Ching Lan Cheng

Validation of the national health insurance research database with ischemic stroke cases in Taiwan

The National Health Insurance Research Database (NHIRD) is commonly used for pharmacoepidemiological research in Taiwan. This study evaluated the validity of the database for patients with a principal diagnosis of ischemic stroke.

Validation of Acute Myocardial Infarction Cases in the National Health Insurance Research Database in Taiwan

Background The aim of this study was to determine the validity of acute myocardial infarction (AMI) diagnosis coding in the National Health Insurance Research Database (NHIRD) by cross-comparisons of discharge diagnoses listed in the NHIRD with those in the medical records obtained from a medical center in Taiwan. Methods This was a cross-sectional study comparing records in the NHIRD and discharge notes in one medical center (DNMC) in the year 2008. Positive predictive values (PPVs) for AMI diagnoses were evaluated by reviewing the relevant clinical and laboratory data recorded in the discharge notes of the medical center. Agreement in comorbidities, cardiac procedures, and antiplatelet agent (aspirin or clopidogrel) prescriptions between the two databases was evaluated. Results We matched 341 cases of AMI hospitalizations from the two databases, and 338 cases underwent complete chart review. Of these 338 AMI cases, 297 were confirmed with clinical and lab data, which yielded a PPV of 0.88. The consistency rate for coronary intervention, stenting, and antiplatelet prescription at admission was high, yielding a PPV over 0.90. The percentage of consistency in comorbidity diagnoses was 95.9% (324/338) among matched AMI cases. Conclusions The NHIRD appears to be a valid resource for population research in cardiovascular diseases.

Compliance with antithrombotic prescribing guidelines for patients with atrial fibrillation-A nationwide descriptive study in Taiwan

OBJECTIVES This study examined compliance with prescribing guidelines for antithrombotic therapy in patients with atrial fibrillation (AF) in Taiwan, using the 2001 joint guideline from the American College of Cardiology, American Heart Association, and European Society of Cardiology. The study also sought to identify factors associated with the appropriate prescribing of antithrombotic therapy. METHODS Patients with AF were identified by the presence of > or =2 inpatient or outpatient claims with an International Classification of Diseases, Ninth Revision, Clinical Modification code of 427.31 in the Taiwanese National Health Insurance claims database between July 1, 2003, and June 30, 2004. Patients were stratified according to their stroke risk (highest, high, low, or lowest) and antithrombotic medication (aspirin, warfarin, ticlopidine/clopidogrel, or none). Based on these categories, rates of prescribed treatments that were compliant with the antithrombotic guidelines were calculated. Antithrombotic therapies were considered guideline compliant when warfarin was prescribed for the highest- or high-risk patients, aspirin was prescribed for low-risk patients, and aspirin or no antithrombotic treatment was prescribed for the lowest-risk patients. Because the role of ticlopidine/clopidogrel in AF remains unclear, prescription of these drugs without aspirin or warfarin was considered noncompliant with the guidelines. RESULTS Of 39,541 identified patients with AF, 70.3% were at high risk for thromboembolic events and 18.3% were at highest risk; however, only 24.7% of the overall population received appropriate antithrombotic therapy. When patients with risk factors for bleeding were excluded, the rate of compliance increased to 26.2%. Factors that were inversely associated with prescription of warfarin included risk factors for bleeding (cancer, predisposition to falls, previous hemorrhage, history of peptic ulcer, cirrhosis, renal dialysis, and psychiatric disease), hypertension, coronary artery disease, thyrotoxicosis, and age > or =60 years. CONCLUSIONS Most of these patients with AF in Taiwan did not receive appropriate antithrombotic therapy over the period studied. Bleeding risk factors, hypertension, coronary artery disease, thyrotoxicosis, and older age were associated with low rates of warfarin use.

