Hospital nurse staffing and surgical outcomes of cardiovascular patients

Abstract

Background:The association between mortality, along with complication rates, and nurse staffing has been previously reported in many countries and studies. However, nurse staffing has not yet been maintained at an optimal staffing level. To improve the nurse staffing level, many policies have been introduced, including “The Graded Fee of Nursing Management for Inpatient System,” but most policies were focused on quantitative aspects. Few studies have considered the relationship between nurse staffing and the rates of mortality and complications in Korea using secondary data, which represent Korean hospitals. Therefore, this study aims to investigate the relationship between nurse staffing and cardiovascular surgery patients’ mortality and complication rates.Methods:This study used the 2010 and 2011 ‘Patient Survey’ dataset. The total population, which had undergone cardiovascular surgery, was 9,131 patients. Among the total population, 4,823 patients were in tertiary hospitals and 4,308 patients were in general hospitals. Among the 212 hospitals, 44 were tertiary hospitals and 168 were general hospitals. A linear mixed-effects model with a random intercept for multilevel data including patient and hospital was used to find the relationship between the level of nurse staffing and the mortality and complication rates. This study adjusted for independent variables at both the patient and hospital levels. At the patient level, age, sex, Charlson comorbidity index, type of admission, admission method, type of insurance, year, and length of stay were included. The type of hospital, ownership, region, teaching, number of beds, number of doctors per 100 beds, number of nurse aids per 100 beds were included at the hospital level.Results:In the linear mixed model, as the number of registered nurses per 100 beds increased, the mortality rate (%) at discharge decreased by 0.02% (P=0.04) in total and by 0.04% (P=0.02) in the general hospitals. However, there was no significant result in the tertiary hospitals. For the complication rate, as the number of registered nurses per 100 beds increased, the complication rate (%) decreased by 0.03% (P<0.0001) in total, by 0.02% (P=0.02) in the tertiary hospitals, and by 0.06% (P<0.0001) in the general hospitals.Conclusions:The proper level of nurse staffing should keep in mind the effects on the mortality and complication rates in the cardiovascular surgery population. Also, the different effects of the hospital type and the severity of patient disease should be considered at the same time when increasing nurse staffing.