Publications

2017
Shimada YJ, Tsugawa Y, Camargo CA, Brown DFM, Hasegawa K. Effect of Bariatric Surgery on Emergency Department Visits and Hospitalizations for Atrial Fibrillation. Am J Cardiol. 2017.Abstract
Atrial fibrillation (AF) and obesity are major health problems in the United States. However, little is known about whether bariatric surgery affects AF-related morbidities. This study investigated whether bariatric surgery is associated with short-term and long-term changes in the risk of emergency department (ED) visits or hospitalizations for AF. We performed a self-controlled case series study of obese adults with AF who underwent bariatric surgery by using population-based ED and inpatient databases in California, Florida, and Nebraska from 2005 to 2011. The primary outcome was ED visit or hospitalization for AF. We used conditional logistic regression to compare each patient's risk of the outcome event during sequential 12-month periods, using presurgery months 13 to 24 as a reference period. Our sample consisted of 523 obese adults with AF who underwent bariatric surgery. The median age was 57 years (interquartile range 48 to 64 years), 59% were female, and 84% were non-Hispanic white. During the reference period, 15.9% (95% confidence interval [CI] 12.7% to 19.0%) of patients had an ED visit or hospitalization for AF. The risk remained similar in the subsequent 12-month presurgery period (adjusted OR [aOR] 1.29 [95% CI, 0.94 to 1.76] p = 0.11). In contrast, the risk significantly increased within 12 months after bariatric surgery (aOR 1.53 [95% CI 1.13 to 2.07] p = 0.006). The risk remained elevated during 13-24 months after bariatric surgery (aOR 1.41 [95% CI, 1.03 to 1.91] p = 0.03). In conclusion, this population-based study demonstrated that bariatric surgery was associated with an increased risk of AF episodes requiring an ED visit or hospitalization for at least 2 years after surgery among obese patients with AF.
Sakai Bizmark R, Chang R-KR, Tsugawa Y, Zangwill KM, Kawachi I. Impact of AHA's 2007 guideline change on incidence of infective endocarditis in infants and children. Am Heart J. 2017;189 :110-119.Abstract
Use a nationally representative sample to assess impacts of new clinical guidelines issued by the American Heart Association (AHA) in 2007 for many types of invasive procedures, with recommendations for significant decreases in antimicrobial prophylaxis use. STUDY DESIGN: Interrupted time series analyses of pediatric hospitalizations for Infective Endocarditis (IE), using the Nationwide Inpatient Sample (NIS) ICD-9-CM diagnostic codes, identified IE hospitalizations for patients <18 years old from 2001 to 2012. Changes in IE incidence before and after 2007 AHA guidelines were evaluated, with differences in IE clinical severity assessed using in-hospital mortality and length of stay. Analyses were stratified by pathogen type and age group (0-9 y/o and 10-17 y/o). RESULTS: With 3,748 patients in the study, we observed rising trends in IE incidence, but no significant difference between pre- and post-guideline. There was a significant trend increase for IE due to viridans group streptococci (VGS) for ages >10 years old, comparing pre-guideline to post-guideline periods, but not in children 0-9 years of age. Neither in-hospital mortality nor length of stay changed significantly during study. CONCLUSIONS: The data did not demonstrate an impact of the 2007 guideline changes on overall incidence of pediatric IE. However, a significant increase in disease incidence trend due to VGS was observed for the 10-17 year-old group, compared pre- and post-guideline.
