Validation of the days alive and out of hospital outcome measure after emergency laparotomy: a retrospective cohort study

An Approach for Combining Clinical Judgment with Machine Learning to Inform Medical Decision Making: Analysis of Nonemergency Surgery Strategies for Acute Appendicitis in Patients with Multiple Long-Term Conditions

BACKGROUND

Machine learning (ML) methods can identify complex patterns of treatment effect heterogeneity. However, before ML can help to personalize decision making, transparent approaches must be developed that draw on clinical judgment. We develop an approach that combines clinical judgment with ML to generate appropriate comparative effectiveness evidence for informing decision making.

METHODS

We motivate this approach in evaluating the effectiveness of nonemergency surgery (NES) strategies, such as antibiotic therapy, for people with acute appendicitis who have multiple long-term conditions (MLTCs) compared with emergency surgery (ES). Our 4-stage approach 1) draws on clinical judgment about which patient characteristics and morbidities modify the relative effectiveness of NES; 2) selects additional covariates from a high-dimensional covariate space (P > 500) by applying an ML approach, least absolute shrinkage and selection operator (LASSO), to large-scale administrative data (N = 24,312); 3) generates estimates of comparative effectiveness for relevant subgroups; and 4) presents evidence in a suitable form for decision making.

RESULTS

This approach provides useful evidence for clinically relevant subgroups. We found that overall NES strategies led to increases in the mean number of days alive and out-of-hospital compared with ES, but estimates differed across subgroups, ranging from 21.2 (95% confidence interval: 1.8 to 40.5) for patients with chronic heart failure and chronic kidney disease to -10.4 (-29.8 to 9.1) for patients with cancer and hypertension. Our interactive tool for visualizing ML output allows for findings to be customized according to the specific needs of the clinical decision maker.

CONCLUSIONS

This principled approach of combining clinical judgment with an ML approach can improve trust, relevance, and usefulness of the evidence generated for clinical decision making.

HIGHLIGHTS

Machine learning (ML) methods have many potential applications in medical decision making, but the lack of model interpretability and usability constitutes an important barrier for the wider adoption of ML evidence in practice.We develop a 4-stage approach for integrating clinical judgment into the way an ML approach is used to estimate and report comparative effectiveness.We illustrate the approach in undertaking an evaluation of nonemergency surgery (NES) strategies for acute appendicitis in patients with multiple long-term conditions and find that NES strategies lead to better outcomes compared with emergency surgery and that the effects differ across subgroups.We develop an interactive tool for visualizing the results of this study that allows findings to be customized according to the user's preferences.

The Cost-Effectiveness of Early High-Acuity Postoperative Care for Medium-Risk Surgical Patients

BACKGROUND

Initiatives in perioperative care warrant robust cost-effectiveness analysis in a cost-constrained era when high-value care is a priority. A model of anesthesia-led early high-acuity postoperative care, advanced recovery room care (ARRC), has shown benefit in terms of hospital and patient outcomes, but its cost-effectiveness has not yet been formally determined.

METHODS

Data from a previously published single-center prospective cohort study of ARRC in medium-risk patients were used to generate a Markov model, which described patient transition between care locations, each with different characteristics and costs. The incremental cost-effectiveness ratio (ICER), using days at home (DAH) and hospital costs, was calculated for ARRC compared to usual ward care using deterministic and probabilistic sensitivity analysis.

RESULTS

The Markov model accurately described patient disposition after surgery. For each patient, ARRC provided 4.3 more DAH within the first 90 days after surgery and decreased overall hospital costs by $1081 per patient. Probabilistic sensitivity analysis revealed that ARRC had a 99.3% probability of increased DAH and a 77.4% probability that ARRC was dominant from the perspective of the hospital, with improved outcomes and decreased costs.

CONCLUSIONS

Early high-acuity care for approximately 24 hours after surgery in medium-risk patients provides highly cost-effective improvements in outcomes when compared to usual ward care.

