[Health services utilization: a systematic review of related factors].

Health services utilization is determined by various factors. In order to study which factors are most important in different countries, a systematic review was conducted from 1970 to 1999. The mean number of visits, proportion of persons who see a doctor, and proportion that concentrate the most visits were similar. Children, childbearing-age women, and the elderly use health care services the most. Lower-income and less educated groups are also significantly associated with more frequent utilization. Increased health needs mediate more frequent utilization by these groups. However, the poorest groups may not receive adequate care, depending on the respective type of health system. Health need is one of the most important determinants in utilization, and if a health system's equity is to be analyzed, one must consider patterns of utilization among social groups in relation to the level of greatest need. Regularly visiting the same physician, a characteristic of accessibility to health care services, can determine more adequate utilization. This factor can reduce differences in health care among groups. The authors conclude by proposing a hierarchy of related factors.