Susumu Kunisawa

Erratum to: Incidence and Prevention of Postoperative Venous Thromboembolism: Are They Meaningful Quality Indicators in Japanese Health Care Settings?

BackgroundVenous thromboembolism (VTE) epidemiology varies widely across surgical procedures. At present, there are few epidemiologic reports regarding VTE in Japan. Japanese VTE prophylaxis guidelines recommend a risk-based approach based on previous epidemiologic statistics. VTE includes deep vein thrombosis (DVT) and pulmonary embolism (PE). PE prevention is the main goal, although the relation between PE and DVT is still controversial.MethodsWe collected administrative data for 1,016,496 surgical patients from 260 hospitals. We analyzed DVT and PE incidence and selected two subgroups for further analysis: gastroenterologic surgery and specific orthopedic surgery (high-frequency group).ResultsOverall DVT incidence was 1947 (0.19%); and the PE incidence was 538 (0.05%). DVT case fatality rate was 3.44% (67/1947); that for PE was 22.86% (123/538). Both overall and subgroup incidences were comparable to those in previous reports. Subgroup analyses in the high-frequency group did not show a relation between DVT and PE. VTE prophylaxis did not show a relation between DVT and PE despite 99% adherence.ConclusionsOur results are consistent with established data regarding DVT and PE incidence. Administrative data available in Japan provides a powerful epidemiologic tool to characterize rare diseases such as DVT and PE. DVT is not a suitable quality indicator in Japan. However, PE is too rare to be considered a rate-based outcome indicator, and VTE prophylaxis is too widely applied to be used as a process indicator. VTE measurement is not a useful quality indicator in Japan to compare hospitals but provides a longitudinal self-survey.

Derivation and Validation of In-Hospital Mortality Prediction Models in Ischaemic Stroke Patients Using Administrative Data

Background: Stroke and other cerebrovascular diseases are a major cause of death and disability. Predicting in-hospital mortality in ischaemic stroke patients can help to identify high-risk patients and guide treatment approaches. Chart reviews provide important clinical information for mortality prediction, but are laborious and limiting in sample sizes. Administrative data allow for large-scale multi-institutional analyses but lack the necessary clinical information for outcome research. However, administrative claims data in Japan has seen the recent inclusion of patient consciousness and disability information, which may allow more accurate mortality prediction using administrative data alone. The aim of this study was to derive and validate models to predict in-hospital mortality in patients admitted for ischaemic stroke using administrative data. Methods: The sample consisted of 21,445 patients from 176 Japanese hospitals, who were randomly divided into derivation and validation subgroups. Multivariable logistic regression models were developed using 7- and 30-day and overall in-hospital mortality as dependent variables. Independent variables included patient age, sex, comorbidities upon admission, Japan Coma Scale (JCS) score, Barthel Index score, modified Rankin Scale (mRS) score, and admissions after hours and on weekends/public holidays. Models were developed in the derivation subgroup, and coefficients from these models were applied to the validation subgroup. Predictive ability was analysed using C-statistics; calibration was evaluated with Hosmer-Lemeshow χ2 tests. Results: All three models showed predictive abilities similar or surpassing that of chart review-based models. The C-statistics were highest in the 7-day in-hospital mortality prediction model, at 0.906 and 0.901 in the derivation and validation subgroups, respectively. For the 30-day in-hospital mortality prediction models, the C-statistics for the derivation and validation subgroups were 0.893 and 0.872, respectively; in overall in-hospital mortality prediction these values were 0.883 and 0.876. Conclusions: In this study, we have derived and validated in-hospital mortality prediction models for three different time spans using a large population of ischaemic stroke patients in a multi-institutional analysis. The recent inclusion of JCS, Barthel Index, and mRS scores in Japanese administrative data has allowed the prediction of in-hospital mortality with accuracy comparable to that of chart review analyses. The models developed using administrative data had consistently high predictive abilities for all models in both the derivation and validation subgroups. These results have implications in the role of administrative data in future mortality prediction analyses.

