Study Design: The study uses 4 years of electronic data obtained from hospital records that include the Nursing Interventions Classification (NIC) to document nursing treatments. This is part of a larger study funded by NINR and AHRQ that is one of the first to conduct nursing outcomes effectiveness research using existing clinical and operational data that reside in several electronic data repositories in a large academic medical center. The sample consisted of 11, 756 hospitalizations from 8,988 patients aged 60 or older admitted for acute care services (7/1/98-6/30/02) in one tertiary care facility who had received the NIC intervention of Fall Prevention or were at risk of falling. Data were analyzed using generalized estimation equation models.

Principal Findings: Chief predictors of cost of hospitalization were 1) medical, pharmacy, and nursing interventions, 2) nursing unit variables (nurse staffing, number of units where the patient resided), and 3) severity of illness. Surprisingly few clinical conditions and no demographic data were related to cost. Most variables related to cost were interventions (medical, pharmacy, and nursing); some were related to increased cost while others were associated with decreased cost. Use of nursing interventions, on average, were less costly that use of medical or pharmacy interventions. For each additional intervention, median cost rose, on average $750.00 for each medical intervention; $183 for each medication; and $159.00 for each nursing intervention.

Conclusions: The model explained 86% of the variance in cost. The majority of variance was related to interventions (nursing, medical and pharmacy).

Implications: Nurses need to work with those in information systems to implement standardized nursing language and to print reports that demonstrate intervention use for their patients.