Statins and Intracerebral Hemorrhage: Collaborative Systematic Review and Meta-analysis

Background— A recent large, randomized trial suggested that statins may increase the risk of intracerebral hemorrhage. Accordingly, we systematically reviewed the association of statins with intracerebral hemorrhage in randomized and observational data. Methods and Results— We screened 17 electronic bibliographic databases to identify eligible studies and consulted with experts in the field. We used DerSimonian-Laird random-effects models to compute summary risk ratios with 95% confidence intervals. Randomized trials, cohort studies, and case-control studies were analyzed separately. Only adjusted risk estimates were used for pooling observational data. We included published and unpublished data from 23 randomized trials and 19 observational studies. The complete data set comprised 248 391 patients and 14 784 intracerebral hemorrhages. Statins were not associated with an increased risk of intracerebral hemorrhage in randomized trials (risk ratio, 1.10; 95% confidence interval, 0.86–1.41), cohort studies (risk ratio, 0.94; 95% confidence interval, 0.81–1.10), or case-control studies (risk ratio, 0.60; 95% confidence interval, 0.41–0.88). Substantial statistical heterogeneity was evident for the case-control studies (I2=66%, P=0.01), but not for the cohort studies (I2=0%, P=0.48) or randomized trials (I2=30%, P=0.09). Sensitivity analyses by study design features, patient characteristics, or magnitude of cholesterol lowering did not materially alter the results. Conclusions— We found no evidence that statins were associated with intracerebral hemorrhage; if such a risk is present, its absolute magnitude is likely to be small and outweighed by the other cardiovascular benefits of these drugs.Background— A recent large, randomized trial suggested that statins may increase the risk of intracerebral hemorrhage. Accordingly, we systematically reviewed the association of statins with intracerebral hemorrhage in randomized and observational data. Methods and Results— We screened 17 electronic bibliographic databases to identify eligible studies and consulted with experts in the field. We used DerSimonian-Laird random-effects models to compute summary risk ratios with 95% confidence intervals. Randomized trials, cohort studies, and case-control studies were analyzed separately. Only adjusted risk estimates were used for pooling observational data. We included published and unpublished data from 23 randomized trials and 19 observational studies. The complete data set comprised 248 391 patients and 14 784 intracerebral hemorrhages. Statins were not associated with an increased risk of intracerebral hemorrhage in randomized trials (risk ratio, 1.10; 95% confidence interval, 0.86–1.41), cohort studies (risk ratio, 0.94; 95% confidence interval, 0.81–1.10), or case-control studies (risk ratio, 0.60; 95% confidence interval, 0.41–0.88). Substantial statistical heterogeneity was evident for the case-control studies (I2=66%, P =0.01), but not for the cohort studies (I2=0%, P =0.48) or randomized trials (I2=30%, P =0.09). Sensitivity analyses by study design features, patient characteristics, or magnitude of cholesterol lowering did not materially alter the results. Conclusions— We found no evidence that statins were associated with intracerebral hemorrhage; if such a risk is present, its absolute magnitude is likely to be small and outweighed by the other cardiovascular benefits of these drugs. # Clinical Perspective {#article-title-52}

Incidence and cumulative recurrence rates of venous thromboembolism in the Taiwanese population

