Background: Isolated systolic hypertension (ISHT) is a subtype of hypertension (HT) that often exhibits wide pulse pressure, and pulse pressure has a strong predictive value for future adverse cardiovascular events. Previous studies have shown the effects of leukocyte count on the prognosis of ischaemic heart disease and HT.

Aim: Thus, in this cross-sectional study, we analysed the relationship between leukocyte counts and subtypes in HT and non-HT groups.

Methods: The study population consisted of 960 consecutive patients who were admitted to the outpatient clinic of our hospital. After ambulatory blood pressure values were assessed, the participants were divided into three groups: ISHT (n = 98), systo-diastolic hypertensives (SDHT, n = 405), and non-hypertensives (non-HT, n = 457).

Results: The subjects in the ISHT group were older than those in the SDHT and non-HT groups (64 ± 10, 53 ± 12, and 52 ± 13, respectively; p < 0.001). The leukocyte and neutrophil counts and neutrophil/lymphocyte (NL) ratios were significantly different in all groups. In subgroup analysis, the leukocyte count, neutrophil count, and N/L ratio were higher in the ISHT and SDHT groups than in the non-HT group (p < 0.001 for all). The leukocyte count, neutrophil count, and N/L ratio were significantly higher in the ISHT group than in the SDHT group (p = 0.023, p = 0.007, p = 0.010, respectively). Neutrophil count (p = 0.012; OR = 1.229, 95% CI 1.046-1.444) was an independent risk factor for ISHT in multivariate logistic regression analysis.

Conclusions: The leukocyte and neutrophil counts and N/L ratios were higher in the ISHT group than in the SDHT and non-HT groups. High neutrophil count was an independent predictor of ISHT.