Nomura S, Sakamoto H, Glenn S, Tsugawa Y, Abe SK, Rahman MM, Brown JC, Ezoe S, Fitzmaurice C, Inokuchi T, et al. Population health and regional variations of disease burden in Japan, 1990-2015: a systematic subnational analysis for the Global Burden of Disease Study 2015. Lancet. 2017.Abstract
BACKGROUND: Japan has entered the era of super-ageing and advanced health transition, which is increasingly putting pressure on the sustainability of its health system. The level and pace of this health transition might vary across regions within Japan and concern is growing about increasing regional variations in disease burden. The Global Burden of Diseases, Injuries, and Risk Factors Study 2015 (GBD 2015) provides a comprehensive, comparable framework. We used data from GBD 2015 with the aim to quantify the burden of disease and injuries, and to attribute risk factors in Japan at a subnational, prefecture-level. METHODS: We used data from GBD 2015 for 315 causes and 79 risk factors of death, disease, and injury incidence and prevalence to measure the burden of diseases and injuries in Japan and in the 47 Japanese prefectures from 1990 to 2015. We extracted data from GBD 2015 to assess mortality, causes of death, years of life lost (YLLs), years lived with disability (YLDs), disability-adjusted life-years (DALYs), life expectancy, and healthy life expectancy (HALE) in Japan and its 47 prefectures. We split extracted data by prefecture and applied GBD methods to generate estimates of burden, and attributable burden due to known risk factors. We examined the prefecture-level relationships of common health system inputs (eg, health expenditure and workforces) to the GBD outputs in 2015 to address underlying determinants of regional health variations. FINDINGS: Life expectancy at birth in Japan increased by 4·2 years from 79·0 years (95% uncertainty interval [UI] 79·0 to 79·0) to 83·2 years (83·1 to 83·2) between 1990 and 2015. However, the gaps between prefectures with the lowest and highest life expectancies and HALE have widened, from 2·5 to 3·1 years and from 2·3 to 2·7 years, respectively, from 1990 to 2015. Although overall age-standardised death rates decreased by 29·0% (28·7 to 29·3) from 1990 to 2015, the rates of mortality decline in this period substantially varied across the prefectures, ranging from -32·4% (-34·8 to -30·0) to -22·0% (-20·4 to -20·1). During the same time period, the rate of age-standardised DALYs was reduced overall by 19·8% (17·9 to 22·0). The reduction in rates of age-standardised YLDs was very small by 3·5% (2·6 to 4·3). The pace of reduction in mortality and DALYs in many leading causes has largely levelled off since 2005. Known risk factors accounted for 34·5% (32·4 to 36·9) of DALYs; the two leading behavioural risk factors were unhealthy diets and tobacco smoking in 2015. The common health system inputs were not associated with age-standardised death and DALY rates in 2015. INTERPRETATION: Japan has been successful overall in reducing mortality and disability from most major diseases. However, progress has slowed down and health variations between prefectures is growing. In view of the limited association between the prefecture-level health system inputs and health outcomes, the potential sources of regional variations, including subnational health system performance, urgently need assessment. FUNDING: Bill & Melinda Gates Foundation, Japan Ministry of Education, Science, Sports and Culture, Japan Ministry of Health, Labour and Welfare, AXA CR Fixed Income Fund and AXA Research Fund.
Goto T, Tsugawa Y, Faridi MK, Camargo CA, Hasegawa K. Reduced risk of acute exacerbation of chronic obstructive pulmonary disease after bariatric surgery: A self-controlled case series study. Chest. 2017.Abstract
BACKGROUND: Obesity is common among individuals with chronic obstructive pulmonary disease (COPD) and associated with increased COPD morbidities. However, little is known about the impact of weight reduction on COPD-related outcomes in obese patients. METHODS: Using the population-based emergency department (ED) and inpatient sample in three U.S. states (California, Florida, and Nebraska), we performed a self-controlled case series study of 481 obese adults (aged 40-65 years) with COPD who underwent bariatric surgery. The primary outcome was an ED visit or hospitalization for acute exacerbation of COPD (AECOPD) from 2005 through 2011. We compared each patient's risk of the outcome during sequential 12-month periods using pre-surgery months 13-24 as the reference period. RESULTS: During 13-24 months before bariatric surgery (i.e., reference period), 28% (95%CI, 24%-32%) of patients had an ED visit or hospitalization for AECOPD. In the subsequent 12-month pre-surgery period, the risk did not change materially (31%; 95%CI, 27%-35%), with an adjusted odds ratio (aOR) of 1.16 (95%CI, 0.88-1.53; P=0.29). By contrast, during the first 12 months after bariatric surgery, the risk declined significantly (12% [95%CI, 9%-15%]; aOR, 0.35 [95%CI, 0.25-0.49]; P<0.001). Likewise, in the subsequent period of 13-24 months after bariatric surgery, the risk remained significantly low (13% [95%CI, 11%-17%]; aOR, 0.39 [95%CI, 0.28-0.55]; P<0.001). CONCLUSIONS: The risk of an ED visit or hospitalization for AECOPD substantially decreased after bariatric surgery in obese patients. This observation suggests the effectiveness of substantial weight reduction on COPD morbidity.