Summary.  Background: Little information is available on the epidemiology of venous thromboembolism (VTE) in Asian populations. Objectives: To investigate VTE incidence, VTE cumulative recurrence rates and risk factors for VTE recurrence among the adult Taiwanese population. Methods: This population‐based cohort study used the Taiwanese National Health Insurance claims databases to identify 5347 adult patients (2463 men, 46.1%) with VTE diagnosed in 2001 and 2002. We calculated the crude incidence of VTE and its recurrence. We also conducted a nested case–control study (n = 3576) among this population to estimate the association between VTE recurrence and exposure to potential VTE risk factors by conditional logistic regression. Results: The crude incidence of VTE was 15.9 per 100 000 person‐years, and its recurrence rate was 5.1% per person‐year. During 11 566 person‐years of follow‐up, the cumulative rates of VTE recurrence at 6, 12, 24, 36 and 47 months were 6.7%, 9.4%, 12.4%, 13.9%, and 14.4%, respectively. By conditional logistic regression, histories of VTE [adjusted odds ratio (OR) 1.71, 95% confidence interval (CI) 1.32–2.16] or malignant neoplasm (adjusted OR 1.64, 95% CI 1.26–1.99), major extremity trauma (adjusted OR 2.76, 95% CI 1.82–4.52), serious neurologic diseases (adjusted OR 1.43, 95% CI 1.12–1.84) or undergoing major surgery (adjusted OR 4.57, 95% CI 1.72–12.50) were associated with higher risks of VTE recurrence. Conclusions: The incidence of VTE is lower in the Taiwanese population than in Caucasians. Most VTE recurrences occur within 12 months, but they continue to occur beyond 1 year. The VTE recurrences are associated with malignancy, history of VTE, and major surgery after a previous VTE.

An investigation of the potential association between retinal detachment and oral fluoroquinolones: a self-controlled case series study

OBJECTIVES A study reported a significant association between oral fluoroquinolones and the development of retinal detachment among current users of oral fluoroquinolones (Etminan M, Forooghian F, Brophy JM et al. JAMA 2012; 307: 1414-9). However, other published studies have discordant results. This study aimed to investigate this association and to estimate the absolute risk of developing retinal detachment in patients exposed to oral fluoroquinolones. METHODS A self-controlled case series study was conducted with data retrieved from the Hong Kong Clinical Data Analysis and Reporting System database and the Taiwan National Health Insurance Research Database. Hong Kong and Taiwanese patients who had prescriptions for oral fluoroquinolones and a procedure for retinal detachment between 2001 and 2012 and between 2000 and 2010, respectively, were defined as cases and included in the analysis. RESULTS A total of 9 events were found during the fluoroquinolone-exposed period and 1407 events were found during the non-exposed period. The adjusted incidence rate ratio in the combined model was 1.26 (0.65-2.47). The crude absolute risk of experiencing retinal detachment whilst on oral fluoroquinolones was ∼1.3 per 200 000 prescriptions. CONCLUSIONS Our study does not support the association between the use of fluoroquinolones and the development of retinal detachment and our findings are strikingly similar to that of the study conducted in Denmark. Doubt is cast on the association between the use of fluoroquinolones and the development of retinal detachment. Therefore, the use of fluoroquinolones should not be precluded based on the current evidence on the risk of retinal detachment. The impact of different ethnicities on the response to fluoroquinolones should also be investigated.

Early statin therapy in patients with acute intracerebral hemorrhage without prior statin use

Statin therapy is beneficial for primary and secondary prevention of ischaemic stroke, but its influence in patients with intracerebral hemorrhage (ICH) is unclear. An assessment was made of the effect of early statin therapy on patients with acute ICH.

Trends in the Incidence and Management of Acute Myocardial Infarction From 1999 to 2008: Get With the Guidelines Performance Measures in Taiwan

Background The American Heart Association Get With the Guidelines (GWTG) program has improved care quality of acute myocardial infarction (AMI) with important implications for other countries in the world. This study evaluated the incidence and care of AMI in Taiwan and assessed the compliance of GWTG in Taiwan. Methods and Results We used the Taiwan National Health Insurance Research Database (1999–2008) to identify hospitalized patients ≥18 years of age presenting with AMI. The temporal trends of annual incidence and care quality of AMI were evaluated. The age‐adjusted incidence of AMI (/100 000 person‐years) increased from 28.0 in 1999 to 44.4 in 2008 (P<0.001). The use of guideline‐based medications for AMI was evaluated. The use of dual antiplatelet therapy (DAPT) increased from 65% in 2004 to 83.9% in 2008 (P<0.001). Angiotensin‐converting enzyme (ACE) inhibitor or angiotensin receptor blocker (ARB) was used in 72.6% in 2004 and 71.7% in 2008 (P=NS) and β‐blocker was used in 60% in 2004 and 59.7% in 2008 (P=NS). Statin use increased from 32.1% to 50.1% from 2004 to 2008 (P<0.001). The in‐hospital mortality decreased from 15.9% in 1999 to 12.3% in 2008 (P<0.0001). Multivariable analysis showed that DAPT, ACE inhibitor/ARB, β‐blocker, and statin use during hospitalization were all associated with reduced in‐hospital mortality in our AMI patients. Conclusions AMI incidence was increasing, but the guideline‐based medications for AMI were underutilized in Taiwan. Quality improvement programs, such as GWTG, should be promoted to improve AMI care and outcomes in Taiwan.

