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Publications

Publications by LIAAD

2022

Process Evaluation of a Mixed Methods Feasibility Study to Identify Hospital Patients with Palliative Care Needs in Portugal

Authors
Antunes, B; Rodrigues, PP; Higginson, IJ; Ferreira, PL;

Publication
ACTA MEDICA PORTUGUESA

Abstract
Introduction: Evidence shows most patients are not recognised by their attending healthcare professionals as having palliative needs. This feasibility study aimed to aid healthcare professionals identify hospital patients with palliative needs. Material and Methods: Mixed-methods, cross-sectional, observational study. The patient inclusion criteria comprised: age over 18 years old, being mentally capable to give consent judged as such by participating healthcare professionals, and if unable, having a legal substitute to consent, having a diagnosis of an incurable, potentially life-threatening illness. Field notes were taken for reflexive purposes. Outcome measures included: Integrated Palliative Care Outcome scale, surprise question, phase of illness, referral request status, The Eastern Cooperative Oncology Group Performance Status and social needs assessment. An interim data collection period meeting assessed implementation outcomes in each context. A web-based survey was sent to all participating healthcare professionals at the end of data collection period to explore overall experiences of participation and implementation outcomes. Results: Forty-two departments in four hospitals were contacted. The study was presented in nine departments. The field notes were vital to understand the recruitment process and difficulties experienced: time constraints, fear of additional work, department dynamics and organisation, relationships between departments and need of training in palliative care and research. One department agreed to participate. There were six participating healthcare professionals and only 45 patients included. Three participating healthcare professionals responded to the web-based survey. Discussion: The response rate was very low. Legislating palliative care is not enough, and an integrated palliative care plan needs to be implemented at country and institution level. Conclusion: There is an urgent need to provide generalist palliative care training to clinicians.

2022

Association between co-morbidities and prescribed drugs in obstructive sleep apnea suspected patients: an inductive rule learning approach (Preprint)

Authors
Ferreira-Santos, D; Pereira Rodrigues, P;

Publication
Journal of Medical Internet Research

Abstract

2022

Effectiveness of Secondary Risk-Reducing Strategies in Patients With Unilateral Breast Cancer With Pathogenic Variants of BRCA1 and BRCA2 Subjected to Breast-Conserving Surgery: Evidence-Based Simulation Study

Authors
Maksimenko, J; Rodrigues, PP; Nakazawa Miklasevica, M; Pinto, D; Miklasevics, E; Trofimovics, G; Gardovskis, J; Cardoso, F; Cardoso, MJ;

Publication
JMIR FORMATIVE RESEARCH

Abstract
Background: Approximately 62% of patients with breast cancer with a pathogenic variant (BRCA1 or BRCA2) undergo primary breast-conserving therapy. Objective: The study aims to develop a personalized risk management decision support tool for carriers of a pathogenic variant (BRCA1 or BRCA2) who underwent breast-conserving therapy for unilateral early-stage breast cancer. Methods: We developed a Bayesian network model of a hypothetical cohort of carriers of BRCA1 or BRCA2 diagnosed with stage I/II unilateral breast cancer and treated with breast-conserving treatment who underwent subsequent second primary cancer risk-reducing strategies. Using event dependencies structured according to expert knowledge and conditional probabilities obtained from published evidence, we predicted the 40-year overall survival rate of different risk-reducing strategies for 144 cohorts of women defined by the type of pathogenic variants (BRCA1 or BRCA2), age at primary breast cancer diagnosis, breast cancer subtype, stage of primary breast cancer, and presence or absence of adjuvant chemotherapy. Results: Absence of adjuvant chemotherapy was the most powerful factor that was linked to a dramatic decline in survival. There was a negligible decline in the mortality in patients with triple-negative breast cancer, who received no chemotherapy and underwent any secondary risk-reducing strategy, compared with surveillance. The potential survival benefit from any risk-reducing strategy was more modest in patients with triple-negative breast cancer who received chemotherapy compared with patients with luminal breast cancer. However, most patients with triple-negative breast cancer in stage I benefited from bilateral risk-reducing mastectomy and risk-reducing salpingo-oophorectomy or just risk-reducing salpingo-oophorectomy. Most patients with luminal stage I/II unilateral breast cancer benefited from bilateral risk-reducing mastectomy and risk-reducing salpingo-oophorectomy. The impact of risk-reducing salpingo-oophorectomy in patients with luminal breast cancer in stage I/II increased with age. Most older patients with the BRCA1 and BRCA2 pathogenic variants in exons 12-24/25 with luminal breast cancer may gain a similar survival benefit from other risk-reducing strategies or surveillance. Conclusions: Our study showed that it is mandatory to consider the complex interplay between the types of BRCA1 and BRCA2 pathogenic variants, age at primary breast cancer diagnosis, breast cancer subtype and stage, and received systemic treatment. As no prospective study results are available at the moment, our simulation model, which will integrate a decision support system in the near future, could facilitate the conversation between the health care provider and patient and help to weigh all the options for risk-reducing strategies leading to a more balanced decision.

