Evaluation of hospital nurse-to-patient staffing ratios and sepsis bundles on patient outcomes

Abstract

•New York state was one of the first to require implementation of sepsis bundles.•Patient-to-nurse staffing ratios vary considerably across hospitals in New York.•Sepsis outcomes vary despite bundle requirements because of nurse staffing.•Requiring minimum nurse staffing along with sepsis bundles may improve outcomes. BackgroundDespite nurses’ responsibilities in recognition and treatment of sepsis, little evidence documents whether patient-to-nurse staffing ratios are associated with clinical outcomes for patients with sepsis.MethodsUsing linked data sources from 2017 including MEDPAR patient claims, Hospital Compare, American Hospital Association, and a large survey of nurses, we estimate the effect of hospital patient-to-nurse staffing ratios and adherence to the Early Management Bundle for patients with Severe Sepsis/Septic Shock SEP-1 sepsis bundles on patients’ odds of in-hospital and 60-day mortality, readmission, and length of stay. Logistic regression is used to estimate mortality and readmission, while zero-truncated negative binomial models are used for length of stay.ResultsEach additional patient per nurse is associated with 12% higher odds of in-hospital mortality, 7% higher odds of 60-day mortality, 7% higher odds of 60-day readmission, and longer lengths of stay, even after accounting for patient and hospital covariates including hospital adherence to SEP-1 bundles. Adherence to SEP-1 bundles is associated with lower in-hospital mortality and shorter lengths of stay; however, the effects are markedly smaller than those observed for staffing.DiscussionImproving hospital nurse staffing over and above implementing sepsis bundles holds promise for significant improvements in sepsis patient outcomes. Despite nurses’ responsibilities in recognition and treatment of sepsis, little evidence documents whether patient-to-nurse staffing ratios are associated with clinical outcomes for patients with sepsis. Using linked data sources from 2017 including MEDPAR patient claims, Hospital Compare, American Hospital Association, and a large survey of nurses, we estimate the effect of hospital patient-to-nurse staffing ratios and adherence to the Early Management Bundle for patients with Severe Sepsis/Septic Shock SEP-1 sepsis bundles on patients’ odds of in-hospital and 60-day mortality, readmission, and length of stay. Logistic regression is used to estimate mortality and readmission, while zero-truncated negative binomial models are used for length of stay. Each additional patient per nurse is associated with 12% higher odds of in-hospital mortality, 7% higher odds of 60-day mortality, 7% higher odds of 60-day readmission, and longer lengths of stay, even after accounting for patient and hospital covariates including hospital adherence to SEP-1 bundles. Adherence to SEP-1 bundles is associated with lower in-hospital mortality and shorter lengths of stay; however, the effects are markedly smaller than those observed for staffing. Improving hospital nurse staffing over and above implementing sepsis bundles holds promise for significant improvements in sepsis patient outcomes. For nearly a decade, New York state has been a leader in efforts to reduce high rates of mortality for people with sepsis. In 2013, after the highly publicized death of a 12-year-old boy with sepsis, New York enacted Rory's Regulations,1New York State Department of Health. Rory's regulations. Available at:https://www.health.ny.gov/facilities/public_health_and_health_planning_council/meetings/2013-02-07/docs/13-01.pdf. Accessed December 14, 2020.Google Scholar which required hospitals to implement evidence-based protocols for the screening, early diagnosis, and timely treatment of patients with severe sepsis and/or septic shock. Included in Rory's Regulations was the public reporting of hospital adherence to protocols. More recently, hospitals in all states followed suit when the Centers for Medicare and Medicaid Services (CMS) implemented a similar public reporting measure based on evidence-based guidelines from the Surviving Sepsis Campaign.2Centers for Medicare & Medicaid. Severe sepsis and septic shock: management bundle (composite measure). Available at: https://cmit.cms.gov/CMIT_public/ViewMeasure?MeasureId=1017. Accessed December 14, 2020.Google Scholar,3Singer M Deutschman CS Seymour CW et al.The third international consensus definitions for