The Burden of Influenza A Virus Hospitalization in the South Batinah Governorate, Oman: A Retrospective Study (2023–2025)

Abstract

Background: The seasonal influenza A virus is a major cause of respiratory morbidity and mortality worldwide, particularly in older adults and those with chronic conditions. Little information is available on hospitalized cases of influenza A in the South Batinah Governorate of Oman. The aim of this study was to describe the clinical and epidemiological features, virologic profile, management, and outcomes of hospitalized patients with laboratory-confirmed influenza A, and to identify factors associated with severe disease.
Methods: This was a retrospective observational study at Rustaq Hospital, a secondary care referral hospital. Participants were 208 patients aged 13 years or older admitted to the medical wards during January 2023 through April 2025 with polymerase chain reaction (PCR)-confirmed influenza A. Demographic, clinical, virologic, treatment, and outcome data were extracted from the Al Shifa electronic health record. Associations with severe disease (intensive care unit admission and/or in-hospital death) were assessed using univariate logistic regression. Statistical significance was defined as a two-sided p < 0.05.
Results: Mean age of the 208 patients was 55.6 ± 20.0 years (median 58.5). Overall, 39.9% (n = 83) were 65 years or older and 49.5% (n = 103) were male. Hypertension was present in 38.5% (n = 80) and diabetes mellitus in 30.8% (n = 64); 15.4% (n = 32) had three or more chronic diseases. The most common presenting symptoms were fever and cough, each in 83.7%. Admissions showed marked seasonal variation (Figure 1A), with 71.6% (n = 149) occurring from September through December and peaking in November. Among the 38.0% (n = 79) of cases that were subtyped, A(H1N1)pdm09 accounted for 92.4% (n = 73). Oseltamivir was given to 90.4% (n = 188) of patients and empiric antibiotics to 82.7% (n = 172). In-hospital mortality was 5.3% (n = 11), ICU admission 5.8% (n = 12), and severe disease 6.7% (n = 14). Only two factors were associated with adverse outcomes: chronic obstructive pulmonary disease (death OR 11.94; severe illness OR 8.55) and chronic kidney disease (death OR 4.79; severe illness OR 4.83).
Conclusions: Hospitalized influenza A cases were predominantly older adults with multiple chronic conditions, and admissions showed marked seasonal variation. Patients with COPD or CKD were at greatest risk of severe illness or death. Despite good adherence to guideline-recommended oseltamivir treatment, the high rate of empiric antibiotic use highlights an opportunity for antimicrobial stewardship. There are also opportunities to improve influenza subtyping and the documentation of vaccination status, and to increase influenza vaccine uptake in at-risk populations.