Comparative Interrupted Time Series Design Research Articles

The Effects of Bookworms Literacy Curriculum on Student Achievement in Grades 2-5

ABSTRACT Purpose In this study, we investigated the effects of a schoolwide program, Bookworms K-5 Reading and Writing, on student achievement. Method The study included seven cohorts of students (N = 8,806) in grades 2–5 in 17 elementary schools across three school years. We used a comparative interrupted time-series design, conducting multilevel growth curve models of Measures of Academic Progress reading scores with up to 10 data points per student. By modeling each student’s growth curve, including a time by treatment interaction term, we were able to estimate the change in students’ achievement trajectories corresponding to the implementation of Bookworms. Results Results confirm a significant positive impact of Bookworms on achievement, with gains compounding over time and producing an overall standardized effect size of .26 by the end of 5th grade. Students who began third grade with relatively weaker achievement experienced more growth than those with average achievement, and those with average achievement experienced more growth than those with the highest achievement. Conclusion This study provides evidence that a comprehensive literacy curriculum that emphasizes high-volume reading of grade-level texts and the use of evidence-based instructional practices produces positive effects on student achievement for students with a range of initial reading achievement.

Impact evaluation of the turnaround arts pilot program: an interrupted time series analysis

The purpose of this study was to conduct an evaluation of the pilot program of the Turnaround Arts reform using a comparative interrupted time series design. Because the only existing evaluation of the Turnaround Arts pilot program lacks clarity and transparency, reanalyzing this program is important to understand the effects of the initiative. I created a unique dataset with nine variables to specifically evaluate the achievement outcomes of the pilot schools, which I paired with similarly matched control schools. Achievement measures included average math and reading language arts (RLA) percent proficient scores for each of the schools from 2010 to 2014 and were collected from the Stanford Education Data Archive. My results indicated that the original Turnaround Arts reform had no statistically significant impacts on the pilot schools achievement measures, an important link in the initiatives theory of action. These results support previous music education literature that found no positive causal effects between music education and non-music achievement scores. School music and arts programs are important for providing children with a well-rounded education; however, justifying the use of arts education for non-arts gains can undermine high-quality arts program development.

The efficacy of Facebook's vaccine misinformation policies and architecture during the COVID-19 pandemic.

Online misinformation promotes distrust in science, undermines public health, and may drive civil unrest. During the coronavirus disease 2019 pandemic, Facebook-the world's largest social media company-began to remove vaccine misinformation as a matter of policy. We evaluated the efficacy of these policies using a comparative interrupted time-series design. We found that Facebook removed some antivaccine content, but we did not observe decreases in overall engagement with antivaccine content. Provaccine content was also removed, and antivaccine content became more misinformative, more politically polarized, and more likely to be seen in users' newsfeeds. We explain these findings as a consequence of Facebook's system architecture, which provides substantial flexibility to motivated users who wish to disseminate misinformation through multiple channels. Facebook's architecture may therefore afford antivaccine content producers several means to circumvent the intent of misinformation removal policies.

Impact of the Affordable Care Act on participation in the Supplemental Nutrition Assistance Program among low-income older Medicare beneficiaries