sepsis and septic shock (Sepsis-3).JAMA. 2016; 315: 801-810Crossref PubMed Scopus (8847) Google Scholar Today, Hospital Compare publicly reports hospitals’ adherence scores on the Early Management Bundle for patients with Severe Sepsis/Septic Shock (SEP-1).2Centers for Medicare & Medicaid. Severe sepsis and septic shock: management bundle (composite measure). Available at: https://cmit.cms.gov/CMIT_public/ViewMeasure?MeasureId=1017. Accessed December 14, 2020.Google Scholar Despite the national adoption of evidence-based protocols for the care of patients with sepsis, few hospitals are consistently delivering the requisite care for sepsis patients,4Barbash IJ Davis B Kahn JM National performance on the Medicare SEP-1 sepsis quality measure.Crit Care Med. 2019; 47: 1026-1032Crossref PubMed Scopus (21) Google Scholar,5Centers for Medicare & Medicaid. Hospital compare. Available at: https://www.medicare.gov/hospitalcompare/search.html. Accessed December 14, 2020.Google Scholar leading to potentially preventable deaths.6Levy MM Dellinger RP Townsend SR et al.The surviving sepsis campaign: results of an international guideline-based performance improvement program targeting severe sepsis.Intensive Care Med. 2010; 36: 222-231Crossref PubMed Scopus (588) Google Scholar, 7Levy MM Rhodes A Phillips GC et al.Surviving sepsis campaign: association between performance metrics and outcomes in a 7.5-year study.Intensive Care Med. 2014; 40: 1623-1633Crossref PubMed Scopus (170) Google Scholar, 8Rhodes A Phillips G Beale R et al.The surviving sepsis campaign bundles and outcome: results from the international multicentre prevalence study on sepsis (the IMPreSS study).Intensive Care Med. 2015; 41: 1620-1628Crossref PubMed Scopus (225) Google Scholar Another evidence-based intervention that has received little attention in the context of caring for patients with sepsis but has been associated with better clinical outcomes for patients with various medical and surgical conditions is patient-to-nurse staffing ratios.9McHugh MD Aiken LH. Windsor C Douglas C Yates P Case for hospital nurse-to-patient ratio legislation in Queensland, Australia, hospitals: an observational study.BMJ Open. 2020; 10e036264Crossref PubMed Scopus (5) Google Scholar, 10Shekelle PG Nurse–patient ratios as a patient safety strategy: a systematic review.Ann Intern Med. 2013; 158: 404-409Crossref PubMed Scopus (112) Google Scholar, 11Griffiths P Ball J Drennan J et al.Nurse staffing and patient outcomes: strengths and limitations of the evidence to inform policy and practice. A review and discussion paper based on evidence reviewed for the National Institute for Health and Care Excellence Safe Staffing guideline development.Int J Nurs Stud. 2016; 63: 213-225Crossref PubMed Scopus (119) Google Scholar Some previous research has shown nurse staffing to be associated with the incidence of hospital acquired infections.12Cimiotti JP Aiken LH Sloane DM Wu ES Nurse staffing, burnout, and health care-associated infection.Am J Infect Control. 2012; 40: 486-490Abstract Full Text Full Text PDF PubMed Scopus (387) Google Scholar Less is known about the associations between patient-to-nurse staffing ratios and clinical outcomes for patients with sepsis; however, some recent research suggests that sepsis patients admitted to hospitals with better nursing resources, including better staffing ratios, have better clinical outcomes including lower odds of mortality, readmission, intensive care unit utilization, shorter lengths of stay, and lower costs of care.13Lasater KB McHugh MD Rosenbaum PR et al.Evaluating the costs and outcomes of hospital nursing resources: a matched cohort study of patients with common medical conditions.J Gen Intern Med. 2020; : 1-8Google Scholar No research prior to this study has considered the association of patient-to-nurse staffing ratios and recommended evidence-based sepsis care bundles on outcomes for sepsis patients. In this study, we directly evaluate whether patient-to-nurse staffing ratios are associated with clinical outcomes for patients admitted with sepsis in 116 New York state hospitals. We simultaneously evaluate the effects of hospital adherence to the SEP-1 evidence-based care bundle on patient outcomes to determine whether and to what extent improving patient-to-nurse staffing ratios might benefit patients. This research question is timely and policy relevant since New York state requires sepsis bundles and is currently considering the Safe Staffing