Mahalanobis' distance and propensity score to construct a controlled matched group in a Brazilian study of health promotion and social determinants

Abstract

In observational epidemiology it is usual to select a control group to study the effects of certain exposures on human health. Intervention studies are well known among epidemiologists but it is not very frequent in other areas of research. In this paper we propose the same idea of intervention studies and the use of three methods for a health promotion research control group selection: Propensity score, Mahalanobis' distance and Mahalanobis within Propensity Calipers. In the original project, "Health and Local Development: a progress review towards the millennium goals with relation to health in the Brazilian cities which develop social agendas", cities with social agendas from Brazil were matched separately by state. In the state of Paraná there are 397 cities. Of these, 34 presented social agendas implemented and active since, at least, 2004. Five variables measured in 2000 were considered for the matching: population size, human development index of income, human development index of education, percentage of literacy and vaccine coverage. As a result, among these three methods, the Mahalanobis by itself was considered the less efficient. In conclusion, the propensity, which is a very simple linear score, presented very good matched sample. However, the Mahalanobis within Calipers was the method that provided the best result.

Keywords

• Análise por pareamento
• Grupos controle
• Distância de Mahalanobis
• Pontuação de propensão
• Análise de pareamento por margem de propensão
• Epidemiologia