Comorbid Diabetes and COVID-19 Linked to Longer Hospitalization

HUMAN BLOOD CELLS–Leukocytes (white blood cells), Erythrocytes (red blood cells), and Thrombocytes (platelets), 400X. The leukocyte to the left with an oval nucleus is a Lymphocyte, an important immune cell. The two leukocytes to the right of the lymphocyte are Neutrophils. They typically have a segmented or lobed nucleus. Neutrophils are excellent phagocytic cells engulfing harmful particles or microorganisms. The Thrombocytes are in the upper right hand corner, they are very important in thrombosis or blood coagulation. The pink-stained cells are erythrocytes–they lack a nucleus hence the central pallor, they contain large amounts of hemoglobin molecules and transport oxygen. This is a normal blood smear using Wright’s stain.
This study found that diabetic patients with COVID-19 had lower lymphocyte counts and hospital stays.

Patients hospitalized for coronavirus disease 2019 (COVID-19) are more likely to have a lower lymphocyte count, reach the minimal lymphocyte count more rapidly, and are hospitalized longer if they have diabetes, a study in Diabetes Research and Clinical Practice suggests.

The study included 63 adult patients with COVID-19 who were admitted to a hospital in China from January 29 to March 15, 2020. Patients were classified as having diabetes (n=16) or not having diabetes (n=47).

Lymphocytes measured and recorded at admission and during treatment were analyzed and compared between groups. Other outcomes assessed in this study included the number of hospitalization days, severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) nucleic acid positive days, and minimal lymphocyte count.

At time of admission, patients with diabetes had a significantly higher maximal C-reactive protein (91.75 vs 17.0 mg/L; P =.004) and fasting glucose (8.81±2.42 vs 6.01±1.89 mmol/L; P =.000).

A lower minimal lymphocyte count was observed in patients with diabetes vs without diabetes (0.67±0.36 vs 1.30±0.54*109/L, respectively; P =.001). Additionally, the investigators found that the minimal lymphocyte count occurred significantly earlier in patients with diabetes compared with the non-diabetes group (2.68±2.33 days vs 5.29±4.95 days, respectively; P =.042).

Patients with diabetes and COVID-19 also had longer hospital stays (20.44±5.24 days vs 17.11±4.78 days; P =.047). A negative correlation was found between the minimal lymphocyte count and both hospital days (R = -0.600; P <.05) and SARS-CoV-2 nucleic acid positive days (R = -0.420; P <.05).

Limitations of the study included the small sample size, the retrospective and single-center design, and the lack of data on specific types of lymphocytes.

Considering there is no clear treatment or cure for COVID-19, and clearance of the virus is associated with lymphocytes and immune function, the investigators suggest providing patients “with symptomatic and support treatment, wait for the recovery of their lymphocyte count and immune function, and wait for virus clearance.”

They add that the avoidance of “drugs that impair lymphocyte and immune function may be beneficial,” particularly in patients with diabetes.


Wu D, Gao S. Analysis of the lymphocyte count in type 2 diabetic patients with coronavirus disease (COVID-19): A retrospective study in a centralized treatment center. Published online July 22, 2020. Diabetes Res Clin Pract. doi:10.1016/j.diabres.2020.108340