for Quality Care Act (A2954/S1032),14New York Senate and Assembly. Safe Staffing for Quality Care Act (A2954/S1032).Google Scholar which would require hospitals to comply with safe nurse staffing ratios. A cross-sectional analysis of multiple linked data sources was undertaken. Data about hospitals were provided from several sources including a large survey of registered nurses licensed in New York state, the 2017 American Hospital Association Annual Survey, and publicly available 2017 Hospital Compare data from the CMS.5Centers for Medicare & Medicaid. Hospital compare. Available at: https://www.medicare.gov/hospitalcompare/search.html. Accessed December 14, 2020.Google Scholar Information about patient characteristics and outcomes was derived from CMS MEDPAR data of Medicare patients hospitalized during 2017. Nurses practicing in hospitals were used as informants about staffing levels and other features of their work environments. The survey of registered nurses was conducted between December 2019 and February 2020. Email addresses of all actively licensed nurses were obtained from the New York state licensure list. All nurses, not a sample, were contacted by email to complete the survey and responses were returned anonymously. Nurses who did not respond to the initial survey invitation received up to 10 follow-up invitations during the study period. Once nurses completed the survey, they no longer received these follow-up invitations; and nurses could opt-out at any time. Nurses were asked to report the name of their hospital employer, which allowed us to aggregate responses from nurses working in the same hospital and create hospital-level measures of nursing resources, such as patient-to-nurse staffing ratios. Additional details of the survey methodology have been reported elsewhere, including results of a nonresponse second survey revealing no response bias in the variables of interest.15Lasater KB Jarrin OF Aiken LH et al.A methodology for studying organizational performance.Med Care. 2019; 57: 742-749Crossref PubMed Scopus (29) Google Scholar The nurse-level response rate was 17% yielding 13,000 responses, an average of 24 registered nurses per hospital working in adult medical surgical units, thus providing reliable estimates of staffing in most acute care general hospitals in New York state.16National Research CouncilNonresponse in Social Science Surveys: A Research Agenda. National Academies Press, 2013Google Scholar The analytic sample of hospitals included acute care hospitals in New York state. Hospitals were included in the sample if they had at least 5 registered nurses who responded to the survey and reported working on a medical-surgical unit as a direct care staff nurse. Among the final sample of 116 study hospitals, the average number of nurse respondents was 24 and ranged from 5 to 139 nurses per hospital. The final patient sample consisted of 52,177 Medicare beneficiaries between the ages of 65 and 99 years old who were discharged from one of the 116 study hospitals between January 1, 2017 and December 31, 2017. To be included in the study sample, patients were required to have a principal diagnosis of sepsis present on admission. ICD-10 codes used to identify sepsis are provided in Appendix 1. The patient outcome variables of interest were in-hospital mortality, 60-day mortality, 60-day readmission, and hospital length of stay. In-hospital mortality was defined as a death occurring during the index admission for sepsis; 60-day mortality was defined as a death occurring either in or outside of the hospital within 60 days of the index admission date. A readmission was identified if a patient was readmitted to a hospital (either the index hospital or some other hospital in our study sample) within 60 days of discharge. Our readmission measure excludes patients who died during the index admission (n = 7,773) or who were transferred out to another hospital (n = 962). Hospital length of stay was calculated during the index hospitalization as the number of days the patient was hospitalized. Patients with lengths of stay longer than 60 days (n = 165) and patients who died during the index admission or who were transferred out to another hospital were excluded. The predictor variables of interest included patient-to-nurse staffing ratios and hospital performance on the sepsis bundle for timely and effective sepsis care (SEP-1). Patient-to-nurse staffing ratios were derived from the survey responses of direct care registered nurses working on medical-surgical units. Nurses were asked to report the number of patients they were assigned during their last shift worked. Responses were averaged among nurses working in the same hospital to create a hospital-level measure of medical-surgical patient-to-nurse staffing. Hospital performance on timely and effective sepsis care was obtained from CMS Hospital Compare data collected between January 1, 2017 and December 31, 2017. The SEP-1 score is a National Inpatient Quality Measure that began in October 2015 as part of CMS’ quality reporting program.17Schorr C Nurses can help improve outcomes in severe sepsis.Am Nurse Today. 