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J Assoc Physicians India. 2019 Mar;67(3):38-41.
Mortality in H1N1: A comparison of patient attributes in outbreaks due to A/California/7/2009 and A/Michigan/45/2015 strains.
Nawal CL1, Agarwal S2, Agrawal A1, Prakash R3, Mital P1, Singh A4, Chejara RS4.
Author information
Abstract
Introduction:
The resurgence of epidemic of Influenza A (H1N1) pdm 09 was phenomenal in 2015 and has become an annual phenomenon. Antigenic drift and reassortment is the rule rather than exception, conferring survival benefit to the virus. As this disease has high mortality, we compared the clinico-epidemiological profile of patients expired in the year 2015 due to "A/California/7/2009" strain with those of expired in the year 2018 due to "A/Michigan/45/2015" strain.
Material and Method:
We collected data of all expired patients in our institute in the year 2015 from 1st January to 30th may as well as 2018 in the same time period. The data of 116 patients who expired in 2015 due to "A/California/7/2009" H1N1 strain were compared with similar data of 30 patients expired in 2018 due to "A/Michigan/45/2015" strain of H1N1. Patients of pneumonia, having age >18 years, positive for H1N1by real-time reverse-transcriptase-polymerase- chain-reaction (RT-PCR) and died in our hospital were included in this study. Clinical features and laboratory data were obtained from the hospital records of the patients. Data analysis was done using SPSS software.
Result:
In 2015 total number of hospitalized patients due to "A/California/7/2009" strain were 571 and 116(20.31%) out of them died, in 2018 those due to "A/Michigan/45/2015" total admission were 177 and 30(16.94%) out of them died (p-0.032). Though it was not statistically significant but it is lesser than in 2015 despite the fact that more patients with co morbidities were affected in 2018. Duration in ICU was significantly longer in 2018(MS) group [5(1-7)] compared to 2015 (CS) group [3(1-17)] with p value of 0.017 (i.e. < 0.05). But both groups were not different in terms of duration on mechanical ventilator. (p-0.257).The 2015 (CS) group had 74.1% with other co-morbidities versus 96.7% of those in 2018 (MS) group (p- 0.015). This implies that the mortality with "A/Michigan/45/2015" infection was mainly seen in the patients who already had one or more co-morbidities unlike "A/California/7/2009" infection.The 2018 (MS) group had significantly higher proportion (60%) of patients with acute kidney injury compared to 34.5% in 2015(CS) (p-0.019). 50% of dead patients in 2018(MS) had anemia compared to 11.2% in 2015(CS) (p<0.001). Deranged liver function test was seen in 46.7% patients in 2018(MS) compared to only 15.5% patients in 2014(CS) (p<0.001).The only reverse trend was shown in case of diabetes, A/California/7/2009 strain affected 27% diabetics compared with 6.7% affected by A/Michigan/45/2015 strain (p=0.030) (Table 5).
Conclusion:
The study showed that though "A/Michigan/45/2015" affected higher number of patients with co morbidities compared to "A/California/7/2009" but had slightly lesser mortality.
? Journal of the Association of Physicians of India 2011.
PMID: 31304704
Mortality in H1N1: A comparison of patient attributes in outbreaks due to A/California/7/2009 and A/Michigan/45/2015 strains.
Nawal CL1, Agarwal S2, Agrawal A1, Prakash R3, Mital P1, Singh A4, Chejara RS4.
Author information
Abstract
Introduction:
The resurgence of epidemic of Influenza A (H1N1) pdm 09 was phenomenal in 2015 and has become an annual phenomenon. Antigenic drift and reassortment is the rule rather than exception, conferring survival benefit to the virus. As this disease has high mortality, we compared the clinico-epidemiological profile of patients expired in the year 2015 due to "A/California/7/2009" strain with those of expired in the year 2018 due to "A/Michigan/45/2015" strain.
Material and Method:
We collected data of all expired patients in our institute in the year 2015 from 1st January to 30th may as well as 2018 in the same time period. The data of 116 patients who expired in 2015 due to "A/California/7/2009" H1N1 strain were compared with similar data of 30 patients expired in 2018 due to "A/Michigan/45/2015" strain of H1N1. Patients of pneumonia, having age >18 years, positive for H1N1by real-time reverse-transcriptase-polymerase- chain-reaction (RT-PCR) and died in our hospital were included in this study. Clinical features and laboratory data were obtained from the hospital records of the patients. Data analysis was done using SPSS software.
Result:
In 2015 total number of hospitalized patients due to "A/California/7/2009" strain were 571 and 116(20.31%) out of them died, in 2018 those due to "A/Michigan/45/2015" total admission were 177 and 30(16.94%) out of them died (p-0.032). Though it was not statistically significant but it is lesser than in 2015 despite the fact that more patients with co morbidities were affected in 2018. Duration in ICU was significantly longer in 2018(MS) group [5(1-7)] compared to 2015 (CS) group [3(1-17)] with p value of 0.017 (i.e. < 0.05). But both groups were not different in terms of duration on mechanical ventilator. (p-0.257).The 2015 (CS) group had 74.1% with other co-morbidities versus 96.7% of those in 2018 (MS) group (p- 0.015). This implies that the mortality with "A/Michigan/45/2015" infection was mainly seen in the patients who already had one or more co-morbidities unlike "A/California/7/2009" infection.The 2018 (MS) group had significantly higher proportion (60%) of patients with acute kidney injury compared to 34.5% in 2015(CS) (p-0.019). 50% of dead patients in 2018(MS) had anemia compared to 11.2% in 2015(CS) (p<0.001). Deranged liver function test was seen in 46.7% patients in 2018(MS) compared to only 15.5% patients in 2014(CS) (p<0.001).The only reverse trend was shown in case of diabetes, A/California/7/2009 strain affected 27% diabetics compared with 6.7% affected by A/Michigan/45/2015 strain (p=0.030) (Table 5).
Conclusion:
The study showed that though "A/Michigan/45/2015" affected higher number of patients with co morbidities compared to "A/California/7/2009" but had slightly lesser mortality.
? Journal of the Association of Physicians of India 2011.
PMID: 31304704