Health-related quality of life is a predictor of readmission following emergency laparotomy

BACKGROUND

Health-related quality of life (HRQoL) is a multidimensional concept used to examine the impact of patient-perceived health status on quality of life. Patients' perception of illness affects outcomes in both medical and elective surgical patients; however, not much is known about how HRQoL effects outcomes in the emergency surgical setting. This study aimed to examine if patient-reported HRQoL was a predictor of unplanned readmission after emergency laparotomy.

METHODS

This study included 215 patients who underwent emergency laparotomy at the Copenhagen University Hospital, Herlev, between August 1, 2021, and July 31, 2022. Patient-reported HRQoL was assessed with the EuroQol group EQ5D index (EQ5D5L descriptive system and EQ-VAS). The population was followed from 0 to 180 days after discharge, and readmissions and days alive and out of hospital were registered. A Cox proportional hazard model was used to examine HRQoL and the risk of readmission within 30 and 180 days.

RESULTS

Within 30 days, 28.4% of patients were readmitted; within 180 days, the number accumulated to 45.1%. Low self-evaluated HRQoL predicted 180-day readmission and was significantly associated with fewer days out of hospital within both 90 and 180 days. Low HRQoL and discharge with rehabilitation were independent risk factors for short- (30-day) and long-term (180-day) emergency readmission.

CONCLUSION

Patient-perceived quality of life is an independent predictor of 180-day readmission, and the number of days out of hospital was correlated to self-reported HRQoL.

Disparities in prehospital and emergency surgical care among patients with perforated ulcers and a history of mental illness: a nationwide cohort study

PURPOSE

To compare patients with and without a history of mental illness on process and outcome measures in relation to prehospital and emergency surgical care for patients with perforated ulcer.

METHODS

A nationwide registry-based cohort study of patients undergoing emergency surgery for perforated ulcer. We used data from the Danish Prehospital Database 2016-2017 and the Danish Emergency Surgery Registry 2004-2018 combined with data from other Danish databases. Patients were categorized according to severity of mental health history.

RESULTS

We identified 4.767 patients undergoing emergency surgery for perforated ulcer. Among patients calling the EMS with no history of mental illness, 51% were identified with abdominal pain when calling the EMS compared to 31% and 25% among patients with a history of moderate and major mental illness, respectively. Median time from hospital arrival to surgery was 6.0 h (IQR: 3.6;10.7). Adjusting for age, sex and comorbidity, patients with a history of major mental illness underwent surgery 46 min (95% CI: 4;88) later compared to patients with no history of mental illness. Median number of days-alive-and-out-of-hospital at 90-day follow-up was 67 days (IQR: 0;83). Adjusting for age, sex and comorbidity, patients with a history of major mental illness had 9 days (95% CI: 4;14) less alive and out-of-hospital at 90-day follow-up.

CONCLUSION

One-third of the population had a history of mental illness or vulnerability. Patients with a history of major mental illness were less likely to be identified with abdominal pain if calling the EMS prior to arrival. They had longer delays from hospital arrival to surgery and higher mortality.

Influence of acute kidney injury and its recovery subtypes on patient-centered outcomes after lung transplantation

This study aimed to investigate the association between acute kidney injury (AKI) recovery subtypes and days alive out of hospital within the first 3 months (DAOH-90) in patients undergoing lung transplantation. Patients who underwent lung transplantation from January 2012 to December 2021 were retrospectively analyzed and stratified into three groups: no-AKI, early recovery AKI (within 7 days), and non-early recovery AKI group. AKI occurred in 86 (35%) of patients, of which 40 (16%) achieved early recovery, and the remaining 46 (19%) did not. The median DAOH-90 was 21 days shorter in the AKI than in the no-AKI (P = 0.002), and 29 days shorter in the non-early recovery AKI group than in the no-AKI group (P < 0.001). Non-early recovery AKI and preoperative tracheostomy status were independently associated with shorter DAOH-90. The prevalence of CKD (76%), and 1-year mortality (48%) were highest in the non-early recovery AKI group. Postoperative AKI was associated with an adverse patient-centered quality measure for perioperative care, and shorter DAOH-90. The non-early recovery AKI group exhibited the worst prognosis in terms of DAOH-90, CKD progression, and 1-year mortality, highlighting the important role of AKI and early-recovery AKI on both the quality of life and clinical outcomes after lung transplantation.

