Relationship of Mean Platelet Volume To MDD: A Retrospective Study.

Background Results of numerous studies show that major depressive disorder (MDD) is associated with a chronic low-grade inflammation, but the underlying mechanism remains unclear. Aim To compare the results of blood cell analysis of MDD patients with healthy controls, and explore the potential value of it as an indicator of immune-inflammation in MDD, especially the mean platelet volume. Methods 103 MDD patients and 106 healthy controls with matched age and gender were recruited. We collected peripheral blood samples from both groups and gathered basic data. For comparison of normally distributed data (age, body mass index, lymphocyte count, white blood cell count, red blood cell count, hematocrit, platelet count and mean corpuscular volume) between groups, single t-test were used; and for comparison of non-normally distributed data (Neutrophil count, neutrophil count, platelet/ lymphocyte ratio, hemoglobin, red blood cell distribution width, mean platelet volume, mean hemoglobin concentration, mean hemoglobin and platelet distribution width), we used Mann-Whitney U-test. Results Compared with healthy controls, the MDD groups showed significantly higher white blood cell count (F=0.443, p=0.004), plateletcrit (F=8.3, p<0.001), neutrophil and lymphocyte ratio (Z=-6.063, p<0.001), neutrophil count (Z=-5.062, p<0.001), platelet/lymphocyte ratio (Z=-2.469, p=0.014), red blood cell distribution width (Z=-2.481, p=0.013) and mean platelet volume (Z=-2.668, p=0.008). In addition they had significantly lower hemoglobin (Z=-3.876, p<0.001), mean hemoglobin amount (Z=-3.005, p=0.003), red blood cell count (F=0.248, p<0.001), lymphocyte count (F=3.826, p=0.004) and hematocrit (F=0.000, p>0.001). Conclusions The results suggest that serum inflammatory response probably exists in people with MDD, and indicators of blood analysis especially mean platelet volume have a potential value as biomarker for inflammation.