We aimed to investigate the association between platelet indices [platelet, plateletcrit (PCT), mean platelet volume (MPV) and platelet distribution width (PDW)] and gastrointestinal bleeding (GIB), as well as determine its severity and prognosis.

500 patients with GIB who were admitted to hospital between March 2014 and February 2017 and diagnosed with “Gastrointestinal System Bleeding”, as well as114 healthy individuals were retrospectively included in the study. Patients' platelet indices were recorded after one week and one month from their files.

Platelet, PCT, MPV and PDW levels were determined to be higher in the patients with bleeding, when compared to the control group (p < 0.001). Within the first week, a significant reduction was determined in patients' platelet, PCT, MPV and PDW values compared to the admission values (p < 0.001). In initial-month controls, a significant reduction was determined in the platelet indices compared to the initial-week values (p < 0.001). A significant association between bleeding severity and increased platelet indexes was determined. Increasing age, female gender, the presence of comorbidities, high levels of platelet indexes, low levels of hemoglobin, and albumin values were all found to be associated with a poor prognosis. PCT, MPV, and PDW were determined as being the independent risk factors that predict the odds of GIB, alongside the independent predictors that predict risk of bleeding severity and the prognosis.

We think that platelet indices may be used in diagnosis of GIB, as well as in predicting bleeding severity and the prognosis.