PHYSIO+++: protocol for a pilot randomised controlled trial assessing the feasibility of physiotherapist-led non-invasive ventilation for patients with hypoxaemia following abdominal surgery

INTRODUCTION

Few clinical trials have investigated physiotherapy interventions to treat hypoxaemia following abdominal surgery. The objective of this study is to determine the feasibility and safety of conducting a clinical trial of physiotherapist-led non-invasive ventilation (NIV).

METHODS AND ANALYSIS

This single-centre, 50-patient, parallel-group, assessor blinded, pilot feasibility randomised controlled trial with concealed allocation will enrol spontaneously ventilating adults with hypoxaemia within 72 hours of major abdominal surgery. Participants will receive either (1) usual care physiotherapy of a single education session (talk), daily walking of 10-15 min (walk) and four sessions of coached deep breathing and coughing (breathe) or (2) usual care physiotherapy plus four 30 min sessions of physiotherapist-led NIV delivered over 2 postoperative days. Primary feasibility and safety outcome measures are; number of eligible patients recruited per week, total time of NIV treatment delivered, acceptability of treatments to patients and clinicians and incidence of adverse events. Secondary feasibility outcomes include measures of recruitment and treatment adherence. Exploratory outcome measures include change in respiratory parameters, postoperative pulmonary complications, length of hospital stay, health-related quality of life, postoperative activity levels and mortality.

ETHICS AND DISSEMINATION

Ethics approval has been obtained from the relevant institution. Results will be published to inform future research.

TRIAL REGISTRATION NUMBER

ACTRN12622000839707.

Composite quality measures of abdominal surgery at a population level: systematic review

BACKGROUND

Measurement of surgical quality at a population level is challenging. Composite quality measures derived from administrative and clinical information systems could support system-wide surgical quality improvement by providing a simple metric that can be evaluated over time. The aim of this systematic review was to identify published studies of composite measures used to assess the overall quality of abdominal surgical services at a hospital or population level.

METHODS

A search was conducted in PubMed and MEDLINE for references describing measurement instruments evaluating the overall quality of abdominal surgery. Instruments combining multiple process and quality indicators into a single composite quality score were included. The identified instruments were described in terms of transparency, justification, handling of missing data, case-mix adjustment, scale branding and choice of weight and uncertainty to assess their relative strengths and weaknesses (PROSPERO registration: CRD42022345074).

RESULTS

Of 5234 manuscripts screened, 13 were included. Ten unique composite quality measures were identified, mostly developed within the past decade. Outcome measures such as mortality rate (40 per cent), length of stay (40 per cent), complication rate (60 per cent) and morbidity rate (70 per cent) were consistently included. A major challenge for all instruments is the reliance of valid administrative data and the challenges of assigning appropriate weights to the underlying instrument components. A conceptual framework for composite measures of surgical quality was developed.

CONCLUSION

None of the composite quality measures identified demonstrated marked superiority over others. The degree to which administrative and clinical data influences each composite measure differs in important ways. There is a need for further testing and development of these measures.

Quantitative futility in emergency laparotomy: an exploration of early-postoperative death in the National Emergency Laparotomy Audit

BACKGROUND

Quantitative futility is an appraisal of the risk of failure of a treatment. For those who do not survive, a laparotomy has provided negligible therapeutic benefit and may represent a missed opportunity for palliation. The aim of this study was to define a timeframe for quantitative futility in emergency laparotomy and investigate predictors of futility using the National Emergency Laparotomy Audit (NELA) database.

