Systems science methods in public health: what can they contribute to our understanding of and response to the cost-of-living crisis?

BACKGROUND

Many complex public health evidence gaps cannot be fully resolved using only conventional public health methods. We aim to familiarise public health researchers with selected systems science methods that may contribute to a better understanding of complex phenomena and lead to more impactful interventions. As a case study, we choose the current cost-of-living crisis, which affects disposable income as a key structural determinant of health.

METHODS

We first outline the potential role of systems science methods for public health research more generally, then provide an overview of the complexity of the cost-of-living crisis as a specific case study. We propose how four systems science methods (soft systems, microsimulation, agent-based and system dynamics models) could be applied to provide more in-depth understanding. For each method, we illustrate its unique knowledge contributions, and set out one or more options for studies that could help inform policy and practice responses.

RESULTS

Due to its fundamental impact on the determinants of health, while limiting resources for population-level interventions, the cost-of-living crisis presents a complex public health challenge. When confronted with complexity, non-linearity, feedback loops and adaptation processes, systems methods allow a deeper understanding and forecasting of the interactions and spill-over effects common with real-world interventions and policies.

CONCLUSIONS

Systems science methods provide a rich methodological toolbox that complements our traditional public health methods. This toolbox may be particularly useful in early stages of the current cost-of-living crisis: for understanding the situation, developing solutions and sandboxing potential responses to improve population health.

Nonpharmaceutical interventions reduce the incidence and mortality of COVID‐19: A study based on the survey from the International COVID‐19 Research Network (ICRN)

The recently emerged novel coronavirus, “severe acute respiratory syndrome coronavirus‐2 (SARS‐CoV‐2),” caused a highly contagious disease called coronavirus disease 2019 (COVID‐19). It has severely damaged the world's most developed countries and has turned into a major threat for low‐ and middle‐income countries. Since its emergence in late 2019, medical interventions have been substantial, and most countries relied on public health measures collectively known as nonpharmaceutical interventions (NPIs). We aimed to centralize the accumulative knowledge of NPIs against COVID‐19 for each country under one worldwide consortium. International COVID‐19 Research Network collaborators developed a cross‐sectional online survey to assess the implications of NPIs and sanitary supply on the incidence and mortality of COVID‐19. The survey was conducted between January 1 and February 1, 2021, and participants from 92 countries/territories completed it. The association between NPIs, sanitation supplies, and incidence and mortality were examined by multivariate regression, with the log‐transformed value of population as an offset value. The majority of countries/territories applied several preventive strategies, including social distancing (100.0%), quarantine (100.0%), isolation (98.9%), and school closure (97.8%). Individual‐level preventive measures such as personal hygiene (100.0%) and wearing facial masks (94.6% at hospitals; 93.5% at mass transportation; 91.3% in mass gathering facilities) were also frequently applied. Quarantine at a designated place was negatively associated with incidence and mortality compared to home quarantine. Isolation at a designated place was also associated with reduced mortality compared to home isolation. Recommendations to use sanitizer for personal hygiene reduced incidence compared to the recommendation to use soap. Deprivation of masks was associated with increased incidence. Higher incidence and mortality were found in countries/territories with higher economic levels. Mask deprivation was pervasive regardless of economic level. NPIs against COVID‐19 such as using sanitizer, quarantine, and isolation can decrease the incidence and mortality of COVID‐19.

Nonpharmaceutical interventions reduce the incidence and mortality of COVID-19: A study based on the survey from the International COVID-19 Research Network (ICRN)

The recently emerged novel coronavirus, "severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2)," caused a highly contagious disease called coronavirus disease 2019 (COVID-19). It has severely damaged the world's most developed countries and has turned into a major threat for low- and middle-income countries. Since its emergence in late 2019, medical interventions have been substantial, and most countries relied on public health measures collectively known as nonpharmaceutical interventions (NPIs). We aimed to centralize the accumulative knowledge of NPIs against COVID-19 for each country under one worldwide consortium. International COVID-19 Research Network collaborators developed a cross-sectional online survey to assess the implications of NPIs and sanitary supply on the incidence and mortality of COVID-19. The survey was conducted between January 1 and February 1, 2021, and participants from 92 countries/territories completed it. The association between NPIs, sanitation supplies, and incidence and mortality were examined by multivariate regression, with the log-transformed value of population as an offset value. The majority of countries/territories applied several preventive strategies, including social distancing (100.0%), quarantine (100.0%), isolation (98.9%), and school closure (97.8%). Individual-level preventive measures such as personal hygiene (100.0%) and wearing facial masks (94.6% at hospitals; 93.5% at mass transportation; 91.3% in mass gathering facilities) were also frequently applied. Quarantine at a designated place was negatively associated with incidence and mortality compared to home quarantine. Isolation at a designated place was also associated with reduced mortality compared to home isolation. Recommendations to use sanitizer for personal hygiene reduced incidence compared to the recommendation to use soap. Deprivation of masks was associated with increased incidence. Higher incidence and mortality were found in countries/territories with higher economic levels. Mask deprivation was pervasive regardless of economic level. NPIs against COVID-19 such as using sanitizer, quarantine, and isolation can decrease the incidence and mortality of COVID-19.