BackgroundThe Affordable Care Act (ACA) provisions, especially Medicaid expansion, are believed to have “spillover effects,” such as boosting participation in the Supplemental Nutrition Assistance Program (SNAP) among eligible individuals in the United States (US). However, little empirical evidence exists about the impact of the ACA, with its focus on the dual eligible population, on SNAP participation. The current study investigates whether the ACA, under an explicit policy aim of enhancing the interface between Medicare and Medicaid, has improved participation in the SNAP among low-income older Medicare beneficiaries.MethodsWe extracted 2009 through 2018 data from the US Medical Expenditure Panel Survey (MEPS) for low-income (≤ %138 Federal Poverty Level [FPL]) older Medicare beneficiaries (n = 50,466; aged ≥ 65), and low-income (≤ %138 FPL) younger adults (aged 20 to < 65 years, n = 190,443). MEPS respondents of > %138 FPL incomes, younger Medicare and Medicaid beneficiaries, and older adults without Medicare were excluded from this study. Using a quasi-experimental comparative interrupted time-series design, we examined (1) whether ACA’s support for the Medicare-Medicaid dual-eligible program, through facilitating the online Medicaid application process, was associated with an increase in SNAP uptake among low-income older Medicare beneficiaries, and (2) in the instance of an association, to assess the magnitude of SNAP uptake that can be explicitly attributed to the policy’s implementation. The outcome, SNAP participation, was measured annually from 2009 through 2018. The year 2014 was set as the intervention point when the Medicare-Medicaid Coordination Office started facilitating Medicaid applications online for eligible Medicare beneficiaries.ResultsOverall, the change in the probability of SNAP enrollment from the pre- to post-intervention period was 17.4 percentage points higher among low-income older Medicare enrollees, compared to similarly low-income, SNAP-eligible, younger adults (β = 0.174, P < .001). This boost in SNAP uptake was significant and more apparent among older White (β = 0.137, P = .049), Asians (β = 0.408, P = .047), and all non-Hispanic adults (β = 0.030, P < .001).ConclusionsThe ACA had a positive, measurable effect on SNAP participation among older Medicare beneficiaries. Policymakers should consider additional approaches that link enrollment to multiple programs to increase SNAP participation. Further, there may be a need for additional, targeted efforts to address structural barriers to uptake among African Americans and Hispanics.

Evaluating the impact of prescriptive authority for psychologists on the rate of deaths attributed to mental illness.

Five states have enacted policies granting prescriptive authority to psychologists in an effort to increase access to psychoactive medications; however, little is known regarding the public health impact of these policies. Policies in two of these states, New Mexico and Louisiana, have had sufficient time to license more than a handful of prescribing psychologists. This study estimates the impact of psychologist prescriptive authority policies in New Mexico and Louisiana on deaths attributable to mental illness and suicides. State-level annual death rates from all 50 states were obtained for deaths with an underlying cause of death attributable to mental illness and to suicide (1999-2013) from the Centers for Disease Control and Prevention's WONDER database. State characteristics were collected for the pre-policy time period (1999-2004). We estimated the impact of the policy on the rates of deaths attributable to mental illness and to suicide using a comparative interrupted time series design, and policy effect estimates were generated for New Mexico and Louisiana separately. We used the synthetic control method to create synthetic New Mexico and synthetic Louisiana for use as the comparators. Immediately following the start of psychologist prescribing, the rate of deaths attributable to mental illness declined by 4.55 deaths per 100,000 (95% CI: [-8.30, -0.79]) in New Mexico relative to the control, but there was no change in Louisiana. There was no immediate change in the suicide rate in either state; however, the annual change in the overall suicide rate was 0.12 suicides per 100,000 (95% CI: [-0.18, -0.06]) per year lower than expected in Louisiana following implementation. These findings suggest that policies granting prescriptive authority to psychologists have the potential to reduce the mental health mortality gap, though considerable questions remain.

Analysis of Long-Term Medical Expenses in Vertebral Fracture Patients.

The objective of this study was to analyze the direct medical expenses of a vertebral fracture cohort (VC) and a matched cohort (MC) over 5 years preceding and following the fracture, analyze the duration of the rise in medical expenses due to the fracture, and examine whether the expenses vary with age group, utilizing a national claims database. Subjects with vertebral fractures and matched subjects were chosen from the National Health Insurance Service Sample cohort (NHIS-Sample) of South Korea. Patients with vertebral fractures were either primarily admitted to acute care hospitals (index admissions) or those who received kyphoplasty or vertebroplasty during the follow-up period (2002-2015). A risk-set matching was performed using 1 : 5 random sampling to simulate a real-world situation. Individual-level direct medical expenses per quarter were calculated for 5 years prior and subsequent to the vertebral fracture. In this analysis using a comparative interrupted time series design, we examined the direct medical expenses of a VC and an MC. A total of 3,923 incident vertebral fracture patients and 19,615 matched subjects were included in this study. The mean age was 75.5 ± 7.4 years, and 69.5% were women. The mean difference in medical expenses between the two groups increased steadily before the fracture. The medical expenses of the VC peaked in the first quarter following the fracture. The cost changes were 1.82 times higher for the VC than for the MC (95% confidence interval, 1.62-2.04; p < 0.001) in the first year. Subsequently, there were no differential changes in medical expenses between the two groups (p > 0.05). In the < 70-year subgroup, there were no differential changes in medical expenses between the two groups (p > 0.05). However, in the ≥ 80-year subgroup, the cost changes for the VC were higher than those for the MC up to 5 years after time zero. Based on our study results, we suggest that health and medical policies for vertebral fractures should be designed to last up to approximately 1 year after the fracture. Health policies should be differentiated according to age group.

