruses. METHODS: We included all adult patients with moderate to severe psoriasis who initiated methotrexate (MTX) or biologic agents in a retrospective cohort study. An episode of alphaherpesviruses infection was defined as filling a prescription for systemic acyclovir, valacyclovir, or famciclovir. Using nationwide registries, we determined the incidence, risk factors, 180-day hospital contacts, and 30-day mortality following infection. RESULTS: We included 7294 patients; 4978 (68%) received MTX, and 2316 (32%) biologic agents. The incidence rates (95% confidence intervals) of alphaherpesviruses were 23 (20-27), 26 (19-35), 17 (11-27), and 6.7 (1.3-21) per 1000 person-years of follow-up in patients on MTX, tumor necrosis factor alpha (TNF-α) inhibitors, interleukin 12/23 (IL-12/23) inhibitors, and interleukin 17 (IL-17) inhibitors, respectively. Males had an unadjusted hazard ratio (HR) of 0.47 (P < .001) for alphaherpesvirus infection. Patients on IL-17 inhibitors had an adjusted HR of 0.24 (P = .048) compared to TNF-α inhibitors. Within 180 days after infection, 13%, 7.5%, and <0.5% of patients on MTX, TNF-α inhibitors, and IL-12/23 or IL-17 inhibitors, respectively, had hospital contacts, and the 30-day mortality for all groups was <0.5%. CONCLUSIONS: The incidence and risk of alphaherpesvirus infections were comparable between patients on MTX and TNF-α inhibitors, whereas use of IL-17 inhibitors was associated with a lower risk.