The impact of design on improved learning in virtual worlds: an experimental study

Virtual worlds are the most advanced form of virtual environments, which offer one of the best platforms for serving various domains. They are, especially, well suited for education, to cope with the physical restrictions imposed due to COVID-19 outbreak, as they offer classroom experience to their users through immersion. They are online interactive spaces which are collaborative, persistent, coherent, and social in nature. Users immersed in these spaces are represented in the form of digital characters called, avatars. Virtual worlds offer advanced navigation methods such as flying and teleporting to facilitate quick learning. This paper analyses the use of a partial but carefully reconstructed cultural heritage site, developed in OpenSimulator framework, for learning both in terms of discourse and quantitative analysis. Discourse analysis compares the developed virtual world presence with traditional content provisioning methods in terms of a large set of well-known characteristics. Quantitative analysis, on the other hand, is based on data collected from users after conducting simple learning experiments. It revealed that the properties such as realism, friendliness, advanced navigation, and being detailed and social in nature greatly attracted user attention in learning. The learning was fast compared with traditional methods, however, it was a little hard for naive users to start exploring the content. Pre and post learning responses of users revealed that their knowledge level was significantly increased. Based on valuable suggestions, it is planned in future, to add intelligence to traditional agents, so they may help in an increased learning experience of users, based on the knowledge gained in earlier sessions.

A computational study of suppression of sharp wave ripple complexes by controlling calcium and gap junctions in pyramidal cells

The hippocampus plays a key role in memory formation and learning. According to the concept of active systems memory consolidation, transiently stored memory traces are transferred from the hippocampus into the neocortex for permanent storage. This phenomenon relies on hippocampal network oscillations, particularly sharp wave ripples [SPW-Rs). In this process prior saved data in the hippocampus may be reactivated. Recent investigations reveal that several neurotransmitters and neuromodulators including norepinephrine, acetylcholine, serotonin, etc., suppress SPW-Rs activity in rodents’ hippocampal slices. This suppression of SPW-Rs may depend on various presynaptic and postsynaptic parameters including decrease in calcium influx, hyperpolarization/depolarization and alteration in gap junctions’ function in pyramidal cells. In this study, we demonstrate the impact of calcium influx and gap junctions on pyramidal cells for the modulation of SPW-Rs in a computational model of CA1.

We used,SPW-Rs model with some modifications. SPW-Rs are simulated with gradual reduction of calcium and with decreasing conductance through gap junctions in PCs. Both, with calcium reduction as well as with conductance reduction through gap junctions, SPW-Rs are suppressed. Both effects add up synergistically in combination.

On the effectiveness of multi-feature evacuation systems: an agent-based exploratory simulation study

Evacuation modeling and simulation are usually used to explore different possibilities for evacuation, however, it is a real challenge to integrate different categories of characteristics in unified modeling space. In this paper, we propose an agent-based model of an evacuating crowd so that a comparative analysis of a different sets of parameters categorized as individual, social and technological aspects, is made possible. In particular, we focus on the question of rationality vs. emotionalism of individuals in a localized social context. In addition to that, we propose and model the concept of extended social influence, thereby embedding technological influence within the social influence, and analyze its impact on the efficiency of evacuation. NetLogo is used for simulating different variations in environments, evacuation strategies, and agents demographics. Simulation results revealed that there is no substantial advantage of informational overload on people, as this might work only in those situations, where there are fewer chances of herding. In more serious situations, people should be left alone to decide. They, however, could be trained in drills, to avoid panicking in such situations and concentrate on making their decisions solely based on the dynamics of their surroundings. It was also learned that distant connectivity has no apparent advantage and can be ruled out while designing an evacuation strategy based on these recommendations.

