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Sunday, March 21, 2010
Grand Hall (Hyatt Regency Atlanta)
Background: The pandemic 2009 H1N1 influenza virus, which began circulating in April, substantially altered the course of the 2009 influenza season. Emerging data suggests that although this virus more heavily afflicts the younger population, it appears to show increased morbidity in pregnant women and the older population.
Objective: To compare the demographic information of patients who tested positive for influenza from April through October 2009, to those from prior influenza seasons.
Methods: Descriptive analysis of all patients with confirmed influenza (in the Emergency Department or inpatient setting) from April through October 2009, compared to those from the three previous influenza seasons (October 2006 through March 2009), at a 920-bed tertiary care hospital.
Results: From April through October 2009, 160 patients had confirmed influenza (94% influenza A, presumably all 2009 H1N1), with 44 (28%) requiring admission and 10 (6%) requiring ICU care. During the three previous influenza seasons, a total of 181 patients had confirmed influenza (77% influenza A), with 72 (40%) requiring admission and 11 (6%) requiring ICU care.
Since April 2009, the 1-29 year age group represented a higher proportion of all positive tests (69% vs. 34%) and of all influenza admissions (55% vs. 31%), compared to previous seasons. Patients aged ≥40 years were significantly more likely to require hospitalization for ≥5 days (93% vs. 59%, p=0.037 by Fisher’s exact test). Of inpatients aged ≤29 years, 33% had a pre-existing co-morbidity this season compared to 41% previously.
The proportion of pregnant women with confirmed influenza this season (6/160, 3.8%) was similar to previous seasons (7/181, 3.9%); however, more were admitted this season (4 of 6, with 2 ICU admissions) than previously (1 of 7, no ICU admissions). The average length of stay for pregnant women with influenza since April 2009 was comparable to those in the same respective age group (7.0 ± 5.3 days vs. 5.1 ± 2.5 days, respectively).
Conclusions: From April through October 2009, a smaller proportion of patients with confirmed influenza required admission; this observation may represent a testing bias. Inpatients were younger and less likely to have underlying medical conditions compared to prior seasons. Those aged ≥40 years were significantly more likely to require hospitalization for ≥5 days than in previous years. While the proportion of pregnant women with influenza was similar, more required admission or ICU care this season. Our findings are consistent with recently published data describing a higher burden of disease in the young, with more severe illness in pregnant women and the older population.
Objective: To compare the demographic information of patients who tested positive for influenza from April through October 2009, to those from prior influenza seasons.
Methods: Descriptive analysis of all patients with confirmed influenza (in the Emergency Department or inpatient setting) from April through October 2009, compared to those from the three previous influenza seasons (October 2006 through March 2009), at a 920-bed tertiary care hospital.
Results: From April through October 2009, 160 patients had confirmed influenza (94% influenza A, presumably all 2009 H1N1), with 44 (28%) requiring admission and 10 (6%) requiring ICU care. During the three previous influenza seasons, a total of 181 patients had confirmed influenza (77% influenza A), with 72 (40%) requiring admission and 11 (6%) requiring ICU care.
Since April 2009, the 1-29 year age group represented a higher proportion of all positive tests (69% vs. 34%) and of all influenza admissions (55% vs. 31%), compared to previous seasons. Patients aged ≥40 years were significantly more likely to require hospitalization for ≥5 days (93% vs. 59%, p=0.037 by Fisher’s exact test). Of inpatients aged ≤29 years, 33% had a pre-existing co-morbidity this season compared to 41% previously.
The proportion of pregnant women with confirmed influenza this season (6/160, 3.8%) was similar to previous seasons (7/181, 3.9%); however, more were admitted this season (4 of 6, with 2 ICU admissions) than previously (1 of 7, no ICU admissions). The average length of stay for pregnant women with influenza since April 2009 was comparable to those in the same respective age group (7.0 ± 5.3 days vs. 5.1 ± 2.5 days, respectively).
Conclusions: From April through October 2009, a smaller proportion of patients with confirmed influenza required admission; this observation may represent a testing bias. Inpatients were younger and less likely to have underlying medical conditions compared to prior seasons. Those aged ≥40 years were significantly more likely to require hospitalization for ≥5 days than in previous years. While the proportion of pregnant women with influenza was similar, more required admission or ICU care this season. Our findings are consistent with recently published data describing a higher burden of disease in the young, with more severe illness in pregnant women and the older population.