METHODS

A two-stage methodology was used; stage one defined a timeframe for futility using an online survey and steering group discussion; stage two applied this definition to patients enrolled in NELA December 2013-December 2020 for analysis. Futility was defined as all-cause mortality within 3 days of emergency laparotomy. Baseline characteristics of this group were compared to all others. Multilevel logistic regression was carried out with potentially clinically important predictors defined a priori.

RESULTS

Quantitative futility occurred in 4% of patients (7442/180,987). Median age was 74 years (range 65-81 years). Median NELA risk score was 32.4% vs. 3.8% in the surviving cohort (p < 0.001). Early mortality patients more frequently presented with sepsis (p < 0.001). Significant predictors of futility included age, arterial lactate and cardiorespiratory co-morbidity. Frailty was associated with a 38% increased risk of early mortality (95% CI 1.22-1.55). Surgery for intestinal ischaemia was associated with a two times greater chance of futile surgery (OR 2.67; 95% CI 2.50-2.85).

CONCLUSIONS

Quantitative futility after emergency laparotomy is associated with quantifiable risk factors available to decision-makers preoperatively. These findings should be incorporated qualitatively by the multidisciplinary team into shared decision-making discussions with extremely high-risk patients.

Predictive Value of the Changes in Neutrophil-Lymphocyte Ratio for Outcomes After Off-Pump Coronary Surgery

Purpose

The neutrophil-to-lymphocyte ratio (NLR) is an extensively analyzed prognostic inflammatory index in cardiac patients. The degree of change in NLR values before and after surgery (delta-NLR) can represent the inflammatory response induced by surgery and serve as a meaningful prognostic biomarker in surgical patients; however, this has not been well investigated. We aimed to investigate the predictive value of the perioperative NLR and delta-NLR for outcomes of off-pump coronary artery bypass (OPCAB) surgery by evaluating "days alive and out of hospital (DAOH)", a novel patient-centered outcome.

Patients and Methods

In this single-center retrospective study, perioperative data, including NLR data, from 1322 patients were analyzed. The primary endpoint was DOAH at 90 days postoperatively (DAOH 90), and the secondary endpoint was long-term mortality. Linear regression analysis and Cox regression analysis were performed to identify independent risk factors for the endpoints. In addition, Kaplan-Meier survival curves were plotted to assess long-term mortality.

Results

The median NLR values significantly increased from 2.2 (1.6-3.1) at baseline to 7.4 (5.4-10.3) postoperatively, with median delta-NLR values of 5.0 (3.2-7.6). Preoperative NLR and delta-NLR were independent risk factors for short DAOH 90 in the linear regression analysis. In Cox regression analysis, delta-NLR, but not preoperative NLR, was an independent risk factor for long-term mortality. When patients were divided into two groups according to delta-NLR, the high delta-NLR group had a shorter DAOH 90 than the low delta-NLR group. Kaplan-Meier curves showed higher long-term mortality in the high delta-NLR group than in the low delta-NLR group.

Conclusion

In OPCAB patients, preoperative NLR and delta-NLR were significantly associated with DAOH 90, and delta-NLR was an independent risk factor for long-term mortality, indicating their role in risk assessment, which is essential for perioperative management.

