Background: Age progression is regarded as a critical risk factor in morbidity and mortality because of a weakened immune system. Although various studies have dealt with electrolyte imbalance in COVID-19 patients, the outcomes of these studies were partially understood. Objective: The current study aims to determine some biochemical parameters in old Iraqi COVID-19 patients and highlight the outcomes according to the aging role in the development of COVID-19 by suggesting new mechanisms. Materials and methods: forty COVID-19 patients were enrolled in the current study and divided into two groups: Gm includes (20) men, and Gf includes (20) women. The parameters (Na+, K+, Cl-, LDH, and Hb ) were determined in sera of patients and control groups, G1: healthy men and G2: healthy women. Results: The results reported that the levels of sodium, chloride, and ( hemoglobin for men) were highly significantly decreased. In contrast, potassium level was highly significantly increased in Gm and Gf compared to G1 and G2, respectively, and hemoglobin level in women was decreased in Gf compared with G2. LDH activity did not significantly increase in Gm compared with G1, while it increased dramatically in Gf compared with G2. The difference between Gm and Gf was non-significant for sodium, potassium, chloride, and hemoglobin, but it was highly significant for lactate dehydrogenase. Conclusions: The present study proposed definite mechanisms to elucidate hyponatremia, hyperkalemia, and hypochloremia in old COVID-19 patients by highlighting both COVID-19 complications and risk factors linked to age progression. At the same time, it revealed an interesting biochemical relationship between higher activity of LDH, hyponatremia, and hypochloremia in the same patients .
