A study of the outcome of confirmed avian flu and swine flu cases admitted to Abbassia Chest Hospital between 2006 and 2010

Introduction Influenza is a serious respiratory illness that can be debilitating and cause complications that lead to hospitalization and death, especially in the elderly. Every year, the global burden of influenza epidemics is believed to be 3–5 million cases of severe illness and 300 000–500 000 deaths. The risk of serious illness and death is highest among persons older than 65 years, children younger than 2 years, and among individuals who have medical conditions that place them at increased risk of developing complications from influenza [1].


Introduction
Influenza is a serious respiratory illness that can be debilitating and cause complications that lead to hospitalization and death, especially in the elderly. Every year, the global burden of influenza epidemics is believed to be 3-5 million cases of severe illness and 300 000-500 000 deaths. The risk of serious illness and death is highest among persons older than 65 years, children younger than 2 years, and among individuals who have medical conditions that place them at increased risk of developing complications from influenza [1].
Influenza type A viruses have conserved their actuality and importance over time with respect to genetic variations and global pandemics. In recent years, their significance has increased because of the appearance of 'bird flu' caused by a highly virulent strain of the H5N1 subtype. Although influenza type A viruses that cause infections in birds (avian influenza) are species specific, some may cross the species barrier to infect humans. Previously, it was believed that direct transmission of virus from birds to humans could not take place, but it came to be true in 1997 in Hong Kong. As avian influenza virus A (H5N1) causes human infections with high morbidity and mortality rates, the probability of human-to-human transmission and its consequences attract a great deal of attention [2].
In March 2009, a novel strain of swine-origin influenza-A H1N1 caused human infection in Mexico, and spread to all regions in the world in the following 3 months. In 11 June 2009, the WHO declared that a global pandemic of influenza A H1N1 was underway. This action was a reflection of the spread of the new H1N1 virus, and not of the severity of illness caused by the virus. As of October 2009, there were about 400 000 confirmed cases and 5000 mortalities due to pandemic H1N1 all over the world. The most important step against pandemic H1N1 is prevention, which means, first of all, the adherence to hygienic rules and the use of vaccination [3].
All data were collected for statistical analysis to find out any possible relationship between the outcome of the disease and the following variables: (1) Age.
(3) Comorbidities [e.g. diabetes mellitus (DM), ischemic heart disease, congestive heart failure, any chronic chest disease such as chronic obstructive pulmonary disease, bronchial asthma or interstitial lung fibrosis, end-stage renal failure, and chronic liver diseases]. (4) Need for invasive or noninvasive mechanical ventilation and its duration. (5) The duration between the start of symptoms and presentation to the hospital. (6) Complication by bacterial pneumonia.

Data management and analysis
Data collected were revised, coded and tabulated using the statistical package for the social sciences (SPSS 15.0.1, 2001; SPSS Inc., Chicago, Illinois, USA) for Windows. Data were presented and suitable analysis was carried out according to the type of data obtained for each parameter. (2) Analytical statistics: (a) The χ 2 -test was used to compare two qualitative variables. (b) The independent samples t-test was used to assess the statistical significance of the difference between two study group means.
P value was used to determine the level of significance. P value more than 0.05 was considered nonsignificant, P value less than 0.05 was considered significant, and P value less than 0.01 was considered highly significant.  [5].

Aim
The aim of this study was to evaluate the clinical and epidemiological features and the treatment outcome of confirmed cases of avian flu and swine flu admitted to Abbassia Chest Hospital between 2006 and 2010.

Patients and methods
This study was a retrospective study that included 213 patients PCR-positive for influenza A H1N1 and 23 patients PCR-positive for influenza A H5N1, who were admitted to Abbassia Chest Hospital during the period from March 2006 to December 2010.
All patients were subjected to the following: (1) Full history taking.
(4) Nasopharyngeal swab, sputum, or bronchial lavageculture and sensitivity. (5) Chest radiology. as shown in Table 1. Forty-one (19.2%) patients were less than 10 years old, 10 (4.7%) patients were more than 61 years old, whereas 161 (75.6%) patients were in the age group of 11-60 years, with no statistical difference with regard to the relation between age distribution and the mortality among the studied patients, as shown in Fig. 1 Relation between risk factors and mortality showed that there was a significant statistical difference in the mortality of cases with end-stage renal failure (100%), whereas there was no statistical difference in the mortality of all other risk factors including hepatic patients (40%), pregnant patients (35.3%), and cardiac patients (31.8), as shown in Table 2.
There was no significant statistical difference with regard to the relation between the presenting time (days) and mortality, although the highest mortality was in the range of 5-6 days (29%), followed by 9-10 days (27.3%) and 7-8 days (26.2%), whereas the least Age distribution among the patients who survived and died in the swine flu group.       Table 10 revealed that the most common duration of illness before hospitalization was between 4 and 7 days in 11 (47.8%) cases, followed by a duration of more than 8 days in 10 (43.5%) cases.
There was a highly statistical difference in routine investigations such as potassium, sodium, magnesium, renal functions (urea/creatinine), liver functions (glutamic oxaloacetic transaminase/glutamic pyruvic transaminase), total protein, albumin, and hemoglobin, whereas there was no statistical difference in the total leukocyte count with regard to mortality, as shown in Table 4.
There was a highly statistical difference with regard to complicating pneumonia in relation to mortality, as shown in Table 5.
There was a highly statistical difference with regard to the need for mechanical ventilation and mortality, as shown in Table 6.

Avian flu cases
In this study, there were 23 PCR-confirmed avian flu cases. This study included four (17.4%) male and 19 (82.6%) female patients, as shown in Table 7. Of them, 14 (60.8%) patients were less than 30 years old, whereas nine (39.2%) were in the age group of 30-60 years, as shown in Table 8. ventilation and mortality. Causes of death were septicemia in nine (56.2%) cases and respiratory failure with acute respiratory distress syndrome in seven (43.8%) cases.