Days Alive and Out of Hospital at 15 Days after Hip Replacement May Be Associated with Long-Term Mortality: Observational Cohort Study

We aimed to evaluate the association between days alive and out of hospital (DAOH) and mortality at 15 days after a hip replacement. From March 2010 to June 2020, we identified 5369 consecutive adult patients undergoing hip replacements and estimated DAOH at 15, 30, 60, and 90 days after surgery. After excluding 13 patients who died within 15 days after surgery, receiver operating characteristic (ROC) curves were then generated to evaluate predictabilities for each follow-up period. We compared the mortality risk according to the estimated thresholds of DAOH at 15 days after hip replacement. ROC analysis revealed areas under the curve of 0.862, 0.877, 0.906, and 0.922 for DAOH at 15, 30, 60, and 90 days after surgery, respectively. The estimated threshold of DAOH during the 15 postoperative days was 6.5. Patients were divided according to this threshold, and propensity score matching was conducted. In a propensity score-matched population with 864 patients in each group, the risk of mortality increased in patients with a lower DAOH 15 (2.8% vs. 8.1%; hazard ratio [HR] = 3.96; 95% confidence interval [CI]: 2.24–6.99; p < 0.001 for one-year mortality, 5.2% vs. 13.0%; HR = 3.82; 95% CI: 2.33–6.28; p < 0.001 for three-year mortality, and 5.9% vs. 15.6%; HR = 3.07; 95% CI: 2.04–4.61; p < 0.001 for five-year mortality). In patients undergoing a hip replacement, DAOH at 15 days after surgery was shown to be associated with increased mortality. DAOH at 15 days may be used as a valid outcome measure for hip replacement.

Days alive and out of hospital at 30 days and outcomes of off-pump coronary artery bypass grafting

Days alive and out of hospital (DAOH) is a simple estimator based on the number of days not in hospital within a defined period. In cases of mortality within the period, DAOH is regarded as zero. It has not been validated solely in off-pump coronary artery bypass grafting (OPCAB). This study aimed to demonstrate a correlation between DAOH and outcome of OPCAB. We identified 2211 OPCAB performed from January 2010 to August 2016. We calculated DAOH at 30 and 60 days. We generated a receiver-operating curve and compared outcomes. The median duration of hospital stay after OPCAB was 6 days. The median DAOH values at 30 and 60 days were 24 and 54 days. The estimated thresholds for 3-year mortality for DAOH at 30 and 60 days were 20 and 50 days. Three-year mortality was higher for short DAOH (1.2% vs. 5.7% and 1.1% vs. 5.6% DAOH at 30 and 60 days). After adjustment, the short DAOH 30 group showed significantly higher mortality during 3-year follow-up (hazard ratio 3.07; 95% confidence interval 1.45-6.52; p = 0.004). DAOH at 30 days after OPCAB showed a correlation with 3-year outcomes. DAOH 30 might be a reliable long-term outcome measure that can be obtained within 30 days after surgery.

Association of frailty with days alive at home in critically ill patients undergoing emergency general surgery: a population-based cohort study

BACKGROUND

Frailty is an established risk factor for morbidity and mortality in older patients undergoing surgery. In people with critical illness before surgery, few data describe patient-centred outcomes. Our objective was to estimate the association of frailty with postoperative days alive at home in older critically ill patients requiring emergency general surgery.

METHODS

A retrospective population-based cohort study was conducted using linked administrative health data in Ontario, Canada from 2009 to 2019. All individuals aged ≥66 yr with an ICU admission before emergency general surgery were included. We compared the count of days alive at home at 30 and 365 days after surgery based on frailty status using a validated, multidimensional index. Unadjusted and multilevel, multivariable adjusted effect estimates were calculated. A sensitivity analysis based on early recovery category was performed.

RESULTS

We identified 7003 eligible patients; 2063 (29.5%) lived with frailty. At 30 days, mean days alive at home with frailty were 4.5 (standard deviation 8.2) and 7.6 (standard deviation 10.2) in those without frailty. In adjusted analysis, frailty was associated with fewer days alive at home at 30 (ratio of means [RoM] 0.68; 95% confidence interval [CI]: 0.60-0.78; P<0.001) and 365 days (RoM 0.72; 95% CI: 0.64-0.82; P<0.001). Individuals with frailty had a higher probability of poor recovery status, with effects increasing across the first postoperative month.

