AIM: The pandemic has generated the need for COVID-19 patients to be treated as best as possible; however, the effect of these treatments on glycemic control has not yet been taken into account. This article aims to determine whether the daily variation of glucose is influenced by the use of corticosteroids in COVID-19 patients treated in Lima-Peru. METHODOLOGY: A prospective cohort study was undertook, in which glucose was measured four times a day in 53 patients hospitalized due to COVID-19. These values were associated with the use of corticosteroids and adjusted for other socio-educational variables, all by means of PA-GEE models. RESULTS: Nested multivariate analysis of daily glucose variation found that those using corticosteroids increased the daily average glucose as well as the first and last glucose measurements, this is, at 6am and 10pm, respectively (all p-values <0.026). An increase in glucose levels was also observed in those with diabetes (all p-values <0.001). In contrast, we found that there was a decrease in the last glucose measurement of the day in obese patients (p-value = 0.044). CONCLUSIONS: The patients who used corticosteroids for the treatment of COVID-19 increased the average glucose per day, especially in the first and last measurement.