Tsugawa Y, Newhouse JP, Zaslavsky AM, Blumenthal DM, Jena AB. Physician age and outcomes in elderly patients in hospital in the US: observational study. BMJ. 2017;357 :j1797.Abstract

Objectives To investigate whether outcomes of patients who were admitted to hospital differ between those treated by younger and older physicians.Design Observational study.Setting US acute care hospitals.Participants 20% random sample of Medicare fee-for-service beneficiaries aged ≥65 admitted to hospital with a medical condition in 2011-14 and treated by hospitalist physicians to whom they were assigned based on scheduled work shifts. To assess the generalizability of findings, analyses also included patients treated by general internists including both hospitalists and non-hospitalists.Main outcome measures 30 day mortality and readmissions and costs of care. Results 736 537 admissions managed by 18 854 hospitalist physicians (median age 41) were included. Patients' characteristics were similar across physician ages. After adjustment for characteristics of patients and physicians and hospital fixed effects (effectively comparing physicians within the same hospital), patients' adjusted 30 day mortality rates were 10.8% for physicians aged <40 (95% confidence interval 10.7% to 10.9%), 11.1% for physicians aged 40-49 (11.0% to 11.3%), 11.3% for physicians aged 50-59 (11.1% to 11.5%), and 12.1% for physicians aged ≥60 (11.6% to 12.5%). Among physicians with a high volume of patients, however, there was no association between physician age and patient mortality. Readmissions did not vary with physician age, while costs of care were slightly higher among older physicians. Similar patterns were observed among general internists and in several sensitivity analyses.Conclusions Within the same hospital, patients treated by older physicians had higher mortality than patients cared for by younger physicians, except those physicians treating high volumes of patients.

Tsugawa Y, Jha AK, Newhouse JP, Zaslavsky AM, Jena AB. Variation in Physician Spending and Association With Patient Outcomes. JAMA Intern Med. 2017.Abstract

Importance: While the substantial variation in health care spending across regions and hospitals is well known, key clinical decisions are ultimately made by physicians. However, the degree to which spending varies across physicians and the clinical consequences of that variation are unknown. Objective: To investigate variation in spending across physicians and its association with patient outcomes. Design, Setting, and Participants: For this retrospective data analysis, we analyzed a 20% random sample of Medicare fee-for-service beneficiaries 65 years and older who were hospitalized with a nonelective medical condition and treated by a general internist between January 1, 2011, and December 31, 2014. We first quantified the proportion of variation in Medicare Part B spending attributable to hospitals, physicians, and patients. We then examined the association between physician spending and patient outcomes, adjusted for patient and physician characteristics and hospital fixed effects (effectively comparing physicians within the same hospital). Our primary analysis focused on hospitalist physicians, whose patients are plausibly quasirandomized within a hospital based on physician work schedule. A secondary analysis focused on general internists overall. To ensure that patient illness severity did not directly affect physician spending estimates, we calculated physicians' spending levels in 2011 through 2012 and examined outcomes of their patients in 2013 and 2014. Exposures: Physicians' adjusted Part B spending level in 2011 through 2012. Main Outcomes and Measures: Patients' 30-day mortality and readmission rates in 2013 and 2014. Results: To determine the amount of variation across physicians we included 485 016 hospitalizations treated by 21 963 physicians at 2837 acute care hospitals for the analysis of hospitalists and 839 512 hospitalizations treated by 50 079 physicians at 3195 acute care hospitals for the analysis of general internists. Variation in spending across physicians within hospital was larger than variation across hospitals (for hospitalists, 8.4% across physicians vs 7.0% across hospitals; for general internists, 10.5% across physicians vs 6.2% across hospitals). Higher physician spending was not associated with lower 30-day mortality (adjusted odds ratio [aOR] for additional $100 in physician spending, 1.00; 95% CI, 0.98-1.01; P = .47) or readmissions (aOR, 1.00; 95% CI, 0.99-1.01; P = .54) for hospitalists within the same hospital. We observed similar patterns among general internists. Conclusions and Relevance: Health care spending varies more across individual physicians than across hospitals. However, higher physician spending is not associated with better outcomes of hospitalized patients. Our findings suggest policies targeting both physicians and hospitals may be more effective in reducing wasteful spending than policies focusing solely on hospitals.

Shimada YJ, Tsugawa Y, Iso H, Brown DFM, Hasegawa K. Association between bariatric surgery and rate of hospitalisations for stable angina pectoris in obese adults. Heart. 2017.Abstract
OBJECTIVE: Obesity and stable angina pectoris (SAP) are important public health problems in the USA. However, little is known about whether weight reduction affects the rate of SAP-related morbidities. This study was designed to test the hypothesis that bariatric surgery is associated with a lower rate of hospitalisations for SAP in obese adults. METHODS: We performed a self-controlled case series study of obese adults with SAP who underwent bariatric surgery using a population-based inpatient database in three states (California, Florida and Nebraska) from 2005 to 2011. The primary outcome was hospitalisation for SAP. We used conditional logistic regression to compare the rate of the outcome event during sequential 12-month periods, using presurgery months 13-24 as a reference period. RESULTS: Our sample consisted of 953 patients with SAP who underwent bariatric surgery. The median age was 57 years, 51% were women, and 78% were non-Hispanic white. During the reference period, 25.3% (95% CI, 22.5% to 28.1%) had a hospitalisation for SAP. The rate remained stable in the subsequent 12-month presurgery period (adjusted OR (aOR) 0.84 (95% CI, 0.69 to 1.02); p=0.07). In the first 12-month period after bariatric surgery, we observed a significantly lower rate (9.1% (95% CI, 7.3% to 11.0%); aOR 0.33 (95% CI, 0.26 to 0.43); p<0.0001). Similarly, the rate remained significantly lower in the subsequent 13-24 months after bariatric surgery (8.7% (95% CI, 6.9% to 10.5%); aOR 0.31 (95% CI, 0.24 to 0.41); p<0.0001). CONCLUSION: In this population-based study of obese adults with SAP, we found that the rate of hospitalisations for SAP was lower by two-thirds after bariatric surgery.
