Rodrigo Hoyos-Bachiloglu

Higher latitude and lower solar radiation influence on anaphylaxis in Chilean children

Recent studies suggest an association between higher latitude, a proxy of vitamin D (VD) status, and allergic diseases. Chile provides an ideal setting to study this association due to its latitude span and high rates of VD deficiency in southern regions. The aim of this study is to explore the associations of latitude and solar radiation with anaphylaxis admission rates.

Association of Kawasaki disease with tropospheric winds in Central Chile: is wind-borne desert dust a risk factor?

It has been found that Kawasaki disease (KD) cases diagnosed in Japan, Hawaii and San Diego, USA increase when tropospheric wind patterns arrive from central Asia, suggesting a common, wind-borne causal agent. We analyzed KD cases hospitalized in Santiago, Chile to look for associations with local, regional and large scale meteorological variables. We compiled monthly data of KD incidence rates, local meteorological variables, large scale wind patterns and several El Niño Southern Oscillation (ENSO) indices for 2001-2010; we considered standardized anomalies in all analyses and used linear time series models to account for data autocorrelation. We found that meteorological variables explain 38% of variance in KD rates. A unit increase in northerly wind at 3 lagged months, temperature at 1 and 3 lagged months and monthly change of ENSO 4 index are associated with changes in KD rates of 0.203 (95% CI 0.049-0.358), 0.181 (95% CI 0.014-0.347), 0.192 (95% CI 0.030-0.353) and -0.307 (95% CI -0.458-0.156), respectively. These results are robust when northerly wind level is changed or when a shorter period (2005-2010) is used to estimate model parameters. We found a statistical association of KD at Santiago, Chile with tropospheric, northerly wind patterns suggesting that dust transported from the Atacama Desert could include a causative agent. A novel result is that ENSO dynamics also explain part of KD variability with a decrease in KD when La Niña is dissipating or El Niño is on the rise; hence climate scale dynamics might be taken into account in future studies worldwide - at least as a potential explanatory variable that may confound KD seasonality on a global scale.

Solar radiation is inversely associated with inflammatory bowel disease admissions

Abstract Objective: To explore the associations between latitude and solar radiation with inflammatory bowel disease admission rates in Chile, the country with the largest variation in solar radiation in the world. Patients and methods: This is an ecological study, which included data on all hospital-admitted population for inflammatory bowel disease between 2001 and 2012, according to different latitudes and solar radiation exposures in Chile. The data were acquired from the national hospital discharge database from the Department of Health Statistics and Information of the Chilean Ministry of Health. Results: Between 2001 and 2012 there were 12,869 admissions due to inflammatory bowel disease (69% ulcerative colitis, 31% Crohn’s disease). Median age was 36 years (IQR: 25–51); 57% were female. The national inflammatory bowel disease admission rate was 6.52 (95% CI: 6.40–6.63) per 100,000 inhabitants with increasing rates over the 12-year period. In terms of latitude, the highest admission rates for pediatric ulcerative colitis and Crohn’s disease, as well as adult ulcerative colitis, were observed in the southernmost region with lowest annual solar radiation. Linear regression analysis showed that regional solar radiation was inversely associated with inflammatory bowel disease admissions in Chile (β: −.44, p = .03). Conclusions: Regional solar radiation was inversely associated with inflammatory bowel disease admission rates in Chile; inflammatory bowel disease admissions were highest in the southernmost region with lowest solar radiation. Our results support the potential role of vitamin D deficiency on inflammatory bowel disease flares.

Primary immunodeficiencies in Chile evaluated through ICD-10 coded hospital admissions

BACKGROUND The epidemiology and hospitalisation trends of primary immunodeficiency (PID) in Chile are unknown. We aimed to evaluate hospitalisation trends and demographic characteristics of PID admissions in Chile. METHODS PID admissions between 2001 and 2010 (ICD-10 codes D70.0, D70.4, D71, 72.0, D76.1, D80-D84, E70.3, G11.3) were reviewed using national hospital discharge databases. RESULTS During the study period, 5486 admissions due to PID were registered (0.03% of total). 58.5% of patients were male and 66.3% were under 18 years. Median length of stay was one day (range 1-403 days). The most frequent diagnoses were hypogammaglobulinaemia (27.6%), unspecified immunodeficiency (21.9%), haemophagocytic lymphohystiocytosis (18.3%) and common variable immunodeficiency (11.2%). There was a significant increase in PID admission rate and in one-day hospitalisations during this period (β=0.2; P=0.001 and β=33; P≤0.001, respectively), however no significant variation was found for longer admissions (β=4.8; P=0.175). The increasing trend in PID admission rate was significant in patients with private, but not public insurance (β=0.53; P≤0.001 vs. β=0.08; P=0.079, respectively). CONCLUSIONS We report an increasing trend in admissions due to PID in Chile over a 10-year period. Increase is mainly due to short hospitalisations, possibly accounting for improvements in IVIG access. Higher admission rates in patients with private vs. public insurance suggest socioeconomic disparities in access to PID treatment. ICD-10 coded hospitalisation databases may be useful to determine hospitalisation trends and demographic characteristics of PID admissions worldwide.

