Swine flu is an acute respiratory tract infection caused by influenza A H1N1 which is characterized by chills, fever, sore throat, muscle pains, severe headache, coughing, weakness/fatigue, and general discomfort. In more serious cases, influenza causes pneumonia, which can be fatal, particularly in the elderly and patients with pre-existing illnesses . Influenza spreads around the world in seasonal epidemics, resulting in the deaths of between 250,000 and 500,000 people every year, up to millions people affected in some pandemic years. On average 41,400 people died each year in the United States between 1979 and 2001 from influenza .
The pandemic influenza A (H1N1) started in southern part of Rajasthan in August 2009 and lasted until November 2010. A large number of H1N1 cases and deaths have been reported during this pandemic . After that, in next two years till August 2012, Southern Rajasthan reported little Influenza activity. In September 2012, this influenza A H1N1 virus once again has resurfaced in this region of India. The number of new cases, including fatal cases, continued to increase since 13th September 2012 in Southern Rajasthan. It lasted till 28th February 2013. Swine flu cases again resurfaced in month of January 2015 in Southern region of India. First death reported on 2nd February 2015. Swine flu positivity continues to increase with peak in the month of February and March 2015. Recently sudden outbreak of swine flu was more severe with high mortality and morbidity in compare to that of year 2012. Epidemic was declared On 12 February 2015 in Rajasthan which declared end on 15 April 2015, however, screening of patients of Influenza-like illness was continue in swine flu OPD and infrequent cases of swine flu were found positive. 491(39.37%) patients were found positive for H1N1 and 62 were expired during this period.
Mortality profile is an analytical tool used to identify the various factors responsible for poor outcomes of disease and it can also used to evaluate quality & efficiency of healthcare providers. Aim of this study is to summarise the clinical and epidemiological factors as well as to identify the risk factors associated with mortality among swine flu cases.
Materials & methods
It is a cross-sectional, descriptive, hospital-based study conducted on deceased patients due to swine flu reported at Maharana Bhupal Government Hospital, Udaipur during the outbreak of Influenza A H1N1 in the year 2015. A total about 491 patients were found to be swine positive was 491(39.37%), out of them 62 (12.63%) were expired
A standardized pre-structured questionnaire with consent was filled by help of bed head tickets and by interview of attendants of deceased patients. The questionnaire included clinical and epidemiological data of patients like age, sex, residence, communication detail, clinical signs & symptoms, exposure history, type & numbers of sample collected, time of report received, treatment taken, co-morbid medical conditions, investigation reports & duration of hospitalization.
In our study overall case fatality rate was 12.63%. Our study reported higher CFR in compare to the study of Gerardo Chowell et al (2011)  which reported overall CFR 1.2% and highest (5.5%) among people over 60 years. In our study CFR for age group, 31-45 years (16.06%) were highest which is comparable with the study finding of Mahendra Singh et al (2013)  at Jodhpur, Rajasthan which stated that highest CFR (20.2%) in the age group of 15-45 years. In contrast to an inception-cohort study conducted by STEVEN A.R. et al (2009)  in all Australian and New Zealand intensive care units (ICUs) during the winter of 2009 which reported case fatality rate 14.3%, our study reported slightly lower CFR (12.63%). Our findings were in contrast to a study of CP Sharma et al (2012)  reported overall CFR observed was 9.7% which was slightly higher among males (10.2%) than females (9.2%). Our findings were also contrary to findings of study of Prakash B Patel et al (2015)  which reported overall CFR observed was 5.91% which was slightly higher among males (6.0%) than females (5.8%) and the difference was not statistically significant. Our study reported higher overall CFR and affected female population.
In our study mortality in the age group of 31-45 years was found to be highest 35.48% (22 cases). In contrast to study of Mahendra Singh et al (2013)  at Jodhpur, Rajasthan this showed 22.4% (13) deaths in the 30 to 45-year age group. In study conducted by CP Sharma et al (2012)  during 2009-2010 in same study area revealed maximum number of deaths 58.6% were reported in 21-40 year age group. Our findings were corroborating with the study findings of Viresh Ashok Nandimath et al (2015) which reported that highest mortality (50.00%) were observed in 31-45 years age group. Our findings were also contrary to study of Hiren Jadawala et al (2015)  which reported highest number of deceased patients (43%) belonged to age group between 40-60 yrs. Our study findings are in contrast with the study of Dr. T. Vasanthi et al (2015)  which showed that case fatality was high in the age group greater than 65 years. Our study findings are in contrast with the study of Dr. Kshitij Domadia et al (2015)  which showed that Maximum mortality was found in the age group greater than 60 years (29.62%). The higher mortality in Southern Rajasthan region as compare to other regions of country may be due to the fact that the study was restricted to a small geographical area when compared to the entire country and sick patients were referred from the adjacent tribal regions and nearby states which have poor medical infrastructure which consequently led to loss of crucial delay in primary treatment.
