The association between nurse staffing levels and a failure to respond to patients with deranged physiology: a retrospective observational study in the UK

Background Responding to abnormalities in patients’ vital signs is a fundamental aspect of nursing. However, failure to respond to patient deterioration is common and often leads to adverse patient outcomes. This study aimed to determine the association between Registered Nurse (RN) and Nursing Assistant (NA) staffing levels and the failure to respond promptly to patients’ abnormal physiology. Methods This retrospective, observational study used routinely collected patients’ vital signs and administrative data, including nursing staffing, from 32 general wards of an acute hospital in England between April 2012 and March 2015. Mixed-effects binomial regression was used to model the relationship between nurse staffing, measured as ‘Hours per Patient Day’ (HPPD), and a composite primary outcome representing failure to respond for patients with National Early Warning Score (NEWS) values > 6 and > 7. Results There were 189,123 NEWS values ≥ 6 and 114,504 NEWS values > 7, affecting 28,098 patients. For patients with NEWS values > 7, failure to respond was significantly associated with levels of RN HPPD ((IRR 0.98, 95% CI 0.96–0.99, p = 0.0001) but not NA HPPD (((IRR 0.99, 95%CI 0.96–1.01, p = 0.238). For patients with NEWS values > 6, no such relationship existed. Conclusions RN, but not NA, staffing levels influence the rates of failure to respond for patients with the most abnormal vital signs (NEWS values > 7). These findings offer a possible explanation for the increasingly reported association between low RN staffing and an increased risk of patient death during a hospital admission.</p