2016; 11: 20-25Google Scholar Chart abstraction is used to identify the percentage of patients who received appropriate care for severe sepsis and septic shock. Appropriate care includes interventions such as obtaining lactate measurements, blood cultures, and delivering a broad-spectrum antibiotic within 3 hours of sepsis onset for individuals with severe sepsis. Additionally, patients with septic shock require intravenous fluids within 3 hours of onset, vasopressors within 5 hours, and repeat volume assessments within 6 hours. Hospital SEP-1 scores can range between 0% and 100% indicated the percentage of patients who received appropriate care for severe sepsis and septic shock. Although it is not within the clinical scope of bedside nurses to order and initiate the sepsis care bundle, nurses are directly responsible for ensuring timely completion of the relevant diagnostic testing and administration of treatments. Thus, the direct care nurse is a key contributor to a hospital's performance on the SEP-1 bundle. Hospital covariations were included in the modeling to control for potentially confounding relationships. The American Hospital Association survey provided data on hospital size, teaching status, and technology capabilities. Size was defined by the number of inpatient beds and categorized as small (≤100 beds), medium (101-250 beds), and large (>250 beds). Teaching status was categorized as nonteaching (no medical trainees), minor teaching (0-4 medical per and teaching medical per Hospitals with the to and/or were defined as a A measure of patient-to-nurse staffing ratios in intensive care was derived from the survey of nurses and included as a control in the covariates were obtained from MEDPAR data and a for whether or not the patient was a from another and 5 variables for which over of the study patients. including and are used to report the number of direct care medical-surgical nurse respondents per hospital and the number of Medicare patients with sepsis within the 116 study hospitals. Patient-to-nurse ratios and SEP-1 scores are reported for the 116 study hospitals and the hospitals are by their of size, teaching status, and technology capabilities. regression models were to odds ratios for mortality and readmission outcomes. negative binomial models with were used to rate ratios for length of stay. are first and for hospital and patient Staffing was as a in the number of patients per nurse. SEP-1 score was as a in the hospital The of medical-surgical nurse respondents and sepsis patients in the 116 study hospitals are in 1. Among the 116 New York hospitals in our sample, we obtained data about patient-to-nurse staffing ratios from registered nurses, with an average of nurses per hospital. Data from 52,177 Medicare patients hospitalized with a principal diagnosis of sepsis were included in our with an average of patients per of medical-surgical nurse respondents in the 116 study hospitals, and the of sepsis patients used in the respondents per of nurse patients per patients used in of of In-hospital and 60-day of in a of the study hospitals and the patient-to-nurse staffing ratios and performance on the CMS sepsis bundle are in The of hospitals in our sample had than beds and did not have a high technology status Hospitals were by their teaching nonteaching minor teaching teaching The average medical-surgical patient-to-nurse staffing ratio among the 116 hospitals was patients per nurse teaching hospitals to have higher staffing ratios as to smaller nonteaching hospitals. The average SEP-1 score was SEP-1 scores were higher better performance on sepsis bundle in hospitals (101-250 and hospitals high technology characteristics of the 116 hospitals in the study sample, and medical-surgical staffing and SEP-1 scores in hospitals with staffing per sepsis and septic shock management bundle of of status in a Among the 52,177 sepsis patients in our sample, died during the index admission and of patients died within 60 days of admission individuals who died during the index hospitalization and those who were transferred were readmitted within 60 days of discharge. 