October 9, 2008
Printer-friendly Version
(PDF)
A mounting volume of evidence clearly demonstrates the strong relationship between
RN staffing and patient outcomes of care—particularly in reducing complications
and death:
- As early as 1988, researchers found associations between nurse staffing and development
of hospital-acquired infections. (Flood & Diers 1988).
- In "one of the clearest demonstrations to date of the impact of nursing staffing
on outcomes for both patients and nurses in acute care hospitals," (Clarke & Aiken
2003), a study in the Journal of the American Medical Association, analyzed data
from 168 Pennsylvania hospitals. After adjusting for patient and hospital characteristics,
each additional patient beyond four per nurse resulted in a 7% greater likelihood
of dying within 30 days of admission and a 7% increase in the likelihood of failure
to rescue. (Aiken, Clarke, Sloane, Sochalski & Silber, 2001).
- In a study published in the New England Journal of Medicine, data from 799 hospitals
in 11 states, including 5,075,969 medical discharges and 1,104,659 surgical discharges
revealed that among medical patients, a higher proportion of hours of nursing care
per day provided by RNs and a greater total number of hours of nursing care per
day provided by RNs were associated with a shorter length of stay, lower rates of
urinary tract infections and upper gastrointestinal bleeding. A higher proportion
of hours of care provided by RNs was also associated with lower rates of pneumonia,
shock or cardiac arrest and failure to rescue. Among surgical patients, a higher
proportion of nursing care provided by RNs was associated with lower rates of urinary
tract infections. A greater number of RN hours of care per day was associated with
lower rates of failure to rescue. The authors summarize their findings, in part,
by noting their estimate that patients treated in whose staffing placed them in
the upper quarter of hospitals studied)have lengths of stay 3-5% shorter and rates
of complication 2-9% lower than those with RN staffing in the lower quarter of hospitals
in the study. (Needleman, Buerhaus, Mattke, Stewart & Zelevinsky, 2002a, 2002b).
- A study of 1609 hospital reports of sentinel events (unanticipated events that result
in death, injury or permanent loss of function), found that 24% of such events were
attributed to nurse staffing levels (Joint Commission on Accreditation of Healthcare
Organizations, 2002).
- Discharge data from 589 acute-care hospitals in 10 states, finding a large and significant
inverse relationship between full-time equivalent RNs per adjusted inpatient day
(RNAPD) and two post-surgical complications—urinary tract infections and pneumonia.
(Kovner & Green, 1988).
- Data from 42 units in a large university hospital found that a higher proportion
of RN hours of care was associated with hospital unit rates of medication errors,
pressure ulcers and patient complaints. Total nursing hours of care were associated
with lower rates of pressure ulcers, patient complaints and mortality. (Blegen,
Goode & Reed, 1998).
- A study of 3763 U.S. hospitals found a decrease in mortality rates as staffing increased
for registered nurses (Bond, Raehl, Petterle & Franke 1999).
- Hospital data from New York and California showed significant relationships between
RNs per adjusted patient days and incidence of urinary tract infections, pneumonia,
pressure ulcers and a weaker but significant relationship to thrombosis and pulmonary
complications. (Lichtig, Knauf & Milholland, 1999)
- A study of 28 university hospitals that had undergone restructuring found an increase
in the rate of patient falls as patient-to-nurse ratios increased. (Sovie and Jawad,
2001).
- Patients undergoing abdominal aortic surgery who were cared for in ICUs with nurse:patient
ratios of 1:3 or more averaged 49% greater lengths of stay in the ICU.. (Pronovost,
Jenckes, Dorman, Garrett, Breslow, Rosenfeld, et al.1999).
- Data for 118,940 patients hospitalized with acute myocardial infarction showed lower
likelihood of in-hospital mortality for patients treated in hospitals with higher
RN staffing levels. (Person, Allison, Kiefe, Weaver, Williams, Centor, et al., 2004).