Paraprofessional Instructional Assistants Raise the Reading Performance of Latina/o First Graders in a Low-Income District

One relatively low-cost mechanism to assist teachers serving many English learner (EL) students and struggling readers is to hire, train, and manage paraprofessionals to provide supplementary instruction to such students. This study evaluated a program in which one district provided instructional aides to all first-grade teachers in the lowest-performing schools. To estimate program effects on reading, we used matched comparison schools in two research designs. One was a comparative interrupted time-series design, which compared school-level test score averages for treatment and comparison schools before and after program implementation. The other analyzed student-level test scores in these schools before and after the program. Both yielded positive estimates of program effects, significant at the p &lt; .10 and p &lt; .05 levels.

The Internal Validity of the School-Level Comparative Interrupted Time Series Design: Evidence From Four New Within-Study Comparisons

Comparative interrupted time series (CITS) designs evaluate impact by modeling the relative deviation from trends among a treatment and comparison group after an intervention. The broad applicability of the design means it is widely used in education research. Like all non-experimental evaluation methods however, the internal validity of a given CITS evaluation depends on assumptions that cannot be directly verified. We provide an empirical test of the internal validity of CITS by conducting four within-study comparisons of school-level interventions previously evaluated using randomized controlled trials. Our estimate of bias across these four studies is 0.03 school-level (or 0.01 pupil-level) standard deviations. The results suggest well-conducted CITS evaluations of similar school-level education interventions are likely to display limited bias.

The comparative interrupted time series design for assessment of diagnostic impact: methodological considerations and an example using point-of-care C-reactive protein testing

BackgroundIn diagnostic evaluation, it is necessary to assess the clinical impact of a new diagnostic as well as its diagnostic accuracy. The comparative interrupted time series design has been proposed as a quasi-experimental approach to evaluating interventions. We show how it can be used in the design of a study to evaluate a point-of-care diagnostic test for C-reactive protein in out-of-hours primary care services, to guide antibiotic prescribing among patients presenting with possible respiratory tract infection. This study consisted of a retrospective phase that used routinely collected monthly antibiotic prescribing data from different study sites, and a prospective phase in which antibiotic prescribing rates were monitored after the C-reactive protein diagnostic was introduced at some of the sites.MethodsOf 8 study sites, 3 were assigned to receive the diagnostic and 5 were assigned as controls. We obtained retrospective monthly time series of respiratory tract targeted antibiotic prescriptions at each site. Separate ARIMA models at each site were used these to forecast monthly prescription counts that would be expected in the prospective phase, using simulation to obtain a set of 1-year predictions alongside their standard errors. We show how these forecasts can be combined to test for a change in prescription rates after introduction of the diagnostic and estimate power to detect this change.ResultsFitted time series models at each site were stationary and showed second-order annual seasonality, with a clear December peak in prescriptions, although the timing and extent of the peak varied between sites and between years. Mean one-year predictions of antibiotic prescribing rates based on the retrospective time series analysis differed between sites assigned to receive the diagnostic and those assigned to control. Adjusting for the trend in the retrospective time series at each site removed these differences.ConclusionsQuasi-experimental designs such as comparative interrupted time series can be used in diagnostic evaluation to estimate effect sizes before conducting a full randomised controlled trial or if a randomised trial is infeasible. In multi-site studies, existing retrospective data should be used to adjust for underlying differences between sites to make outcome data from different sites comparable, when possible.

