Passage of a bill in 1999 requiring minimum nurse-to-patient ratios in California hospitals increased the number of nurses but resulted in mixed quality of care, according to a new study in the journal Health Services Research.
"This was a wonderful opportunity to examine whether minimum staffing levels made any real difference in a variety of different outcomes that are of interest not only to researchers, but to health professionals, policy makers and the public," said lead author Barbara A. Mark, Ph.D., R.N, at the University of North Carolina School of Nursing.
Mark's research team studied changes in California hospitals' staffing from 2000 to 2006 and compared those changes to staffing changes in hospitals in states with no staffing ratio mandate.
"Ultimately, as we would have expected, those hospitals that had the largest staffing shortfalls increased staffing the most, and we were surprised that even hospitals that probably didn't have shortfalls also increased staffing—although not nearly as much," said Mark. "However, hospitals with the greatest shortfalls also relied more on licensed vocational nurses to meet the ratios than other hospitals did." Licensed practical or vocational nurses care for patients under the direction of a registered nurse or physician.
The researchers also found that staffing increases were associated with a decrease in the number of patients who died following a complication, known as "failure to rescue." This decrease was most apparent in those hospitals that had the largest staffing increase and those hospitals that were well-staffed when the legislation was implemented, she said.
Surprisingly, they also found that some rates of infections due to medical care such as those related to intravenous lines and catheters , increased more in California than in hospitals without nurse staffing regulations. The authors suspect that the staffing increases may have led to both better discovery and reporting of hospital acquired infections.
"A substantial body of existing research shows that nurse staffing matters in keeping care safe and delivering care reliably," said Jack Needleman, Ph.D., professor of health services and associate director of the UCLA Patient Safety Institute.
"The paper shows a trend toward growth in staffing has occurred across the country in hospitals with low levels of staffing, but the California legislation appears to have encouraged substantially greater growth. The impact on quality is less clear from this paper and I think reflects the fact that many factors influence quality. For example, when hospitals go about increasing staffing, particularly when they are required to by legislation, we don't know what changes they make in other operations that may decrease safety and reliability of care."
Mark agrees that more research is needed. "What we as researchers still don't know, and what this study doesn't answer is what is the best, most effective nurse-to-patient ratio and what factors play into determining that ratio?" she said. "Obviously, patients that are more or less sick need more or less time from nurses."
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Mark, B.A., et al. (2012) California's Minimum Nurse Staffing Legislation:Results from a Natural Experiment, Health Services Research, In Press.