Regional solar radiation is inversely correlated with incidence and severity of tuberculosis in Chile.

Vitamin D (VD) deficiency has been linked to increased incidence and morbidity of tuberculosis (TB). Chile has large variations in solar radiation (SR; a proxy of VD status) and high prevalence of VD deficiency in its southernmost regions with low SR. We investigated the correlation between regional SR and rates of TB incidence, admissions and deaths in Chile by reviewing national records on prospectively collected mandatory disease notifications, admissions and mortality between 2001 and 2011. Over the study period, 26 691 new TB notifications were registered. The TB incidence rate was 14·77 (95% confidence intervals (CIs) 14·60-14·95), admission rate was 12·12 (95% CI 11·96-12·28) and mortality rate was 1·61 (95% CI 1·55-1·67) per 100 000 population per year. Multivariable linear regressions adjusting for significant demographic TB risk factors in Chile (regional prevalence of HIV infection, rates of migration from TB-endemic countries and rates of imprisonment) revealed an independent and highly statistically significant inverse association between SR and TB incidence rate (β -1·05, 95% CI -1·73 to -0·36, P = 0·007), admission rate (β -1·58, 95% CI -2·23 to -0·93, P < 0·001), and mortality rate (β -0·15, 95% CI -0·23 to -0·07, P = 0·002). These findings support a potential pathogenic role of VD deficiency in TB incidence and severity.

Potenciales consecuencias neurocognitivas de infección por virus respiratorio sincicial humano

Human respiratory syncytial virus (RSV) infection remains as a major cause of morbidity and mortality among pediatric population. Immune response is poor and unable to establish a long term effective protection against this virus. Of particular interest has been the description of extrapulmonary manifestations of RSV infection in liver, kidney, endocrine system, heart and brain, associated to infection of peripheral blood. In the central nervous system (CNS), recent studies in animals have suggested long term neurocognitive impairment due to a direct damage from the virus. This was prevented in rats by a recombinant BCG vaccine expressing a nucleoprotein N of RSV that produces an effective immune response against the virus, not allowing its dissemination to the CNS. These findings in animal models highlight the importance of conducting more specific studies in children affected with severe infection by RSV. Therefore, our group is currently conducting an assessment of the possible long-term cognitive impairment in children under 2 years. The results of this study could be a strong argument to continue looking for an effective method for protecting against RSV infection.

A140: Pediatric Rheumatology Admissions in Chile, 2001–2010: Unavailability of a Pediatric Rheumatologist May Hinder a Correct Diagnosis

Pediatric rheumatologic diseases (PRDs) comprise a group of complex conditions that involve considerable disease burden and are sometimes life‐threatening. The American College of Rheumatology and the British Society for Pediatric and Adolescent Rheumatology recommend that a Pediatric Rheumatologist (PR) be involved in the care of children affected by PRDs. In Chile, there is a very small group of pediatric rheumatologists; most of them in Santiago. Between years 2000–2010 there were 9 centers in Santiago with a Pediatric Rheumatologist, one in Concepcion (IX Region) and one in Temuco (X Region). Patients living far from a tertiary center with a PR may miss the opportunity of a timely diagnosis and treatment. The purpose of this study was to evaluate trends in PRD admissions in Chile in a 10‐year period.

Rising incidence of Kawasaki disease in Chile: analysis of national discharge databases between 2001 and 2007

Results Seven hundred eighty-six hospitalizations attributable to KD were identified between 2001 and 2007, representing 0.03% of hospitalizations in children younger than 18 years. Median age of diagnosis was 1 year (range 0-17). Twenty-five percent of patients were younger than 1 year, 60% were between 1 and 4 years, 11% between 5 and 9 years, and 4% between 10 and 17 years. Male to female ratio was 1.6:1. Median length of hospital stay was 5 days (range 1-152). Highest hospitalization rates occurred in late winter and spring (August-November) with a smaller peak in summer (February-March). Sixty percent of patients had public health insurance and 30% of patients had private health insurance, which was overrepresented among KD patients. Fifty-two percent of cases were hospitalized in the Metropolitan Region (Santiago), which had the highest KD hospitalization rate in the country. Hospitalization rate attributable to KD among children younger than 5 years was 7.6 (95% CI 7.1-7.9). Hospitalization rates significantly increased from the 2001-2004 period to the 2005-2007 period: 6.3 (95% CI 5.9-6.6) to 9.3 (95% CI 8.4-10.4), (P < 0.001). Estimated incidence of KD, assuming 10% readmission rates, was 5.7 (95% CI 5.4-6.1) per 100,000 children younger than five years for the 2001-2004 period and 8.4 (95% CI 7.6-9.6) for the 2005-2007 period (P < 0.001). Two patients died during a hospitalization attributable to KD, resulting in an acute lethality rate of 0.25%.