Goto Y, Goto T, Hagiwara Y, Tsugawa Y, Watase H, Okamoto H, Hasegawa K. Techniques and outcomes of emergency airway management in Japan: An analysis of two multicentre prospective observational studies, 2010-2016. Resuscitation. 2017.Abstract
OBJECTIVES: Continuous surveillance of emergency airway management practice is imperative in improving quality of care and patient safety. We aimed to investigate the changes in the practice of emergency airway management and the related outcomes in the emergency departments (EDs) in Japan. METHODS: We conducted an analysis of the data from two prospective, observational, multicentre registries of emergency airway management-the Japanese Emergency Airway Network (JEAN)-1 and -2 Registries from April 2010 through May 2016. RESULTS: We recorded 10,927 ED intubations (capture rate, 96%); 10,875 paediatric and adult patients were eligible for our analysis. The rate of rapid sequence intubation (RSI) use as the initial intubation method significantly increased from 28% in 2010 to 53% in 2016 (Ptrend=0.03). Likewise, the rate of video laryngoscope (VL) use as the first intubation device increased significantly from 2% in 2010 to 40% in 2016 (Ptrend<0.001), with a significant decrease in the rate of direct laryngoscope use from 97% in 2010 to 58% in 2016 (Ptrend<0.001). Concurrent with these changes, the overall first-attempt success rate also increased from 68% in 2010 to 74% in 2016 (Ptrend=0.02). By contrast, the rate of adverse events did not change significantly over time (Ptrend=0.06). CONCLUSION: By using data from two large, multicentre, prospective registries, we characterised the current emergency airway management practice, and identified their changes in Japan. The data demonstrated significant increases in the rate of RSI and VL use on the first attempt and the first-attempt success rate over the 6-year study period.
Tsugawa Y, Jena AB, Orav EJ, Jha AK. Quality of care delivered by general internists in US hospitals who graduated from foreign versus US medical schools: observational study. BMJ. 2017;356 :j273.Abstract

OBJECTIVE:  To determine whether patient outcomes differ between general internists who graduated from a medical school outside the United States and those who graduated from a US medical school. DESIGN:  Observational study. SETTING:  Medicare, USA. PARTICIPANTS:  20% national sample of data for Medicare fee-for-service beneficiaries aged 65 years or older admitted to hospital with a medical condition in 2011-14 and treated by international or US medical graduates who were general internists. The study sample for mortality analysis included 1 215 490 admissions to the hospital treated by 44 227 general internists. MAIN OUTCOME MEASURES:  Patients' 30 day mortality and readmission rates, and costs of care per hospital admission, with adjustment for patient and physician characteristics and hospital fixed effects (effectively comparing physicians within the same hospital). As a sensitivity analysis, we focused on physicians who specialize in the care of patients admitted to hospital ("hospitalists"), who typically work in shifts and whose patients are plausibly quasi-randomized based on the physicians' work schedules. RESULTS:  Compared with patients treated by US graduates, patients treated by international graduates had slightly more chronic conditions. After adjustment for patient and physician characteristics and hospital fixed effects, patients treated by international graduates had lower mortality (adjusted mortality 11.2% v 11.6%; adjusted odds ratio 0.95, 95% confidence interval 0.93 to 0.96; P<0.001) and slightly higher costs of care per admission (adjusted costs $1145 (£950; €1080) v $1098; adjusted difference $47, 95% confidence interval $39 to $55, P<0.001). Readmission rates did not differ between the two types of graduates. Similar differences in patient outcomes were observed among hospitalists. Differences in patient mortality were not explained by differences in length of stay, spending level, or discharge location. CONCLUSIONS:  Data on older Medicare patients admitted to hospital in the US showed that patients treated by international graduates had lower mortality than patients cared for by US graduates.

