Information Storage and Retrieval for Probe Storage using Optical Diffraction Patterns

A novel method for fast information retrieval from a probe storage device is considered. It is shown that information can be stored and retrieved using the optical diffraction patterns obtained by the illumination of a large array of cantilevers by a monochromatic light source. In thermo-mechanical probe storage, the information is stored as a sequence of indentations on the polymer medium. To retrieve the information, the array of probes is actuated by applying a bending force to the cantilevers. Probes positioned over indentations experience deflection by the depth of the indentation, probes over the flat media remain un-deflected. Thus the array of actuated probes can be viewed as an irregular optical grating, which creates a data-dependent diffraction pattern when illuminated by laser light. We develop a low complexity modulation scheme, which allows the extraction of information stored in the pattern of indentations on the media from Fourier coefficients of the intensity of the diffraction pattern. We then derive a low-complexity maximum likelihood sequence detection algorithm for retrieving the user information from the Fourier coefficients. The derivation of both the modulation and the detection schemes is based on the Fraunhofer formula for data-dependent diffraction patterns. We show that for as long as the Fresnel number F<0.1, the optimal channel detector derived from Fraunhofer diffraction theory does not suffer any significant performance degradation.Comment: 14 pages, 11 figures. Version 2: minor misprints corrected, experimental section expande

Evaluating the long-term effects of a data-driven approach to reduce variation in emergency department pathology investigations: study protocol for evaluation of the NSW Health Pathology Atlas of variation

IntroductionVariation in test ordering is a major issue in Australia and globally with significant financial and clinical impacts. There is currently a lack of research identifying and remediating variation in the use of pathology tests in emergency departments (EDs). In 2019, NSW Health Pathology introduced the Pathology Atlas of Variation that uses a data-driven tool (the Atlas Analytical Model) to investigate test order variation across New South Wales (NSW) and engage with local health districts (LHDs) to reduce variation. The objectives of this study are to evaluate whether this data-driven approach is associated with: (1) a reduction in test order variation; (2) improvements in patient outcomes and (3) cost benefits, for the five most frequent ED presentations.Methods and analysisThis is a large multisite study including 45 major public hospitals across 15 LHDs in NSW, Australia. The Atlas Analytical Model is a data analytics and visualisation tool capable of providing analytical insights into variation in pathology investigations across NSW EDs, which will be used as feedback to inform LHDs efforts to reduce variation. Interrupted time series analyses using 2 years pre Atlas (2017–2018) and 2 years post Atlas (2021–2022) data will be conducted. Study data will be obtained by linking hospital and laboratory databases. Funnel plots will be used to identify EDs with outlying pathology test ordering practices. The outcome measures include changes in test ordering practices, ED length of stay, hospital admission and cost benefits (total pathology costs per ED encounter).Ethics and disseminationThe study has received ethical approval from the NSW Population and Health Service Research Ethics Committee (reference, 2019/ETH00184). The findings of the study will be published in peer-reviewed journals and disseminated via presentations at conferences. We will also engage directly with key stakeholders to disseminate the findings and to inform policies related to pathology testing in the ED.</jats:sec

COVID-19: protocol for observational studies utilizing near real-time electronic Australian general practice data to promote effective care and best-practice policy—a design thinking approach

Background: Health systems around the world have been forced to make choices about how to prioritize care, manage infection control and maintain reserve capacity for future disease outbreaks. Primary healthcare has moved into the front line as COVID-19 testing transitions from hospitals to multiple providers, where tracking testing behaviours can be fragmented and delayed. Pooled general practice data are a valuable resource which can be used to inform population and individual care decision-making. This project aims to examine the feasibility of using near real-time electronic general practice data to promote effective care and best-practice policy. Methods: The project will utilize a design thinking approach involving all collaborators (primary health networks [PHNs], general practices, consumer groups, researchers, and digital health developers, pathology professionals) to enhance the development of meaningful and translational project outcomes. The project will be based on a series of observational studies utilizing near real-time electronic general practice data from a secure and comprehensive digital health platform [POpulation Level Analysis and Reporting (POLAR) general practice data warehouse]. The study will be carried out over 1.5 years (July 2020–December 2021) using data from over 450 general practices within three Victorian PHNs and Gippsland PHN, Eastern Melbourne PHN and South Eastern Melbourne PHN, supplemented by data from consenting general practices from two PHNs in New South Wales, Central and Eastern Sydney PHN and South Western Sydney PHN. Discussion: The project will be developed using a design thinking approach, leading to the building of a meaningful near real-time COVID-19 geospatial reporting framework and dashboard for decision-makers at community, state and nationwide levels, to identify and monitor emerging trends and the impact of interventions/policy decisions. This will integrate timely evidence about the impact of the COVID-19 pandemic related to its diagnosis and treatment, and its impact across clinical, population and general practice levels

