On the basis of clinical experience, most nurses assume that patients consume differential amounts of nursing resources by their length of stay (LOS) day in the hospital. This study examined patients' use of nursing resources for clinically paired Diagnostic Related Groups (DRGs) using two approaches. First, nursing resources were aggregated and examined for the entire hospital stay. Second, nursing resources were disaggregated into daily patterns of nursing resource use for cohorts of patients with equal lengths of stay.

This study used extant hospital utilization data from a single acute-care community hospital. The study DRGs were selected as clinically similar pairs that were differentiated by co-morbidity, complications, or a more involved disease process. Nine of the 10 study DRGs were identified from a list of the top 25 high frequency admissions for the study institution.

Common demographic and hospital resource utilization data were retrieved, including a severity of illness measure using MedisGroups. Measures of nursing resource use were derived from the Medicus Acuity Patient Classification System. Nursing resources measures were patient specific, by hospital day and nursing unit. Nursing resources were quantified as nursing acuity days and nursing hours; the latter was based on actual productivity, not budgeted hours.

The findings indicated that DRGs characterized by co-morbidity, complications, or a more involved disease process used greater amounts of mean total nursing care hours and a greater percentage of relatively high nursing acuity days than their clinical DRG counterparts. Additional findings were that for these study DRGs, the relevant measure for intensive care resource use was days of intensive care and not the number of admissions or the mean LOS.

In this study, surprisingly, for almost any LOS within a DRG, there were very few differences in mean daily nursing care hours by hospital day. Further, when cohorts of patients with identical LOS between clinical DRGs were matched and examined, very few differences were found in mean daily nursing care hours. The implications from these findings are that DRGs tend to be homogeneous within themselves for mean daily nursing care hours by hospital day and that other interpretations should be approached cautiously.