CONCLUSIONS

In patients with critical illness requiring emergency general surgery, frailty is associated with fewer days alive at home. This information should be discussed with critically ill patients before emergent surgical intervention to better inform decision-making.

An evaluation of the outcome metric 'days alive and at home' in older patients after hip fracture surgery

'Days alive and at home' is a validated measure that estimates the time spent at home, defined as the place of residence before admission to hospital. We evaluated this metric in older adults after hip fracture surgery and assessed two follow-up durations, 30 and 90 days. Patients aged ≥ 70 years who underwent hip fracture surgery were identified retrospectively via hospital admission and government mortality records. Patients who successfully returned home and were still alive within 90 days of surgery were distinguished from those who were not. Regression models were used to examine which variables were associated with failure to return home and number of days at home among those who did return, within 90 days of surgery. We analysed the records of 825 patients. Median (IQR [range]) number of days at home within 90 days (n = 788) was 54 (0-76 [0-88]) days and within 30 days (n = 797) it was 2 (0-21 [0-28]) days. Out of these, 274 (35%) patients did not return home within 90 days and 374 (47%) within 30 days after surgery. Known peri-operative risk-factors such as older age, pre-operative anaemia and postoperative acute renal impairment were associated with failure to return home. This study supports days alive and at home as a useful patient-centred outcome measure in older adults after hip fracture surgery. We recommend that this metric should be used in clinical trials and measured at 90, rather than 30, postoperative days. As nearly half of this patient population did not return home within 30 days, the shorter time-period catches fewer meaningful events.

Effectiveness of emergency surgery for five common acute conditions: an instrumental variable analysis of a national routine database

The effectiveness of emergency surgery vs. non-emergency surgery strategies for emergency admissions with acute appendicitis, gallstone disease, diverticular disease, abdominal wall hernia or intestinal obstruction is unknown. Data on emergency admissions for adult patients from 2010 to 2019 at 175 acute National Health Service hospitals in England were extracted from the Hospital Episode Statistics database. Cohort sizes were: 268,144 (appendicitis); 240,977 (gallstone disease); 138,869 (diverticular disease); 106,432 (hernia); and 133,073 (intestinal obstruction). The primary outcome was number of days alive and out of hospital at 90 days. The effectiveness of emergency surgery vs. non-emergency surgery strategies was estimated using an instrumental variable design and is reported for the cohort and pre-specified sub-groups (age, sex, number of comorbidities and frailty level). Average days alive and out of hospital at 90 days for all five cohorts were similar, with the following mean differences (95%CI) for emergency surgery minus non-emergency surgery after adjusting for confounding: -0.73 days (-2.10-0.64) for appendicitis; 0.60 (-0.10-1.30) for gallstone disease; -2.66 (-15.7-10.4) for diverticular disease; -0.07 (-2.40-2.25) for hernia; and 3.32 (-3.13-9.76) for intestinal obstruction. For patients with 'severe frailty', mean differences (95%CI) in days alive and out of hospital for emergency surgery were lower than for non-emergency surgery strategies: -21.0 (-27.4 to -14.6) for appendicitis; -5.72 (-11.3 to -0.2) for gallstone disease, -38.9 (-63.3 to -14.6) for diverticular disease; -19.5 (-26.6 to -12.3) for hernia; and - 34.5 (-46.7 to -22.4) for intestinal obstruction. For patients without frailty, the mean differences (95%CI) in days alive and out of hospital were: -0.18 (-1.56-1.20) for appendicitis; 0.93 (0.48-1.39) for gallstone disease; 5.35 (-2.56-13.28) for diverticular disease; 2.26 (0.37-4.15) for hernia; and 18.2 (14.8-22.47) for intestinal obstruction. Emergency surgery and non-emergency surgery strategies led to similar average days alive and out of hospital at 90 days for five acute conditions. The comparative effectiveness of emergency surgery and non-emergency surgery strategies for these conditions may be modified by patient factors.