Characterising deviation from treat-to-target strategies for early rheumatoid arthritis: the first three years

INTRODUCTION: Treat-to-target (T2T) strategies using a protocol of pre-defined adjustments of disease-modifying anti-rheumatic drugs (DMARDs) according to disease activity improve outcomes for patients with rheumatoid arthritis (RA). However, successful implementation may be limited by deviations from the protocol. The aim of this study was to determine the prevalence of protocol deviation, explore the reasons and identify subsets of patients in whom treatment protocols are more difficult to follow. METHODS: In this retrospective cohort study, treatment-naïve patients with RA of less than one year's duration, attending a dedicated early arthritis clinic between 2001 and 2013, were followed for three years from initiation of combination therapy with conventional DMARDs which was subsequently modified according to a T2T protocol. At each clinic visit, whether deviation from the protocol occurred, the type of deviation and the reasons for deviation were assessed. The relationship between protocol deviations and baseline variables was determined using linear regression analysis. RESULTS: In total, 198 patients contributed 3,654 clinic visits. The prevalence of protocol deviations was 24.5% and deviation in at least at one clinic visit was experienced by 90.4% of patients. The median time to first deviation was 30 weeks. Continuing existing treatment rather than intensifying therapy was the most common type of deviation (59.9%). Patient and physician related factors were the most common reasons for deviation, each accounting for 24.7% of deviations, followed by toxicities (23.3%) and comorbidities (20.0%). The prevalence of protocol deviations was lower among patients who achieved remission after three years (13.1%; 162 deviations out of 1,228 visits) compared with those who were not in remission (30.9%; 523/1692) (P<0.0001). On multivariate analysis, only body mass index (P=0.003) and helplessness score (P=0.04) were independent predictors of protocol deviations although the predictive power of the model was not strong (R2=0.17). CONCLUSIONS: Deviation from a T2T protocol occurred in one quarter of visits, indicating that applying the T2T approach is feasible in clinical practice. Failure to escalate dose when indicated was commonly encountered, and just under half of the observed deviations were related to either toxicities or comorbidities and were therefore justifiable on clinical grounds.Nasir Wabe, Michael J Sorich, Mihir D Wechalekar, Leslie G Cleland, Leah McWilliams, Anita Lee, Llewellyn Spargo, Robert G Metcalf, Cindy Hall, Susanna M Proudman, and Michael D Wies

Timing of respiratory virus molecular testing in emergency departments and its association with patient care outcomes: A retrospective observational study across six Australian hospitals

© 2019 Author(s). Objective: A rapid molecular diagnostic test (RMDT) offers a fast and accurate detection of respiratory viruses, but its impact on the timeliness of care in the emergency department (ED) may depend on the timing of the test. The aim of the study was to determine if the timing of respiratory virus testing using a RMDT in the ED had an association with patient care outcomes. Design: Retrospective observational study. Setting: Linked ED and laboratory data from six EDs in New South Wales, Australia. Participants: Adult patients presenting to EDs during the 2017 influenza season and tested for respiratory viruses using a RMDT. The timing of respiratory virus testing was defined as the time from a patient's ED arrival to time of sample receipt at the hospital laboratory. Outcome measures: ED length of stay (LOS), >4 hour ED LOS and having a pending RMDT result at ED disposition. Results: A total of 2168 patients were included. The median timing of respiratory virus testing was 224 min (IQR, 133-349). Every 30 min increase in the timing of respiratory virus testing was associated with a 24.0 min increase in the median ED LOS (95% CI, 21.8-26.1; p4 hours in ED (OR, 1.51; 95% CI, 1.41 to 1.63; p<0.001) and a 4% increase in the likelihood of having a pending RMDT result at ED disposition (OR, 1.04; 95% CI, 1.02 to 1.05; p<0.001) after adjustment for confounders. Conclusion: The timing of respiratory virus molecular testing in EDs was significantly associated with a range of outcome indicators. Results suggest the potential to maximise the benefits of RMDT by introducing an early diagnostic protocol such as triage-initiated testing

