Linkage of Emergency Medical Services and Hospital Data: A Necessary Precursor to Improve Understanding of Outcomes of Prehospital Care.

Objective: Linking emergency medical services (EMS) data to hospital outcomes is important for quality assurance and research initiatives. However, non-linkage due to missing or incomplete patient information may increase the risk of bias and distort findings. The purpose of this study was to explore if an optimization strategy, in addition to an existing linkage process, improved the linkage rate and reduced selection and information bias. Methods: 4,150 transported patients in a metropolitan EMS system in Alberta, Canada from 2016/17 were linked to two Emergency Department (ED) databases by a standard strategy using a unique health care number, date/time of ED arrival, and hospital name. An optimized strategy added additional linkage steps incorporating last name, year of birth, and a manual search. The strategies were compared to assess the rate of linkage, and to describe event and patient-level characteristics of unlinked records. Results: The standard strategy resulted in 3,650 out of 4,150 (88.0%) linked records (95% CI 86.9%-88.9%). Of the 500 non-linked records, an additional 381 were linked by the optimized strategy (n = 4,031/4,150 [97.1%; 95% CI: 96.6%-97.6%]). There were no false positive linkages. The highest linkage failure was in 25 to 34 year-old patients (n = 93/478, 19.5%), males (n = 236/1975, 12.0%), Echo level events (n = 15/77, 19.5%), and emergency transport (45/231, 19.5%). The optimized strategy improved linkage in these groups by 68.8% (64/93), 79.2% (187/236), 40.0% (6/15), and 51.1% (23/45) respectively. For dispatch card, the highest linkage failure occurred in Card 24-Pregnancy/Childbirth/Miscarriage (n = 30/44, 68.2%), Card 27-Stab/Gunshot/Penetrating Trauma (n = 6/17, 35.3%), and Card 9-Cardiac/Respiratory Arrest/Death (n = 12/46, 26.1%). The optimized strategy improved linkage by 10.0% (3/30), 83.3% (5/6), and 41.7% (5/12) respectively. For the 119 unlinked records, 71 (59.7%) had sufficient information for linkage, but no appropriately matching records could be found. Conclusion: An optimized sequential deterministic strategy linking EMS data to ED outcomes improved the linkage rate without increasing the number of false positive links, and reduced the potential for bias. Even with adequate information, some records were not linked to their ED visit. This study underscores the importance of understanding how data are linked to hospital outcomes in EMS research and the potential for bias.

The association between paramedic service system hospital offload time and response time.

OBJECTIVE: To address an important care issue in Canada, we tested the association between paramedic system hospital offload and response time, while considering the impact of other system-level factors. METHODS: Data from Calgary, Alberta (2014-2017), included median offload (exposure) and response (outcome) time aggregated by hour, with covariates paramedic system episodes of care-dispatch and arrival of a response unit-and hospital transport arrivals (collectively called volume), time of day, and season. Analyses used linear regression and modified Poisson models. RESULTS: 301,105 EMS episodes of care over 26,193 1-h periods were included. For any given 1-h period, the median (IQR) across all episodes of care for offload time, response time, episodes of care, and hospital transport arrivals were 55.3 (45.7, 66.3) min, 8.6 (7.6, 9.8) min, 12 (8, 16) episodes, and 8 (5, 10) hospital arrivals, respectively. Multivariable modelling revealed a complex association differing over levels of exposure and covariates, requiring description using "light stress" and "heavy stress" system scenarios. The light scenario was defined as median offload of 30 min and volume < 10th percentile (six episodes and four hospital arrivals), in the summer, and the heavy scenario as median offload of 90 min and volume > 90th percentile (17 episodes and 13 hospital arrivals), in the winter. An increase is reported in minutes:seconds for median hourly response time between scenarios by time of day: 1:04-4:16 (0000-0559 h.), 0:42-2:05 (0600-1159 h.), 0:57-3:01 (1200-1759 h.), and 0:18-2:21 (1800-2359 h.). CONCLUSIONS: Increasing offload is associated with increased response time; however the relationship is complex, with a greater impact on response time noted in select situations such as high volume in the winter. These observations illustrate the interdependence of paramedic, ED, and inpatient systems and provide high-yield targets for polices to mitigate the risk to community availability of paramedic resources at times of high offload delay/system stress.

