Congenital hepatic artery aneurysm simulating pancreatic carcinoma

The authors report a case of a hepatic artery aneurysm that simulated a mass in the head of the pancreas. The correct diagnosis was made preoperatively based on several findings: curvilinear calcification within the mass on CT, a well-defined cystic collection on ultrasound, absence of biliary duct dilatation or jaundice, and presence of other aneurysms.     

Serological status: a predictor of response to intensive therapy in rheumatoid arthritis

BackgroundRheumatoid arthritis is the most common chronic inflammatory disease in the UK. Serological status such as rheumatoid factor (RF) and anti-citrullinated peptide antibody (ACPA) positivity predict poor outcomes. Early intensive treatment regimens targeting remission reduce disease activity, structural damage, and long-term disability. However, we do not know whether all patients with active disease should have such intensive treatment regimens. Can serological status be used to predict the need for intensive therapy?MethodsWe analysed samples from a published randomised controlled trial which compared four treatment regimens in patients with early active rheumatoid arthritis (disease duration <2 years): methotrexate monotherapy, double therapy (methotrexate plus either ciclosporin or prednisolone), and triple therapy (methotrexate plus ciclosporin plus prednisolone). The trial randomised 467 patients (68% female, median age 54 years [IQR 46–63]). Disease activity was assessed with the disease activity score of 28 joints (DAS28). Remission was defined as DAS28 less than 2·6 at 24 months. RF isotypes (IgM and IgA) and ACPA levels were measured with commercial ELISA kits. Statistical analysis used Pearson's chi-squared test.Findings402 (86%) patients were positive for IgM RF, 346 (74%) for IgA RF, and 346 (74%) for ACPA. 98 (21%) patients achieved remission at 24 months. In RF IgM negative cases (n=65) the proportion of patients achieving remission at 24 months was similar in all treatment groups (25%, 22%, and 30% for monotherapy, double therapy, and triple therapy, respectively). In RF IgM positive cases, significantly fewer patients achieved remission with monotherapy (13/65, 17%) and double therapy (24/157, 15%) than with triple therapy (27/80, 34%) (p=0·001). There were similar, consistent findings with IgA RF and ACPA, with significantly more seropositive patients achieving remission with triple therapy than with monotherapy.InterpretationContemporary treatment of rheumatoid arthritis emphasises the use of intensive therapy to achieve remission. However, we have shown that not all patients require such an aggressive approach to therapy. Given the heterogeneity of the diease, treatment should be personalised to the individual, which would minimise costs of treatment as well as potentially toxic side-effects. Our study shows that only seropositive patients with rheumatoid arthritis should be given more intensive therapies.FundingNational Institute for Health Research.     

Individual,Social, and Environmental Factors Associated with Initiating Methamphetamine Injection: Implications for Drug Use and HIV Prevention Strategies

The purpose of this study was to determine the incidence and predictors of initiating methamphetamine injection among a cohort of injection drug users (IDU). We conducted a longitudinal analysis of IDU participating in a prospective study between June 2001 and May 2008 in Vancouver, Canada. IDU who had never reported injecting methamphetamine at the study’s commencement were eligible. We used Cox proportional hazards models to identify the predictors of initiating methamphetamine injection. The outcome was time to first report of methamphetamine injection. Time-updated independent variables of interest included sociodemographic characteristics, drug use patterns, and social, economic and environmental factors. Of 1317 eligible individuals, the median age was 39.9 and 522 (39.6%) were female. At the study’s conclusion, 200 (15.2%) participants had initiated injecting methamphetamine (incidence density: 4.3 per 100 person-years). In multivariate analysis, age (adjusted hazard ratio [aHR]: 0.96 per year older, 95%CI: 0.95–0.98), female sex (aHR: 0.58, 95%CI: 0.41–0.82), sexual abuse (aHR: 1.63, 95%CI: 1.18–2.23), using drugs in Vancouver’s drug scene epicentre (aHR: 2.15 95%CI: 1.49–3.10), homelessness (aHR: 1.43, 95%CI: 1.01–2.04), non-injection crack cocaine use (aHR: 2.06, 95%CI: 1.36–3.14), and non-injection methamphetamine use (aHR: 3.69, 95%CI: 2.03–6.70) were associated with initiating methamphetamine injection. We observed a high incidence of methamphetamine initiation, particularly among young IDU, stimulant users, homeless individuals, and those involved in the city’s open drug scene. These data should be useful for the development of a broad set of interventions aimed at reducing initiation into methamphetamine injection among IDU.     

Increased influenza-related healthcare utilization by residents of an urban aboriginal community

Most studies describing high rates of acute respiratory illness in aboriginals have focused on rural or remote communities. Hypothesized causes include socioeconomic deprivation, limited access to healthcare, and a high prevalence of chronic disease. To assess influenza rates in an aboriginal community while accounting for healthcare access, deprivation and chronic disease prevalence, we compared rates of influenza-related outpatient and emergency-department visits in an urban Mohawk reserve (Kahnawá:ke) to rates in neighbouring regions with comparable living conditions and then restricted the analysis to a sub-population with a low chronic disease prevalence, i.e. those aged <20 years. Using medical billing claims from 1996 to 2006 we estimated age-sex standardized rate ratios. The rate in Kahnawá:ke was 58% greater than neighbouring regions and 98% greater in the analysis of those aged <20 years. Despite relatively favourable socioeconomic conditions and healthcare access, rates of influenza-related visits in Kahnawá:ke were elevated, particularly in the younger age groups.     

A latent process model for forecasting multiple time series in environmental public health surveillance

This paper outlines a latent process model for forecasting multiple health outcomes arising from a common environmental exposure. Traditionally, surveillance models in environmental health do not link health outcome measures, such as morbidity or mortality counts, to measures of exposure, such as air pollution. Moreover, different measures of health outcomes are treated as independent, while it is known that they are correlated with one another over time as they arise in part from a common underlying exposure. We propose modelling an environmental exposure as a latent process, and we describe the implementation of such a model within a hierarchical Bayesian framework and its efficient computation using integrated nested Laplace approximations. Through a simulation study, we compare distinct univariate models for each health outcome with a bivariate approach. The bivariate model outperforms the univariate models in bias and coverage of parameter estimation, in forecast accuracy and in computational efficiency. The methods are illustrated with a case study using healthcare utilization and air pollution data from British Columbia, Canada, 2003–2011, where seasonal wildfires produce high levels of air pollution, significantly impacting population health. Copyright © 2016 John Wiley & Sons, Ltd.