Tsugawa Y, Jena AB, Figueroa JF, Orav EJ, Blumenthal DM, Jha AK. Comparison of Hospital Mortality and Readmission Rates for Medicare Patients Treated by Male vs Female Physicians. JAMA Intern Med. 2017;177 (2) :206-213.Abstract

Importance: Studies have found differences in practice patterns between male and female physicians, with female physicians more likely to adhere to clinical guidelines and evidence-based practice. However, whether patient outcomes differ between male and female physicians is largely unknown. Objective: To determine whether mortality and readmission rates differ between patients treated by male or female physicians. Design, Setting, and Participants: We analyzed a 20% random sample of Medicare fee-for-service beneficiaries 65 years or older hospitalized with a medical condition and treated by general internists from January 1, 2011, to December 31, 2014. We examined the association between physician sex and 30-day mortality and readmission rates, adjusted for patient and physician characteristics and hospital fixed effects (effectively comparing female and male physicians within the same hospital). As a sensitivity analysis, we examined only physicians focusing on hospital care (hospitalists), among whom patients are plausibly quasi-randomized to physicians based on the physician's specific work schedules. We also investigated whether differences in patient outcomes varied by specific condition or by underlying severity of illness. Main Outcomes and Measures: Patients' 30-day mortality and readmission rates. Results: A total of 1 583 028 hospitalizations were used for analyses of 30-day mortality (mean [SD] patient age, 80.2 [8.5] years; 621 412 men and 961 616 women) and 1 540 797 were used for analyses of readmission (mean [SD] patient age, 80.1 [8.5] years; 602 115 men and 938 682 women). Patients treated by female physicians had lower 30-day mortality (adjusted mortality, 11.07% vs 11.49%; adjusted risk difference, -0.43%; 95% CI, -0.57% to -0.28%; P < .001; number needed to treat to prevent 1 death, 233) and lower 30-day readmissions (adjusted readmissions, 15.02% vs 15.57%; adjusted risk difference, -0.55%; 95% CI, -0.71% to -0.39%; P < .001; number needed to treat to prevent 1 readmission, 182) than patients cared for by male physicians, after accounting for potential confounders. Our findings were unaffected when restricting analyses to patients treated by hospitalists. Differences persisted across 8 common medical conditions and across patients' severity of illness. Conclusions and Relevance: Elderly hospitalized patients treated by female internists have lower mortality and readmissions compared with those cared for by male internists. These findings suggest that the differences in practice patterns between male and female physicians, as suggested in previous studies, may have important clinical implications for patient outcomes.

2016
Mizuno A, Tsugawa Y, Shimizu T, Nishizaki Y, Okubo T, Tanoue Y, Konishi R, Shiojiri T, Tokuda Y. The Impact of the Hospital Volume on the Performance of Residents on the General Medicine In-Training Examination: A Multicenter Study in Japan. Intern Med. 2016;55 (12) :1553-8.Abstract
Objective Although several studies have been conducted worldwide on factors that might improve residents' knowledge, the relationship between the hospital volume and the internal medicine residents' knowledge has not been fully understood. We conducted a cross-sectional study to compare the relationships of the hospital volume and hospital resources with the residents' knowledge assessed by the In-training Examination. Methods We conducted a retrospective survey and a clinical knowledge evaluation of postgraduate year 1 and 2 (PGY-1 and -2) resident physicians in Japan by using the General Medicine In-training Examination (GM-ITE) in 2014. We compared the ITE score and the hospital volume. Results A total of 2,015 participants (70.6% men; age, 27.3±2.9 years old) from 208 hospitals were retrospectively analyzed. Generalized estimating equations were used, and the results revealed that an increasing number of hospitalizations, decreasing staff number, decreasing age and PGY-2 were significantly associated with higher GM-ITE scores. Conclusion The hospital volume, such as the number of hospitalizations, is thus considered to have a positive impact on the GM-ITE scores.
