Using machine learning to assess the extent of busy ambulances and its impact on ambulance response times: A retrospective observational study.

BACKGROUND: Ambulance response times are considered important. Busy ambulances are common, but little is known about their effect on response times. OBJECTIVE: To assess the extent of busy ambulances in Central Norway and their impact on ambulance response times. DESIGN: This was a retrospective observational study. We used machine learning on data from nearby incidents to assess the probability of up to five different ambulances being candidates to respond to a medical emergency incident. For each incident, the probability of a busy ambulance was estimated by summing the probabilities of candidate ambulances being busy at the time of the incident. The difference in response time that may be attributable to busy ambulances was estimated by comparing groups of nearby incidents with different estimated busy probabilities. SETTING: Medical emergency incidents with ambulance response in Central Norway from 2013 to 2022. MAIN OUTCOME MEASURES: Prevalence of busy ambulances and differences in response times associated with busy ambulances. RESULTS: The estimated probability of busy ambulances for all 216,787 acute incidents with ambulance response was 26.7% (95% confidence interval (CI) 26.6 to 26.9). Comparing nearby incidents, each 10-percentage point increase in the probability of a busy ambulance was associated with a delay of 0.60 minutes (95% CI 0.58 to 0.62). For incidents in rural and urban areas, the probability of a busy ambulance was 21.6% (95% CI 21.5 to 21.8) and 35.0% (95% CI 34.8 to 35.2), respectively. The delay associated with a 10-percentage point increase in busy probability was 0.81 minutes (95% CI 0.78 to 0.84) and 0.30 minutes (95% CI 0.28 to 0.32), respectively. CONCLUSION: Ambulances were often busy, which was associated with delayed ambulance response times. In rural areas, the probability of busy ambulances was lower, although the potentially longer delays when ambulances were busy made these areas more vulnerable.

Gestational age at birth and hospitalisations for infections among individuals aged 0-50 years in Norway: a longitudinal, register-based, cohort study.

Background: Preterm birth is associated with increased risk of childhood infections. Whether this risk persists into adulthood is unknown and limited information is available on risk patterns across the full range of gestational ages. Methods: In this longitudinal, register-based, cohort study, we linked individual-level data on all individuals born in Norway (January 01, 1967-December 31, 2016) to nationwide hospital data (January 01, 2008-December 31, 2017). Gestational age was categorised as 23-27, 28-31, 32-33, 34-36, 37-38, 39-41, and 42-44 completed weeks. The analyses were stratified by age at follow-up: 0-11 months and 1-5, 6-14, 15-29, and 30-50 years. The primary outcome was hospitalisation due to any infectious disease, with major infectious disease groups as secondary outcomes. Adjusted hospitalisation rate ratios (RRs) for any infection and infectious disease groups were estimated using negative binomial regression. Models were adjusted for year of birth, maternal age at birth, parity, and sex, and included an offset parameter adjusted for person-time at risk. Findings: Among 2,695,830 individuals with 313,940 hospitalisations for infections, we found a pattern of higher hospitalisation risk in lower gestational age groups, which was the strongest in childhood but still evident in adulthood. Comparing those born very preterm (28-31) and late preterm (34-36) to full-term (39-41 weeks), RRs (95% confidence interval) for hospitalisation for any infectious disease at ages 1-5 were 3.3 (3.0-3.7) and 1.7 (1.6-1.8), respectively. At 30-50 years, the corresponding estimates were 1.4 (1.2-1.7) and 1.2 (1.1-1.3). The patterns were similar for the infectious disease groups, including bacterial and viral infections, respiratory tract infections (RTIs), and infections not attributable to RTIs. Interpretation: Increasing risk of hospitalisations for infections in lower gestational age groups was most prominent in children but still evident in adolescents and adults. Possible mechanisms and groups that could benefit from vaccinations and other prevention strategies should be investigated. Funding: St. Olav's University Hospital and Norwegian University of Science and Technology, Norwegian Research Council, Liaison Committee for education, research and innovation in Central Norway, European Commission, Academy of Finland, Sigrid Jusélius Foundation, Foundation for Pediatric Research, and Signe and Ane Gyllenberg Foundation.

