To determine the direct medical costs of type 1 diabetes mellitus (T1DM) to the National Brazilian Health-Care System (NBHCS) and quantify the contribution of each individual component to the total cost.

A retrospective, cross-sectional, nationwide multicentre study was conducted between 2008 and 2010 in 28 public clinics in 20 Brazilian cities. The study included 3180 patients with T1DM (mean age 22 years ± 11.8) who were surveyed while receiving health care from the NBHCS. The mean duration of their diabetes was 10.3 years (± 8.0). The costs of tests and medical procedures, insulin pumps, and supplies for administration, and supplies for self-monitoring of blood glucose (SMBG) were obtained from national and local health system sources for 2010–2011. Annual direct medical costs were derived by adding the costs of medications, supplies, tests, medical consultations, procedures and hospitalizations over the year preceding the interview.

The average annual direct medical cost per capita was 1319.15 United States dollars (US$). Treatment-related expenditure – US$ 1216.33 per patient per year – represented 92.20% of total direct medical costs. Insulin administration supplies and SMBG (US$ 696.78 per patient per year) accounted for 52.82% of these total costs. Together, medical procedures and haemodialysis accounted for 5.73% (US$ 75.64 per patient per year) of direct medical costs. Consultations accounted for 1.94% of direct medical costs (US$ 25.62 per patient per year).

Health technologies accounted for most direct medical costs of T1DM. These data can serve to reassess the distribution of resources for managing T1DM in Brazil’s public health-care system.