Brazil's aging population and the rising number of people reliant upon the country's supplementary healthcare system have elicited the concern of public and private managers regarding the increase in healthcare costs. In this paper, the costs per gender, per type of medical expenses and per age group of a major Brazilian self-managed healthcare provider between 2007 and 2013 were analyzed. This healthcare provider is of interest because, besides portraying a single condition of revenue growth restricted to the existing contributors, it also replicates the demographic profile expected for Brazil in 2050, when approximately one-third of its population will be over 60 years of age. The analyses confirm the current literature as they show an increase in healthcare plan usage by the elderly and the difference between admission rates by gender. They also reveal an increase in average length of stay in hospital and the increase in medical costs far above inflation, especially for materials and medicines. It is hoped that this study will help scholars and others interested in comparisons of medical expense trends, especially by age and sex, and that it encourages further collaboration on the sustainability of health insurance providers in Brazil.