General practitioners ending their practice and impact on patients' health, healthcare use and mortality: a protocol for national registry cohort studies in Norway, 2008 to 2021.

INTRODUCTION: Continuous general practitioner (GP) and patient relations associate with positive health outcomes. Termination of GP practice is unavoidable, while consequences of final breaks in relations are less explored. We will study how an ended GP relation affects patient's healthcare utilisation and mortality compared with patients with a continuous GP relation. METHODS AND ANALYSIS: We link national registries data on individual GP affiliation, sociodemographic characteristics, healthcare use and mortality. From 2008 to 2021, we identify patients whose GP stopped practicing and will compare acute and elective, primary and specialist healthcare use and mortality, with patients whose GP did not stop practicing. We match GP-patient pairs on age and sex (both), immigrant status and education (patients), and number of patients and practice period (GPs). We analyse the outcomes before and after an ended GP-patient relation, using Poisson regression with high-dimensional fixed effects. ETHICS AND DISSEMINATION: This study protocol is part of the approved project Improved Decisions with Causal Inference in Health Services Research, 2016/2159/REK Midt (the Regional Committees for Medical and Health Research Ethics) and does not require consent. HUNT Cloud provides secure data storage and computing. We will report using the STROBE guideline for observational case-control studies and publish in peer-reviewed journals, accessible in NTNU Open and present at scientific conferences. To reach a broader audience, we will summarise articles in the project's web page, regular and social media, and disseminate to relevant stakeholders.

How do busy hospital circumstances affect mortality and readmission within 60 days: A cohort study of 680 000 acute admissions in Norway.

OBJECTIVE: To study mortality and readmissions for older patients admitted during more and less busy hospital circumstances. DESIGN: Cohort study where we identified patients that were admitted to the same hospital, during the same month and day of the week. We estimated effects of inflow of acute patients and the number of concurrent acute inpatients. Mortality and readmissions were analysed using stratified Cox-regression. SETTING: All people 80 years and older acutely admitted to Norwegian hospitals between 2008 and 2016. MAIN OUTCOME MEASURES: Mortality and readmissions within 60 days from admission. RESULTS: Among 294 653 patients with 685 197 admissions, mean age was 86 years (standard deviation 5). Overall, 13% died within 60 days. An interquartile range difference in inflow of acute patients was associated with a hazard ratio (HR) of 0.99, 95% confidence interval (95% CI) 0.98 to 1.00). There was little evidence of differences in readmissions, but a 7% higher risk (HR 1.07, 95% CI 1.06 to 1.09) of being discharged outside ordinary daytime working hours. CONCLUSIONS: Older patients admitted during busier circumstances had similar mortality and readmissions to those admitted during less busy periods. Yet, they showed a higher risk of discharge outside daytime working hours. Despite limited effects of busyness on a hospital level, there could still be harmful effects of local situations.

High ward occupancy, bedspacing, and 60 day mortality for patients with myocardial infarction, stroke, and heart failure.

AIMS: To study the consequences of crowded wards among patients with cardiovascular disease. METHODS AND RESULTS: This is a cohort study among 201 801 patients with 258 807 admissions who were acutely admitted for myocardial infarction (N = 107 895), stroke (N = 87 336), or heart failure (N = 63 576) to any Norwegian hospital between 2008 and 2016. The ward admitting most patients with the given clinical condition was considered a patient's home ward. We compared patients with the same condition admitted when home ward occupancy was different, at the same hospital and during comparable time periods. Occupancy was standardized such that a one-unit difference corresponded to the interquartile range in occupancy in the given month. One interquartile increase in home ward occupancy was associated with 7% higher odds of admission to an alternate ward [odds ratio (OR) 1.07, 95% confidence interval (CI) 1.09 to 1.11], and length of stay was shorter (-0.10 days, 95% CI -0.18 to -0.09). Patients with heart failure had 15% higher odds of admission to alternate wards (OR 1.15, 95% CI 1.08 to 1.23) and increased mortality [hazard ratio (HR) 1.08, 95% CI 1.03 to 1.15]. We found no apparent effect on mortality for patients with myocardial infarction (HR 0.99, 95% CI 0.94 to 1.05) or stroke (HR 1.00, 95% CI 0.96 to 1.05). CONCLUSIONS: Patients with heart failure had higher risk of admission to alternate wards when home ward occupancy was high. These patients may be negatively affected by full wards.