Goto T, Yoshida K, Tsugawa Y, Filbin MR, Camargo CA, Hasegawa K. Mortality trends in U.S. adults with septic shock, 2005-2011: a serial cross-sectional analysis of nationally-representative data. BMC Infect Dis. 2016;16 :294.Abstract
BACKGROUND: We aimed to investigate mortality trends in hospitalized patients with septic shock in the US. To achieve this objective, we tested hypothesis that mortality decreased in patients identified by the code of septic shock while mortality did not change in those with septic shock identified by vasopressor use. METHODS: We conducted a serial cross-sectional analysis using Nationwide Inpatient Sample database from 2005 through 2011. First, we identified all adult patients aged ≥18 years hospitalized for septic shock by the following criteria: 1) primary ICD-9 diagnosis of infection plus procedure code for vasopressor use, 2) primary ICD-9 diagnosis of infection plus septic shock in non-primary field, and 3) primary ICD-9 diagnosis of septic shock. Second, we stratified all identified patients by record of vasopressor use. The outcome of interest was year-to-year changes in the in-hospital all-cause mortality. RESULTS: From 2005 to 2011, we identified 109,812 weighted hospitalizations with septic shock. Overall, there was a significant downward trend in in-hospital mortality (from 46 % in 2005 to 42 % in 2011; P trend  = 0.003); the adjusted mortality also decreased significantly (OR for comparison of 2005 with 2011, 0.98; 95 % CI, 0.96-1.00; P < 0.001). In stratified analysis, the mortality trend was not significant in the subgroup with vasopressor use (from 42 % in 2005 to 40 % in 2011; P trend =0.57); similarly, the adjusted mortality did not change significantly (OR, 1.01; 95 % CI, 0.97-1.05; P =0.62). By contrast, there was a downward trend in mortality in the subgroup without vasopressor use (from 47 % in 2005 to 43 % in 2011; P trend =0.002); likewise, the adjusted mortality decreased significantly (OR, 0.97; 95 % CI, 0.95-0.99; P =0.002) CONCLUSIONS: From 2005 to 2011, we found a modest decrease in in-hospital mortality among patients identified with septic shock. However, in the subgroup with vasopressor use, we found no significant change in mortality. Our data challenge the conventional wisdom that mortality in this population has improved during the last decade.
Hasegawa K, Tsugawa Y, Clark S, Eastin CD, Gabriel S, Herrera V, Bittner JC, Camargo CA. Improving Quality of Acute Asthma Care in US Hospitals: Changes Between 1999-2000 and 2012-2013. Chest. 2016;150 (1) :112-22.Abstract
BACKGROUND: Little is known about the longitudinal change in the quality of acute asthma care for hospitalized children and adults in the United States. We investigated whether the concordance of inpatient asthma care with the national guidelines improved over time, identified hospital characteristics predictive of guideline concordance, and determined whether guideline-concordant care is associated with a shorter hospital length of stay (LOS). METHODS: This study was an analysis of data from two multicenter chart review studies of hospitalized patients aged 2 to 54 years with acute asthma during two time periods: 1999-2000 and 2012-2013. Outcomes were guideline concordance at the patient and hospital levels, and association of patient composite concordance with hospital LOS. RESULTS: The analytic cohort for the comparison of guideline concordance comprised 1,634 patients: 834 patients from 1999-2000 vs 800 patients from 2012-2013. Over these 15 years, inpatient asthma care became more concordant at the hospital-level, with the mean composite score increasing from 74 to 82 (P < .001). However, during 2012-2013, wide variability in guideline concordance of acute asthma care remained across hospitals, with the greatest variation in provision of individualized written action plan at discharge (SD, 36). Guideline concordance was significantly lower in Midwestern and Southern hospitals compared with Northeastern hospitals. After adjusting for severity, patients who received care perfectly concordant with the guidelines had significantly shorter hospital LOS (-14% [95% CI, -23 to -4]; P = .009). CONCLUSIONS: Between 1999 and 2013, the guideline concordance of acute asthma care for hospitalized patients improved. However, interhospital variability remains substantial. Greater concordance with evidence-based guidelines was associated with a shorter hospital LOS.
Goto T, Tsugawa Y, Mansbach JM, Camargo CA, Hasegawa K. Trends in Infectious Disease Hospitalizations in US Children, 2000 to 2012. Pediatr Infect Dis J. 2016;35 (6) :e158-63.Abstract
BACKGROUND: Although infectious diseases (IDs) remain a major public health problem in US children, there have been no recent efforts to examine comprehensively the change in epidemiology of ID hospitalizations. METHODS: A serial cross-sectional analysis using the Kids' Inpatient Database 2000, 2003, 2006, 2009, and 2012. We identified children ≤19 years of age with a primary diagnosis of IDs. Outcomes were national rate of ID hospitalizations, in-hospital mortality, length-of-stay and hospitalization-related direct costs. Negative binomial and multivariable logistic models were constructed to test the change in hospitalization rate and in-hospital mortality, respectively. RESULTS: We identified 3,691,672 weighted hospitalizations for IDs, accounting for 24.5% of all pediatric hospitalizations. From 2000 to 2012, the rate of overall ID hospitalizations decreased from 91.0 to 75.8 per 10,000 US children (P < 0.001). The most frequently listed ID subgroup was lower respiratory infections (42.8% of all ID hospitalizations in 2012). Although the hospitalization rate for most ID subgroups decreased, the hospitalization rate for skin infections significantly increased (67.6% increase; P < 0.001). The multivariable model demonstrated a significant decline in in-hospital mortality (odds ratio for comparison of 2012 with 2000, 0.63; 95% confidence interval, 0.51-0.79). From 2000 to 2012, there was no significant change in the median length-of-stay (2 days in 2000 to 2 days in 2012; Ptrend = 0.33). The median direct cost for ID hospitalization increased from $3452 in 2003 to $3784 in 2012 (P = 0.007), with the nationwide direct cost of $4.4 billion in 2012. CONCLUSIONS: We found a statistically significant decline in overall ID hospitalization rate among US children from 2000 to 2012, whereas skin infections statistically significantly increased. In addition, the median direct cost per ID hospitalization increased by 10% during the study period.
