Capturing Intravenous Thrombolysis for Acute Stroke at the ICD‐9 to ICD‐10 Transition: Case Volume Discontinuity in the United States National Inpatient Sample

Background Transition from International Classification of Diseases ( ICD ) Ninth and Tenth Revisions ( ICD‐9 and ICD‐10 ) for hospital discharge data was mandated for US hospitals on October 1, 2015. We examined the volume of patients receiving thrombolysis in ischemic stroke (IS) identified using ICD codes within this transition period in the 2015 to 2016 National Inpatient Sample, a weighted 20% sample of all inpatient US hospital discharges. Methods and Results During the ICD‐10 period, 2 case identification strategies were used. Codes for IS were combined with: (1) only the ICD‐10 code for thrombolytic given into a peripheral vein and (2) all new ICD‐10 codes mapped to the ICD‐9 code for all thrombolysis. On visual inspection there was an obvious discontinuity in the volume of patients with IS treated with IV thrombolysis corresponding to 3 time periods: ICD‐9 (study period 1), transition (period 2), and ICD‐10 (period 3). With Strategy 1, analysis using a linear spline with 2 knots shows that the volume of patients with IS treated with IV thrombolysis was significantly different between study periods 1 and 2 (slope difference −1880, 95% CI −2834 to −928, P =0.005), and periods 2 to 3 (slope difference 1980, 95% CI 1207–2754, P = 0.002). With Strategy 2, volumes did not change significantly between periods 1 to 2, though there was a significant difference between periods 2 and 3 (slope difference 719, 95% CI 91–1347, P =0.034). Conclusions The significant discontinuity in thrombolysis volumes for IS during the transition period for ICD‐9 to ICD‐10 coding suggests that more rigorous validation of US administrative data during this time period may be necessary for research, resource planning, and quality assurance.

Testing and Interpreting Interaction Effects

Researchers often want to test whether the association between two or more variables depends on the value of a different variable. To do this, they usually test interactions, often in the form of moderated multiple regression (MMR) or its extensions. If there is an interaction effect, it means the relationship being tested does differ as the other variable (moderator) changes. While methods for determining whether an interaction exists are well established, less consensus exists about how to understand, or probe, these interactions. Many of the common methods (e.g., simple slope testing, regions of significance, use of Gardner et al.’s typology) have some reliance on post hoc significance testing, which is unhelpful much of the time, and also potentially misleading, sometimes resulting in contradictory findings. A recommended procedure for probing interaction effects involves a systematic description of the nature and size of interaction effects, considering the main effects (estimated after centering variables) as well as the size and direction of the interaction effect itself. Interaction effects can also be more usefully plotted by including both a greater range of moderator values and showing confidence bands. Although two-way linear interactions are the most common in the literature, three-way interactions and nonlinear interactions are also often found. Again, methods for testing these interactions are well known, but procedures for understanding these more complex effects have received less attention—in part because of the greater complexity of what such interpretation involves. For three-way linear interactions, the slope difference test has become a standard form of interpretation and linking the findings with theory; however, this is also prone to some of the shortcomings described for post hoc probing of two-way effects. Descriptions of three-way interactions can be improved by using some of the same principles used for two-way interactions, as well as by the appropriate use of the slope difference test. For nonlinear effects, the complexity is greater still, and a different approach is needed to explain these effects more helpfully, focusing on describing the changing shape of the effects across values of the moderator(s). Some of these principles can also be carried forward into more complex models, such as multilevel modeling, structural equation modeling, and models that involve both mediation and moderation.

2015 Guidelines for Cardiopulmonary Resuscitation and survival after adult and paediatric out-of-hospital cardiac arrest

Aims To evaluate whether the introduction of the 2015 Guidelines for Cardiopulmonary Resuscitation were associated with a change in outcomes after out-of-hospital cardiac arrest (OHCA). Methods and results Patients with OHCA were divided into adults (≥18 years) and paediatric cases (<18 years). An interrupted time-series analysis was used to compare survival before (pre-guidelines 1 January 2013 to 31 October 2015) and after (post-guidelines 1 May 2016 to 31 December 2018) introduction of the 2015 guidelines. We fitted a regression model after dividing the time-period into segments with separate intercept and slope estimates. We included 309 499 adults and 8668 children with OHCA. There was no difference in the change in survival to hospital discharge with a favourable functional outcome per year between the two periods for adults {slope difference: −0.07% [95% confidence interval (CI) −0.30 to 0.16], P = 0.55} and paediatric cases [slope difference: −0.01% (95% CI −1.35 to 1.32), P = 0.98]. Likewise, we found no immediate change in survival to hospital discharge with a favourable functional outcome between the two periods for adults [0.20% (95% CI −0.21 to 0.61), P = 0.33] and paediatric cases [−1.08 (95% CI −3.44 to 1.27), P = 0.37]. Conclusion Publication of the 2015 Guidelines for Cardiopulmonary Resuscitation was not associated with an increase in survival to hospital discharge with a favourable functional outcome after OHCA. Outcomes for OHCA have not improved the last 6 years in the USA.

