Epidemiology and registry studies of stroke in Japan

Regional variations in in-hospital mortality, care processes, and spending in acute ischemic stroke patients in Japan

BACKGROUND

Little is known about the regional variations in ischemic stroke care in Japan. This study investigates the regional variations and associations among outcomes, care processes, spending, and physician workforce availability in acute ischemic stroke care.

METHODS

Using administrative claims data from National Claims Database, we identified National Health Insurance beneficiaries aged 65 years and older and Long Life Medical Care System beneficiaries from 9 prefectures who had been hospitalized for acute ischemic stroke between April 2010 and March 2012. Patients were grouped according to their subprefectural regions of residence known as secondary medical areas (SMAs). Performances in 8 outcome and process of care measures were analyzed in each SMA. Multilevel regression models with 2 levels (patient and regional) were used to analyze age- and sex-adjusted in-hospital mortality, hospitalization spending, and tissue plasminogen activator (tPA) utilization rate. The associations between regional supply of physicians for stroke care and the various quality measures were investigated.

RESULTS

We analyzed 49,440 acute ischemic stroke patients. The regional variations among SMAs in in-hospital mortality, spending, and tPA utilization were 3.2-, 1.7-, and 5.9-fold, respectively. Higher physician supply was significantly associated with lower in-hospital mortality and higher spending. Additionally, spending had a significantly negative correlation with regional continuity of care planning rate but a significantly positive correlation with rehabilitation rate.

CONCLUSIONS

The study revealed substantial regional variations in Japanese ischemic stroke care. Improving the allocative efficiency of physicians and establishing continuity of care networks may be useful in mitigating regional disparities and reconstructing the stroke care system.

Prevalence of asthma with airflow limitation, COPD, and COPD with variable airflow limitation in older subjects in a general Japanese population: the Hisayama Study

BACKGROUND

Elucidating the prevalence of asthma and chronic obstructive pulmonary disease (COPD) is important for designing a public health strategy. Recent studies have discriminated a phenotype of COPD with variable airflow limitation (COPD-VAL) associated with asthma-COPD overlap syndrome. Its prevalence remains uncertain. The age and occupational distributions in the town of Hisayama and in Japan are nearly identical. Each disease's prevalence was estimated for the town's residents.

METHODS

In 2008, town residents (≥ 40 years) were solicited to participate in a health checkup. Individuals with abnormal spirometry (forced expiratory volume in 1s/forced vital capacity [FEV1/FVC]<70% and/or %FVC<80%) were recommended for further evaluations. Two pulmonologists in a blinded fashion reviewed their medical records, including bronchodilator reversibility. Individuals with airflow limitation were classified as having asthma, COPD, COPD-VAL, or other diseases. The prevalence of each disease was then estimated.

RESULTS

A total of 2100 residents (43.4% of residents in the age group) completed spirometry. In 455 residents with abnormal spirometry, 190 residents had further evaluations, and the medical records of 174 residents were reviewed. The prevalence of asthma with airflow limitation, COPD, and COPD-VAL, were 2.0%, 8.4%, and 0.9%, respectively. The prevalence of COPD and COPD-VAL were higher in men and smokers than in women and never-smokers. The prevalence of COPD, but not COPD-VAL or asthma, increased with age.

CONCLUSION

The prevalence of asthma with airflow limitation, COPD, and COPD-VAL were estimated in a population of residents (≥ 40 years) in Hisayama.