Spectrum and Burden of Influenza Infection: An Approach to Identify Predictors of Morbidity and Mortality Rate from the Patients of the Northwest of Iran

The objective of this research is to analyze influenza-induced complications, symptoms, and the interaction of morbidity and mortality rates in hospitalized influenza cases based on age-sex dispersion, influenza virus subtype, prescribed medications, and underlying conditions.
We performed this retrospective study using a dataset of 10,517 hospitalized individuals, including 3,101 laboratory-confirmed influenza cases from patients of all ages who had attended hospitals in the Northwest of Iran due to respiratory complications.
The most prevalent strain which circulated annually was influenza A/H3N2. In contrast to previous studies, our findings suggested that influenza A/H1N1 has the highest mortality rate and the most severe complications.
Regardless of virus type/subtype, the most susceptible age group for influenza was 0-9 years old in both males and females. Meanwhile the high-risk age group among males was 50-59 years old and among females were over 80 age group (mortality rate ≈ 20%). Chronic obstructive pulmonary disease (COPD) (32%) and cardiovascular disease (CVD) (30%) were the most prevalent active underlying diseases among the patients who died, with the latter being more prevalent in males over the age of 70. Patients with a history of chemotherapy had the highest mortality rate. Patients who were prescribed a combination of antibiotics and antivirals had better outcomes with lowest mortality rate.
Our findings demonstrated that annual influenza seasons are often marked by changes in influenza types and subtypes, with variations in the severity. Development of a standardized set of arrays that best correspond with infections, can be useful in guiding diagnostic and therapeutic decisions.