Malaria, transmitted by Anopheles mosquitoes, remains a serious public health problem in tropical regions. Among the infecting species, Plasmodium falciparum is the main cause of the most severe forms of the disease, associated with a higher risk of complications and death. In the Brazilian Legal Amazon, a highly endemic region, hospitalizations due to this infection represent a significant burden for the Unified Health System (SUS), affecting mortality, length of stay, and healthcare costs.

To analyze the frequency, clinical outcomes, and economic impact of hospitalizations for Plasmodium falciparum malaria in the Legal Amazon between 2014 and 2024.

Cross-sectional study using data from the SUS Hospital Information System (SIH/SUS), obtained via DATASUS. Hospitalizations related to P. falciparum malaria in the Legal Amazon regions between January 2014 and December 2024 were included. Variables assessed included number of hospitalizations, deaths, mortality rate, mean length of stay, total and average costs, as well as seasonality and temporal autocorrelation (lag-1).

A total of 6,188 hospitalizations for P. falciparum malaria were recorded during the period. Total expenditure was R$ 5,860,696.77, with an average cost per hospitalization of R$ 714.79. The mean length of stay was 8.61 days. There were 496 in-hospital deaths, with an average mortality rate of 5.74%. The year with the highest number of hospitalizations was 2024 (1,157 cases; 18.7%), and the lowest was 2016 (205 hospitalizations; 3.3%). October had the highest number of hospitalizations (556; 8.99%) and January the lowest (488; 7.89%). Lag-1 autocorrelation showed stability in length of stay (r = 0.76) and a downward trend in mortality (r = 0.74).

Hospitalizations for P. falciparum malaria in the Legal Amazon had a substantial impact on SUS over the last decade, with relevant mortality and significant costs. The downward trend in case fatality may reflect advances in early diagnosis and hospital care, although the stability in length of stay points to persistent challenges in clinical management. These findings reinforce the need for continued investment in epidemiological surveillance, hospital infrastructure, and public policies targeted at region-specific malaria control in the Amazon.