Figueroa JF, Tsugawa Y, Zheng J, Orav JE, Jha AK. Association between the Value-Based Purchasing pay for performance program and patient mortality in US hospitals: observational study. BMJ. 2016;353 :i2214.Abstract
OBJECTIVE: To determine the impact of the Hospital Value-Based Purchasing (HVBP) program-the US pay for performance program introduced by Medicare to incentivize higher quality care-on 30 day mortality for three incentivized conditions: acute myocardial infarction, heart failure, and pneumonia. DESIGN: Observational study. SETTING: 4267 acute care hospitals in the United States: 2919 participated in the HVBP program and 1348 were ineligible and used as controls (44 in general hospitals in Maryland and 1304 critical access hospitals across the United States). PARTICIPANTS: 2 430 618 patients admitted to US hospitals from 2008 through 2013. MAIN OUTCOME MEASURES: 30 day risk adjusted mortality for acute myocardial infarction, heart failure, and pneumonia using a patient level linear spline analysis to examine the association between the introduction of the HVBP program and 30 day mortality. Non-incentivized, medical conditions were the comparators. A secondary outcome measure was to determine whether the introduction of the HVBP program was particularly beneficial for a subgroup of hospital-poor performers at baseline-that may benefit the most. RESULTS: Mortality rates of incentivized conditions in hospitals participating in the HVBP program declined at -0.13% for each quarter during the preintervention period and -0.03% point difference for each quarter during the post-intervention period. For non-HVBP hospitals, mortality rates declined at -0.14% point difference for each quarter during the preintervention period and -0.01% point difference for each quarter during the post-intervention period. The difference in the mortality trends between the two groups was small and non-significant (difference in difference in trends -0.03% point difference for each quarter, 95% confidence interval -0.08% to 0.13% point difference, P=0.35). In no subgroups of hospitals was HVBP associated with better outcomes, including poor performers at baseline. CONCLUSIONS: Evidence that HVBP has led to lower mortality rates is lacking. Nations considering similar pay for performance programs may want to consider alternative models to achieve improved patient outcomes.
Wang DE, Tsugawa Y, Figueroa JF, Jha AK. Association Between the Centers for Medicare and Medicaid Services Hospital Star Rating and Patient Outcomes. JAMA Intern Med. 2016;176 (6) :848-50.
Shimada YJ, Tsugawa Y, Brown DFM, Hasegawa K. Bariatric Surgery and Emergency Department Visits and Hospitalizations for Heart Failure Exacerbation: Population-Based, Self-Controlled Series. J Am Coll Cardiol. 2016;67 (8) :895-903.Abstract
BACKGROUND: The United States is battling obesity and heart failure (HF) epidemics. Although studies have suggested relationships between obesity and HF morbidity, little is known regarding the effects of substantial weight reduction in obese patients with HF. OBJECTIVES: This study investigated whether bariatric surgery is associated with a decreased rate of HF exacerbation. METHODS: We performed a self-controlled case series study of obese patients with HF who underwent bariatric surgery, using the population-based emergency department (ED) and inpatient sample in California, Florida, and Nebraska. Primary outcome was ED visit or hospitalization for HF exacerbation from 2005 to 2011. We used conditional logistic regression to compare the outcome event rate during sequential 12-month periods, using pre-surgery months 13 to 24 as the reference period. RESULTS: We identified 524 patients with HF who underwent bariatric surgery. During the reference period, 16.2% of patients had an ED visit or hospitalization for HF exacerbation. The rate remained unchanged in the subsequent 12-month pre-surgery period (15.3%; p = 0.67). In the first 12-month period after bariatric surgery, we observed a nonsignificantly reduced rate (12.0%; p = 0.052). However, the rate was significantly lower in the subsequent 13 to 24 months after bariatric surgery (9.9%; adjusted odds ratio: 0.57; p = 0.003). By contrast, there was no significant reduction in the rate of HF exacerbation among obese patients who underwent nonbariatric surgery (i.e., cholecystectomy, hysterectomy). CONCLUSIONS: Our findings indicate that bariatric surgery is associated with a decline in the rate of HF exacerbation requiring ED evaluation or hospitalization among obese patients with HF.