Assessment of the Running Slope Difference (RSD) t-Test, a new statistical method for detecting climate trend turning

<p>Global mean surface air temperature (GMT) rose roughly 0.85 °C from 1880 to 2012 (IPCC 2013), attributing mainly to an increase in atmospheric greenhouse gases. For different decadal timescale periods in the past 100 years, the warming rate of different periods may significantly different. For example, IPCC AR1 (1990) point out that GMT between 1910-1940 and 1975-1990 are significantly warming, meanwhile GMT stay nearly constant between 1940 and early 1970. The phenomenon of two nearby periods showing significantly different trends is knowing as trend turning, this phenomenon is common in climate time series and crucial when climate change is investigated. However, the available detection methods for climate trend turnings are relatively few, especially for the methods which have the ability of detecting multiple trend turnings. We propose a new methodology named as the running slope difference (RSD) t-test to detect multiple trend turnings. This method employs a t-distributed statistic of slope difference to test the sub-series trends difference of the time series, thereby identify the turning-points. We compare the RSD t-test method with some other existing trend turning detection methods with an idealized time series case and several climate time series cases. And we also report the Monte Carlo simulation used to evaluate this method’s detection ability. Results show that the RSD t-test method is an effective tool for detecting trend turning in time series, and this method has three major advantages: ability to detect multiple turning-points, capacity to detect all three types of trend turning, and great performance of avoiding false alarm.</p>

Extreme ultraviolet quasar colours from GALEX observations of the SDSS DR14Q catalogue

ABSTRACT The rest-frame far to extreme ultraviolet (UV) colour–redshift relationship has been constructed from data on over $480\, 000$ quasars carefully cross-matched between SDSS Data Release 14 and the final GALEX photometric catalogue. UV matching and detection probabilities are given for all the quasars, including dependencies on separation, optical brightness, and redshift. Detection limits are also provided for all objects. The UV colour distributions are skewed redward at virtually all redshifts, especially when detection limits are accounted for. The median GALEX far-UV minus near-UV (FUV − NUV) colour–redshift relation is reliably determined up to z ≈ 2.8, corresponding to rest-frame wavelengths as short as 400 Å. Extreme UV (EUV) colours are substantially redder than found previously, when detection limits are properly accounted for. Quasar template spectra were forward modelled through the GALEX bandpasses, accounting for intergalactic opacity, intrinsic reddening, and continuum slope variations. Intergalactic absorption by itself cannot account for the very red EUV colours. The colour–redshift relation is consistent with no intrinsic reddening, at least for SMC-like extinction. The best model fit has a FUV continuum power-law slope αν, FUV = −0.34 ± 0.03 consistent with previous results, but an EUV slope αν, EUV = −2.90 ± 0.04 that is much redder and inconsistent with any previous composite value (all ≳ −2.0). The EUV slope difference can be attributed in part to the tendency of previous studies to preferentially select UV brighter and bluer objects. The weak EUV flux suggests quasar accretion disc models that include outflows such as disc winds.

Decrease in blood donation rates in Japan: a time series analysis

ABSTRACT: Objective: To clarify that one of the causes for the decrease in blood donation (BD) rates was the introduction of the 400 ml BD program in 1986. Method: BP rates were monitored over 48 years (1965-2012) and were divided into pre- and post-intervention periods prior to analysis. An interrupted time series analysis was performed using annual data on BD rates, and the impact of the 400 ml BD program was investigated. Results: In a raw series, autoregressive integrated moving average analysis revealed a significant change in slope between the pre- and post-intervention periods in which the intervention factor was the 400 ml BD program. The parameters were as follows: intercept (initial value) = 0.315, confidence interval (CI) = (0.029, 0.601); slope (pre-intervention) = 0.316, CI = (0.293, 0.340); slope difference = -0.435, CI = (-0.462, -0.408); slope (post-intervention) = -0.119, CI = (-0.135, -0.103); all, p = 0.000; goodness-of-fit, R2 = 0.963. After adjusting for stationarity and autocorrelation, the parameters were as follows: intercept (initial value) = -0.699, CI = (-0.838, -0.560); slope (pre-intervention) = 0.136, CI = (0.085, 0.187); slope difference = -0.165, CI = (-0.247, -0.083); slope (post-intervention) = -0.029, CI = (-0.070, 0.012); all, p = 0.000 (except for slope (post-intervention), p = 0.170); goodness-of-fit, R2 = 0.930. Conclusion: One of the causes for decrease in BD rates may be due to the introduction of the 400 ml BD program in Japan.