INTERNAL AND EXTERNAL VALIDITY OF THE COMPARATIVE INTERRUPTED TIME‐SERIES DESIGN: A META‐ANALYSIS

AbstractThis paper meta‐analyzes 12 heterogeneous studies that examine bias in the comparative interrupted time‐series design (CITS) that is often used to evaluate the effects of social policy interventions. To measure bias, each CITS impact estimate was differenced from the estimate derived from a theoretically unbiased causal benchmark study that tested the same hypothesis with the same treatment group, outcome data, and estimand. In 10 studies, the benchmark was a randomized experiment and in the other two it was a regression‐discontinuity study. Analyses revealed the average standardized CITS bias to be between −0.01 and 0.042 standard deviations; and all but one bias estimate from individual studies fell within 0.10 standard deviations of its benchmark, indicating that the near zero mean bias did not result from averaging many large single study differences. The low mean and generally tight distribution of individual bias estimates suggest that CITS studies are worth recommending for future causal hypothesis tests because: (1) over the studies examined, they generally resulted in high internal validity; and (2) they also promise high external validity because the empirical tests we synthesized occurred across a wide variety of settings, times, interventions, and outcomes.

The Effects of Home Health Value-Based Purchasing on Home Health Care Quality in For-Profit and Nonprofit Agencies: A Comparative Interrupted Time-Series Analysis, 2012–2018

Beginning in 2016, the Home Health Value-Based Purchasing (HHVBP) model incentivized U.S. Medicare-certified home health agencies (HHAs) in nine states to improve quality of patient care and patient experience. Here, we quantified HHVBP effects upon quality over time (2012-2018) by HHA ownership (i.e., for-profit vs. nonprofit) using a comparative interrupted time-series design. Our outcome measures were Care Quality and Patient Experience indices composed of 10 quality of patient care measures and five patient experience measures, respectively. Overall, 17.7% of HHAs participated in the HHVBP model of which 81.4% were for-profit ownership. Each year after implementation, HHVBP was associated with a 1.59 (p < .001) percentage point increase in the Care Quality index among for-profit HHAs and a 0.71 (p = .024) percentage point increase in the Patient Experience index among nonprofits. The differences of quality improvement under the HHVBP model by ownership indicate variations in HHA leadership responses to HHVBP.

Changes in Opioid Prescribing Following the Implementation of State Policies Limiting Morphine Equivalent Daily Dose in a Commercially Insured Population.

Prescription opioid mortality doubled 2002-2016 in the United States. Given the association between high-dose opioid prescribing and opioid mortality, several states have enacted morphine equivalent daily dose (MEDD) policies to limit high-dose prescribing. The study objective is to evaluate the impact of state-level MEDD policies on opioid prescribing among the privately insured. Claims data, 2010-2015 from 9 policy states and 2 control states and a comparative interrupted time series design were utilized. Primary outcomes were any monthly opioid use and average monthly MEDD. Stratified analyses evaluated theorized weaker policies (guidelines) and theorized stronger policies (passive alert systems, legislative acts, and rules/regulations) separately. Patient groups explicitly excluded from policies (eg, individuals with cancer diagnoses or receiving hospice care) were also examined separately. Analyses adjusted for covariates, state fixed effects, and time trends. Both guideline and strong policy implementation were both associated with 15% lower odds of any opioid use, relative to control states. However, there was no statistically significant change in the use of high-dose opioids in policy states relative to control states. There was also no difference in direction and significance of the relationship among targeted patient groups. MEDD policies were associated with decreased use of any opioids relative to control states, but no change in high-dose prescribing was observed. While the overall policy environment in treatment states may have discouraged opioid prescribing, there was no evidence of MEDD policy impact, specifically. Further research is needed to understand the mechanisms through which MEDD policies may influence prescribing behavior.

