This study, published in the journal, Health Services Research,  shows an association–two or more things happening at the same time— not cause.

That is an important difference, one often lost in the headlines.

That said, this is an interesting study about the association found by a nurse researcher between nurse staff ratios and patient survival rates.

California has a state law which sets minimum nurse staffing levels per shift. When the researcher compared California’s staffing levels with New Jersey and Pennsylvania, the data point to an opportunity to prevent deaths if the standard set in California were used in other states.

Why would one not accept these findings as showing causality?

• California patients could be different than those in other parts of the country.
• There is an early adopter effect which could be influencing care. The first clinicians to use or try a new approach tend to be especially enthusiastic and diligent.
• There could be important differences among the hospitals’ care delivery system, which are not part of the study data.

Good nurses work harder than almost anyone. The idea that proper nurse: patient ratios is important is obvious. Hospital patients count on nurses all day, every day, when they are in the hospital. Doctors come and go.

However, the means of arriving at that balanced ratio is complicated by a variety of factors— which may be hospital-specific or patient population-specific.

Unfortunately, setting these ratios is not as easy as it may sound.

The New York Times

“A state law in California requires to maintain certain minimal levels of nurses on duty. Now a study suggests that the requirement may be saving lives.

“The study, published online last month by the journal Health Services Research, compares the outcomes of 1.1 million general surgery patients in 2005-6 in more than 800 hospitals in three states — California, where nurses in medical-surgical units are limited to five patients at a time; and New Jersey and Pennsylvania, where nurses’ patient loads averaged more than six. (Emphasis added)

“Researchers concluded that 225 hospital deaths in New Jersey, or 13.9 percent of all deaths in general surgery, and 200 deaths in Pennsylvania, or 10.6 percent, could have been averted with rules similar to California’s.

“The lead author, Linda H. Aiken, a registered nurse, acknowledged that the analysis did not prove that the California rules improved patients’ outcomes. But she said it was the most likely explanation.”

Source: New York Times, May 10, 2010