Red cell distribution width-to-platelet ratio (RPR) as a predictor of prolonged stay at hospital for COVID-19 inpatients.

Abstract

Aims/background: We looked at novel hematological composites like the neutrophil-to-lymphocyte ratio, platelet-to-lymphocyte ratio, monocyte-to-lymphocyte ratio, red cell distribution width-to-lymphocyte ratio, red cell distribution width-to-platelet ratio, leukocyte-to-C reactive protein ratio, and lymphocyte-to-C reactive protein ratio as explanatory variables for COVID-19 patients´ hospital length of stay (LoS).

Methods: The association of hematological indices with LoS was analyzed on 2930 COVID-19 patients using the univariate and multivariable Cox proportional hazards regression models with enter method. The Kaplan-Meier survival estimates were applied to LoS.

Results: The survivors´ mean LoS was 7.8 ± 24.0 days, but the deaths´ mean LoS was 38.6 ± 41.9 days (W = 31338, p < 0.01). Every hematological scores representative of the inflammatory status was significantly correlated in the univariate analysis with a prolonged LoS (p < 0.001). In the multivariate analysis, it was discovered that just the monocyte-to-lymphocyte and lymphocyte-to-C reactive protein ratios had not achieved statistical significance. However, most systemic inflammation measures showed hazards ratios close to one. One exemption was the red cell distribution width-to-platelet ratio (RPR) index, which can increase the probability of a longer hospital stay by up to ten times (HR(IC95%) = 0.092(0.03-0.29); p < 0.001).

Conclusion: The most effective biomarker to identify COVID-19 patients at high risk for extended hospital stay was RPR.

Highlights: IntroductionDetermining hospital Length of Stay (LoS) is vital for resource management, especially for future COVID-19 outbreaks.Previous studies have primarily focused on sociodemographic and clinical attributes, along with resource availability, but have not accounted for other factors like routine laboratory tests, which can significantly impact LoS predictions.This study examines novel hematology scores as predictors of LoS, emphasizing their importance in resource-limited settings like Ecuador.MethodsThis retrospective cohort study analyzed 2,930 COVID-19 patients admitted to Hospital IESS Quito Sur in Ecuador focusing on confirmed cases with complete blood count (CBC) values to assess LoS.The study explored various hematological ratios, such as the neutrophil-to-lymphocyte ratio (NLR) and red cell distribution width-to-lymphocyte ratio (RLR), as potential predictors of LoS and in-hospital outcomes for COVID-19 patients, using a combination of univariate and multivariable Cox proportional hazards regression models.Kaplan-Meier survival estimates and log-rank tests were used to analyze survival and discharge probabilities over time, highlighting sex-dependent effects and the significant association between selected hematological indices and patient outcomes.ResultsThe mean LoS for survivors was significantly shorter compared to those who died (p < 0.001), indicating that longer hospitalization was associated with higher mortality risk.Women had a shorter average LoS (with lower mortality risk (p < 0.001), suggesting an asymmetrical hospitalization pattern based on sex.While most hematological markers had minimal clinical relevance for LoS, the red cell distribution width-to-platelet ratio (RPR) stood out, increasing the likelihood of a longer hospital stay by up to tenfold, making it a critical factor in predicting prolonged hospitalization.DiscussionMen had longer hospital stays and higher mortality rates than women, likely due to differing inflammatory responses, though hyperinflammation markers like NLR, PLR, and Leu-CPR had minimal clinical impact.RPR had the strongest link to longer hospital stays, indicating a higher risk of extended hospitalization in severe COVID-19 cases.Elevated RPR is tied to oxidative stress and coagulation issues, suggesting early identification could help reduce prolonged stays and complications.ConclusionResearch generally points to clinical complications from COVID-19 as the main factor behind prolonged hospitalizations, underlining the importance of early identification and management of these issues.