Association of Implementing an Incentive Metric in the Oregon Medicaid Program With Effective Contraceptive Use

Reducing unintended pregnancy is a national public health priority. Incentive metrics are increasingly used by health systems to improve health outcomes and reduce costs, but limited data exist on the association of incentive metrics with contraceptive use. To evaluate whether an association exists between implementing an incentive metric and effective contraceptive use within the Oregon Medicaid program. In this state-level, claims-based cohort study, a comparative interrupted time series design was used to evaluate whether the implementation of an effective contraceptive use incentive metric on January 1, 2015, was associated with changes in contraceptive use among Oregon Medicaid adult enrollees when compared with commercially insured women. The participants were adult women at risk of pregnancy (18-50 years of age) living in Oregon from January 1, 2012, through December 31, 2017, and enrolled in Medicaid (532 337 person-years) or in commercial health insurance (1 131 738 person-years). Implementation of an effective contraceptive use incentive metric as defined using the 2019 Oregon Health Authority specifications. International Classification of Diseases, Ninth Revision codes; International Statistical Classification of Diseases and Related Health Problems, Tenth Revision codes; and Current Procedural Terminology codes were used to identify contraceptive use. Annual rates of effective contraceptive use were measured through health insurance claims. The final analyses included 532 337 Medicaid person-years and 1 131 738 privately insured person-years. Women enrolled in Medicaid were younger than those with private insurance (47.5% vs 33.2% of women in 2013 younger than 30 years), and approximately 40% of Medicaid enrollees (vs fewer than 10% of women with private insurance) resided in rural locations. Demographic characteristics within each group remained similar before and after the incentive metric was implemented. In the comparative interrupted time series model, relative to the commercially insured comparison group, effective contraceptive use among Medicaid enrollees for all ages combined increased 3.6% (95% CI, 3.1%-4.1%) 1 year after the start of the incentive metric, 7.5% (95% CI, 6.8%-8.2%) at the end of 2 years, and 11.5% (95% CI, 10.5%-12.4%) at the end of 3 years. Prior to the introduction of the incentive, contraceptive use rates among the youngest cohort of Medicaid enrollees (18-24 years of age) were decreasing; following the introduction of the incentive, contraceptive use increased steadily among all enrollees. Among women aged 18 to 24 years, the effective contraceptive use rate increased 16.5 percentage points (95% CI, 14.4-18.6 percentage points) after 3 years. The largest initial increase in contraceptive use was among women enrolled in Medicaid who were 30 to 34 years of age (4.9%; 95% CI, 3.4%-6.3%). Implementation of the effective contraceptive use incentive metric was associated with a significant increase in contraceptive use among Medicaid enrollees relative to a commercially insured comparison group. This finding is relevant given national efforts aimed at adopting a similar metric for widespread use.

The heterogeneous effect of marijuana decriminalization policy on arrest rates in Philadelphia, Pennsylvania, 2009–2018

BackgroundMarijuana decriminalization holds potential to reduce health inequities. However, limited attention has focused on assessing the impact of decriminalization policies across different populations. This study aims to determine the differential effect of a marijuana decriminalization policy change in Philadelphia, PA on marijuana arrests by demographic characteristics. MethodsUsing a comparative interrupted time series design, we assessed whether the onset of marijuana decriminalization in Philadelphia County was associated with reduction in arrests rates from 2009 to 2018 compared to Dauphin County. Stratified models were used to describe the differential impact of decriminalization across different demographic populations. ResultsCompared to Dauphin, the mean arrest rate for all marijuana-related crimes in Philadelphia declined by 19.9 per 100,000 residents (34.9% reduction), 17.1 per 100,000 residents (43.1% reduction) for possession, and 2.8 per 100,000 resident (15.9% reduction) for sales/manufacturing. Arrest rates also differed by demographic characteristics post-decriminalization. Notably, African Americans had a greater absolute/relative reduction in possession-based arrests than Whites. However, relative reductions for sales/manufacturing-based arrests was nearly 3 times lower for African Americans. Males had greater absolute/relative reduction for possession-based arrests, but lower relative reduction for sales/manufacturing-based arrests compared to females. There were no substantial absolute differences by age; however, youths (vs. adults) experienced higher relative reduction in arrest rates. ConclusionsFindings suggest an absolute/relative reduction for possession-based arrests post-decriminalization; however, relative disparities in sales/manufacturing-based arrests, specifically for African Americans, increased. More consideration towards the heterogeneous effect of marijuana decriminalization are needed given the unintended harmful effects of arrest on already vulnerable populations.