Universal pharmacological thromboprophylaxis for total knee arthroplasty may not be necessary in low-risk populations: a nationwide study in Taiwan

Summary.  Background: Thromboprophylaxis should be universally administered in major orthopedic surgery. However, epidemiology of venous thromboembolism (VTE) following major knee surgery in Asia is scarce. Objective: To describe the use of thromboprophylaxis and calculate the incidence and risk factors of symptomatic VTE following major knee surgery in Taiwan. Methods: We used Taiwan’s National Health Insurance Research Database to retrospectively identify patients (≧45 years) who underwent major knee surgery from 1998 to 2007 and collected the medical records within 3 months after the discharge. Logistic regression analysis was used to determine the risk factors of symptomatic VTE after the surgery. Results: We identified 113 844 patients (mean age, 69.0 ± 7.7 years; female, 75.2%) receiving major knee arthroplasties. The mean length of stay was 9.1 ± 3.3 days. The overall pharmacological thromboprophylaxis rate was 2.2%. The 3‐month cumulative incidence of procedure‐related symptomatic VTE was 0.46% (95% CI, 0.42–0.50%). The median time to the first post‐operation VTE was 7 days, with 85.4% occurring within 2 weeks after the discharge. Logistic regression analysis showed that previous VTE, malignancy, heart failure and neurologic disorder with extremity paralysis or pararesis were independent risk factors (P < 0.05) for symptomatic VTE following major knee arthroplasties. Conclusions: The thromboprophylaxis rate is low, which may be due to the very low incidence of symptomatic VTE after the surgery in Taiwan. Most symptomatic VTE occurred within 2 weeks after the surgery. Universal thromboprophylaxis for knee arthroplasties may not be necessary in Taiwan, but it should be considered in some high‐risk populations.

The role of chemoprevention by selective cyclooxygenase-2 inhibitors in colorectal cancer patients - a population-based study

BackgroundThere are limited population-based studies focusing on the chemopreventive effects of selective cyclooxygenase-2 (COX-2) inhibitors against colorectal cancer. The purpose of this study is to assess the trends and dose–response effects of various medication possession ratios (MPR) of selective COX-2 inhibitor used for chemoprevention of colorectal cancer.MethodsA population-based case–control study was conducted using the Taiwan Health Insurance Research Database (NHIRD). The study comprised 21,460 colorectal cancer patients and 79,331 controls. The conditional logistic regression was applied to estimate the odds ratios (ORs) for COX-2 inhibitors used for several durations (5 years, 3 years, 1 year, 6 months and 3 months) prior to the index date.ResultsIn patients receiving selective COX-2 inhibitors, the OR was 0.51 (95% CI=0.29~0.90, p=0.021) for an estimated 5-year period in developing colorectal cancer. ORs showing significant protection effects were found in 10% of MPRs for 5-year, 3-year, and 1-year usage. Risk reduction against colorectal cancer by selective COX-2 inhibitors was observed as early as 6 months after usage.ConclusionOur results indicate that selective COX-2 inhibitors may reduce the development of colorectal cancer by at least 10% based on the MPRs evaluated. Given the limited number of clinical reports from general populations, our results add to the knowledge of chemopreventive effects of selective COX-2 inhibitors against cancer in individuals at no increased risk of colorectal cancer.