The Association Between Tibial Slope and Revision Anterior Cruciate Ligament Reconstruction in Patients ≤21 Years Old: A Matched Case-Control Study Including 317 Revisions

Background: There is evidence that tibial slope may play a role in revision risk after anterior cruciate ligament reconstruction (ACLR); however, prior studies are inconsistent. Purpose: To determine (1) whether there is a difference in lateral tibial posterior slope (LTPS) or medial tibial posterior slope (MTPS) between patients undergoing revised ACLR and those not requiring revision and (2) whether the medial-to-lateral slope difference is different between these 2 groups. Study Design: Case-control study; Level of evidence, 3. Methods: We conducted a matched case-control study (2006-2015). Cases were patients aged ≤21 years who underwent revision surgery after primary unilateral ACLR; controls were patients aged ≤21 years without revision who were identified from the same source population. Controls were matched to cases by age, sex, body mass index, race, graft type, femoral fixation device, and post-ACLR follow-up time. Tibial slope measurements were made by a single blinded reviewer using magnetic resonance imaging. The Wilcoxon signed rank test and McNemar test were used for continuous and categorical variables, respectively. Results: No difference was observed between revised and nonrevised ACLR groups for LTPS (median: 6° vs 6°, P = .973) or MTPS (median: 4° vs 5°, P = .281). Furthermore, no difference was found for medial-to-lateral slope difference (median: −1 vs −1, P = .289). A greater proportion of patients with revised ACLR had an LTPS ≥12° (7.6% vs 3.8%) and ≥13° (4.7% vs 1.3%); however, this was not statistically significant after accounting for multiple testing. Conclusion: We failed to observe an association between revision ACLR surgery and LTPS, MTPS, or medial-to-lateral slope difference. However, there was a greater proportion of patients in the revision ACLR group with an LTPS ≥12°, suggesting that a minority of patients who have more extreme values of LTPS have a higher revision risk after primary ACLR. A future cohort study evaluating the angle that best differentiates patients at highest risk for revision is needed.

Idea Generation and Goal Derived Categories

Semantic search and retrieval of information plays an important role in creative idea generation. This study was designed to examine how semantic and temporal clustering varies when asking participants to generate ideas about uses for objects compared with generating members of goal-derived categories. Participants generated uses for three objects: brick, hammer, picture frame, and also generated members of the following goal-derived categories: things to take in case of a fire, things to sell at a garage sale, and ways to spend lottery winnings. Using response-time analysis and semantic analysis, results illustrated that all six prompts generally led to exponentialcumulative response-time distributions. However, the proportion of temporally clustered responses, defined using the slope-difference algorithm, was higher for goal-derived category responses compared with object uses. Despite that, overall pairwise semantic similarity was higher for object uses than for goal derived exemplars. The effect of prompt on pairwise semantic similarity is likely the result of context-dependency of exemplars from goal-derived categories. However, the current analysis contains a potential confound such that special instructions to give “common and uncommon” responses were provided only for the object-uses prompts. The confound is likely minimal, but future work is necessary to illustrate the robustness of the results.

Value of the 6-Hour Postoperative Ionized Calcium Slope in Predicting Post- Thyroidectomy Occurrence of Hypocalcemia

Objective: To determine the value of the 6-hour postoperative ionized Calcium (iCa) slope, versus 6-hour postoperative Calcium alone, in predicting the occurrence of hypocalcemia in patients who underwent thyroid surgery in a tertiary hospital in Metro Manila. Methods: Study Design: Retrospective Cross-Sectional Study Setting: Tertiary Private Hospital Subjects: Pre-operative and 6-hour postoperative ionized calcium determinations were analyzed in 59 patients of the ENT-HNS department in a tertiary hospital in Metro Manila who underwent thyroid surgery from January 2009 to December 2013. Results: The 6-hr postoperative iCa slope (difference between the pre-operative and 6-hour postoperative iCa levels) of ≥0.18 mmol/L correctly predicted 57.1% of patients who eventually developed hypocalcemia, with a specificity of 81.6%, and a positive predictive value of 63.2%. In contrast, the 6-hour postoperative iCa measurement identified only 23.8% (5 out of 21) patients who developed hypocalcemia. Conclusion: The 6-hr postoperative iCa slope increased the probability of identifying patients who developed hypocalcemia from 23.8% to 57.1%. However, as a single determination, this may not suffice to take the place of serial iCa measurements after thyroid surgery. Keywords: ionized calcium (iCa), hypocalcemia, thyroidectomy