Pricing of First and Second Generation Tyrosine Kinase Inhibitors (TKIs) Pre- and Post-Transition of Imatinib to Generic Status

Background: At its introduction in 2001, the list price of imatinib was $26,400/y; in February 2016, just prior to the transition to the generic status, the list price had risen to $120,000/y. While a transition to generic status was projected to reduce the list price, the magnitude and rate of decline in a real-world setting remains unknown. Further, the pricing patterns of 2nd generation TKIs (dasatinib and nilotinib) pre- to post- imatinib generic transition are not known. We address these gaps in this report. Methods: Truven Health MarketScan Database was used to determine the monthly drug expenditures for 1155 patients with CML diagnoses between 9/1/2014 and 11/30/2017 and receiving imatinib, nilotinib, or dasatinib as single agents. Patients were either commercially insured (n=977) or insured by Medicaid (n=178); median age at diagnosis was 50y; 54% were males. Expenditure for 30-day blocks/patient for imatinib, dasatinib, or nilotinib was calculated and pricing was adjusted via consumer price index for medical services in 2017. A single interrupted time series (ITS) method evaluated imatinib monthly expenditures for the health plan from 9/1/2014 to 11/30/2017, with imatinib switching to generic at 2/1/2016 as the "interruption". The initial six-month period post-interruption was excluded to allow for the new price structure to stabilize, resulting in a post-interruption period of observation from 8/1/2016 to 11/30/2017 (generic phase). Nilotinib and dasatinib were evaluated using a comparative ITS design. Results: Pre-generic vs. generic imatinib: As shown in Figures 1A and 1B, there was a significant (p&lt;0.001) pre-generic increase in expenditure (commercial insurance: $173/patient/month, p&lt;0.001; Medicaid: $199/patient/month, p=0.001). Controlling for secular trends, there was a statistically significant (p&lt;0.001) reduction over the 6-month interruption (2/2016-8/2016: between the pre-generic and generic phase: commercial: $2,255/patient; Medicaid: $2,125/patient). This was followed by a continued small decline in expenditure during the generic phase (commercial, -$60/month/patient; p=0.04; Medicaid: -$203/month/patient; p=0.001). The annual health plan expenditure for imatinib during 2017 was estimated at $116,324. Difference-in-difference of slopes from pre-generic to generic phase (imatinib vs. nilotinib; imatinib vs. dasatinib): As shown in Figures 1A and 1B, the monthly per patient expenditures associated with both nilotinib and dasatinib maintained an increasing trend in both the pre-generic and generic phase of imatinib, resulting in a significant difference-in-difference slope for both commercially-insured patients (nilotinib: $-211, p=0.002; dasatinib: $-192, p=0.003) and Medicaid patients (nilotinib: $-350, p=0.002; dasatinib: $-243, p&lt;0.001). This indicates that nilotinib and dasatinib had a greater magnitude of increase in expenditure from 2014 to 2017 than the decline in expenditure for imatinib for the same time period. Conclusion: After the switch to generic, the monthly expenditure for imatinib declined; the decline was steeper for Medicaid patients than commercially-insured patients. Although the proportions of patients receiving brand name versus generic imatinib are not known, the percent change in Imatinib expenditure over the time period analyzed was modest. Nilotinib and dasatinib health plan expenditure demonstrated a continued increase over time. Disclosures No relevant conflicts of interest to declare.

Interrupted time series analyses on the effect on integrated care among the older population

