During a pandemic, length of hospital stay (LOS) is critical to managing high patient volumes and preserves access to care related to non-COVID-19 for maintaining the healthcare system. Moreover, identification of prolonged hospital stay may allow physicians to reevaluate critical patients, focused delivery of specific interventions, and improve the efficiency of hospital care.

Furthermore, in previous recent studies, attention has been paid to patients with diabetes and COVID-19 infection may require a prolonged LOS. However, there is little evidence on prognostic factors associated with an extension of hospitalization in mild or moderate illness due to COVID-19 infection. Therefore, it is crucial to determine the most vulnerable patients with diabetes mellitus even if they have a non-severe COVID-19 infection during the pandemic.

We hypothesize that the clinically relevant inflammatory parameters may have an impact on LOS in older adults with diabetes and non-severe COVID-19 infection. Therefore, we aim to investigate whether baseline inflammatory parameters on admission hospitals as possible predictors of prolonged LOS in older adults with diabetes and non-severe COVID-19 infection during the pandemic.

Inclusion Criteria:

• We included all hospitalized Covid-19 patients with diabetes mellitus according to the any established diagnosis prior to admission or American Diabetes Association guidelines for diagnostic criteria

Exclusion Criteria:

• The patients with severe Covid-19 infection, secondary diabetes or type 1 diabetes mellitus were excluded.

The date of hospital admission and discharge of patients and baseline clinical characteristics including age, sex, comorbidities (hypertension, cardiovascular disease, chronic obstructive pulmonary disease and others), diabetes medications (oral anti-diabetic drugs or insulin), and laboratuary parameters of within 24 hours of admission (levels of white blood cell (WBC), lymphocyte neutrophil, hemoglobin (Hb), platelet, fasting glucose, glycated hemoglobin, aspartate aminotransferase (AST) , c-reactive protein (CRP), ferritin, and procalcitonin) were recorded from medical records and collected by two trained fellow geriatricians.