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Safe Staffing for Quality Care Act (A2954/S1032).Google Scholar In this study, we additional patient in a to be and associated with a higher of in-hospital and 60-day mortality, readmission, as as longer lengths of stay, even after accounting for hospital and patient have been policy efforts over the last to reduce mortality among sepsis Rory's Regulations in the of New York state and CMS sepsis bundles that to hospitals This study that patients in hospitals with adherence to the SEP-1 sepsis bundle have lower in-hospital mortality and shorter lengths of stay. No significant were between hospital adherence to the SEP-1 bundle and 60-day mortality or the effects of nurse staffing on patient outcomes are than is hospital adherence to the SEP-1 bundle. For additional patient per nurse is associated with 12% higher odds of in-hospital mortality with a in SEP-1 adherence associated with a in in-hospital SEP-1 scores were associated with shorter lengths of stay, but staffing had than as large an effect on shorter lengths of stay, even when accounting for hospitals’ SEP-1 the effect of staffing was large and significant in of 60-day mortality and while the SEP-1 scores no Nurse staffing levels have not been in to of the of the SEP-1 bundle. it is not to nurse staffing are associated with sepsis above and hospitals’ adherence to the SEP-1 bundles. The interventions the SEP-1 bundle and the care of a septic patient are on nurses with the and to for and of sepsis, to blood in a timely and to antibiotic and and which requires and The that sepsis patient outcomes would be by a minimum safe hospital nurse staffing the one currently in New York state, in to the such as Rory's Regulations to adherence to the SEP-1 bundles. to nurse staffing ratios may not reduce mortality and readmission among sepsis patients as we but is to patients with a range of medical and surgical as previous research has C The association of registered nurse staffing levels and patient outcomes: systematic review and Care. PubMed Scopus Google Scholar, M A of hospital registered nurse staffing and quality of PubMed Scopus Google Scholar, LH Sloane DM J Hospital nurse staffing and patient mortality, nurse burnout, and PubMed Scopus Google Scholar, LH JP Sloane DM et of nurse staffing and nurse on patient in hospitals with nurse work Nurs 2012; PubMed Scopus Google Scholar, LH Sloane DM et al.Nurse staffing and and hospital mortality in a observational 2014; Full Text Full Text PDF PubMed Scopus Google Scholar The study be considered in the context of strengths and this was a cross-sectional and can not a between nurse staffing and patient other multiple of data have shown nurse staffing to be associated with patient outcomes over LH Sloane DM et and patients’ patient safety in hospitals a PubMed Scopus Google Scholar Our study a measure of nurse staffing derived from staff nurses providing direct clinical care on medical-surgical in a large and sample of New York hospitals. of nurse staffing on measures of staffing by and nurse in direct as as patient care and in as as inpatient which a measure of the for nurses at the we on publicly available data from Hospital Compare of hospital-level adherence to the SEP-1 bundle to whether and to what extent sepsis patients appropriate and timely The SEP-1 bundle an or such that for a hospital to for appropriate and timely sepsis they to have all the interventions within the bundle. Hospitals that some of the interventions are not for those Despite public attention to high and potentially from a diagnosis of sepsis as as adherence to evidence-based sepsis care the average hospital appropriate sepsis care to a little than of patients. Nurses are to the and treatment of sepsis; and the clinical outcomes for with sepsis are associated with hospital nurses’ In this study, we that additional patient in a nurses’ is associated with higher odds of as as higher odds of readmission and longer lengths of stay, which suggests attention to patient-to-nurse staffing ratios may be to adherence to sepsis care and improving patient outcomes.

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