ABSTRAIT: OBJECTIF: Afin de régler un problème important de soins au Canada, nous avons testé l'association entre le déchargement du système paramédical et le temps de réponse, tout en tenant compte de l'incidence d'autres facteurs au niveau du système. MéTHODES: Les données de Calgary, en Alberta (2014-2017) incluent le temps médian de déchargement (exposition) et de réponse (résultat) agrégé par heure, qui s'agit co-variables épisodes de soins du système paramédical - répartition et arrivée d'une unité d'intervention - et arrivées de transport hospitalier (collectivement appelé volume), l'heure et la saison. Les analyses ont utilisé la régression linéaire et des modèles de Poisson modifiés. RéSULTATS: 301105 épisodes de soins médicaux d'urgence sur 26193 périodes d'une heure ont été inclus. Pour une période d'une heure donnée, la médiane (QRI) pour tous les épisodes de soins pour le temps de déchargement, le temps de réponse, les épisodes de soins et les arrivées par transport à l'hôpital était de 55,3 (45,7, 66,3) minutes, 8,6 (7,6, 9,8) minutes, 12 (8, 16) épisodes et 8 (5, 10) arrivées à l'hôpital, respectivement. La modélisation multi-variable a révélé une association complexe qui varie selon les niveaux d'exposition et les co-variables, et qui nécessite une description à l'aide de scénarios de systèmes de « stress léger ¼ et de « stress lourd ¼. Le scénario léger a été défini comme un déchargement médian de 30 minutes, volume inférieur au 10e percentile (six épisodes et quatre arrivées à l'hôpital), pendant l'été. Le scénario lourd comme déchargement médian de 90 minutes, volume > 90e percentile (17 épisodes et 13 arrivées à l'hôpital), en hiver. Une augmentation est rapportée en minutes: secondes pour le temps de réponse horaire médian entre des scénarios par heure du jour : 1:04-4:16 (0000-0559 h.), 0:42-2:05 (0600-1159 h.), 0:57-3:01 (1200-1759 h.), et 0:18-2:21 (1800-2359 h.). CONCLUSIONS: L'augmentation du déchargement est associée à une augmentation du temps de réponse, mais la relation est complexe, avec un impact plus important sur le temps de réponse noté dans certaines situations, comme un volume élevé en hiver. Ces observations illustrent l'interdépendance des systèmes paramédicaux, des services d'urgence et des services aux patients hospitalisés et fournissent des cibles à haut rendement pour les politiques afin d'atténuer le risque pour la disponibilité des ressources paramédicales dans la collectivité en période de retard élevé ou de stress systémique.

Anti-thymocyte globulins capable of binding to T and B cells reduce graft-vs-host disease without increasing relapse.

Anti-thymocyte globulin (ATG) is polyclonal, containing Ab specificities capable of binding to various immune-cell subsets implicated in the pathogenesis of GVHD, including T cells, B cells, natural killer cells, monocytes/macrophages, neutrophils and DC. We wished to determine which ATG specificities are important for GVHD prevention. We measured day 7 serum levels of 23 ATG specificities in 120 hematopoietic cell transplant recipients whose myeloablative conditioning included 4.5 mg/kg ATG (thymoglobulin). High levels of ATG specificities capable of binding to T- and B-cell subsets were associated with a low likelihood of acute GVHD (aGVHD). High levels of these ATG specificities were associated with increased rates of viral but not bacterial or fungal infections. They were not associated with an increased risk of malignancy relapse; on the contrary, high levels of ATG specificities capable of binding to regulatory T cells and invariant NKT cells were associated with a low risk of relapse. In conclusion, high levels of ATG antibodies to Ag(s) expressed on T and B cells are associated with a low risk of aGVHD and a high risk of viral but not bacterial or fungal infections. These antibodies have neutral or beneficial effects on relapse.

IL15 levels on day 7 after hematopoietic cell transplantation predict chronic GVHD.

Chronic GVHD (cGVHD) is an important complication of allogeneic hematopoietic cell transplantation (HCT). As preemptive therapy might be efficacious if administered early post transplant, we set out to determine whether cGVHD can be predicted from the serum level of a biomarker on day 7 or 28. In a discovery cohort of 153 HCT recipients conditioned with BU, fludarabine and rabbit antithymocyte globulin (ATG), we determined serum levels of B-cell-activating factor, vascular endothelial growth factor, soluble TNF-α receptor 1, soluble IL2 receptor α, IL5, IL6, IL7, IL15, γ-glutamyl transpeptidase, cholinesterase, total protein, urea and ATG. Patients with low levels of IL15 (<30.6 ng/L) on day 7 had 2.7-fold higher likelihood of developing significant cGVHD (needing systemic immunosuppressive therapy) than patients with higher IL15 levels (P<0.001). This was validated in a validation cohort of 105 similarly-treated patients; those with low IL15 levels had 3.7-fold higher likelihood of developing significant cGVHD (P=0.001). Low IL15 was not associated with relapse; it trended to be associated with acute GVHD and was associated with low infection rates. In conclusion, low IL15 levels on day 7 are predictive of cGVHD, and thus could be useful in guiding preemptive therapy.