Predictors, mortality, and health outcomes of intensive phase non-adherence to a regimen in patients with drug-susceptible tuberculosis: a nationwide linkage database.

OBJECTIVES: The clinical importance of adhering to the regimen in tuberculosis patients has been widely investigated, but most studies were conducted in controlled settings and in limited populations. We aimed to measure the level of real-world adherence during intensive phase and investigate the predictors and the risk of mortality and health outcomes of intensive phase non-adherence in tuberculosis patients. STUDY DESIGN: We conducted a nationwide cohort study by linking the Korean National Tuberculosis Surveillance System and the National Health Information Database. METHODS: We included all incident drug-susceptible tuberculosis patients who initiated the regimens recommended by the World Health Organization from 2013 to 2018. Adherence was measured using the proportion of days covered (poor [<50%], moderate [50%-79%], and high [≥80%]). We used logistic regression model to assess predictors and the Cox proportional hazard model to evaluate the risk of mortality and health outcomes with intensive phase non-adherence. RESULTS: Of 46,818 patients, there were 8% and 11% with poor and moderate adherent groups, respectively. Age ≥45 years, insulin use, and history of renal failure were predictors of non-adherence. Compared with high adherent group, poor and moderate adherent groups were associated with a substantial risk of mortality (poor: hazard ratio, 2.14 [95% confidence interval, 1.95-2.34]; moderate: 1.76 [1.62-1.92]). Similar trends were observed for health outcomes. Stratified analyses showed a higher risk of mortality in patients with medical aid, low income, and history of renal failure, systematic corticosteroids, and immunomodulators. CONCLUSIONS: Non-adherence during intensive phase increased mortality risk by twofold, underscoring targeted intervention for high-risk population, including advanced diabetes, and immunocompromised patients.

Neonatal and maternal adverse outcomes and exposure to nonsteroidal anti-inflammatory drugs during early pregnancy in South Korea: A nationwide cohort study.

BACKGROUND: Existing data on the use of nonsteroidal anti-inflammatory drugs (NSAIDs) during late pregnancy is well established, providing assurance. However, the use of NSAIDs during early pregnancy remains inconclusive owing to conflicting findings on adverse neonatal outcomes as well as the limited data on adverse maternal outcomes. Therefore, we sought to investigate whether early prenatal exposure to NSAIDs was associated with neonatal and maternal adverse outcomes. METHODS AND FINDINGS: We conducted a nationwide, population-based cohort study using Korea's National Health Insurance Service (NHIS) database with a mother-offspring cohort constructed and validated by the NHIS to include all live births in women aged 18 to 44 years between 2010 and 2018. We defined exposure to NSAIDs as at least two records of NSAID prescriptions during early pregnancy (first 90 days of pregnancy for congenital malformations and first 19 weeks for nonmalformation outcomes) and compared against three distinct referent groups of (1) unexposed, no NSAID prescription during the 3 months before pregnancy start to end of early pregnancy; (2) acetaminophen-exposed, at least two acetaminophen prescriptions during early pregnancy (i.e., active comparator); and (3) past users, at least two NSAID prescriptions before the start of pregnancy but no relevant prescriptions during pregnancy. Outcomes of interest were adverse birth outcomes of major congenital malformations and low birth weight and adverse maternal outcomes of antepartum hemorrhage and oligohydramnios. We estimated relative risks (RRs) with 95% CIs using generalized linear models within a propensity score (PS) fine stratification weighted cohort that accounted for various potential confounders of maternal sociodemographic characteristics, comorbidities, co-medication use, and general markers of burden of illness. Of 1.8 million pregnancies in the PS weighted analyses, exposure to NSAIDs during early pregnancy was associated with slightly increased risks for neonatal outcomes of major congenital malformations (PS-adjusted RR, 1.14 [CI, 1.10 to 1.18]) and low birth weight (1.29 [1.25 to 1.33]), and for maternal outcome of oligohydramnios (1.09 [1.01 to 1.19]) but not antepartum hemorrhage (1.05 [0.99 to 1.12]). The risks of overall congenital malformations, low birth weight, and oligohydramnios remained significantly elevated despite comparing NSAIDs against acetaminophen or past users. Risks of adverse neonatal and maternal outcomes were higher with cyclooxygenase-2 selective inhibitors or use of NSAIDs for more than 10 days, whereas generally similar effects were observed across the three most frequently used individual NSAIDs. Point estimates were largely consistent across all sensitivity analyses, including the sibling-matched analysis. Main limitations of this study are residual confounding by indication and from unmeasured factors. CONCLUSIONS: This large-scale, nationwide cohort study found that exposure to NSAIDs during early pregnancy was associated with slightly higher risks of neonatal and maternal adverse outcomes. Clinicians should therefore carefully weigh the benefits of prescribing NSAIDs in early pregnancy against its modest, but possible, risk of neonatal and maternal outcomes, where if possible, consider prescribing nonselective NSAIDs for <10 days, along with continued careful monitoring for any safety signals.

Real-world data emulating randomized controlled trials of non-vitamin K antagonist oral anticoagulants in patients with venous thromboembolism.

