Pneumonia is a common illness in all parts of the world. It is a major cause of death among all age groups. Mortality from pneumonia generally decreases with age until late adulthood. Elderly individuals, however, are at particular risk for pneumonia and associated mortality. More cases of pneumonia occur during the winter months than during other times of the year. Pneumonia occurs more commonly in males than females, and more often in African Americans than caucasians. People who are hospitalized for any reason are also at high risk for pneumonia. Following urinary tract infections, pneumonia is the second most common cause of nosocomial infections, and its prevalence is 15-20% of the total number.
Epidemiology and Demographics
Table 1. Incidence of pneumococcal infections in the United States.
Invasive Pneumococcal Disease Incidence by Age Group, 1998 and 2008. Obtained from CDC [1]
United States of America
It is the seventh most common cause of death in the United States
It causes around 500,000 hospitalizations and 65,000 deaths annually.
International
It is a common illness in all parts of the world, but countries like India, China, Pakistan, Bangladesh, Indonesia and Nigeria have high rates of childhood pneumonia.[2]
Age
The incidence is higher in children and elderly.
In children, the majority of deaths occur in the newborn period, with over two million worldwide deaths a year.
In fact, the WHO estimates that one in three newborn infant deaths are due to pneumonia.
Mortality decreases with age until late adulthood; elderly individuals are particularly at risk for CAP and associated mortality.
Seasonal
More common during winter months than during other times of the year.
Gender
CAP occurs more commonly in males than females
Race
More common in African Americans than caucasians.
Mortality
Patients hospitalized with pneumonia have a mortality rate of 12-14%.
Percentage of adults aged 65 and over who had ever received a pneumococcal vaccination: United States, 1997–2012 Graph obtained from CDC [4]
As many as 400,000 hospitalizations from pneumococcal pneumonia are estimated to occur annually in the United States. Pneumococci accounts for about 30% of adult community-acquired pneumonia. [5]
In 2012, 59.9% of adults 65 years and older received a pneumococcal vaccination.[6]
In 2010, the number of discharges for patient admitted with pneumonia in hospitals in the US was 1.1 million patients. The average length of stay for pneumonia patients admitted to hospitals was 5.2 days.[6]
An increasing rate of CAP is seen with age. Approximately 5 to 6 cases of pneumonia per 1000 persons are observed among adults. A pronounced seasonal effect on the number of patients presenting to the emergency department is also noted. During the winter months, there is an approximately 50% rise in the number of cases compared to the summer months.[7]
About 3.5 million deaths yearly have been attributed to lower respiratory tract infections (LRTI). LTRIs are the third most common cause of overall death and the leading cause of death from infectious diseases worldwide.[9]
Pneumonia is the ninth leading cause of death in the United States.
The number of deaths in the US in 2011 attributed to pneumonia was 52,294. [6]
Pneumonia mortality rate was 16.8 deaths per 100,000 in the US in 2011. [6]
A higher mortality rate is seen in invasive diseases, nursing home patients and severe bacteremia.
More than 40 % mortality rate is seen in ICU admitted patients.
The percentage of hospital inpatient deaths from pneumonia in the US 2006 was 3.4%. [10]
Age
Individuals older than 85 years of age are at a particularly high risk of developing CAP that can reach an annual rate of 5-10%.[11]
Individuals younger than 3 years and older than 65 years of age are more likely to be hospitalized with severe symptoms and complications.
Gender
The risk of CAP is similar in males and females.
Incidence of Community–Acquired Pneumonia in 2010 in Children 0–4 Years of Age in 192 Countries[12]
▸ Click on the following regions to expand the data.
Pneumonia has accounted for approximately 20% of all hospital-associated infections and 27% and 24% of all infections acquired in the medical intensive-care unit (ICU) and coronary care unit, respectively. [13]
Incidence
The incidence of HAP is 5-15 cases per 1 000 hospital admissions. [14]
The incidence of VAP is 6 to 20 times more than in patients without mechanical support.
Age
Females
Males
18-44 years
5%
4%
45-64 years
14%
13%
≥ 65 years
34%
30%
Total
53%
47%
Table adapted from 2009–2011 National Medicare Patient Safety Monitoring System [15]
Mortality
HAP and VAP are nosocomial infections with a high mortality in contrast with other nosocomial infections.
This higher mortality rate is associated with MDR pathogens.
Age
HAP is more commonly reported in patients > 65 years, probably due to the fact that this age population is more commonly hospitalized.
Gender
There is no predominance in gender, although some data reports a higher incidence among females.
Ventilator-associated Pneumonia
VAP occurs in up to 25% of all people who require mechanical ventilation.
VAP can develop at any time during ventilation, but occurs more often in the first few days after intubation.
This is because the intubation process itself contributes to the development of VAP.
VAP occurring early after intubation typically involves fewer resistant organisms and is thus associated with a more favorable outcome.
Because respiratory failure requiring mechanical ventilation is itself associated with a high mortality, determination of the exact contribution of VAP to mortality has been difficult.
As of 2006, estimates range from 33% to 50% death in patients who develop VAP.
Mortality is more likely when VAP is associated with certain microorganisms (Pseudomonas, Acinetobacter), blood stream infections, and ineffective initial antibiotics.
↑Magill, Shelley S.; Edwards, Jonathan R.; Bamberg, Wendy; Beldavs, Zintars G.; Dumyati, Ghinwa; Kainer, Marion A.; Lynfield, Ruth; Maloney, Meghan; McAllister-Hollod, Laura; Nadle, Joelle; Ray, Susan M.; Thompson, Deborah L.; Wilson, Lucy E.; Fridkin, Scott K. (2014). "Multistate Point-Prevalence Survey of Health Care–Associated Infections". New England Journal of Medicine. 370 (13): 1198–1208. doi:10.1056/NEJMoa1306801. ISSN0028-4793.
↑"Guidelines for the Management of Adults with Hospital-acquired, Ventilator-associated, and Healthcare-associated Pneumonia". American Journal of Respiratory and Critical Care Medicine. 171 (4): 388–416. 2005. doi:10.1164/rccm.200405-644ST. ISSN1073-449X.
↑Eckenrode, Sheila; Bakullari, Anila; Metersky, Mark L.; Wang, Yun; Pandolfi, Michelle M.; Galusha, Deron; Jaser, Lisa; Eldridge, Noel (2014). "The Association between Age, Sex, and Hospital-Acquired Infection Rates: Results from the 2009–2011 National Medicare Patient Safety Monitoring System". Infection Control and Hospital Epidemiology. 35 (S3): S3–S9. doi:10.1086/677831. ISSN0899-823X.
