Adult-onset Still's disease (AOSD) is a rare disease, and large epidemiological studies of this disease are limited. Furthermore, it has been difficult to show the incidence and characteristics of severe AOSD complications due to the rarity of this disease. The aim of our study was to describe the demographics of AOSD and the incidence and characteristics of severe complications. Using a large Japanese administrative database, we identified hospitalized patients with AOSD and described the demographics. We also calculated the incidence of severe complications (i.e., macrophage activation syndrome [MAS] and disseminated intravascular coagulation [DIC]) and in-hospital mortality in AOSD patients, and then analyzed the age-controlled difference between men and women. We identified 513 patients with AOSD (mean age: 53.1 years; women 64.1 %). According to the age distribution, there was no distinct peak age. The thirties and the sixties were relatively large age groups. There were 76 patients of AOSD with MAS or DIC observed in this study. The incidence of severe complications was 14.8 %, 95 % CI [11.9, 18.2]. Women were more likely to have severe complications than men after controlling for age (odds ratio: 2.07; [1.14, 3.73]; p = 0.014). AOSD does not predominantly affect young adults in our study population. Elderly AOSD patients can be observed more than before due to global population aging. Severe complications are more likely to occur in women than in men.

Among antineutrophil cytoplasmic antibody (ANCA)-associated vasculitides (AAV), granulomatosis with polyangiitis (GPA) and proteinase 3-ANCA-positive AAV (PR3-AAV) are prevalent in European populations, while microscopic polyangiitis (MPA) and myeloperoxidase-ANCA-positive AAV (MPO-AAV) are predominant in the Japanese. We previously demonstrated association of DRB1*09:01-DQB1*03:03 haplotype, a haplotype common in East Asians but rare in the European populations, with MPA/MPO-AAV, suggesting that a population difference in HLA-class II plays a role in the epidemiology of this disease. To gain further insights, we increased the sample size and performed an extended association study of DRB1 and DPB1 with AAV subsets in 468 Japanese patients with AAV classified according to the European Medicines Agency algorithm (MPA: 285, GPA: 92, eosinophilic GPA [EGPA]: 56, unclassifiable: 35) and 596 healthy controls. Among these patients, 377 were positive for MPO-ANCA and 62 for PR3-ANCA. The significance level was set at α = 3.3x10-4 by applying Bonferroni correction. The association of DRB1*09:01 with MPO-AAV was confirmed (allele model, P = 2.1x10-4, odds ratio [OR] = 1.57). Protective association of DRB1*13:02 was detected against MPO-AAV (allele model, P = 2.3x10-5, OR = 0.42) and MPA (dominant model, P = 2.7x10-4, OR = 0.43). A trend toward increased frequency of DPB1*04:01, the risk allele for GPA in European populations, was observed among Japanese patients with PR3-AAV when conditioned on DRB1*13:02 (Padjusted = 0.0021, ORadjusted = 3.48). In contrast, the frequency of DPB1*04:01 was decreased among Japanese patients with MPO-AAV, and this effect lost significance when conditioned on DRB1*13:02 (Padjusted = 0.16), suggesting that DRB1*13:02 or other allele(s) in linkage disequilibrium may be responsible for the protection. The differential association of DPB1*04:01 with PR3-AAV and MPO-AAV and difference in DPB1*04:01 allele frequencies between populations supported the hypothesis that the HLA-class II population difference may account in part for these epidemiologic characteristics. Furthermore, taken together with our previous observations, the haplotype carrying DRB1*13:02 was suggested to be a shared protective factor against multiple autoimmune diseases.

BackgroundSulfamethoxazole-trimethoprim (SMX/TMP) is a standard drug for the prophylaxis of Pneumocystis pneumonia (PJP) in immunosuppressed patients with systemic rheumatic diseases, but is sometimes discontinued due to adverse events (AEs). The objective of this non-blinded, randomized, 52-week non-inferiority trial was to quest an effective chemoprophylaxis regimen for PJP with a low drug discontinuation rate. Results at week 24 were reported.MethodsAdult patients with systemic rheumatic diseases who started prednisolone ≥0.6 mg/kg/day were randomized into three dosage groups: a single-strength group (SS, SMX/TMP of 400/80 mg daily), half-strength group (HS, 200/40 mg daily), and escalation group (ES, started with 40/8 mg daily, increasing incrementally to 200/40 mg daily). The primary endpoint was non-incidence rates (non-IR) of PJP at week 24.ResultsOf 183 patients randomly allocated at a 1:1:1 ratio into the three groups, 58 patients in SS, 59 in HS, and 55 in ES started SMX/TMP. A total of 172 patients were included in the analysis. No cases of PJP were reported up to week 24. Estimated non-IR of PJP in patients who received daily SMX/TMP of 200/40 mg, either starting at this dose or increasing incrementally, was 96.8–100% using the exact confidence interval as a post-hoc analysis. The overall discontinuation rate was significantly lower with HS compared to SS (p = 0.007). The discontinuation rates due to AEs were significantly lower with HS (p = 0.006) and ES (p = 0.004) compared to SS. The IR of AEs requiring reduction in the dose of SMX/TMP (p = 0.009) and AEs of special interest (p = 0.003) were different among the three groups with significantly higher IR in SS compared to HS and ES.ConclusionsAlthough there were no PJP cases, the combined group of HS and ES had an excellent estimated non-IR of PJP and both were superior in safety to SS. From the perspective of feasibility and drug discontinuation rates, the daily half-strength regimen was suggested to be optimal for prophylaxis of PJP in patients with systemic rheumatic diseases.Trial registrationThe University Hospital Medical Information Network Clinical Trials Registry number is UMIN000007727, registered 10 April 2012.Electronic supplementary materialThe online version of this article (doi:10.1186/s13075-016-1206-8) contains supplementary material, which is available to authorized users.

Achieving structural remission, functional remission and LDA in clinical practice in EORA patients are realistic goals. Our results indicate significant benefits for a therapeutic strategy targeting LDA for EORA patients in clinical practice.