99Increasing prevalence of primary biliary cholangitis in Victoria, Australia

Background The prevalence of primary biliary cholangitis (PBC) reported in different countries varies significantly and in some parts of the world appears to be increasing. The aim of this study was to determine the 2013 prevalence of PBC in Victoria, Australia, and to determine the time trend by comparing it with previous studies undertaken in 1991 and 2002. Methods Four case-finding methods were used to identify cases of PBC in Victoria: (1) physicians’ survey; (2) tertiary hospital search; (3) liver transplant database search; and (4) private pathology antimitochondrial antibody search. Results The prevalence of PBC in Victoria, Australia, is 189.0 per million using all four methods. The average annual increase in prevalence from 1991 to 2013 was 7.7 per million per year. Using the same case-finding methods as the 1991 Victorian prevalence study (methods 1 and 2), the prevalence of PBC increased from 19.1 per million in 1991 to 49.4 per million in 2002 (P < 0.001) and to 80.7 per million in 2013 (P < 0.001). Conclusions The current prevalence of PBC in Victoria is significantly higher than previously reported. The use of private pathology-based case-finding methods is important in identifying the maximum number of PBC cases. Key messages PBC prevalence in Victoria increased significantly since previous surveys, to 189 per million persons. Including pathology-based case ascertainment yields improved identification of cases.

Ventricular arrhythmia predicts poor outcome in polymyositis/dermatomyositis with myocardial involvement

Objective Myocardial involvement (MCI) is known to increase morbidity and mortality in polymyositis (PM) and dermatomyositis (DM). This study aims to investigate whether complicating with ventricular arrhythmia (VA) predicts poor outcomes in patients with PM/DM-related myocardial involvement (PM/DM-MCI). Methods We reviewed all PM/DM-MCI patients admitted in Peking Union Medical College Hospital from October 1997 to April 2019. VA and the other possible risk factors for the composite end point, including death from any cause and rehospitalization for cardiac causes, were analysed. Results A total of 75 PM/DM-MCI patients (44 PM and 31 DM) were enrolled, of which 27 (36%) met the composite end point during a median follow-up of 24 months. Independent prognostic factors for the composite end point includes VA (HR 4.215, 95% CI [1.737, 10.230]), NT-proBNP > 3415 pg/ml (HR 2.606, 95% CI [1.203, 5.646]), interstitial lung disease (HR 2.688, 95% CI [1.209, 5.978]), and anti-cardiac remodelling therapy (HR 0.302, 95% CI [0.115, 0.792]). The 3-year event-free survival rate of patients without VA was significantly higher than that of patients with VA (63.3% vs 40.7%, p = 0.034). Skin lesions (OR 0.163, 95% CI [0.051, 0.523]) and positive antimitochondrial antibody (OR 3.484, 95% CI [1.192, 10.183]) were independent predictors of VA. Conclusion VA provides prognostic insights for PM/DM-MCI patients and predicts poor outcome. Polymyositis and positive antimitochondrial antibody are closely associated with the presence of VA in PM/DM-MCI.

Investigation of the dual cascade algorithm in the diagnosis of antinuclear antibodies

Background The dual cascade algorithm which involves screening and confirmation of antinuclear antibodies (ANAs) by further reflex testing is widely used in the detection of ANAs. We aimed to investigate this algorithm which is commonly used in many laboratories. Methods A total of 475 sera obtained from patients with a clinical suspicion of systemic autoimmune rheumatic diseases (SARDs) upon which three expert assessors agreed for interpretation in the indirect immunofluorescence (IIF) test were determined and tested by the line immunoassay (LIA) containing 16 antigens. The results of the tests were statistically compared and evaluated. Results In 141 of the sera (29.7%), there was an agreement between ANA-IIF(+) and LIA(+) results. The overall agreement rate between the two tests for positivity and negativity only was 85.5% with a Cohen’s κ coefficient of 0.69. In 118 of these 141 sera (83.7%), pattern and associated ANA agreement was detected with an overall agreement rate of 80.6% and a Cohen’s κ coefficient of 0.57. The highest agreement between the pattern and associated ANAs was seen in centromere, dense fine speckled (DFS) and cytoplasmic reticular patterns. In these patterns, the rate of anti-centromere-associated protein B (CENP-B), anti-DFS and anti-antimitochondrial antibody M2 (anti-AMA-M2) antibodies were 93.4%, 92.3% and 66.7%, respectively. Conclusions We found an overall moderate agreement between IIF screening and LIA confirmation tests. However, the level of agreement varies according to the pattern type. The discrepancy in agreement rates may cause false reflex test requests. Our results highlight the need for collaboration between clinical and laboratory professionals in selected cases instead of the reflex testing approach.

Epidemiology of primary biliary cholangitis and its factors: An updated systematic review

Background To understand the latest data on the prevalence and incidence rates for primary biliary cholangitis (PBC) and its factors, we systematically reviewed recent studies on epidemiology of PBC.Methods Case-finding and general population-based studies reporting prevalence and/or incidence rates for PBC were systematically identified by searching electronic databases combined with manual searching.Results A total of 37,452 PBC patients from 22 studies based on cases and 6 based on general population were included, which covered over 112.62 million inhabitants and 107,490 individuals undergoing health check-ups. As for case-finding studies, global prevalence and incidence rates for PBC ranged from 2.6 to 58.2 per 100,000 inhabitants and 0.8 to 5.3 per 100,000 inhabitants/year during the past decade, in which the variable data are associated with gender, age, race and region. Of the individuals undergoing health check-ups, 1,034 were positive for type M2 antimitochondrial antibody (AMA-M2) and 150 were diagnosed as PBC, and prevalence rates of positive AMA-M2 and PBC ranged from 430.7 to 1,456.9 and 49.2 to 276.6 per 100,000 individuals. The prevalence ratios of male/female were 1:2.2 and 1:4.1 in individuals with positive AMA-M2 and in PBC patients.Conclusions Global prevalence and incidence rates for PBC vary widely, which were significantly affected by gender, age, race and region. Studies based on general population showed a much higher prevalence of PBC and AMA-M2, and the association of gender with AMA-M2 may be far less than that with PBC in real world.