The spatial epidemiology of asthma: a chronic non-communicable disease and a neglected epidemic

© 2014 Kameel et al; licensee Herbert Publications Ltd. This is an Open Access article distributed under the terms of Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0). This permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. Introduction It is estimated that about 300 million individuals of all ages and ethnic backgrounds live with asthma. This number is expected to increase to 400 million by 2025, which will increase the burden of providing care worldwide [1]. In the United States (US) asthma accounts for 25% of the 2 million visits to emergency rooms [2]. Asthma also accounts for more than 10 million outpatient visits and 500,000 hospitalizations in the US yearly [2]. In Barbados between 1970-1990 admissions to an acute setting increased from 36 to 360 patients per month despite an increase of only 10% in the island’s population during that time [3]. Similarly for the one year period 1999 in Trinidad 5.3% of all adult admissions and 23% of pediatric admission to the emergency room were asthma related [4]. As a result acute asthma impacts significantly on emergency facilities. Thus morbidity continues to be high despite effective treatments [5]. Consensus guidelines consistently highlight the aim and objectives of treatment: (1) to eliminate or minimize asthma symptoms, (2) to achieve the best possible lung function and (3) to prevent asthma exacerbations, the latter being the primary focus of this study [6,7]. According to the Global Initiative for Asthma (GINA), [8] asthma is defined as a chronic inflammatory disorder of the airways resulting in hyper-responsiveness, bronchial constriction and excessive mucus formation. The clinical diagnosis is based on the clinical presentation and investigation [6], which may include lung function tests and chest radiograph to sputum cell counts (total and differential) [9], and fraction of nitric oxide in exhaled breath [10]. Asthma may be classified according to the age of onset into childhood or adult or according to nature of severity of symptoms (acute/chronic). Childhood asthma is a complex phenomenon, Abstract Objectives: The aim of this study was to measure the occurrence of acute exacerbations of asthma at an Emergency Health Facility for the period 2010-12, and to describe its spatial distribution using ARC GIS 10.0 (ESRI). Design: The study design is an observational cross sectional study in which cases of acute exacerbations of asthma treated at an Emergency Department of a semi rural 24hr health facility were reviewed. The address of each patient was geocoded and mapped. Setting: An emergency health facility offering 24x7 service. Participants: All patients who met the criteria for an acute exacerbation of asthma during the period 201012. Main outcome measures: The occurrence and geographic distribution of asthma presenting for rescue therapy. Results: The number of cases of acute exacerbations asthma increased in each consecutive year. Spatially, while the geographical distribution of cases was diffuse we identified a cluster (Valencia). Using spatial overlay there was a correlation with temperature and humidity. Conclusions: Over the three year period 2010-2012 there was an increase in the occurrence of acute exacerbations of asthmatic requiring emergency care, emphasizing that Asthma is still an important Public Health challenge.