Methods for identifying health state transitions from administrative data: the case of metastasis in prostate cancer

Introduction Health administrative data are a rich source of population-based information, useful for building state transition models for medical decision making. These models require identification of health state transitions and associated times. Indirect methods are needed to predict this information, as it is rarely available in administrative data. Objectives and Approach We considered a set of criteria to identify transitions to metastasis for prostate cancer patients in administrative data, utilizing dates of diagnostic and medical billing codes for secondary malignancy, palliative radiation therapy, chemotherapy and bone disorders or procedures. We evaluated the criteria using the true date of metastasis from medical charts of 195 patients linked to health care administrative data in Ontario, Canada. We also built a recursive partitioning tree to optimally combine these criteria and construct rules for identifying metastatic patients. For the evaluation, both misclassification and discrepancy between true and predicted dates for the true positives were considered. Results Criteria involving chemotherapy drugs or hospital visits with secondary malignancy ICD10 diagnosis gave the best results, with high sensitivity and specificity. Criteria involving bone related problems, radiation therapy or diagnosis of metastatic cancer in physician billing data were very specific but not sensitive. The criterion involving prescriptions for narcotics was sensitive but not specific. The fitted tree was parsimonious involving only two of the criteria, while improving the accuracy over individual criteria. Most criteria gave a “delayed” prediction, with criterion based on chemotherapy giving on average the smallest delay, as well as exhibiting the least variability. Criteria involving narcotics and bone related problems predicted metastasis date very prematurely, probably triggered by conditions other than prostate cancer. Conclusion/Implications Several criteria from administrative databases satisfactorily classified prostate cancer patients with metastasis. A classification tree was built and improved the results over single criteria, demonstrating the added benefits in using advanced statistical learning methods for this task. However, “transition to metastasis” dates were predicted inaccurately, often with significant delay

Direct wire read out electronics for the Hasylab-Zeuthen-Wirescanner

Wire scanners are used to measure the profile and the position of particle beams and are therefore ubiquitous in accelerator facilities. A wire passes through the electron beam, causing a charge on the wire and the deflection of beam particles itself. The particles bended by the wire are detected by a scintillation counter. The maximum of the photomultiplier signal corresponds with the center of the beam profile. Independent information is provided when detecting the charge deposited on the wire. Following, is a short introduction of the physical difficulty of detecting the signal influenced on the wire, a possible realization of the necessary electronics and showingpreliminary results of measurements carried out at the Tesla Test Facility TTF I inHamburg and the Photon Injector PITZ at Zeuthen

Factors Affecting Referral and Patient Access to Heart Function Clinics in Ontario: A Qualitative Study of Stakeholders

Background: Though heart failure patients benefit from multidisciplinary care in heart function clinics (HFCs), utilization is suboptimal and inequitable. This study investigated factors influencing referral and patient access to HFCs from multiple stakeholders' perspectives, namely policy-makers (PM), providers at HFCs and patients. Methods: In this qualitative study, semi-structured interviews with a purposive sample of Ontario stakeholders were conducted between February-June 2020 and July-December 2022 (paused due to pandemic) via Teams. Interview transcripts were concurrently analyzed using systematic text condensation with Nvivo. Two authors coded individually, with disagreements discussed with senior author. Results: Interviews with 7 HFCs (6 physicians, 1 nurse), 6 PM and 4 patients were completed before saturation; 5 themes emerged. First, with regard to health system organization, stakeholders reported gaps related to continuity of care, limited capacity and insufficient funding. Second, with regard to referral appropriateness and timeliness, sub-themes related to unclear referral criteria, varying clinic scope, and delays in triage, testing and time-to-visit. The third theme related to clinic characteristics, raised issues of varying clinic services and composition of healthcare professions/expertise. The fourth theme regarding patient factors related to comorbidity/frailty, socioeconomic status, barriers due to location (parking, traffic) and affinity to specific providers. The final theme related to the COVID-19 pandemic concerned increased referral volumes, loss to follow-up care, transition to online delivery modalities and patient refusal of in-person visits. Many facilitators to improve HFC referral and access were raised. Conclusions: Resources must be provided, and stakeholders brought together to standardize and integrate the HF care continuum.The authors are grateful to other members of the expert advisory panel who gave input on the ideas and the interview guide, including Drs. Doug Lee and Sean Virani, and the patient partners from the HeartLife Foundation. The study was approved by the institutional review boards of University Health Network (CAPCR ID#19-6171) and York University, Toronto. All participants provided written informed consent. This research was supported through a postdoctoral fellowship from the Ted Rogers Centre for Heart Research, University Health Network, Canada. No other specific grant was received from any funding agency in the public, commercial or not-for-profit sectors. The authors have no conflicts of interest to disclose.Scopu