- Data from hospitals in states participating in the National Inpatient Sample (NIS)
maintained by the federal Agency for Healthcare Research and Quality showed that
higher levels of nurse staffing were associated with lower rates of pneumonia. (Kovner,
Jones, Zhan, Gergen & Basu (2002).
- An increase of 1 hour of RN care per patient day in California hospitals was associated
with an 8.9% decrease in the odds of pneumonia. A 10% increase in proportion of
RNs was associated with a 9.5% decrease in the odds of pneumonia. (Cho, Ketefian,
Barkauskas & Smith 2003).
- Rates of bloodstream infections related to central venous catheter use in eight
intensive care units were significantly associated with the use of “float” nurses
(Alonso-Echanove, Edwards, Richards, Brennan, Venezia, Keen, et al., 2003).
- Data from 1751 units in hospitals participating in the National Database of Nursing
Quality Indicators found that higher rates of patient falls were associated both
with fewer nursing hours per patient day and a lower percentage of RNs. (Dunton,
Gajewski, Taunton & Moore, 2004).
- In a study of 19 teaching hospitals in Ontario, Canada, a lower proportion of RNs
employed on a hospital nursing unit was associated with higher numbers of medication
errors and wound infections. (McGillis Hall, Doran & Pink 2004).
- A nurse-patient ratio of 1:2 was associated with a higher incidence of unplanned
extubation relative to a nurse-to-patient ratio of 1:1. (Marcin, Rutan, Rapetti,
Brown, Rahnamayi & Pretzlaff).
- Analyzing data from two large hospital studies compared nurse staffing levels ranging
from four to eight patients per nurse, mortality among medical and surgical patients
decreased as staffing increased. (Rothberg, Abraham, Lindenauer & Rose, 2005).
Nurse staffing decisions need to be based on the wide range of factors that have
an impact on patient outcomes, including overall numbers and proportions of RNs:
- Other important factors that have been examined include level of education (Aiken,
Clarke, Cheung, Sloane & Silber, 2003; Estabrooks, Midodzi, Cummings, Ricker & Giovanetti,
2005) and experience level (Tourangeau, Giovanetti, Tu & Wood, 2002; Blegen, Vaughn
& Goode 2001).
- Additional research has pointed to the association between the use of “float” nurses
(nurses assigned to units outside of their usual specialty areas) and greater incidence
of bloodstream infections among intensive care unit (ICU) patients with central
venous catheters (Alonso-Echanove, Edwards, Richards, Brennan, Venezia, Keen, et
al., 2003).
- An analysis of outcomes data for 18,142 patients discharged from 49 acute care hospitals
in Alberta, Canada, found an association between higher proportion of casual or
temporary (such as agency) nurses and 30-day mortality rates (Estabrooks, Midodzi,
Cummings, Ricker & Giovanetti, 2005).
Enhancing nurse staffing does not pose a significant cost for hospitals and in fact
may result in cost savings:
- Lichtig, Knauf & Milholland (1999) suggested that by decreasing adverse outcomes
(particularly those that are likely to result in increased length of stay), increased
RN staffing could result in modestly decreased hospital costs.
- Earlier, Flood & Diers (1988) had similarly suggested an association between staffing
levels and lower hospital costs resulting from decreased rates of nosocomial infections.
- Most recently, Needleman and his colleagues (2006) examined the data used in their
2002 study (discussed earlier) in order to determine the impact on hospital costs
of different adjustments in nurse staffing. Under different potential staffing scenarios,
they found that increasing overall hours of nursing care (irrespective of overall
skill mix) would lead to a significant reduction in length of stay, patient deaths
and other adverse outcomes, at net increase of hospital costs of 1.5% percent or
less. Increasing RN hours as a proportion of nursing hours without increasing overall
nursing hours (i.e., increasing skill mix while holding nurse staffing hours steady)
was associated with a small net reduction in costs.
- A study of patient mortality and length of stay data from two large hospital studies
compared staffing ratios ranging from 8:1 to 4:1 and noted the cost-effectiveness
of increased nurse staffing (Rothberg, Abraham, Lindenauer & Rose, 2005).
