Age, not blood inflammation scores, tracked COVID-19 deaths in a Lima hospital study

Adults hospitalized with COVID-19 at a national hospital in Lima, Peru, died at a rate of 9.5 percent, and in a new analysis the strongest predictor of that outcome was not any of the widely used blood-based inflammation scores but the patient’s age. In the multivariable model, age showed a consistent association with mortality (adjusted prevalence ratio: 1.12; 95% confidence interval: 1.06–1.18), and orotracheal intubation was positively associated with the outcome (adjusted prevalence ratio: 6.88; 95% confidence interval: 1.13–41.99). The three hematological indices under study, which combine routine blood counts and C-reactive protein into single numbers, lost their statistical association with mortality once the researchers accounted for other clinical and demographic variables.

The study, published in Frontiers in Virology, was conducted at the Guillermo Almenara Irigoyen National Hospital and included 116 adult patients with confirmed COVID-19. It was designed as an observational, analytical, cross-sectional investigation, meaning that all measurements were taken at a single point in each patient’s hospital stay rather than tracked forward over time. The researchers, led by Jesús Rojas Jaimes and colleagues at institutions including Continental University, Universidad Científica del Sur, and Seguro Social del Peru, set out to test whether simple ratios derived from standard blood tests could serve as standalone predictors of death in a Peruvian hospital setting, where the independent value of such indices had remained uncertain.

Three indices formed the core of the analysis.

The association between the inflammatory indices (neutrophil/lymphocyte index, platelet/lymphocyte index, and lymphocyte/C-reactive protein index) and intrahospital mortality was evaluated via log-binomial regression, adjusting for clinical covariables and demographics. In the initial bivariate analysis, which examined each variable without adjustment, the platelet-to-lymphocyte index showed a significant association with mortality, with a raw prevalence ratio of 5.34 and a 95 percent confidence interval running from 1.09 to 26.11. The mortality rate was 9.5% (11/116), and the confidence interval for the platelet/lymphocyte index in the bivariate analysis was wide (1.09–26.11).

Once the model adjusted for clinical covariables and demographic factors, the platelet-to-lymphocyte index no longer maintained an independent association with death. Its adjusted prevalence ratio was 2.80, with a 95% confidence interval of 0.31–25.71, a range that includes the null value of 1; the index did not maintain an independent association with mortality following adjustment. The neutrophil-to-lymphocyte and lymphocyte-to-C-reactive protein indices likewise did not demonstrate an independent relationship with mortality in the adjusted model. The authors conclude that these indices would be useful only as complementary components within broader, multifactorial clinical risk models rather than as standalone predictors.

Age emerged as the most consistent factor in the multivariable model. Each additional year was associated with a 12 percent increase in the adjusted prevalence of death, with a 95 percent confidence interval of 1.06 to 1.18. Because that interval lies entirely above 1, the association was consistent within this cohort.

Orotracheal intubation, a marker of the most severe respiratory failure, was also independently associated with death, showing an adjusted prevalence ratio of 6.88 and a 95 percent confidence interval of 1.13 to 41.99. The association was positive, though the confidence interval (1.13–41.99) was wide.

Indices derived from hematological parameters have been proposed as simple tools for estimating severity and mortality in patients with COVID-19; however, their independent relationship with mortality remains uncertain in hospital environments in Peru.

The study was observational, analytical, and cross-sectional, so the reported prevalence ratios describe associations rather than causal effects. With only 11 deaths among 116 patients, the confidence intervals around several estimates were broad, and the results come from a single hospital cohort of hospitalized adults. The authors conclude that the evaluated inflammatory indices did not demonstrate an independent relationship with mortality in the adjusted regression model, and that their utility would be complementary within multifactorial clinical risk models.

Subject of Research: Hematological inflammation indices and in-hospital mortality among adults hospitalized with COVID-19 in Lima, Peru

Article Title: Inflammatory response and mortality indices in patients hospitalized with COVID-19 in Lima, Peru

Article References: Orihuela, J., Jaimes, J. R., Quiroz-Narvaez, C., & Arenas, J. (2026). Inflammatory response and mortality indices in patients hospitalized with COVID-19 in Lima, Peru. Frontiers in Virology, 6, 1980771. https://doi.org/10.3389/fviro.2026.1980771

Image Credits: AI Generated

DOI: 10.3389/fviro.2026.1980771

Keywords: COVID-19, in-hospital mortality, neutrophil-lymphocyte ratio, platelet-lymphocyte ratio, C-reactive protein, log-binomial regression, Peru, hospitalized adults, biomarkers, inflammation, prevalence ratio, risk prediction