Interrelationships among mortality rates, drug costs, total cost of care, and length of stay in United States hospitals: summary and recommendations for clinical pharmacy services and staffing

Abstract

We evaluated interrelationships and associations among mortality rates, drug costs, total cost of care, and length of stay in United States hospitals. Relationships between these variables and the presence of clinical pharmacy services and pharmacy staffing also were explored. A database was constructed from the 1992 American Hospital Association's Abridged Guide to the Health Care Field, the 1992 National Clinical Pharmacy Services database, and 1992 Health Care Finance Administration mortality data. A severity of illness-adjusted multiple regression analysis was employed to determine relationships and associations. Study populations ranged from 934-1029 hospitals (all hospitals for which variables could be matched). The only pharmacy variable associated with positive outcomes with all four health care outcome measures was the number of clinical pharmacists/occupied bed. That figure tended to have the greatest association (slope) with reductions in mortality rate, drug costs, and length of stay. As clinical pharmacist staffing levels increased from the tenth percentile (0.34/100 occupied beds) to the ninetieth percentile (3.23/100 occupied beds), hospital deaths declined from 113/1000 to 64/1000 admissions (43% decline). This resulted in a reduction of 395 deaths/hospital/year when clinical pharmacist staffing went from the tenth to the ninetieth percentile. This translated into a reduction of 1.09 deaths/day/hospital having clinical pharmacy staffing between these staffing levels, or 320 dollars of pharmacist salary cost/death averted. Three hospital pharmacy variables were associated with reduced length of stay in 1024 hospitals: drug protocol management (slope -1.30, p=0.008), pharmacist participation on medical rounds (slope -1.71, p<0.001), and number of clinical pharmacists/occupied bed (slope -26.59, p<0.001). As drug costs/occupied bed/year increased, severity of illness-adjusted mortality rates decreased (slope -38609852, R(2) 8.2%, p<0.0001). As the total cost of care/occupied bed/year increased, those same mortality rates decreased (slope -5846720642, R(2) 14.9%, p<0.0001). Seventeen clinical pharmacy services were associated with improvements in the four variables.