Association of Geographical Factors With Administration of Tissue Plasminogen Activator for Acute Ischemic Stroke

Background Intravenous tissue plasminogen activator (tPA) is an effective treatment for acute ischemic stroke if administered within a few hours of stroke onset. Because of this time restriction, tPA administration remains infrequent. Ambulance use is an effective strategy for increasing tPA administration but may be influenced by geographical factors. The objectives of this study are to investigate the relationship between tPA administration and ambulance use and to examine how patient travel distance and population density affect tPA utilization. Methods and Results We analyzed administrative claims data from 114 194 acute ischemic stroke cases admitted to 603 hospitals between July 2010 and March 2012. Mixed‐effects logistic regression models of patients nested within hospitals with a random intercept were generated to analyze possible predictive factors (including patient characteristics, ambulance use, and driving time from home to hospital) of tPA administration for different population density categories to investigate differences in these factors in various regional backgrounds. Approximately 5.1% (5797/114 194) of patients received tPA. The composition of baseline characteristics varied among the population density categories, but adjustment for covariates resulted in all factors having similar associations with tPA administration in every category. The administration of tPA was associated with patient age and severity of stroke symptoms, but driving time showed no association. Ambulance use was significantly associated with tPA administration even after adjustment for covariates. Conclusion The association between ambulance use and tPA administration suggests the importance of calling an ambulance for suspected stroke. Promoting ambulance use for acute ischemic stroke patients may increase tPA use.

The Impact of Patient Profiles and Procedures on Hospitalization Costs through Length of Stay in Community-Acquired Pneumonia Patients Based on a Japanese Administrative Database

Background Community-acquired pneumonia is a common cause of patient hospitalization, and its burden on health care systems is increasing in aging societies. In this study, we aimed to investigate the factors that affect hospitalization costs in community-acquired pneumonia patients while considering the intermediate influence of patient length of stay. Methods Using a multi-institutional administrative claims database, we analyzed 30,041 patients hospitalized for community-acquired pneumonia who had been discharged between April 1, 2012 and September 30, 2013 from 289 acute care hospitals in Japan. Possible factors associated with hospitalization costs were investigated using structural equation modeling with length of stay as an intermediate variable. We calculated the direct, indirect (through length of stay), and total effects of the candidate factors on hospitalization costs in the model. Lastly, we calculated the ratio of indirect effects to direct effects for each factor. Results The structural equation model showed that higher disease severities (using A-DROP, Barthel Index, and Charlson Comorbidity Index scores), use of mechanical ventilation, and tube feeding were associated with higher hospitalization costs, regardless of the intermediate influence of length of stay. The severity factors were also associated with longer length of stay durations. The ratio of indirect effects to direct effects on total hospitalization costs showed that the former was greater than the latter in the factors, except in the use of mechanical ventilation. Conclusions Our structural equation modeling analysis indicated that patient profiles and procedures impacted on hospitalization costs both directly and indirectly. Furthermore, the profiles were generally shown to have greater indirect effects (through length of stay) on hospitalization costs than direct effects. These findings may be useful in supporting the more appropriate distribution of health care resources.

Development of a risk-adjusted in-hospital mortality prediction model for community-acquired pneumonia: a retrospective analysis using a Japanese administrative database

BackgroundCommunity-acquired pneumonia (CAP) is a common cause of patient hospitalization and death, and its burden on the healthcare system is increasing in aging societies. Here, we develop and internally validate risk-adjustment models and scoring systems for predicting mortality in CAP patients to enable more precise measurements of hospital performance.MethodsUsing a multicenter administrative claims database, we analyzed 35,297 patients hospitalized for CAP who had been discharged between April 1, 2012 and September 30, 2013 from 303 acute care hospitals in Japan. We developed hierarchical logistic regression models to analyze predictors of in-hospital mortality, and validated the models using the bootstrap method. Discrimination of the models was assessed using c-statistics. Additionally, we developed scoring systems based on predictors identified in the regression models.ResultsThe 30-day in-hospital mortality rate was 5.8%. Predictors of in-hospital mortality included advanced age, high blood urea nitrogen level or dehydration, orientation disturbance, respiratory failure, low blood pressure, high C-reactive protein levels or high degree of pneumonic infiltration, cancer, and use of mechanical ventilation or vasopressors. Our models showed high levels of discrimination for mortality prediction, with a c-statistic of 0.89 (95% confidence interval: 0.89-0.90) in the bootstrap-corrected model. The scoring system based on 8 selected variables also showed good discrimination, with a c-statistic of 0.87 (95% confidence interval: 0.86-0.88).ConclusionsOur mortality prediction models using administrative data showed good discriminatory power in CAP patients. These risk-adjustment models may support improvements in quality of care through accurate hospital evaluations and inter-hospital comparisons.

