# Association between hemoglobin-to-red blood cell distribution width ratio and rheumatoid arthritis in US adults: evidence from the national health and nutrition examination survey 2009–2018

## TL;DR

This study found that a blood ratio called HRR is linked to a lower risk of rheumatoid arthritis, suggesting it could help identify people at risk.

## Contribution

The study identifies HRR as a potential biomarker for rheumatoid arthritis risk through large-scale population data.

## Key findings

- Higher HRR quartiles were associated with significantly lower rheumatoid arthritis risk (OR = 0.68 for quartile 4 vs. 1).
- Restricted cubic spline analysis confirmed a linear inverse relationship between HRR and rheumatoid arthritis risk.

## Abstract

This cross-sectional study aimed to investigate the association between the hemoglobin-to-red blood cell distribution width ratio (HRR) and rheumatoid arthritis in adults.

Cross-sectional data from 22,352 participants in the National Health and Nutrition Examination Survey (NHANES) 2009–2018 were analyzed. HRR was defined as hemoglobin concentration (g/dL) divided by red blood cell distribution width (%) and grouped into quartiles. The multivariable logistic regression model and restricted cubic spline (RCS) models assessed the connection between HRR and rheumatoid arthritis, adjusted for demographics, socioeconomic factors, and comorbidities.

Our findings reveal a significant negative correlation between HRR measurements and rheumatoid arthritis susceptibility. Higher HRR quartiles showed progressively lower rheumatoid arthritis risk (quartile 4 vs. quartile 1: OR = 0.68, 95 % CI: 0.56,0.83). RCS revealed an inverse linear association after adjustment (P for overall <0.001; P for nonlinear = 0.174).

HRR is inversely associated with rheumatoid arthritis risk, suggesting its potential as a biomarker for rheumatoid arthritis risk stratification. Nevertheless, additional investigations are required to corroborate these observations.

•Hemoglobin-to-red cell distribution width ratio (HRR) may be a potential biomarker for rheumatoid arthritis risk assessment.•Multivariable logistic regression showed a significant inverse association between HRR and rheumatoid arthritis risk.•Restricted cubic spline analysis confirmed a linear inverse relationship between HRR and rheumatoid arthritis risk.

Hemoglobin-to-red cell distribution width ratio (HRR) may be a potential biomarker for rheumatoid arthritis risk assessment.

Multivariable logistic regression showed a significant inverse association between HRR and rheumatoid arthritis risk.

Restricted cubic spline analysis confirmed a linear inverse relationship between HRR and rheumatoid arthritis risk.