The primary objective of our study is to assess the incidence of new onset diabetes mellitus (NOD) induced by Covid-19 in hospitalized patients and identify associated factors. Specifically, we aim to elucidate the factors related with hyperglycemia in this patient cohort and we supervised this glycemic status three months post-discharge.
Among the 202 previously non-diabetic Covid-19 patients admitted to our hospital, comprising 94 males and 108 females, the mean age was 52.45 years, with a standard deviation of 16.24. Upon admission, almost 50% of patients (100 out of 202) exhibited FBG above 126mg/dL or BG above 200mg/dL (NOH/NOD). This rate significantly surpasses the similar results reported by Zhang et al (16% out of 166 patients) (ref) and Li et al (21% out of 453) (13). In the study of Fadini et al as well, 11% of the cohort of their patients were diagnosed with NOD(14).
Laboratory data in our dataset encompassed values such as D-dimer, Lactate dehydrogenase (LDH), Aspartate aminotransferase (AST), Alanin aminotransferase (ALT), Alkaline phosphatase (ALP), Creatinine (Cr), and Blood Urea (Urea). A comparative analysis between normal patients (Normoglycemic) and patients with hyperglycemia during hospitalization revealed significant differences, particularly in D-dimer levels. The mean D-dimer in the hyperglycemic group was 2949, a higher value was noticed than the normal group's mean of 1010, a finding consistent with Cerielleo A's study (15), although this was not significant (P-value above 0.05) in our study.
Regarding the duration of hospitalization, hyperglycemic patients exhibited a longer stay (mean of 8.1 days) compared to normoglycemic patients (mean of 5.89 days), with a significant p-value of < 0.001. Other variables showed higher values in the hyperglycemic group, although these findings did not reach statistical significance (P-values > 0.05). Fadini et al.'s study similarly found an increased need for ICU admission and higher mortality in hyperglycemic patients while in our study 13 patients out of the hyperglycemic group were admitted for ICU while in the normoglycemic group this value is only five patients (14).
What is unique in our study is that we supervised glycemic status of our patients three months post discharge to assess their condition after discharge. Among 97 patients almost 47.5% (46 out of 97) still were suffering from hyperglycemia and have taken anti-diabetic drugs. Several causative etiologies can be assigned to this phenomenon, SARS-CoV-2 infection itself could maintain hyperglycemia status even after the convalescence (16). Due to the nature of the study almost all patients had taken some corticosteroid dosages prior or during the hospitalization, this could potentiate hyperglycemia status even after the discharge (17–18). Some patients had taken Tocilizumab therapy during the hospitalization, this measure could be a potential cause of exacerbation of glycemic status in this study (19).
The strength of this study is not only the investigation of the relation of hyperglycemia with Covid-19 in patients without prior history of hyperglycemia and factors related to it, but also surveillance of patients three months post-discharge.
However, certain limitations must be acknowledged. Firstly, our study employed a single-center, retrospective, and observational design. Secondly, the sample size was relatively small. Thirdly, the study population consisted mostly of seriously ill patients from government-assigned hospitals, potentially introducing selection bias. Notably, all patients had taken corticosteroids before hospital admission, which may have influenced elevated fasting blood glucose (FBG) values. Due to the retrospective nature of our study, we were unable to measure HbA1c levels on the day of admission, potentially resulting in pre-existing high HbA1c levels for some patients who later developed new-onset hyperglycemia or diabetes we suggest a similar study with larger sample size for a more accurate result.
For the aim further investigation into causative role of Covid-19 in the development of diabetes-mellitus in patients post-discharge, it is suggested to implement data-driven machine-learning or artificial intelligence models by using data in this study and similar studies.
In conclusion, our study contributes to the understanding of COVID-19-induced hyperglycemia, especially in patients without prior hyperglycemic conditions. In this study we found that Covid-19 can cause hyperglycemia in moderate to severe forms of the disease and this status can endure to be diabetes later after discharge.