Abstract Background Current health and social care systems in most European countries, are highly fragmented into specialist services, and poorly designed to provide health and social care for patients with multiple health problems and social needs. As some groups of patients might have greater difficulties navigating in a fragmented and divided system than others, current system also risks increasing inequalities in access and use of health and social care services. The aim of this study is to investigate if a comprehensive integrated care system perform better than ‘standard care’ in regards to emergency department visits, hospitalization for ambulatory care sensitive conditions (ACSC), costs and re-admissions as well as increase equity in health care among older people. Methods This study is an intervention study based on a comparative interrupted time series design comparing data from Norrtälje, where an integrated care system was implemented in 2006, with other areas of Stockholm county with a standard care system. The time series consists of register data from 2000-2015, obtained from the Stockholm County Council’s administrative database of healthcare utilization and population data on socio-demographic characteristics from national registers. Preliminary results The preliminary results based on data from 2000-2011 suggest that the introduction of an integrated care system in Norrtälje did not affect the rate of hospitalization for ACSC, costs or rates of emergency department visits. When stratifying on income group we saw that the lowest income group did improve in some of the outcomes. Conclusions The integrated care system in Norrtälje seems to have no significant effect on the outcome measures included. Whether socioeconomic inequity was affected is still to be investigated further. Key messages In this study we used interrupted time series to investigate organisational changes in the health care sector. Introducing integrated care in Norrtälje seems to have little effect on register based outcome measures.

PNS16 IMPROVING ACCESS TIME IN NUCLEAR CARDIOLOGY TOWARDS QUALITY DELIVERY OF HEALTHCARE SERVICES

This research aims to explore the timeliness of access to outpatient myocardial perfusion imaging (MPI) in a nuclear cardiology facility which caters for cardiac and non-cardiac scans. Access is a key health system performance indicator to measure quality delivery of healthcare services at an institutional level. The final (impact) outcome is to increase the proportion of patients undergoing MPI within an access time (AT) of <14 calendar days(gold standard) from 2% to 50% or higher over 6 months. AT is defined as the interval difference between the MPI request and scheduled appointment in days. Interventions are directed at best practices to address gaps and deficiencies within the system. First, the backlog reduction plan was aimed at elimination of backlog by recalibration of the scheduling system. Secondly, the surge contingency plan enables the utilization of available non-cardiac appointment slots to perform outpatient MPI. Thirdly, the adaptive workforce plan utilizes staggered working hours to accommodate for increase in number of appointment slots. A theory of change was developed to outline a road map of the sequence of events connecting the resources to the activities, and how it can lead to the desired short-, intermediate-, and long-term outcomes and impact. A comparative interrupted time series design is used. AT to outpatient cardiac computed tomography will serve as the comparison group to account for any time-varying fixed effect. Data are collected at various points over time before and after an intervention to determine whether the intervention had an effect significantly greater than the underlying trend to demonstrate causal-and-effect provided the parallel trend assumption is met. A qualitative survey will be performed to understand patient expectations on AT. Findings are aimed to guide evidence-based policy making in nuclear cardiology prior to wider implementation across other modalities in cardiac imaging for quality improvement and system management.

Evaluating Missouri's Handgun Purchaser Law: A Bracketing Method for Addressing Concerns About History Interacting with Group.

In the comparative interrupted time series design (also called the method of difference-in-differences), the change in outcome in a group exposed to treatment in the periods before and after the exposure is compared with the change in outcome in a control group not exposed to treatment in either period. The standard difference-in-difference estimator for a comparative interrupted time series design will be biased for estimating the causal effect of the treatment if there is an interaction between history in the after period and the groups; for example, there is a historical event besides the start of the treatment in the after period that benefits the treated group more than the control group. We present a bracketing method for bounding the effect of an interaction between history and the groups that arises from a time-invariant unmeasured confounder having a different effect in the after period than the before period. The method is applied to a study of the effect of the repeal of Missouri's permit-to-purchase handgun law on its firearm homicide rate. We estimate that the effect of the permit-to-purchase repeal on Missouri's firearm homicide rate is bracketed between 0.9 and 1.3 homicides per 100,000 people, corresponding to a percentage increase of 17% to 27% (95% confidence interval: 0.6, 1.7 or 11%, 35%). A placebo study provides additional support for the hypothesis that the repeal has a causal effect of increasing the rate of state-wide firearm homicides.