Common Predisposing Factors in Mortality of Patients After Undergoing Mitral Valve Surgery at a Tertiary Care Hospital in Karachi

Background

Isolated mitral valve replacement is a routinely performed procedure at our institute due to higher prevalence of rheumatic heart disease in every age category. Hardly any researches are available that dictate the predictors of surgical mortality in isolated mitral valve procedure. The aim of this study was to identify the most prevailing pre-operative factors in patients who had mortality after isolated mitral valve surgery.

Methodology

A retrospective observational study of two years was performed from January 2018 to December 2019 at the Adult Cardiac Surgery Department of a tertiary care cardiac center in Karachi, Pakistan. Patients of either gender of age ranging from 16 to 65 years who had mortality within 30 days after isolated mitral valve surgery were included in the study. Variables assessed from records were anemia, New York Heart Association (NYHA) functional classification, prolonged symptoms, poor nutritional status, degree of left ventricular (LV) dysfunction, valve pathology, pulmonary artery hypertension, and cardiac arrhythmias.

Results

We report our isolated mitral valve mortality rate of 5.5% (38/697) in the two-year duration. The most commonly encountered pre-operative factors were severe mitral regurgitation and pulmonary artery hypertension, which were observed in 32 (84.2%) and 23 (60.5%) patients, respectively. Other factors that were common to these patients were higher NYHA functional class (class III in 23 [60.5%] and class IV in 9 [23.7%]), prolonged duration of symptoms (20 [52.6%]), and right ventricular dysfunction (moderate in 21 [55.3%] and severe in 7 [18.4%]).

Conclusions

The outcome of our study suggests that severe mitral regurgitation, pulmonary artery hypertension, high NYHA functional class, LV dysfunction, and prolonged symptoms were the common predisposing factor in patients with peri-operative mortality after isolated MVR.

An Overview of First 100 Cardiac Surgery Cases at a Newly Developed Satellite Center in Sukkur, Pakistan

Introduction

The aim of this research is to evaluate the in-hospital and early outcomes of the first 100 adult cardiac surgeries performed at a newly developed satellite center in Sukkur, Pakistan.

Methods

This is an audit of the first 100 adult cardiac surgeries performed at a newly developed satellite center of the National Institute of Cardiovascular Diseases (NICVD) at Sukkur, Pakistan, from March 2018 to November 2018 with 12 months of post-operative follow-up. Patients were offered off-pump coronary artery bypass (OPCAB), on-pump coronary artery bypass (ONCAB), mitral valve replacement (MVR), aortic valve replacement (AVR), minimally invasive cardiac surgery (MICS), and congenital adult congenital heart disease (ACHD) procedures by expert faculty of NICVD with a minimum of five years of post-fellowship experience.

Results

The mean age was 47.11 ± 14.6 years, with a male predominance of 77%. Hypertension and smoking were the most common risk factors that were observed in 32% and 33%, respectively, followed by diabetes and dyslipidemia with a frequency of 20% and 9%, respectively. The mean EuroSCORE (European System for Cardiac Operative Risk Evaluation) II for this patient cohort was 1.165 ± 0.50, with a maximum score of 2.3 in one patient. Out of 100 procedures, 51 were ONCAB, 19 were OPCAB, 16 were MVR, three were AVR, nine were ACHD, and two were MICS. Survival status post-operative as well as after one year was 100%. The frequency of post-operative bleeding was 7%, mean post-operative mechanical ventilation time was 213 ± 273 hours, and in-hospital stay was 5.41 ± 0.165 days. Lost to follow-up at one year was 4% (four). During the follow-up assessment, 39.5% of the patients had complained of mild-to-moderate intensity retrosternal pain and 4.2% had superficial surgical site infection of the sternal wound. A significant improvement in functional class was observed in 38.5% of patients, whereas 4.2% (four) had a significant drop in functional class post-operatively.

Conclusion

Providing tertiary care and early cardiac surgical facility to the people of Sukkur at their doorstep, in a newly developed satellite center, has resulted in improved outcomes, early quality treatment facility, and avoidance of long travel time.

Conversion from Off to On-Pump Coronary Artery Bypass Grafting. Is it Avoidable?