High volumes of recent surgical admissions, time to surgery, and 60-day mortality.

AIMS: Few studies have investigated potential consequences of strained surgical resources. The aim of this cohort study was to assess whether a high proportion of concurrent acute surgical admissions, tying up hospital surgical capacity, may lead to delayed surgery and affect mortality for hip fracture patients. METHODS: This study investigated time to surgery and 60-day post-admission death of patients 70 years and older admitted for acute hip fracture surgery in Norway between 2008 and 2016. The proportion of hospital capacity being occupied by newly admitted surgical patients was used as the exposure. Hip fracture patients admitted during periods of high proportion of recent admissions were compared with hip fracture patients admitted at the same hospital during the same month, on similar weekdays, and times of the day with fewer admissions. RESULTS: Among 60,072 patients, mean age was 84.6 years (SD 6.8), 78% were females, and median time to surgery was 20 hours (IQR 11 to 29). Overall, 14% (8,464) were dead 60 days after admission. A high (75th percentile) proportion of recent surgical admission compared to a low (25th percentile) proportion resulted in 20% longer time to surgery (95% confidence interval (CI) 16 to 25) and 20% higher 60-day mortality (hazard ratio 1.2, 95% CI 1.1 to 1.4). CONCLUSION: A high volume of recently admitted acute surgical patients, indicating probable competition for surgical resources, was associated with delayed surgery and increased 60-day mortality. Cite this article: Bone Joint J 2021;103-B(2):264-270.

Hospitals´ Discharge Tendency and Risk of Death - An Analysis of 60,000 Norwegian Hip Fracture Patients.

PURPOSE: A reduction in the length of hospital stay may threaten patient safety. This study aimed to estimate the effect of organizational pressure to discharge on 60-day mortality among hip fracture patients. PATIENTS AND METHODS: In this cohort study, hip fracture patients were analyzed as if they were enrolled in a sequence of trials for discharge. A hospital's discharge tendency was defined as the proportion of patients with other acute conditions who were discharged on a given day. Because the hospital's tendency to discharge would affect hip fracture patients in an essentially random manner, this exposure could be regarded as analogous to being randomized to treatment in a clinical trial. The study population consisted of 59,971 Norwegian patients with hip fractures, hospitalized between 2008 and 2016, aged 70 years and older. To calculate the hospital discharge tendency for a given day, we used data from all 5,013,773 other acute hospitalizations in the study period. RESULTS: The probability of discharge among hip fracture patients increased by 5.5 percentage points (95% confidence interval (CI)=5.3-5.7) per 10 percentage points increase in hospital discharges of patients with other acute conditions. The increased risk of death that could be attributed to a discharge from organizational causes was estimated to 3.7 percentage points (95% CI=1.4-6.0). The results remained stable under different time adjustments, follow-up periods, and age cut-offs. CONCLUSION: This study showed that discharges from organizational causes may increase the risk of death among hip fracture patients.

Health personnel's perceptions of pressure on capacity in the specialist health services. / Helsepersonells oppfattelse av kapasitetspress i spesialisthelsetjenesten.

