| Cho et al. (2003) [16] can’t tell Moderate USA | Examine the effects of nurse staffing on adverse events, morbidity, mortality and medical costs | Existing databases from 232 acute care hospitals and 124,204 patients in 20 surgical diagnosis-related groups. 857 patients with hemorrhagic and ischemic stroke who were admitted to ICUs of 185 Korean hospitals | An increase of one hour worked by registered nurses per patient per day was associated with an 8.9% decrease in the odds of pneumonia. Hospitals with higher ICU staffing were more likely to fully provide basic care. Better staffing were associated with lower in-hospital and 30-day mortality. 30-day mortality had a more distinct decrease with lower staffing rates | Direct consequence: Patient harm |
| Cho & Yun (2009) [34] Cross-sectional design including a survey Moderate Korea | To examine differences in provision of basic nursing care and in-hospital and 30-day mortality by nurse staffing of ICUs and general wards among acute stroke patients | ICUs of 185 Korean hospitals | Better staffing was associated with lower in-hospital and 30-day mortality. 30-day mortality had a more distinct decrease with lower staffing rates. | Direct consequences: Mortality |
| Cimotti et al. (2006) [35] Prospective cohort study Strong Canada | To examine the association between registered nurse staffing and healthcare associated bloodstream infections in infants in neonatal intensive care units. | 2675 infants admitted to the NICUs for more than 48 hours and all registered nurse who worked in the same NICUs during the study | A greater number of hours of care provided by RNs in NICU 2 were associated with decreased risk of bloodstream infections. Number of hours of care provided by RNs in NICU 1 was not associated with bloodstream infections. | Direct consequences: Patient harm |
| de Cordova et al. (2014) [37] Longitudinal study Moderate USA | Examine the association between night nurse staffing and work force characteristics and length of stay (LOS) | Monthly observations of administrative data from 138 acute care hospitals (N = 8243) | Higher night staffing and higher skill mix were associated with reduced LOS | Direct consequences: Patient harm |
| Daud-Gallotti et al. (2012) [36] Prospective cohort study Strong Brazil | Evaluate the role of nursing workload in the occurrence of HAI in medical intensive care units. | 195 ICU-Patients | 22% developed HAI (healthcare-associated infection). Average NAS (Nursing activity score) and average proportion of non-compliance with NPC (Non-compliance to the nurse’s patient-care plans) were significantly higher in HAI patients. Only excessive nursing workload and severity of the patient’s clinical condition remained as risk factors to HAI. | Direct consequences: Patient harm |
| Duffield et al. (2011) [17] Longitudinal, Retrospective study combined with a cross-sectional study Moderate Australia | Examine the relationship of nurse staffing and workload, in the context of the work environment, to patient outcomes. | Data from the public hospital system. Five years of data for 80 public hospitals | Increased RN staff were associated with significantly decreased rates of pressure ulcer, pneumonia, and sepsis, GI bleeding, physiological/metabolic derangement, pulmonary failure, sepsis and shock. There were several nursing-tasks left undone or postponed as a consequence of heavy workload. | Direct and indirect consequences: Poor basic care quality and patient harm |