2022

Helping early obstructive sleep apnea diagnosis with machine learning: A systematic review (Preprint)

Authors
Ferreira-Santos, D; Amorim, P; Silva Martins, T; Monteiro-Soares, M; Pereira Rodrigues, P;

Publication

Abstract
BACKGROUND

American Academy of Sleep Medicine guidelines suggests that clinical prediction algorithms can be used to screen obstructive sleep apnea (OSA) patients without replacing polysomnography (PSG) – the gold standard.

OBJECTIVE

We aimed to identify, gather, and analyze existing machine learning approaches that are being used for disease screening in adult patients suspected of OSA.

METHODS

We searched MEDLINE, Scopus and ISI Web of Knowledge databases for evaluating the validity of different machine learning techniques, with PSG as the gold standard outcome measures. This systematic review was registered in PROSPERO under reference CRD42021221339.

RESULTS

Our search retrieved 5479 articles, of which 63 articles were included. We found 23 studies performing diagnostic models’ development alone, 26 with added internal validation, and 14 applying the clinical prediction algorithm to an independent sample (although not all reporting the most common discrimination metrics - sensitivity and/or specificity). Logistic regression was applied in 35 studies, linear regression in 16, support vector machine in 9, neural networks in 8, decision trees in 6, and Bayesian networks in 4. Random forest, discriminant analysis, classification and regression tree, and nomogram were each performed in 2 studies, while Pearson correlation, adaptative neuro-fuzzy inference system, artificial immune recognition system, genetic algorithm, supersparse linear integer models, and k-nearest neighbors’ algorithm each in 1 study. The best AUC was .98 [.96-.99] for age, waist circumference, Epworth somnolence, and oxygen saturation as predictors in a logistic regression.

CONCLUSIONS

Although high values were obtained, they still lack external validation results in large cohorts and a standard OSA criteria definition.

2022

Flexible Fine-grained Data Access Management for Hyperledger Fabric

Authors
Parente, J; Alonso, AN; Coelho, F; Vinagre, J; Bastos, P;

Publication
2022 FOURTH INTERNATIONAL CONFERENCE ON BLOCKCHAIN COMPUTING AND APPLICATIONS (BCCA)

Abstract
As blockchains go beyond cryptocurrencies into applications in multiple industries such as Insurance, Healthcare and Banking, handling personal or sensitive data, data access control becomes increasingly relevant. Access control mechanisms proposed so far are mostly based on requester identity, particularly for permissioned blockchain platforms, and are limited to binary, all-or-nothing access decisions. This is the case with Hyperledger Fabric's native access control mechanisms and, as permission updates require consensus, these fall short regarding the flexibility required to address GDPR-derived policies and client consent management. We propose SDAM, a novel access control mechanism for Fabric that enables fine-grained and dynamic control policies, using both contextual and resource attributes for decisions. Instead of binary results, decisions may also include mandatory data transformations as to conform with the expressed policy, all without modifications to Fabric. Results show that SDAM's overhead w.r.t baseline Fabric is acceptable. The scalability of the approach w.r.t to the number of concurrent clients is also evaluated and found to follow Fabric's.

2022

Poster: User Sessions on Tor Onion Services: Can Colluding ISPs Deanonymize Them at Scale?

Authors
Lopes, D; Medeiros, P; Dong, JD; Barradas, D; Portela, B; Vinagre, J; Ferreira, B; Christin, N; Santos, N;

Publication
Proceedings of the 2022 ACM SIGSAC Conference on Computer and Communications Security, CCS 2022, Los Angeles, CA, USA, November 7-11, 2022

Abstract
Tor is the most popular anonymity network in the world. It relies on advanced security and obfuscation techniques to ensure the privacy of its users and free access to the Internet. However, the investigation of traffic correlation attacks against Tor Onion Services (OSes) has been relatively overlooked in the literature. In particular, determining whether it is possible to emulate a global passive adversary capable of deanonymizing the IP addresses of both the Tor OSes and of the clients accessing them has remained, so far, an open question. In this paper, we present ongoing work toward addressing this question and reveal some preliminary results on a scalable traffic correlation attack that can potentially be used to deanonymize Tor OS sessions. Our attack is based on a distributed architecture involving a group of colluding ISPs from across the world. After collecting Tor traffic samples at multiple vantage points, ISPs can run them through a pipeline where several stages of traffic classifiers employ complementary techniques that result in the deanonymization of OS sessions with high confidence (i.e., low false positives). We have responsibly disclosed our early results with the Tor Project team and are currently working not only on improving the effectiveness of our attack but also on developing countermeasures to preserve Tor users' privacy.

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