An evaluation of the effects of lowering blood alcohol concentration limits for drivers on the rates of road traffic accidents and alcohol consumption: a natural experiment

SummaryBackgroundDrink driving is an important risk factor for road traffic accidents (RTAs), which cause high levels of morbidity and mortality globally. Lowering the permitted blood alcohol concentration (BAC) for drivers is a common public health intervention that is enacted in countries and jurisdictions across the world. In Scotland, on Dec 5, 2014, the BAC limit for drivers was reduced from 0·08 g/dL to 0·05 g/dL. We therefore aimed to evaluate the effects of this change on RTAs and alcohol consumption.MethodsIn this natural experiment, we used an observational, comparative interrupted time-series design by use of data on RTAs and alcohol consumption in Scotland (the interventional group) and England and Wales (the control group). We obtained weekly counts of RTAs from police accident records and we estimated weekly off-trade (eg, in supermarkets and convenience stores) and 4-weekly on-trade (eg, in bars and restaurants) alcohol consumption from market research data. We also used data from automated traffic counters as denominators to calculate RTA rates. We estimated the effect of the intervention on RTAs by use of negative binomial panel regression and on alcohol consumption outcomes by use of seasonal autoregressive integrated moving average models. Our primary outcome was weekly rates of RTAs in Scotland, England, and Wales. This study is registered with ISRCTN, number ISRCTN38602189.FindingsWe assessed the weekly rate of RTAs and alcohol consumption between Jan 1, 2013, and Dec 31, 2016, before and after the BAC limit came into effect on Dec 5, 2014. After the reduction in BAC limits for drivers in Scotland, we found no significant change in weekly RTA rates after adjustment for seasonality and underlying temporal trend (rate ratio 1·01, 95% CI 0·94–1·08; p=0.77) or after adjustment for seasonality, the underlying temporal trend, and the driver characteristics of age, sex, and socioeconomic deprivation (1·00, 0·96–1·06; p=0·73). Relative to RTAs in England and Wales, where the reduction in BAC limit for drivers did not occur, we found a 7% increase in weekly RTA rates in Scotland after this reduction in BAC limit for drivers (1·07, 1·02–1·13; p=0·007 in the fully-adjusted model). Similar findings were observed for serious or fatal RTAs and single-vehicle night-time RTAs. The change in legislation in Scotland was associated with no change in alcohol consumption, measured by per-capita off-trade sales (−0·3%, −1·7 to 1·1; p=0·71), but a 0·7% decrease in alcohol consumption measured by per-capita on-trade sales (−0·7%, −0·8 to −0·5; p<0·0001).InterpretationLowering the driving BAC limit to 0·05 g/dL from 0·08 g/dL in Scotland was not associated with a reduction in RTAs, but this change was associated with a small reduction in per-capita alcohol consumption from on-trade alcohol sales. One plausible explanation is that the legislative change was not suitably enforced—for example with random breath testing measures. Our findings suggest that changing the legal BAC limit for drivers in isolation does not improve RTA outcomes. These findings have significant policy implications internationally as several countries and jurisdictions consider a similar reduction in the BAC limit for drivers.FundingNational Institute for Health Research Public Health Research Programme.

Intervention study on the effect of integrated care on equity in healthcare

Background: Continuity, integration, and collaboration between health and social care providers are essential if we are to adapt to the needs of an ageing population. The aim of this study is to investigate if a comprehensive integrated care system is better at avoiding emergency department visits and hospitalization for ambulatory care sensitive conditions ACSC and increase equity in health care in comparison to “standard care” among older people. Methods: This study is an intervention study based on a comparative interrupted time series design comparing data from Norrtalje, where an integrated care system was implemented in 2006, with other areas of Stockholm county whit the standard care system. The time series will consist of register data from 2000-2015, obtained from the Stockholm County Council’s administrative database for analysis and follow-up of healthcare utilization and from the Longitudinal Integration database for Health Insurance and labour market studies from Statistics Sweden. Preliminary results: The preliminary descriptive results based on data from 2000-2011 suggest that the introduction of an integrated care system in Norrtalje did not affect the rate of hospitalization for ACSC. When stratifying on income group we saw that the lowest income group decreased the rate of ACSC after 2006, however income group 2 and 3 increased. Further analytical analyses are needed in order to interpret these trend changes. Conclusion: The integrated care system in Norrtalje seems to have no effect on the rate of hospitalization for ACSC. Whether socioeconomic inequity in rates of ACSC was affected is still to be investigated. The results of the effect on emergency department visits is jet to be performed.