In reference to Relation of mean platelet volume and red blood cell distribution width with epistaxis.

We applaud the work by Kemal et al., in their well-presented article. The authors found lower mean platelet volume (MPV) and red blood cell distribution (RDW) levels in epistaxis. It is worth noting that any process resulting in the release of immature erythrocyte/platelet or increased destruction of red blood cell/platelet will change the levels of RDW/MPV. Moreover, it has been reported that RDW is an index affected by many factors such as anemia, renal or hepatic dysfunction, thyroid disease, transfusion, acute or chronic inflammation, neurohumoral activation, malnutrition (i.e., iron, vitamin B12, and folic acid), ethnicity, bone marrow depression, and use of some medications (i.e., erythropoietin and antibiotics). Meanwhile, MPV may act through thrombosis, which is also affected by many factors such as diabetes mellitus, prediabetes, obesity, coronary heart disease, hypercholesterolemia, smoking, metabolic syndrome, hypertension, statins, antihypertensive drug use, and atrial fibrillation. In addition, a decreased MPV has been reported in patients with ulcerative colitis, rheumatoid arthritis, and ankylosing spondylitis, and it has also been reported that hypothyroidism increases MPV values. Thus, it would have been better if the authors had listed these RDW/MPV-affecting factors in greater detail. In addition, several issues should be noted. First, the time elapsed between blood sampling and RDW/ MPV measuring was not clearly defined; the length of this interval may significantly alter their levels. Second, from Table II we found that the average age of subjects in the control group was significantly higher than that of subjects in the epistaxis group. Levels of RDW have been shown to be associated with age. Finally, from Table I, we saw that whether the level of MPV or RDW, the differences between the two groups were small. The difference between the two groups was statistically significant, and considering the above-mentioned limitations of this study and the relatively small sample size, this small difference may not be clinically significant.