Our review shows that compared to placebo, the biologics ixekizumab, secukinumab, brodalumab, guselkumab, certolizumab, and ustekinumab are the best choices for achieving PASI 90 in people with moderate to severe psoriasis on the basis of moderate- to high-certainty evidence. At class level, the biologic treatments anti-IL17, anti-IL12/23, anti-IL23, and anti-TNF alpha were significantly more effective than the small molecules and the conventional systemic agents, too. This NMA evidence is limited to induction therapy (outcomes were measured between 12 to 16 weeks after randomisation) and is not sufficiently relevant for a chronic disease. Moreover, low numbers of studies were found for some of the interventions, and the young age (mean age of 44 years) and high level of disease severity (PASI 20 at baseline) may not be typical of patients seen in daily clinical practice.Another major concern is that short-term trials provide scanty and sometimes poorly reported safety data and thus do not provide useful evidence to create a reliable risk profile of treatments. Indeed, we found no significant difference in the assessed interventions and placebo in terms of SAEs. Methotrexate appeared to have the best safety profile, but as the evidence was of very low to moderate quality, we cannot be sure of the ranking. In order to provide long-term information on the safety of the treatments included in this review, it will be necessary to evaluate non-randomised studies and postmarketing reports released from regulatory agencies as well.In terms of future research, randomised trials comparing directly active agents are necessary once high-quality evidence of benefit against placebo is established, including head-to-head trials amongst and between conventional systemic and small molecules, and between biological agents (anti-IL17 versus anti-IL23, anti-IL23 versus anti-IL12/23, anti-TNF alpha versus anti-IL12/23). Future trials should also undertake systematic subgroup analyses (e.g. assessing biological-naïve patients, baseline psoriasis severity, presence of psoriatic arthritis, etc.). Finally, outcome measure harmonisation is needed in psoriasis trials, and researchers should look at the medium- and long-term benefit and safety of the interventions and the comparative safety of different agents.

SummaryBackground A validated tool for the dynamic severity assessment of hidradenitis suppurativa/acne inversa (HS) is lacking. Objectives To develop and validate a novel dynamic scoring system to assess the severity of HS. Methods A Delphi voting procedure was conducted among the members of the European Hidradenitis Suppurativa Foundation (EHSF) to achieve consensus towards an initial HS Severity Score System (HS4). Strengths and weaknesses of HS4 were examined by a multicentre prospective study. Multivariate logistic regression, discriminant analysis and receiver operating characteristic curves, as well as examination for correlation (Spearman's rho) and agreement (Cohen's kappa) with existing scores, were engaged to recognize the variables for a new International HS4 (IHS4) that was established by a second Delphi round. Results Consensus HS4 was based on number of skin lesions, number of skin areas involved and Dermatology Life Quality Index (DLQI), and was evaluated by a sample of 236 patients from 11 centres. Subsequently, a multivariate regression model calculated adjusted odds ratios for several clinical signs. Nodules, abscesses and draining tunnels resulted as the scoring variables. Three candidate scores were presented to the second Delphi round. The resulting IHS4 score is arrived at by the number of nodules (multiplied by 1) plus the number of abscesses (multiplied by 2) plus the number of draining tunnels (multiplied by 4). A total score of 3 or less signifies mild, 4-10 signifies moderate and 11 or higher signifies severe disease. Cohen's kappa was fair (j = 0Á32) compared with Hurley classification, and moderate (j = 0Á49) compared with Expert Opinion.

Background: A needs assessment for patients with hidradenitis suppurativa (HS) will support advancements in multidisciplinary care, treatment, research, advocacy, and philanthropy.

Linked Comment: Jemec. Br J Dermatol 2019; 180:975. Plain language summary available online

Background There is no consensus on core outcome domains for hidradenitis suppurativa (HS). Heterogeneous outcome measure instruments in clinical trials likely leads to outcome reporting bias and limits the ability to synthesise evidence. Objectives To achieve global multi-stakeholder consensus on a Core Outcome Set (COS) of domains regarding what to measure in clinical trials for HS. Methods Six stakeholder groups participated in a Delphi process which included five anonymous e-Delphi rounds and four face-to-face consensus meetings to reach consensus on the final COS. The aim was for a 1:1 ratio of patients: Health Care Professionals (HCPs). Results A total of 41 patients and 52 HCPs from 19 countries in four continents participated in the consensus process which yielded a final COS that included five domains: pain, physical signs, HS specific quality of life, global assessment and progression of course. A sixth domain, symptoms, was highly supported by patients and not by healthcare professionals but is recommended for the core domain set. Conclusions Routine adoption of the COS in future HS trials should ensure that core outcomes of importance to both patients and HCPs are collected.

