Aims The aim of the study was to review the assessment of acute medical admissions with “Flu like illness” and to identify useful tools in risk-stratifying severity of illness.

Methods This was a retrospective observational study. We reviewed the assessment of all inpatients diagnosed with “flu like illness” from November 2010 to March 2011 at a district general hospital. We evaluated potential risk-stratification tools with respect to adverse outcomes (length of admission and intensive care unit (ITU) admission): Co-morbidities (diabetes mellitus, immunosuppression, pregnancy, chronic respiratory, heart, renal and liver disease), CURB-65 score, C-reactive protein (CRP) and chest x-ray findings (CXR).

Results 27 patients were identified; 6 Male, 19 Female; mean age 40.1. 22 had virology swabs; 12 (62%) were positive for H1N1, 5 (24%) Influenza B and 2 (9%) Influenza A. Length of admission (LOA) ranged from 1 to 30 days (mean 8.3 days). Seven patients required ITU admission. 14 (52%) had no co-morbidities. Six (86%) of seven ITU patients had no co-morbidities. LOA did not differ between patients with co-morbidities and those without (10 vs 10.9 days respectively). 17 (63%) patients had CURB-65 of zero. Five (71%) of seven ITU patients had a CURB-65 of less than three. CURB-65 was poorly correlated with LOA (R²=0.22). CRP on admission ranged from <4 to 511 mmol/l (mean 121 mmol/l). Mean CRP of ITU patients was 240 mmol/l; in contrast to 79 mmol/l in non-ITU cases. CRP was poorly correlated with increased LOA (R²=0.16). 25 patients had CXR on admission and 12 (48%) had abnormal findings. Patients with bilateral CXR changes had a mean LOA of 21 days compared with 3.5 days in those with normal CXR. Six (86%) of seven ITU patients had abnormal CXR.

Conclusion A raised CRP and abnormal CXR findings on admission were associated with adverse outcomes. Co-morbidities and CURB-65 correlated poorly with disease severity. These findings may be explained by the high prevalence of H1N1 influenza in winter 2010. Current Health Protection Agency guidelines place strong emphasis on CURB-65 and co-morbidities in risk-stratification. We recommend the inclusion of CRP on initial assessment and stronger emphasis on CXR changes.