Vital horoscope: longitudinal data collection in the Iranian primary health care system.

Despite their importance longitudinal methods of data collection are complex time-consuming and expensive. With longer periods of observation the problems of population movement and loss to follow-up become important. This is particularly the case in developing countries with high rates of rural-to-urban migration and residential mobility within major urban centres. A more practical alternative involves repeated data collection on well-defined communities on a regular monthly or annual basis. Combining such data-gathering exercises with a practical programme of intervention or service delivery can justify the expense involved and ensure the viability of the project.Since its establishment in 1985 the Primary Health Care (PHC) Network of the Islamic Republic of Iran has provided a unique opportunity for longitudinal data collection concerning the total population of a large number of rural communities (villages) on an annual basis (Naghavi and others 2005). This article strives to describe this PHC-based management information system and show the type of longitudinal information collected by it. To achieve this aim the article begins with a description of the sophisticated but simple management information system developed to support the PHC Network the most innovative component of which is the "vital horoscope" which is described at some length in the article. Finally the trends of changes in basic demographic and health indicators of the rural population of the Islamic Republic of Iran as revealed by an analysis of vital horoscope data collected between 1993 and 2003 are presented. The combination of cross-sectional and longitudinal data afforded by the vital horoscope is important for obtaining a nuanced and comprehensive picture of the demographic and health status of the population nationally and in different provinces and districts and for providing valuable information on the reach and effectiveness of the public health services. (excerpt)