Swine flu
In the present study, we found that 170 (79.8%) patients recovered, whereas 43 (20.2%) patients died. This result agrees with that of Kumar et al. [6], who studied the pneumonia. Table 13 shows that there was a highly statistical difference with regard to the need for mechanical  HS, highly significant.        [10] who studied 63 critically ill patients in Brazil, with their age ranging from 13 to 65 years, and a mean of 35 years: 70% were below 40 years old and 30% were above 40 years old; 84% of the patients below 40 years recovered and 16% of the patients below 40 years died, with no agerelated difference in mortality. In contrast, this result disagrees with that of Rello et al. [7], who studied 32 critically ill patients in Spain, with their age ranging from 31 to 52 years and a mean of 40±13.9 years. The mortality was more common in young adults, and this difference may be because the age of the patients included in that study ranged from 31 to 52 years and also due to the smaller number of patients in this study.
Symptoms in the patients studied in the avian flu group. mechanically ventilated: two (5%) of them recovered, whereas 95% of them died, with a highly significant statistical relation between mechanical ventilation and mortality. This agrees with the study of Rello et al. [7] who studied 32 critically ill patients in Spain: eight (25%) of them were not ventilated, whereas 24 (75%) were ventilated. The number of recovered patients was 26: 78.5% of them were mechanically ventilated, and 21.5% of them were not. The number of deaths was six: 100% of them were mechanically ventilated, with mechanical ventilation-related mortality.
In contrast, this result disagrees with Duarte et al. [10] who studied 63 critically ill patients in Brazil: 71.4% of them were mechanically ventilated, whereas 28.6% were not. The number of recovered patients was 38: 20 (52.6%) patients were mechanically ventilated and 18 (47.4%) were not. The number of deaths was 25: 14 (53%) patients were mechanically ventilated, whereas 11 (47%) were not, with no mechanical ventilationrelated difference in mortality. The difference between the two studies may be due to the fact that 26 out of the 63 patients in the study of Duarte et al. [10] were RT-PCR negative.

Avian cases
In the present study, there was a female predominance Female predominance was also reported by Fasina et al. [12] in their study on 85 AI confirmed cases in Egypt, as they found that 62.3% (53/85) of the cases were female and 37.5% (32/85) were male patients.
In the current study, the mean age of the patients who survived was 30.75 years, and the mean age of the patients who died was 28.9 years (range 11-60 years): 91.2% of cases occurred among individuals under the age of 40 years.
Dudley et al. [13] in their study noted that the age group of 20-39 years was the predominantly affected group, which is in agreement with the results of this study. In addition, similar results were reported by Giriputro et al. [14] in their study on 27 AI confirmed case in Indonesia, they reported that AI in humans was predominately a disease of young age and adolescence, as the mean age was 16 years, and the oldest patient was 40 years old.
In the current study, fever and cough were the main complaints, 78.2% (18/23) each, followed Regarding the relation between mechanical ventilation and the final outcome, we found that 40 patients were with the study of Kandun et al. [18], who studied eight critically ill patients in Indonesia: four (50%) required mechanical ventilation, with a mortality of 100%; it also agrees with the study of Waleed et al. [16], who had 14/15 mechanically ventilated patients with a mortality of 85.7%.

Conclusion
The following conclusions were made from the present study: (1) The age and the sex of the patient did not affect the morality of swine flu. (2) Some comorbidities, such as DM, cardiac illness, and chronic chest illness, have no implication on mortality. However, renal conditions and the need for mechanical ventilation were associated with a high mortality rate in swine flu cases. (3) If swine flu is complicated with bilateral severe pneumonia that necessitates mechanical ventilation, the mortality rate will be high. (4) Influenza A (H5N1) is an infection characterized by fever, respiratory symptoms (shortness of breath, respiratory failure), abnormalities on chest radiograph, and a history of close contact with poultry. (5) Women in the age group of 20-39 years had the greatest tendency to be affected with avian flu. (6) Early hospitalization after infection will increase the chance of recovery. As result of the delay in reaching definitive care and administration of oseltamivir (Tamiflu), mortality will increase. (7) Although fever was the most common symptom, 6.9% of swine patients and 21.7% of avian patients in our study did not have fever. Tran et al. [15] in their study reported that the prominent clinical features on admission were those of severe influenza syndrome with fever, cough, diarrhea present in 70% (7/10) of the patients, which is in agreement of the results of this study. This result is also in agreement with Waleed et al. [16], who in his study reported that fever was the main complaint occurring in 93.3% (14/15)  In the present study, 47.8% of the patients had elevated liver enzymes (serum glutamic oxaloacetic transaminase, serum glutamic pyruvic transaminase) with a mortality of 90.1%, followed by leukopenia and elevated creatinine (39.1% each) with a mortality of 88.9 and 100%, respectively, hypokalemia with a mortality of 62.5%, elevated urea with a mortality of 100%, followed by leukocytosis (21.7%) with a mortality of 100%, hypocalcemia, hypoproteinemia, and hypoalbuminemia (17.4%) with a mortality of 50, 100, and 100%, respectively, followed by hypomagnesemia and anemia (4.3%) with a mortality of 0 and 100%, respectively. Waleed et al. [16] reported in their study that 73.3% of the patients had elevated aspartate aminotransferase (53.3%) and elevated alanine aminotransferase. Chotpitayasunondh et al. [17] reported in their study that 58% of the patients had leukopenia and 33% of the patients had elevated serum creatinine (>1.5 mg/dl).