Effect of adherence to protocolized targeted intensifications of disease-modifying antirheumatic drugs on treatment outcomes in rheumatoid arthritis: results from an Australian early arthritis cohort

Objective: To investigate the association between adherence to treat-to-target (T2T) protocol and disease activity, functional outcomes, and radiographic outcomes in early rheumatoid arthritis (RA). Methods: Data from a longitudinal cohort of patients with early RA were used. Adherence was determined at each followup visit over 3 years according to predefined criteria. The primary endpoint was remission according to Disease Activity Score in 28 joints (DAS28) and Simplified Disease Activity Index (SDAI) criteria. Functional and radiographic outcomes measured by modified Health Assessment Questionnaire and modified total Sharp score, respectively, were secondary endpoints. Results: A total of 198 patients with 3078 clinic visits over 3 years were included in this analysis. After adjusting for relevant variables, although there was no significant association between adherence to T2T and remission rate after 1 year, the associations reached significance after 3 years for both DAS28 (OR 1.71, 95% CI 1.16-2.50; p = 0.006) and SDAI criteria (OR 1.94, 95% CI 1.06-3.56; p = 0.033). After 3 years, adherence was also associated with improvement in physical function (β=0.12, 95% CI 0.06-0.18; p < 0.0001). None of the radiographic outcomes were associated with adherence after either 1 or 3 years, although there was a trend for higher adherence to be associated with less radiographic progression at the end of the study (p = 0.061). Conclusion: Increased adherence to T2T was associated with better longterm disease activity and functional outcomes, which suggests that the benefit of a T2T protocol may be enhanced by ensuring adequate adherence.Nasir T. Wabe, Michael J. Sorich, Mihir D. Wechalekar, Leslie G. Cleland, Leah McWilliams, Anita T.Y. Lee, Llewellyn D. Spargo, Robert G. Metcalf, Cindy Hall, Susanna M. Proudman, and Michael D. Wies

Drug-induced toxicity and patient reported outcomes in rheumatoid arthritis patients following intensive treated-to-target strategy: does ceasing therapy due to toxicity worsen outcomes in long term?

Aim: While the introduction of the treat-to-target (T2T) strategy has been an important advance in the management of rheumatoid arthritis (RA), the potential for increased toxicity due to use of concurrent drugs could adversely affect patient reported outcomes (PROs). The objective was to determine whether the cessation of therapy due to toxicity affects long-term improvement in PROs in patients treated according to T2T strategy. Methods: A total of 149 patients from an inception cohort of early RA were included. The occurrence and severity of toxicity were monitored at each visit over 3 years. PROs studied were function (measured using health assessment questionnaire); pain, fatigue and patient global assessment (PtGA) all assessed using a 100 mm visual analogue scale; helplessness and health-related quality of life (HRQoL). For each PRO, effect of drug withdrawal was measured by comparing mean change in PROs among patients with no/temporary vs. permanent withdrawal. In addition, effects of frequency of drug withdrawals, weeks to withdrawal and number of drugs withdrawn were analysed using linear regression. Result: After 3 years, 56 (37.4%) patients ceased at least one drug permanently due to toxicity. Patients with no/temporary withdrawal (n = 93) achieved significantly greater improvement in function (mean change = -0.54 vs. -0.31, p = 0.033), pain (mean change = -39.82 vs. -5.02, p = 0.018), fatigue (mean change = -29.14 vs. -14.76, p = 0.015) and PtGA (mean change = -29.64 vs. -17.00, p = 0.018) compared with their counterparts. Higher frequency of withdrawals was associated with lesser improvements in function, pain, fatigue and PtGA, while the number of drugs withdrawn and the weeks to withdrawal had lesser effects. However, the cessation of the drugs due to their toxicity did not have a significant association with HRQoL and helplessness. Conclusion: Improvements in function, pain, fatigue and PtGA at 3 years were diminished for patients who ceased drugs due to toxicity while broader measures of HRQoL were not affected.N. Wabe, M.J. Sorich, M.D. Wechalekar, L.G. Cleland, L. McWilliams, A. Lee, C. Hall, L. Spargo, R. Metcalf, S.M. Proudman, M.D. Wies