gms | German Medical Science

Background: The burden of IAH and related direct costs may vary considerably in different age groups and relate to specific influenza subtypes. We therefore initiated a retrospective study in a large tertiary care University Hospital (Würzburg, Germany).

Methods: All patients with any ICD-10 discharge diagnosis for influenza (J09-J11), hospitalized for at least one day during the years 2010 to 2013, were identified from the hospital routine documentation database; demographic data, all ICD-10 and procedural codes and costs per patient were extracted. IAH were verified by medical chart review and laboratory confirmation.

Results: Their median length of stay was 4 (IQR 3-9) days and 2% needed intensive care. In children, the influenza subtypes A(H1N1)pdm09/A(H3N2)/B accounted for 30/67/54 IAH, with average per-patient costs of 2,579/2,378/1,673 EUR (p<0.001). In 73 adults 18-65 years of age median length of stay of IAH was 12 days (IQR 5-20) and 47% needed intensive care (16% ECMO) and 13 (18%) died. 44% were immunocompromised and 7% were pregnant. A(H1N1)pdm09/A(H3N2)/B accounted for 53/11/9 IAH. Per influenza subtype, 57%/27%/11% needed intensive care (p=0.015); 23%/0%0% ECMO (p=0.067); 23%/9%/0% died (p=0.186); average per-patient costs were 23,527/8,148/4,828 EUR (p=0.044). In 23 patients >65 years of age median length of stay was 10 days (IQR 6-17) and 26% needed intensive care, while 3 (13%) died. A(H1N1)pdm09/A(H3N2)/B accounted for 7/6/10 IAH, with average per-patient costs of 14,760/7,877/5,520 EUR per subtype (p=0.831).

Conclusion: The majority of IAH occurred in children at toddler age. In adults 18-65 years of age, however, severe complications were more frequent and often associated with A(H1N1)pdm09, resulting in high per-patient costs.