Prognostic relevance of differential blood count in pulmonary arterial hypertension
Differential blood count is routinely done at the time of diagnostic work-up and during follow-up of pulmonary arterial hypertension (PAH), however it is unknown if specific cell types are of prognostic relevance.
Aims and objectives:
We aimed to analyze white cell differential counts of PAH patients and to assess if specific cell types may be of prognostic relevance.
Patients and methods:
In this retrospective study we included n = 83 newly diagnosed PAH patients and n = 71 patients who underwent right heart catheterization and had normal hemodynamics. White blood cell differential counts of these two groups were analyzed and compared using Mann Whitney U test. Area under the curve was calculated for each cell type as well as for neutrophil-to-lymphocyte ratio (NLR). Survival analysis was performed based on the best cut-off values. Data are presented as mean ± standard deviation.
The relative and absolute number of lymphocytes in patients with PAH was decreased as compared to controls (22.3 ± 10% vs. 25.4 ± 8.8% p < 0.006, 1.5 ± 0.7 vs. 1.6 ± 0.6 p < 0.025 respectively). There was a significant elevation in the relative neutrophil counts in PAH as compared to controls (66.8 ± 11.5% vs. 64.4 ± 10.7%, p < 0.037). There were no differences in monocyte or eosinophil counts between the two groups. NLR was elevated in PAH as compared to controls (3.8 ± 2.5 vs. 3.3 ± 2.7 p < 0.008). A cut-off for NLR of ≥2.62 identified patients with PAH with a sensitivity of 69% and specificity of 56%. Overall 5-year survival of PAH patients with NLR ≤2.62 was significantly better as compared to those below cut-off (69% vs. 47% p < 0.038).
Neutrophil-to-lymphocyte ratio is a simple tool which is of prognostic relevance for PAH.