BACKGROUND: Increasing the utilisation of unused capacity in hospitals is a health policy goal, but there is concern that little unused capacity remains. The objective of the study was to examine how healthcare personnel experience and deal with pressure on capacity in the somatic specialist health services. MATERIAL AND METHOD: In this qualitative study, we conducted semi-structured interviews with unit heads and doctors and nurses involved in discharging patients in two Norwegian hospital trusts. Nine interviews (both individual and group) with altogether 19 informants were carried out in the period October 2017-February 2018. The interviews were analysed using systematic text condensation. RESULTS: Pressure on hospital capacity was described as continual pressure to treat more patients. The informants used the term 'undercapacity': a situation in which increased demands without sufficient resources were detrimental to something or someone. Elderly patients who had completed their treatment and were waiting for the provision of municipal services were regarded as particularly vulnerable, since they were often overrepresented among the patients moved between departments and wards in order to free up capacity when beds were urgently needed. The hospital staff felt they had little influence on the type of municipal services the patients were offered following discharge. INTERPRETATION: The informants stated that their daily work was negatively affected by undercapacity. Health professionals' perceptions of pressure on hospital capacity constitute vital knowledge in policy formation in the field.

Real-time forecasting of emergency department arrivals using prehospital data.

BACKGROUND: Crowding in emergency departments (EDs) is a challenge globally. To counteract crowding in day-to-day operations, better tools to improve monitoring of the patient flow in the ED is needed. The objective of this study was the development of a continuously updated monitoring system to forecast emergency department (ED) arrivals on a short time-horizon incorporating data from prehospital services. METHODS: Time of notification and ED arrival was obtained for all 191,939 arrivals at the ED of a Norwegian university hospital from 2010 to 2018. An arrival notification was an automatically captured time stamp which indicated the first time the ED was notified of an arriving patient, typically by a call from an ambulance to the emergency service communication center. A Poisson time-series regression model for forecasting the number of arrivals on a 1-, 2- and 3-h horizon with continuous weekly and yearly cyclic effects was implemented. We incorporated time of arrival notification by modelling time to arrival as a time varying hazard function. We validated the model on the last full year of data. RESULTS: In our data, 20% of the arrivals had been notified more than 1 hour prior to arrival. By incorporating time of notification into the forecasting model, we saw a substantial improvement in forecasting accuracy, especially on a one-hour horizon. In terms of mean absolute prediction error, we observed around a six percentage-point decrease compared to a simplified prediction model. The increase in accuracy was particularly large for periods with large inflow. CONCLUSIONS: The proposed model shows increased predictability in ED patient inflow when incorporating data on patient notifications. This approach to forecasting arrivals can be a valuable tool for logistic, decision making and ED resource management.

The effect of emergency department delays on 30-day mortality in Central Norway.

OBJECTIVE: To assess whether prolonged length of stay in the emergency department was associated with risk of death. METHODS: We analysed data from 165,183 arrivals at St. Olav's University Hospital's emergency department from 2011 to 2018, using an instrumental variable method. As instruments for prolonged length of emergency department stay, we used indicators measured before arrival of the patient. These indicators were used to study the association between prolonged length of emergency department stay and risk of death, being discharged from the emergency department and length of hospitalisation for those who were hospitalised. RESULTS: Mean length of stay in the emergency department was 2.9 hours, and 30-day risk of death was 3.4%. Per hour prolonged length of stay in the emergency department, the overall change in risk of death was close to zero, with a narrow 95% confidence interval of -0.5 to 0.7 percentage points. Prolonged emergency department stay was associated with a higher probability of being discharged from the emergency department without admission to the hospital. We found no substantial differences in length of hospitalisation for patients who were admitted. CONCLUSION: In this study, prolonged emergency department stay was not associated with increased risk of death.

Time of admission and mortality after hip fracture: a detailed look at the weekend effect in a nationwide study of 55,211 hip fracture patients in Norway.

