# Predictors of Fatal Outcomes among Pediatric Patients Hospitalized for Rocky Mountain Spotted Fever, Sonora, Mexico, 2004–2024

## TL;DR

This study identifies factors that increase the risk of death in children hospitalized with Rocky Mountain Spotted Fever in Sonora, Mexico, emphasizing the importance of timely treatment and vulnerable populations.

## Contribution

The study provides new insights into predictors of fatal outcomes in pediatric RMSF cases in a specific geographic region over two decades.

## Key findings

- The overall case-fatality rate was 19.8%, with a significant decrease observed from 2004–2013 to 2014–2024.
- Delayed doxycycline treatment, older age, Indigenous background, and abnormal lab markers were associated with fatal outcomes.
- 16% of survivors experienced life-altering sequelae, such as amputations and neurological deficits.

## Abstract

The tickborne disease Rocky Mountain spotted fever (RMSF) remains life-threatening among children in northern Mexico. We retrospectively investigated 500 pediatric RMSF patients hospitalized in Sonora during 2004–2024. We analyzed clinical, laboratory, and sociodemographic data to identify predictors of fatality by using descriptive statistics and multivariable logistic regression. We found that the overall case-fatality rate was 19.8%, decreasing over time from 31.4% (2004–2013) to 14.5% (2014–2024). Fatal outcomes were associated with delayed doxycycline treatment (>5 days after symptom onset), older age, Indigenous background, and abnormal laboratory markers. Among survivors, 16% had life-altering sequelae, including amputations and neurologic deficits. Cases occurred year-round, predominantly in urban settings. Timely doxycycline administration remains a critical factor in reducing mortality rates. Vulnerable populations, including persons living in poverty, children >10 years of age, and Indigenous communities, require targeted interventions. Strengthening early diagnosis and understanding mechanisms underlying severe disease and death could improve RMSF outcomes in endemic regions.