The effect of staff nursing on length of stay and mortality

OBJECTIVES. Specialized hospital units developed historically for the effic iency of physicians, but their existence has created an opportunity for sta ff nurses to specialize as well. This study was done to test the hypothesis that specialized staff nursing has an effect on patient outcome as length of stay (LOS) and mortality, using casemix information and controlling for physician volume. METHODS. Sixteen Diagnosis Related Groups associated with particular specia lty units in Yale New Haven Hospital were selected. Five years of data (FY 1987-FY 1993) from a period in which specialized unit configuration was rel atively stable were obtained (N = 11,316). Data elements included basic pat ient characteristics, especially diagnosis and procedure codes, physician i dentifiers as scrambled code numbers, length of stay, length of intensive c are unit stay, and discharge disposition. Specialized nursing units were de fined by the percentage of patients in a given diagnosis related group disc harged from that unit. Patient age and differential intensive care unit use were used for risk adjustment. RESULTS. In 13 of the 16 diagnosis related groups, patients cared for on sp ecialized nursing units had shorter lengths of stay; the difference was sta tistically significant in nine. In the seven Diagnosis Related Groups with any deaths, the mortality on the specialized unit(s) was lower; the differe nce was statistically significant in four. Physician volume, defined as mor e or fewer than 20 discharges per diagnosis related group had little or no effect on either length of stay or mortality. CONCLUSIONS. The notion that nurses improve at caring for similar patients of a stable group of physicians as their experience increases has common se nse appeal. If the findings of this study can be replicated in other instit utions, with the refinements suggested here, it may be possible to separate the effects of multidisciplinary practice on outcomes and to track the eff ect of hospital reeingineering projects that change patient mix or nursing specialization. Studying one hospital in depth suggested that interhospital studies of cost and quality may need to consider nursing specialization al ong with other comparisons.