Background and purpose - There are numerous studies on the weekend effect for hip fracture patients, with conflicting results. We analyzed time of admission and discharge, and the association with mortality and length of hospital stay in more detail. Patients and methods - We used data from 61,211 surgically treated hip fractures in 55,211 patients, admitted to Norwegian hospitals 2008-2014. All patients were aged 50 years or older. Data were analyzed with Cox and Poisson regression. Results - Mortality within 30 days did not differ substantially by day of admission, although admissions on Sundays and holidays had a slightly increased mortality. The hazard ratios were 1.1 (95% confidence interval [CI] 0.97-1.2) for Sundays, and 1.2 (CI 0.98-1.4) for holidays, relative to Mondays. For patients admitted between 6:00 am and 7:00 am the hazard ratio was 1.4 (CI 1.1-1.8) relative to patients admitted between 2:00 pm and 3:00 pm. Discharges during weekends and holidays were associated with a substantial higher mortality than weekday discharges. Patients admitted from Friday to Sunday generally stayed in hospital for a shorter time than patients admitted during other days. Interpretation - Our results indicate that the discussion on weekday versus weekend admission effects might have distracted attention from other important factors, such as time of day of admission, and day of discharge from hospital treatment.

Actigraphy as an objective intra-individual marker of activity patterns in acute-phase bipolar disorder: a case series.

BACKGROUND: Actigraphy could be an objective alternative to clinical ratings of motor activity in bipolar disorder (BD), which is of importance now that increased activity and energy are added as cardinal symptoms of (hypo)mania in the DSM-5 and commonly used rating scales give inadequate information about motor symptoms. To date, most actigraphy studies have been conducted in groups and/or used mean activity levels as the variable of interest. The novelty of this case series is therefore to indicate the potential of actigraphy and non-parametric analysis as an objective and personalized marker of intra-individual activity patterns in different phases of BD. To our knowledge, this is the first case series that provides an objective assessment of non-linear dynamics in within-person activity patterns during acute BD episodes. RESULTS: We report on three cases of bipolar I disorder with 24-h actigraphy recordings undertaken during the first few days of two or more separate admissions for an acute illness episode, including admissions for individuals in different phases of BD, or with different levels of severity in the same phase of illness. For each recording, we calculated mean activity levels over 24 h, but especially focused on key measures of variability and complexity in activity. Intra-individual activity patterns were found to be different according to phase of illness, but showed consistency within the same phase. With increasing psychotic symptoms, there was evidence of a lower overall level and greater irregularity in activity. As such, sample entropy (a measure of irregularity) may have particular utility in characterizing mania and psychotic symptoms, while assessment of the distribution of rest versus activity over 24 h may distinguish between phases of BD within an individual. CONCLUSIONS: This case series indicates that objective, intra-individual, real-time recordings of patterns of activity may have clinical impact as a valuable adjunct to clinical observation and symptom ratings. We suggest that actigraphy combined with detailed mathematical analysis provides a biological variable that could become an important tool for developing a personalized approach to diagnostics and treatment monitoring in BD.

An integral equation formulation for the diffraction from convex plates and polyhedra.

A formulation of the problem of scattering from obstacles with edges is presented. The formulation is based on decomposing the field into geometrical acoustics, first-order, and multiple-order edge diffraction components. An existing secondary-source model for edge diffraction from finite edges is extended to handle multiple diffraction of all orders. It is shown that the multiple-order diffraction component can be found via the solution to an integral equation formulated on pairs of edge points. This gives what can be called an edge source signal. In a subsequent step, this edge source signal is propagated to yield a multiple-order diffracted field, taking all diffraction orders into account. Numerical experiments demonstrate accurate response for frequencies down to 0 for thin plates and a cube. No problems with irregular frequencies, as happen with the Kirchhoff-Helmholtz integral equation, are observed for this formulation. For the axisymmetric scattering from a circular disc, a highly effective symmetric formulation results, and results agree with reference solutions across the entire frequency range.

Efficient evaluation of edge diffraction integrals using the numerical method of steepest descent.

For the problem of edge diffraction from an edge of finite length a frequency-domain solution, obtained from an analytical time-domain solution, has been presented by Svensson et al. [Acta. Acust. Acust. 95, 568-572]. This formulation takes the form of a Fourier-type integral whose evaluation is expensive in the high frequency range. This paper demonstrates that by using tailored highly oscillatory quadrature methods based on asymptotic properties of the integral, accurate approximations in the high frequency case can be obtained with little computational effort.