Improving the assessment of prescribing: Use of a ‘substitution index’

Objectives To analyse the current and potential utilization of generic drugs in Japan, to examine the maximum possible cost savings from generic drug use and to develop a fairer measure to assess the level of generic drug substitution. Methods We conducted a cross-sectional retrospective analysis of nine million dispensing records during January to March 2010 in Kyoto Prefecture. Maximum potential quantity-based shares were defined as the quantity of generic drugs used plus the quantity of branded drugs that could have been replaced by generic drugs divided by the quantity of all drugs dispensed. We developed a ‘substitution index’, defined as the proportion of generic drugs out of the total drugs substitutable with generic drugs (based on quantity rather than cost). Results Generic drugs had a quantity-based share of 17.9%, a cost-based share of 8.9% and a maximum potential quantity-based share of 50.1%, which is lower than the actual generic drug shares of some other countries. The maximum possible cost savings as a result of generic drug substitution was 16.5%. We also observed wide variations in maximum potential quantity-based shares between health care sectors and health care institutions. Conclusions Simple comparisons based on quantity-based shares may misrepresent the actual generic drug use. A substitution index that takes into account the maximum potential quantity-based share of generic drugs as a fairer measure may promote more realistic goals and encourage generic drug usage.

Estimating the disease burden of methicillin-resistant Staphylococcus aureus in Japan: Retrospective database study of Japanese hospitals

Objectives The nationwide impact of antimicrobial-resistant infections on healthcare facilities throughout Japan has yet to be examined. This study aimed to estimate the disease burden of methicillin-resistant Staphylococcus aureus (MRSA) infections in Japanese hospitals. Design Retrospective analysis of inpatients comparing outcomes between subjects with and without MRSA infection. Data source A nationwide administrative claims database. Setting 1133 acute care hospitals throughout Japan. Participants All surgical and non-surgical inpatients who were discharged between April 1, 2014 and March 31, 2015. Main outcome measures Disease burden was assessed using hospitalization costs, length of stay, and in-hospital mortality. Using a unique method of infection identification, we categorized patients into an anti-MRSA drug group and a control group based on anti-MRSA drug utilization. To estimate the burden of MRSA infections, we calculated the differences in outcome measures between these two groups. The estimates were extrapolated to all 1584 acute care hospitals in Japan that have adopted a prospective payment system. Results We categorized 93 838 patients into the anti-MRSA drug group and 2 181 827 patients into the control group. The mean hospitalization costs, length of stay, and in-hospital mortality of the anti-MRSA drug group were US

Examining sufficiency and equity in the geographic distribution of physicians in Japan: a longitudinal study

33 548, 75.7 days, and 22.9%, respectively; these values were 3.43, 2.95, and 3.66 times that of the control group, respectively. When extrapolated to the 1584 hospitals, the total incremental burden of MRSA was estimated to be US

Survival analyses of postoperative lung cancer patients: an investigation using Japanese administrative data

2 billion (3.41% of total hospitalization costs), 4.34 million days (3.02% of total length of stay), and 14.3 thousand deaths (3.62% of total mortality). Conclusions This study quantified the approximate disease burden of MRSA infections in Japan. These findings can inform policymakers on the burden of antimicrobial-resistant infections and support the application of infection prevention programs.

The economic burden of methicillin-resistant Staphylococcus aureus in community-onset pneumonia inpatients

Objectives The objective of this study was to longitudinally examine the geographic distribution of physicians in Japan with adjustment for healthcare demand according to changes in population age structure. Methods We examined trends in the number of physicians per 100 000 population in Japans secondary medical areas (SMAs) from 2000 to 2014. Healthcare demand was adjusted using health expenditure per capita. Trends in the Gini coefficient and the number of SMAs with a low physician supply were analysed. A subgroup analysis was also conducted where SMAs were divided into 4 groups according to urban–rural classification and initial physician supply. Results The time-based changes in the Gini coefficient and the number of SMAs with a low physician supply indicated that the equity in physician distribution had worsened throughout the study period. The number of physicians per 100 000 population had seemingly increased in all groups, with increases of 22.9% and 34.5% in urban groups with higher and lower initial physician supply, respectively. However, after adjusting healthcare demand, physician supply decreased by 1.3% in the former group and increased by 3.5% in the latter group. Decreases were also observed in the rural groups, where the number of physicians decreased by 4.4% in the group with a higher initial physician supply and 7.6% in the group with a lower initial physician supply. Conclusions Although the total number of physicians increased in Japan, demand-adjusted physician supply decreased in recent years in all areas except for urban areas with a lower initial physician supply. In addition, the equity of physician distribution had consistently deteriorated since 2000. The results indicate that failing to adjust healthcare demand will produce misleading results, and that there is a need for major reform of Japans healthcare system to improve physician distribution.