Our study reported that majority of deceased patients 46(74.19%) belong to rural background. Mortality during swine flu outbreak was highest in females of rural background 27(43.55%). It coincides with the study conducted by CP Sharma et al (2012)  which showed that death were more in the cases belong to rural areas (58.6%) and rural females (52.8%). Our findings corroborates with the study of Chintal Vyas et al (2013)  which reported that death among females (34.2%) was higher than males (22.7%) in pandemic period. Our findings were also contrary to study of Hiren Jadawala et al (2015)  which reported that deaths were almost equally distributed among male and female. Our study findings corroborate with the study of Dr. Kshitij Domadia et al (2015)  which reported that more mortality was seen in females (24.28%) compared to males (19.70%). Reason of more swine flu morbidity and mortality in rural population might be lack of knowledge of preventive measures and delayed availability of treatment facilities.
In our study delay in hospitalization from onset of symptoms was observed median 6.5 days (range 2-20). Our findings corroborate with the study of Rogelio Perez-Padilla et al (2009)  which reported delay in hospitalization from onset of symptoms was median 6 days (range 4-13). In the study of Chintal Vyas et al (2013)  delay in hospitalization was much lower during pandemic period (4.6±1.7 days) while equivalent during the post-pandemic period (6.3±2.5 days) in compare to our study. Our study reported that majority of expired patients 44(70.97%) had delay of 4-7 days in admission after onset of symptoms. Our finding was similar to study of Hiren Jadawala et al (2015)  which reported that majority of expired patients (57.4%) has delay of more than 2 days in admission from onset of symptoms.
Our study reported that majority of expired patients 37(59.68%) were diagnosed within 4-7 days of onset of symptoms while majority of survived patients (38.90%) were diagnosed within 3-5 days of onset of symptoms.
Our study reported that majority of patients 42(67.74%) were expired within 3 days of hospitalization. Our study finding corroborates with the study of Viresh Ashok Nandimath et al (2015)  which reported that majority of patients 9 (75.00%) were expired within 2 days of hospitalization. In our study median duration of hospital stay in expired patients was 2 days (range 0-8) which is much lower than the study of Rogelio Perez-Padilla et al (2009)  which reported duration of hospitalization in expired patients was median 9 days (range 4-18). Our study reported that median duration from onset of symptoms to death was 9 days (range 4-24) which is much lower than the study of Rogelio Perez-Padilla et al (2009)  which reported median duration from onset of symptoms to death was 14 days (range 10-23). In our study mean duration of hospital stay in expired patients was 2.71± 2.07 days which is much lower than the study of Dr. Kshitij Domadia et al (2015)  which reported mean duration of hospitalization in expired patients was 9.9 days. It shows that the progression of disease was rapid in present outbreak.
In our study majority of expired patients, 37(59.68%) were not having any risk factors. Among expired patients Pregnancy (11.29%), Diabetes mellitus (12.90%), and hypertension (11.29%) were most common risk factors. In contrast to our findings, the study of Viresh Ashok Nandimath et al (2015)  reported that majority of expired patients 9(75.00%) were having any risk factors while hypertension and diabetes were most common risk factors similar to our study. In contrast to our findings, the study of CP Sharma et al (2012)  reported that high-risk factors were present in majority (79.31%) of expired patients while Pregnancy (27.5%) was most common followed by diabetes mellitus (17.2%) similar to our study. Our study findings corroborate with the study of Dr. V. R. Malkar et al (2012)  which showed that majority of patients 36(60.00%) were not having any risk factor. Study findings of Kashinkunti MD et al (2013)  reported that diabetes (50%) and hypertension (45.5%) are most common risk factors. In contrary to our study findings the study of Hiren Jadawala et al (2015)  reported that out of 47 patients, 26 (55.3%) had high-risk factors (like hypertension, diabetes, ischemic heart disease, thyroid disorder, liver disorder, seizures, malignancy, pregnancy) in which Hypertension (25.5%) was most common.