Summary Background Epidemiology data regarding hidradenitis suppurativa (HS) are conflicting and prevalence estimates vary 80‐fold, from 0·05% in a population‐based study to 4%. Objectives To assess the hypothesis that previous population‐based studies underestimated true HS prevalence by missing undiagnosed cases. Methods We performed a population‐based observational and case–control study using the U.K. Clinical Practice Research Datalink (CPRD) linked to hospital episode statistics data. Physician‐diagnosed cases in the CPRD were identified from specific Read codes. Algorithms identified unrecognized ‘proxy’ cases, with at least five Read code records for boils in flexural skin sites. Validation of proxy cases was undertaken with general practitioner (GP) questionnaires to confirm criteria‐diagnosed cases. A case–control study assessed disease associations. Results On 30 June 2013, 23 353 physician‐diagnosed HS cases were documented in 4 364 308 research‐standard records. In total, 68 890 proxy cases were identified, reduced to 10 146 criteria‐diagnosed cases after validation, extrapolated from 107 completed questionnaires (61% return rate). Overall point prevalence was 0·77% [95% confidence interval (CI) 0·76–0·78%]. An additional 18 417 cases had a history of one to four flexural skin boils. In physician‐diagnosed cases, odds ratios (ORs) for current smoker and obesity (body mass index > 30 kg m‐2) were 3·61 (95% CI 3·44–3·79) and 3·29 (95% CI 3·14–3·45). HS was associated with type 2 diabetes, Crohn disease, hyperlipidaemia, acne and depression, and not associated with ulcerative colitis or polycystic ovary syndrome. Conclusions Contrary to results of previous population‐based studies, HS is relatively common, with a U.K. prevalence of 0·77%, one‐third being unrecognized, criteria‐diagnosed cases using the most stringent disease definition. If individuals with probable cases are included, HS prevalence rises to 1·19%.

Summary Hidradenitis suppurativa (HS) is a long‐term skin disease affecting young adults, causing multiple boils in skin crease sites such as the armpits and groins. The boils are painful, may produce pus and leave disfiguring scars. How common HS is remains controversial, with recent reports using USA medical insurance data suggesting about 0.1% of the population is affected, which is lower than European studies using self‐reported questionnaires (completed by the patient). This may be because insurance databases miss undiagnosed cases. Our study team based in the UK aimed to use UK electronic data recorded by General Practitioners (GPs) to identify known and previously undiagnosed cases of HS. We identified undiagnosed cases by looking for patients who had seen their GP for at least 5 skin boils and validated their diagnosis by sending some of the GPs a questionnaire to double‐check. Out of 4.3 million patients in the GP database, we found 23,000 diagnosed HS patients and 10,000 undiagnosed patients, showing that 0.77% of the UK population has HS. Including probable cases, who had 1‐4 skin boil consultations, the figure rises to 1.19%. Comparing people with HS to similar people without HS, there are higher rates of smoking and obesity (both 3 times more common), as well as type 2 diabetes, Crohn's disease, raised fat levels in the blood, acne, high blood pressure and depression. However a link was not found between HS and ulcerative colitis or polycystic ovary syndrome. In conclusion, we found that HS is relatively common, nearly 10 times more common than the estimates using USA insurance data. People with HS have higher rates of risk factors for heart disease and stroke and so checking for these conditions is important.

SummaryThe recent hidradenitis suppurativa (HS) Cochrane review identified outcome measure heterogeneity as an important issue to address when designing future HS trials. Our objective was to follow the Harmonising Outcome Measures for Eczema (HOME) roadmap, by performing a systematic review of HS outcome measure instruments to inform the development of an HS core outcome set. We performed a systematic review to identify validation evidence for outcome measure instruments used in HS randomized controlled trials (RCTs), and assessed the methodological quality of all HS outcome measure validity studies using the COnsensusbased Standards for the selection of health Measurement INstruments (COSMIN) checklist. The 12 RCTs included in the Cochrane review utilized 30 outcome measure instruments, including 16 physician-reported instruments, 11 patientreported instruments and three composite measures containing elements of both. Twenty-seven (90%) of the instruments lacked any validation data. Two further instruments have been developed and partially validated. Of the seven studies meeting our inclusion criteria, six were of 'fair' or 'poor' methodological quality, in part because most of the studies were not primarily designed for instrument validation. The HiSCR instrument is supported by good-quality validation data, but there are gaps, including assessment of internal consistency, inter-rater reliability and minimal clinically important difference, and convergent validity fell below the acceptable range for some comparisons. Multiple, usually unvalidated, outcome measure instruments have been used in HS RCTs. Where validation evidence is available there are issues of low methodological quality or incomplete validity assessment and so, currently, no instruments can be fully recommended.What's already known about this topic?• The recent hidradenitis suppurativa (HS) Cochrane review identified heterogeneity of outcome measure instruments as an important obstacle in the design of future HS trials.• The Harmonising Outcome Measures for Eczema (HOME) initiative provides a roadmap for developing a core outcomes set in HS.What does this study add?• Twenty-seven of the 30 outcome measure instruments used in HS randomized controlled trials are not supported by any formal validation data.• Where available, validation evidence is generally of relatively low methodological quality, or remains incomplete, and so no instruments can be fully recommended currently.