Background

With the emergence of new technologies to stabilize the heart off-pump coronary artery bypass grafting (OPCAB), there is an increasing trend that is being observed throughout the world. In certain circumstances, OPCAB needs to be converted to on-pump CABG (ONCAB). In this study, we aim to identify certain risk factors mandating conversions and their associated short-term outcomes.

Methods

After approval from the institutional ethical review committee and exemption from informed consent, retrospective data of 100 patients meeting the inclusion criteria who underwent OPCAB operations at our institution from August 2018 to July 2019 were included. Preoperative, intraoperative, and postoperative variables were recorded and compared in conversion and non-conversion groups. This study was conducted at the National Institute of Cardiovascular Diseases, Karachi, Pakistan.

Results

A total of 100 patients were included in this study, out of which 82% (82) were male, with age ranging between 18 and 77 years with a mean age of 56.34 ± 8.3 years. In nine of the cases, OPCAB was emergently converted to ONCAB due to arrhythmias. In nine (9%) cases, off-pump CABG was emergently converted to on-pump CABG (ONCAB). Emergent conversion was due to arrhythmias in five cases, due to hypotension during OM graft in two cases, and due to hypotension during ramus graft for the remaining two cases. The emergent conversion was significantly associated with higher New York Heart Association (NYHA) functional classification and comorbid conditions such as chronic obstructive pulmonary disease (COPD).

Conclusion

Emergency conversion from off-pump to OPCAB is the most catastrophic event causing higher morbidity and mortality. Conversion rate was observed to be 9% with arrhythmias being the common cause and patients with higher NYHA status and COPD at baseline were found to be at increased risk of emergency conversion. Considering our results in patients with diagnosed COPD and higher NYHA status, the decision for off-pump CABG should be wisely taken carefully weighing the risks and benefits.

Initial Experience of Minimally Invasive Concomitant Aortic and Mitral Valve Replacement/Repair at a Tertiary Care Cardiac Centre of a Developing Country

Introduction

Minimally invasive double valve replacement (DVR) surgery through a small transverse anterior thoracotomy is an alternate technique to sternotomy for concomitant aortic and mitral valve (AVR, MVR) surgery. The aim of this study was to evaluate the in-hospital and early outcomes of direct vision minimal invasive double valve surgery (DVMI-DVR) at a tertiary care cardiac center of a developing country.

Methods

This study was conducted at the National Institute of Cardiovascular Diseases Karachi, Pakistan from January 2018 to September 2018. Nineteen consecutive patients undergoing DVMI-DVR for aortic and mitral disease without any prior cardiac surgery were included in this study. For all procedures, access was obtained through small transverse anterior thoracotomy incision with wedge resection (Chaudhry’s Wedge) of sternum opposite to the third and fourth costosternal joints. Patients were observed during their hospital stay and the following variables were observed the length of hospital stay (LOHS), ventilator support, intensive care unit (ICU) stay, pain score, and mortality. The pain score was assessed using the visual analog scale (VAS).

Results

The male/female ratio was 11:8 with a mean age of 35 ± 12 years with mean EuroSCORE of 6.6 ± 3.5%. The mean total bypass time was 129.8 ± 23.83 min (range: 98-181 minutes). The mean mechanical ventilation time was 3.16 ± 1.12 hours (range: 2-6 hours). The mean intensive care unit (ICU) stay was 41.84 ± 8.36 hours. The mean post-operative LOHS was 5.63 ± 1.12 days (range: 4-8 days). We had zero frequency of wound infection and surgical mortality. The mean pain score was 4.32 (on a predefined pain scale of one to nine with a high value indicating severe pain).

Conclusion

Minimally invasive DVR surgery is a safe and reproducible technique with comparable outcomes such as postoperative pain score (4.32 ± 2.05), ventilation time (3.16 ± 1.12 hours), ICU stay (41.84 ± 8.36 hours), and hospital stay (5.63 ± 1.12 days). In terms of mortality, operative times, ICU stay, and hospital stay, the minimally invasive DVR is at least comparable to those achieved with median sternotomy. Further prospective randomized studies are needed to validate our findings.

