Nonlinear association of nurse staffing and readmissions uncovered in machine learning analysis.

OBJECTIVE: Several studies of nurse staffing and patient outcomes found a curvilinear or U-shaped relationship, with benefits from additional nurse staffing diminishing or reversing at high staffing levels. This study examined potential diminishing returns to nurse staffing and the existence of a "tipping point" or the level of staffing after which higher nurse staffing no longer improves and may worsen readmissions. DATA SOURCES/STUDY SETTING: The Readiness Evaluation And Discharge Interventions (READI) study database of over 130,000 adult (18+) inpatient discharges from 62 medical, surgical, and medical-surgical (noncritical care) units from 31 United States (US) hospitals during October 2014-March 2017. STUDY DESIGN: Observational cross-sectional study using a fully nonparametric random forest machine learning method. Primary exposure was nurse hours per patient day (HPPD) broken down by registered nurses (nonovertime and overtime) and nonlicensed nursing personnel. The outcome was 30-day all-cause same-hospital readmission. Partial dependence plots were used to visualize the pattern of predicted patient readmission risk along a range of unit staffing levels, holding all other patient characteristics and hospital and unit structural variables constant. DATA COLLECTION/EXTRACTION METHODS: Secondary analysis of the READI data. Missing values were imputed using the missing forest algorithm in R. PRINCIPAL FINDINGS: Partial dependence plots were U-shaped, showing the readmission risk first declining and then rising with additional nurse staffing. The tipping points were at 6.95 and 0.21 HPPD for registered nurse staffing (nonovertime and overtime, respectively) and 2.91 HPPD of nonlicensed nursing personnel. CONCLUSIONS: The U-shaped association was consistent with diminishing returns to nurse staffing suggesting that incremental gains in readmission reduction from additional nurse staffing taper off and could reverse at high staffing levels. If confirmed in future causal analyses across multiple outcomes, accompanying investments in infrastructure and human resources may be needed to maximize nursing performance outcomes at higher levels of nurse staffing.

Effectiveness of home health care in reducing return to hospital: Evidence from a multi-hospital study in the US.

BACKGROUND: Home health care, a commonly used bridge strategy for transitioning from hospital to home-based care, is expected to contribute to readmission avoidance efforts. However, in studies using disease-specific samples, evidence about the effectiveness of home health care in reducing readmissions is mixed. OBJECTIVE: To examine the effectiveness of home health care in reducing return to hospital across a diverse sample of patients discharged home following acute care hospitalization. RESEARCH DESIGN: Secondary analysis of a multi-site dataset from a study of discharge readiness assessment and post-discharge return to hospital, comparing matched samples of patients referred and not referred for home health care at the time of hospital discharge. SETTING: Acute care, Magnet-designated hospitals in the United States PARTICIPANTS: The available sample (n = 18,555) included hospitalized patients discharged from medical-surgical units who were referred (n = 3,579) and not referred (n = 14,976) to home health care. The matched sample included 2767 pairs of home health care and non- home health care patients matched on patient and hospitalization characteristics using exact and Mahalanobis distance matching. METHODS: Unadjusted t-tests and adjusted multinomial logit regression analyses to compare the occurrence of readmissions and Emergency Department/Observation visits within 30 and 60-days post-discharge. RESULTS: No statistically significant differences in readmissions or Emergency Department /Observation visits between home health care and non-home health care patients were observed. CONCLUSIONS: Home health care referral was not associated with lower rates of return to hospital within 30 and 60 days in this US sample matched on patient and clinical condition characteristics. This result raises the question of why home health care services did not produce evidence of lower post-discharge return to hospital rates. Focused attention by home health care programs on strategies to reduce readmissions is needed.