# Presentation: 677612

## Burden estimates to support prioritization of public health problems

**Notes:**
CDC developed this publication to present national estimates of healthcare-associated infections and to discuss the challenges and opportunities for improving national public health surveillance of healthcare-associated infections.

## Challenges to National Estimates of Healthcare-Associated Infections in U.S. Hospitals

- No single source of representative data available to estimate burden in the United States
- In 2002, available data were
- National Nosocomial Infections Surveillance System
- American Hospital Association Survey
- National Hospital Discharge Survey

**Notes:**
The main challenge to deriving estimates is that no single source of representative data is available to estimate the burden of healthcare-associated infections in the United States.  For the estimates in 2002, we used available data from the National Nosocomial Infections Surveillance System, the American Hospital Association Survey, and the National Hospital Discharge Survey.

## Calculation of estimates of healthcare-associated infections in U.S. hospitals among adults and children outside of intensive care units, 2002

- HRN = high risk newbornsWBN -= well-baby nurseriesICU = intensive care unitSSI = surgical site infectionsBSI – bloodstream infectionsUTI = urinary infectionsPNEU = pneumonia

- Klevens, Edwards, Richards, et al. *Pub Health Rep* 2007;122:160-6

**Notes:**
The greatest challenge was to estimate the number of infections outside of intensive care units. We chose the surgical site for our calculations because the number of surgical procedures is available for the U.S. population in the NHDS.  We multiplied the number of surgical procedures in the National Hospital Discharge Survey by the surgical site infection rate from NNIS 2002 surveillance.  From this estimate, we subtracted surgical site infections among newborns and among adults and children in intensive care units, which yielded the total number of such infections among hospitalized adults and children outside of intensive care units, i.e., 244,385, shown here in the blue circle.  Surgical site infections accounted for 20% of all healthcare-associated infections in NNIS hospital-wide surveillance; thus, we used that percentage to estimate the number of infections for other body sites.

## Rates of Healthcare-Associated Infections in Newborns, Adults, and Children by Site of Infection, National Nosocomial Infections Surveillance (NNIS) System

**	****	*****Well-baby nursery*****a****	*****High-risk nursery*****b****	*****Intensive care unit*****b****	****	****	****	*****(adults and children)*****Patient-days****c**	7,436,520	4,835,702	30,236,811**Major site of infection****	****	*****Rate of infection per 1,000 patient-days***	**Urinary tract**	0.19	0.5	  3.38	**Bloodstream**	0.76	  3.06	  2.71	**Pneumonia**	0.24	  0.91	  3.33	**Surgical site**	  0.003	0.2	  0.95	**Other**	1.37	  2.21	  2.67	**Total**	2.56	  6.88	13.04aFrom NNIS hospital-wide surveillance, 1990-1995bFrom NNIS surveillance 2002, high-risk nursery and ICU componentcFrom the National Hospital Discharge Survey (NHDS) for the U.S. population in non-federal hospitals

**Notes:**
These results show the rates of healthcare-associated infections per 1,000 patient-days and the number of patient-days for 3 subpopulations: newborns in well-baby nurseries, newborns in high-risk units, and adults and children in intensive care units. The rates of infections are listed by body site for the 3 subpopulation. Of these groups, adults and children in intensive care units contributed the greatest number of patient-days and had the greatest risk of healthcare-associated infection. 

## Estimated Number of Healthcare-Associated Infections in U.S. Hospitals by Subpopulation and Major Site of Infection, United States,  2002

**	****	****	****	*****Outside of******	******	******	******Intensive care******	******intensive care******Major site******	******Well-baby******	******High-risk******	******unit (adults******	******units (adults******	******Unadjusted******	******Adjusted******of infection******	******nursery******	******nursery******	******and children)******	******and children)*****a****	*****total******	******total*****b****	*****Percentage*****Urinary tract**	  1,413	  2,418	102,200	   424,060	   530,091	   561,667	  32**Bloodstream**	  5,652	14,797	  81,942	   133,368	   235,759	   248,678	  14**Pneumonia**	  1,785	  4,400	100,689	   129,519	   236,393	   250,205	  15**Surgical site**	       21	     967	  28,725	   244,385	   274,098	   290,485	  22**Other**	10,188	10,687	  80,732	   263,810	   365,417	   386,090	  17**Total**	19,059	33,269	394,288	1,195,142	1,641,758	1,737,125	100aSee proportions applied from description in Figure.bAdjusted for inclusion of federal hospitals by multiplying non-newborn values by 1.06

- Klevens, Edwards, Richards, et al. *Pub Health Rep* 2007;122:160-6

**Notes:**
This result combines the 4 subpopulations and lists the number of healthcare-associated infections by body site. After adjusting the total for inclusion of federal facilities, a total of 1,737,125 healthcare-associated infections in hospitals in the United States was estimated (shown here in the gray box).

## Burden of Healthcare-Associated Infections in the United States, 2002

- 1.7 million infections in hospitals
- Most (1.3 million) were outside of ICUs
- 9.3 infections per 1,000 patient-days
- 4.5 per 100 admissions
- 99,000 deaths associated with infections
- 36,000 – pneumonia
- 31,000 – bloodstream infections

- Klevens, Edwards, Richards, et al. *Pub Health Rep* 2007;122:160-6

**Notes:**
To summarize results of CDC’s findings, about 1.7 million healthcare-associated infections occurred in U.S. hospitals.  Of these, most (1.3 million) were outside of intensive care units.  These numbers can also be presented as 9.3 infections per 1,000 patient-days, or 4.5 per 100 admissions. There were an estimated 99,000 deaths associated with these infections.  The body sites associated with the greatest number of deaths were the estimated 36,000 deaths from pneumonia, and 31,000 from bloodstream infections.