Hasegawa K, Gibo K, Tsugawa Y, Shimada YJ, Camargo CA. Age-Related Differences in the Rate, Timing, and Diagnosis of 30-Day Readmissions in Hospitalized Adults With Asthma Exacerbation. Chest. 2016;149 (4) :1021-9.Abstract
BACKGROUND: Reducing hospital readmissions has attracted attention from many stakeholders. However, the characteristics of 30-day readmissions after asthma-related hospital admissions in adults are not known. It is also unclear whether older adults are at higher risk of 30-day readmission. OBJECTIVES: To investigate the rate, timing, and principal diagnosis of 30-day readmissions in adults with asthma and to determine age-related differences. METHODS: Retrospective cohort study of adults hospitalized for asthma exacerbation using the population-based inpatient samples of three states (California, Florida, and Nebraska) from 2005 through 2011. Patients were categorized into three age groups: younger (18-39 years), middle aged (40-64 years), and older (≥ 65 years) adults. Outcomes were 30-day all-cause readmission rate, timing, and principal diagnosis of readmission. RESULTS: Of 301,164 asthma-related admissions at risk for 30-day readmission, readmission rate was 14.5%. Compared with younger adults, older adults had significantly higher readmission rates (10.1% vs 16.5%; OR, 2.15 [95% CI, 2.07-2.23]; P < .001). The higher rate attenuated with adjustment (OR, 1.19 [95% CI, 1.13-1.26]; P < .001), indicating that most of the age-related difference is explained by sociodemographics and comorbidities. For all age groups, readmission rate was highest in the first week after discharge and declined thereafter. Overall, only 47.1% of readmissions were assigned respiratory diagnoses (asthma, COPD, pneumonia, and respiratory failure). Older adults were more likely to present with nonrespiratory diagnoses (41.7% vs 53.8%; P < .001). CONCLUSIONS: After asthma-related admission, 14.5% of patients had 30-day readmission with wide range of principal diagnoses. Compared with younger adults, older adults had higher 30-day readmission rates and proportions of nonrespiratory diagnoses.
Goto T, Yoshida K, Tsugawa Y, Camargo CA, Hasegawa K. Infectious Disease-Related Emergency Department Visits of Elderly Adults in the United States, 2011-2012. J Am Geriatr Soc. 2016;64 (1) :31-6.Abstract
OBJECTIVES: To investigate the frequency of infectious disease (ID)-related emergency department (ED) visits of elderly adults in the United States. DESIGN: Cross-sectional analysis. SETTING: Nationwide emergency department sample in 2011-12. PARTICIPANTS: Individuals in the ED aged 65 and older with a primary diagnosis of an ID. MEASUREMENTS: ID-related ED visits, hospitalizations, hospital-based mortality. RESULTS: During 2012, a weighted estimate of 3,123,909 ED visits for IDs was calculated in elderly U.S. adults. This accounted for 13.5% (3.1 million visits) of all ED visits of elderly adults; this burden was higher than that for myocardial infarction and congestive heart failure combined. The rate of ID-related ED visits was 7,231 per 100,000 elderly adults. The most-common diagnoses were lower respiratory infections (26.2%; 95% confidence interval (CI)=25.7-26.6%), urinary tract infections (25.3%, 95% CI=25.0-25.7%), and septicemia (18.9%, 95% CI=18.3-19.6%). Of all ID-related ED visits, 1,786,657 (57.2%, 95% CI=56.6-57.7%) resulted in hospitalization. The leading cause of hospitalization was septicemia, accounting for 32.2% (95% CI=31.1-33.3%) of all ID-related hospitalizations through EDs, followed by lower respiratory infections (27.8%, 95% CI=27.2-28.4%). Overall, 123,894 individuals (4.0%, 95% CI=3.8-4.1%) died during their ED visit or hospitalization. Of these, septicemia was the leading cause of mortality (74.7%, 95% CI=73.8-75.6%), followed by lower respiratory infections (15.2%, 95% CI=14.6-15.9%). Analysis of the 2011 data gave similar results for the burden of ID-related ED visits, hospitalizations, and mortality. CONCLUSION: Using a nationally representative sample, it was found that the public health burden of IDs in elderly U.S. adults was substantial, as measured by ED visits, subsequent hospitalizations, and hospital-based mortality.
Goto T, Tsugawa Y, Camargo CA, Hasegawa K. Sex differences in the risk of hospitalization among patients presenting to US emergency departments with asthma exacerbation, 2010-2012. J Allergy Clin Immunol Pract. 2016;4 (1) :149-51.e2.

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