Electronic health records (EHRs) can provide researchers with extraordinary opportunities for population-based research. The National Health Insurance system of Taiwan was established in 1995 and covers more than 99.6% of the Taiwanese population; this system's claims data are released as the National Health Insurance Research Database (NHIRD). All data from primary outpatient departments and inpatient hospital care settings after 2000 are included in this database. After a change and update in 2016, the NHIRD is maintained and regulated by the Data Science Centre of the Ministry of Health and Welfare of Taiwan. Datasets for approved research are released in three forms: sampling datasets comprising 2 million subjects, disease-specific databases, and full population datasets. These datasets are de-identified and contain basic demographic information, disease diagnoses, prescriptions, operations, and investigations. Data can be linked to government surveys or other research datasets. While only a small number of validation studies with small sample sizes have been undertaken, they have generally reported positive predictive values of over 70% for various diagnoses. Currently, patients cannot opt out of inclusion in the database, although this requirement is under review. In conclusion, the NHIRD is a large, powerful data source for biomedical research.

Background. The interpretation of the change scores of the Barthel Index (BI) in follow-up or outcome studies has been hampered by the fact that its minimal clinically important difference (MCID) has not been determined. Objective. This article was written to establish the MCID of the BI in stroke patients. Methods. Both anchor-based and distribution-based methods were used to establish the MCID. In the anchor-based method, 43 stroke inpatients participated in a follow-up study designed to determine the MCID of the BI using patients' global ratings of the activities of daily living function on a 15-point Likert-type scale. The mean change scores on the 20-point scale of the BI of the MCID group, based on the patients' ratings on the Likert-type scale, served as the first estimate of the MCID. In the distribution-based method, 56 chronic stroke patients participated in the test-retest reliability study to determine the MCID of the BI. One standard error of measurement (SEM) served as the second estimate for the MCID. The larger MCID value of the 2 estimates was chosen as the MCID of the BI. Results. In the anchor-based study, there were 20 patients in the MCID group, with a mean change score of 1.85 points (ie, the first MCID estimate). In the distribution-based study, the SEM based on test-retest agreement was 1.45 points (ie, the second MCID estimate). The MCID of the BI in stroke patients was estimated to be 1.85 points. Conclusion. The authors' results, within the limitations of their design, suggest that if the mean BI change score within a stroke group has reached 1.85 points in a study, the change score on the BI can be perceived by patients as important and beyond measurement error (ie, such a change score is clinically important).

Purpose: Statins have potential protective effects against cancers, but no studies have focused on patients with chronic hepatitis B virus (HBV) infection. The purpose of this study was to investigate the association between the use of statins in HBV-infected patients and the risk of hepatocellular carcinoma (HCC). Patients and Methods: We conducted a population-based cohort study from the Taiwan National Health Insurance Research Database. A total of 33,413 HBV-infected patients were included as the study cohort. Each patient was individually tracked from 1997 to 2008 to identify incident cases of HCC since 1999. Subsequent use of statin, other lipid-lowering agents, aspirin, and angiotensin-converting enzyme inhibitors was identified. Cox proportional hazards regression was used to calculate the hazard ratios (HRs) and 95% CIs for the association between the use of statins and the occurrence of HCC in the HBV-infected cohort. Results: There were 1,021 HCCs in the HBV cohort during the follow-up period of 328,946 person-years; the overall incidence rate was 310.4 HCCs per 100,000 person-years. There was a dose-response relationship between statin use and the risk of HCC in the HBV cohort. The adjusted HRs were 0.66 (95% CI, 0.44 to 0.99), 0.41 (95% CI, 0.27 to 0.61), and 0.34 (95% CI, 0.18 to 0.67) for statin use of 28 to 90, 91 to 365, and more than 365 cumulative defined daily doses (cDDDs), respectively, relative to no statin use (< 28 cDDDs). Conclusion: Statin use may reduce the risk for HCC in HBV-infected patients in a dose-dependent manner. Further mechanistic research is needed.

OBJECTIVE: Perfluoroalkyl chemicals (PFCs) have been used worldwide in a variety of consumer products. The effect of PFCs on glucose homeostasis is not known. RESEARCH DESIGN AND METHODS: We examined 474 adolescents and 969 adults with reliable serum measures of metabolic syndrome profile from the National Health and Nutrition Examination Survey 1999–2000 and 2003–2004. RESULTS: In adolescents, increased serum perfluorononanoic acid (PFNA) concentrations were associated with hyperglycemia (odds ratio [OR] 3.16 [95% CI 1.39–7.16], P < 0.05). Increased serum PFNA concentrations also have favorable associations with serum HDL cholesterol (0.67 [0.45–0.99], P < 0.05). Overall, increased serum PFNA concentrations were inversely correlated with the prevalence of the metabolic syndrome (0.37 [0.21–0.64], P < 0.005). In adults, increased serum perfluorooctanoic acid concentrations were significantly associated with increased β-cell function (β coefficient 0.07 ± 0.03, P < 0.05). Increased serum perfluorooctane sulfate (PFOS) concentrations were associated with increased blood insulin (0.14 ± 0.05, P < 0.01), homeostasis model assessment of insulin resistance (0.14 ± 0.05, P < 0.01), and β-cell function (0.15 ± 0.05, P < 0.01). Serum PFOS concentrations were also unfavorably correlated with serum HDL cholesterol (OR 1.61 [95% CI 1.15–2.26], P < 0.05). CONCLUSIONS: Serum PFCs were associated with glucose homeostasis and indicators of metabolic syndrome. Further clinical and animal studies are warranted to clarify putative causal relationships.

The Chang Gung Research Database (CGRD) is a de-identified database derived from original medical records of Chang Gung Memorial Hospital (CGMH), which comprises seven medical institutes located from the northeast to southern regions of Taiwan. The volume of medical services performed in CGMH is large, and clinical and scientific studies based on the CGRD are reported to be of high quality. However, the CGRD as a useful database for research has not been analyzed before. The objective of the study was to analyze the CGRD with regard to its characteristics and coverage of Taiwan's population. We performed a nationwide cohort study using population-based data from the Taiwan National Health Insurance Research Database (NHIRD). All patients who had any medical record of outpatient visits or admission between January 1, 1997, and December 31, 2010, were included, and the sex ratio, age distribution, socioeconomic status, urbanicity, severity of illness, prevalence of specific disease, and coverage of the CGRD were analyzed. The sex ratio, age distribution, socioeconomic status, and urbanicity of the population of the CGRD are different from those of Taiwan NHIRD and medical centers in Taiwan (all the pairwise p < 0.05). The severity of comorbidities, and prevalence of specific diseases of the population of the CGRD are significantly higher than those of Taiwan NHIRD and medical centers in Taiwan for both outpatient and inpatient samples (all the pairwise p < 0.05). The overall coverage of the CGRD was 21.2% for outpatients and 12.4% for inpatients. The disease-specific coverage of the CGRD was 27-34% for outpatients and 14-21% for inpatients. The CGRD is a multi-institutional, original medical record-based research database with high overall and disease-specific coverage of Taiwan. The population of the CGRD has significantly higher severity of comorbidities, and prevalence of specific diseases than those of Taiwan NHIRD and medical centers in Taiwan.