Hemoglobin-to-red blood cell distribution width ratio is negatively associated with stroke: a cross-sectional study from NHANES

Numerous studies have suggested that the hemoglobin-to-red blood cell distribution width ratio (HRR) is associated with the onset, progression, and prognosis of various diseases. However, to the best of our knowledge, no research has conducted statistical analyses to determine the association between HRR and stroke. This cross-sectional study was conducted among adults with complete data on hemoglobin-red cell distribution width ratio (HRR) and stroke from the 2005-2018 National Health and Nutrition Examination Survey (NHANES). HRR was calculated by dividing hemoglobin (HGB) in grams per deciliter (g/dL) by the red blood cell distribution width (RDW). Weighted multivariable logistic regression and generalized additive models were employed to investigate the independent and nonlinear relationships between HRR and stroke. Threshold effects were assessed using two-piece linear regression models. Additionally, subgroup analyses and interaction tests were performed. A total of 36,215 participants were included, with 2.92% classified as stroke patients. The prevalence of stroke decreased across increasing tertiles of HRR (Q1: 5.07%; Q2: 2.63%; Q3: 1.69%; P < 0.0001). A negative association between HRR and stroke was observed in both unadjusted and adjusted models. In Model III, each one-unit increase in HRR was associated with a 58% reduction in the likelihood of stroke (Model III: OR = 0.42, 95% CI: 0.29-0.63). Subgroup analyses and interaction tests revealed that the association between HRR and stroke was BMI-dependent (P < 0.05), with the negative association only observed in participants with BMI < = 25 and BMI 25-30, but not in those with BMI > 30. Using a two-piece linear regression model, a threshold effect was identified at a BMI of 30 (K = 1.16). To the left of this breakpoint, there was a negative association between HRR and stroke (OR = 0.55, 95% CI: 0.27-0.97), whereas no such association was detected to the right of the breakpoint (OR = 6.49, 95% CI: 0.75-56.11). HRR is negatively associated with the likelihood of stroke, with a lower risk of stroke in individuals with higher HRR levels.