Postoperative Atrial Fibrillation Among Patients Undergoing Isolated Coronary Artery Bypass Grafting

Introduction Postoperative atrial fibrillation (AF) is the commonest of all the known cardiac arrhythmias after cardiac surgery. The postoperative AF has both short- and long-term adverse impacts on patients, like prolonged intensive care unit (ICU) stay, increased frequency of reoperations, myocardial infarction, increased use of inotropes, and intra-aortic balloon pump (IABP). There is a paucity of data regarding the postoperative AF after isolated coronary artery bypass grafting (CABG) and its risk factors in our geographic location. Therefore, the aim of this study was to determine the frequency of postoperative atrial fibrillation among patients undergoing isolated CABG at a tertiary care hospital of Karachi, Pakistan. Methods This prospective observational study was conducted on 163 consecutively selected patients undergoing first time isolated CABG at the Department of Cardiothoracic Surgery, Aga Khan University Hospital, Karachi. Patients with redo-sternotomy, preoperative atrial fibrillation and with other cardiac pathology were excluded from the study. Postoperative AF was defined in the patients with postoperative 12-lead electrocardiographic (ECG) finding of absence of P waves, replaced by unorganized electrical activity and irregular R-R intervals. Data analysis was carried out using IBM SPSS Statistics for Windows, Version 21.0 (IBM Corp., Armonk, NY, USA). Results A total of 163 patients were enrolled with the mean age of 58.66 ± 9.77 years ranging between 40 and 85 years with male predominance of 81% (132). The most common comorbidity was hypertension in about 68.1% (111), followed by diabetes mellitus in 54.6% (89) patients. Postoperative AF was observed in 42 (25.8%) patients. Most of the patients who developed postoperative AF, were overweight with mean body mass index (BMI) of 27.04 ± 4.85 kg/m², 76.2% (32) had a history of hypertension, diabetes mellitus was associated with 33.3% (14) patients with postoperative AF and 50.0% (21) of them were smokers. Distribution of coronary artery disease in patients with postoperative AF was observed as three vessels coronary artery disease (3VCAD) in 83.3% (35), two-vessel coronary artery disease (2VCAD) was present in 7.1% (three), and rest of 9.5% (four) patients had single-vessel coronary artery disease (SVCAD). Conclusion The frequency of postoperative atrial fibrillation in our study was found to be 25.9% which is comparable to world literature. An important finding that comes through this study is a younger population undergoing CABG, which raises the possibility of early manifestation of ischemic heart disease in our region. This, however, needs further investigation. We were unable to point out the factors predictive of postoperative AF; studies with larger sample size would help in that regard.

Modeling human factors influencing herding during evacuation

Purpose

It has been witnessed that many incidents of crowd evacuation have resulted in catastrophic results, claiming lives of hundreds of people. Most of these incidents were a result of localized herding that eventually turned into global panic. Many crowd evacuation models have been proposed with different aspects of interests. The purpose of this paper is to attempt to bring together many of these aspects to study evacuation dynamics.

Design/methodology/approach

The proposed agent-based model, in a hypothetical physical environment, uses perception maps for routing decisions which are constructed from agents’ personal observations of the surroundings as well as information gathered through distant communication. Communication is governed by a trust model which measures the authenticity of the information being shared. Agents are of two types; emotional and rational. The trust model is combined with a game-theoretic model to resolve conflict of agents’ own type with that of types of agents in the neighborhood.

Findings

Evacuation dynamics in different environmental and exit strategies are evaluated on the basis of reduced herding and evacuation time. Using this integrated information sharing model, agents gain an overall view of the environment, sufficient to select the optimal path towards exits with respect to reduced herding and evacuation time.

Originality/value

The proposed model has been formulated and established using an agent-based simulation integrating important modeling aspects. The paper helps in understanding the interplay between technological and humanistic aspects in smart and pervasive environments.

Trust reality-mining: evidencing the role of friendship for trust diffusion

Value sensitive design is driven by the motivation of making social and moral values central to the development of ICT systems. Among the most challenging concerns when imparting shared values like accountability, transparency, liberty, fairness and trust into information technology are reliable and comprehensive formal and computational models of those values. This paper, educated by trust theories and models from cognitive science, social sciences and artificial intelligence, proposes a novel stochastic computational model of trust, encapsulating abstractions of human cognitive capabilities and empirically evidenced social interaction patterns. Qualitative and quantitative features of trust are identified, upon which our formal model is phrased. Reality mining methods are used to validate the model based on a real life community dataset. We analyze the time-varying dynamics of the interaction and communication patterns of the community, consider varying types of relationships as well as their symmetry. Social network data analysis shows that our model better fits the evolved friendships compared to a well designed synthetic trust model, which is used as the baseline.