Influenza is an acute viral respiratory disease with diverse clinical manifestations. Despite extensive research, ambiguities remain regarding its prognostic factors. In this cross-sectional retrospective study, conducted during 2021 on 993 samples (546 males 447 females) from patients with suspected acute viral respiratory infections who were hospitalized in hospitals of Golestan Province, we evaluated the clinical and laboratory findings of patients with influenza. The samples were sent to the provincial molecular diagnostics laboratory for real-time polymerase chain reaction (PCR) molecular testing. All samples were also tested for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Test results, along with demographic, clinical, and laboratory data, were collected using a standardized questionnaire. Of the 993 samples tested for influenza, 174 were reported as positive. All, but one, of these positive cases were influenza A. From 993 tests for SARS-CoV-2, 271 cases were also reported as positive. Additionally, 11 patients had influenza and SARS-CoV-2 co-infection. The mean age of influenza patients hospitalized in the intensive care unit (ICU) was determined to be 55.60±15.11 years, while in other wards, it was 37.51±12.1 years (P<0.05). Regarding gender, the ICU-hospitalized male-to-female ratio was 3 times and 1.35 times in other wards (P<0.05). In ICU-hospitalized patients, the highest percentage of clinical symptoms belonged to fever, cough, chills, and anorexia, and in patients hospitalized in other wards, the highest percentage belonged to fever, followed by cough, chest pain, and chills. There was a statistically significant difference between ICU-hospitalized patients and those hospitalized in other wards for symptoms, such as anorexia, arthralgia, myalgia, sore throat, cough, nausea, headache, and chills (P<0.05). Blood factors, such as white blood cell (WBC) count, neutrophil and lymphocyte percentages, hemoglobin, erythrocyte sedimentation rate (ESR), and platelets, were evaluated, and no statistically significant difference was observed between the two patient groups. Biochemical factors, including blood urea nitrogen (BUN), creatinine, sodium, potassium, liver enzymes, such as alanine aminotransferase (ALT), aspartate aminotransferase (AST), alkaline phosphatase (ALP), lactate dehydrogenase (LDH), creatine phosphokinase (CPK), and direct and indirect bilirubin, were also examined, and no significant difference was found between the two patient groups. Additionally, other factors, such as oxygen and carbon dioxide saturation percentages, bicarbonate, and blood pH were assessed, and a statistically significant difference was found between the two groups for oxygen and carbon dioxide saturation percentages (P<0.05). Based on the findings of this study, age and gender are effective factors in the severity of influenza. Men and older adults are at particular risk for ICU hospitalization. The high prevalence of influenza A and cases of SARS-CoV-2 co-infection also highlight the importance of accurate diagnosis and appropriate treatment. Given the increased risk of infection and disease severity among the elderly, implementing preventive programs, such as annual influenza and coronavirus disease 2019 (COVID-19) vaccinations, is essential for this group. Additionally, attention to laboratory findings like blood oxygen levels can be effective in the early identification of high-risk patients.