BACKGROUND: Emulating randomized controlled trials (RCTs) by real-world evidence (RWE) studies would benefit future clinical and regulatory decision-making by balancing the limitations of RCT. We aimed to evaluate whether the findings from RWE studies can support regulatory decisions derived from RCTs of non-vitamin K antagonist oral anticoagulants (NOACs) in patients with venous thromboembolism (VTE). METHODS: Five landmark trials (AMPLIFY, RE-COVER II, Hokusai-VTE, EINSTEIN-DVT, and EINSTEIN-PE) of NOACs were emulated using the South Korean nationwide claims database (January 2012 to August 2020). We applied an active comparator and new-user design to include patients who initiated oral anticoagulants within 28 days from their VTE diagnoses. The prespecified eligibility criteria, exposure (each NOAC, such as apixaban, rivaroxaban, dabigatran, and edoxaban), comparator (conventional therapy, defined as subcutaneous heparin followed by warfarin), and the definition of outcomes from RCTs were emulated as closely as possible in each separate emulation cohort. The primary outcome was identical to each trial, which was defined as recurrent VTE or VTE-related death. The safety outcome was major bleeding. Propensity score matching was conducted to balance 69 covariates between the exposure groups. Effect estimates for outcomes were estimated using the Mantel-Haenszel method and Cox proportional hazards model and subsequently compared with the corresponding RCT estimates. RESULTS: Compared to trial populations, real-world study populations were older (range: 63-69 years [RWE] vs. 54-59 years [RCT]), with more females (55-60.5% vs. 39-48.3%) and had a higher prevalence of active cancer (4.2-15.4% vs. 2.5-9.5%). The emulated estimates for effectiveness outcomes showed superior effectiveness of NOAC (AMPLIFY: relative risk 0.81, 95% confidence interval 0.70-0.94; RE-COVER II: hazard ratio [HR] 0.60, 0.37-0.96; Hokusai-VTE: 0.49, 0.31-0.78; EINSTEIN-DVT: 0.54, 0.33-0.89; EINSTEIN-PE: 0.50, 0.34-0.74), when contrasted with trials that showed non-inferiority. For safety outcomes, all emulations except for AMPLIFY and EINSTEIN-DVT yielded results consistent with their corresponding RCTs. CONCLUSIONS: This study revealed the feasibility of complementing RCTs with RWE studies by using claims data in patients with VTE. Future studies to consider the different demographic characteristics between RCT and RWE populations are needed.

Association of adverse respiratory events with sodium-glucose cotransporter 2 inhibitors versus dipeptidyl peptidase 4 inhibitors among patients with type 2 diabetes in South Korea: a nationwide cohort study.

BACKGROUND: Impaired respiratory function remains underrecognized in patients with type 2 diabetes (T2D), despite common pulmonary impairment. Meanwhile, there is little data available on the respiratory effects of sodium glucose cotransporter 2 inhibitors (SGLT2i). Hence, we examined the association between SGLT2i use and the risk of adverse respiratory events in a real-world setting. METHODS: We conducted a population-based, nationwide cohort study using an active-comparator new-user design and nationwide claims data of South Korea from January 2015 to December 2020. Among individuals aged 18 years or older, propensity score matching was done to match each new user of SGLT2is with dipeptidyl peptidase 4 inhibitors (DPP4is), with patients followed up according to an as-treated definition. The primary outcome was respiratory events, a composite endpoint of acute pulmonary edema, acute respiratory distress syndrome (ARDS), pneumonia, and respiratory failure. Secondary outcomes were the individual components of the primary outcome and in-hospital death. Cox models were used to estimate hazard ratios (HRs) and 95% CIs. RESULTS: Of 205,534 patient pairs in the propensity score matched cohort, the mean age of the entire cohort was 53.8 years and 59% were men, with a median follow-up of 0.66 years; all baseline covariates achieved balance between the two groups. Incidence rates for overall respiratory events were 4.54 and 7.54 per 1000 person-years among SGLT2i and DPP4i users, respectively, corresponding to a rate difference of 3 less events per 1000 person-years (95% CI - 3.44 to - 2.55). HRs (95% CIs) were 0.60 (0.55 to 0.64) for the composite respiratory endpoint, 0.35 (0.23 to 0.55) for acute pulmonary edema, 0.44 (0.18 to 1.05) for ARDS, 0.61 (0.56 to 0.66) for pneumonia, 0.49 (0.31 to 0.76) for respiratory failure, and 0.46 (0.41 to 0.51) for in-hospital death. Similar trends were found across individual SGLT2is, subgroup analyses of age, sex, history of comorbidities, and a range of sensitivity analyses. CONCLUSIONS: These findings suggest a lower risk of adverse respiratory events associated with patients with T2D initiating SGLT2is versus DPP4is. This real-world evidence helps inform patients, clinicians, and guideline writers regarding the respiratory effects of SGLT2i in routine practice.

Association of sodium-glucose cotransporter 2 inhibitors with post-discharge outcomes in patients with acute heart failure with type 2 diabetes: a cohort study.

BACKGROUND: Given the cumulative evidence on the effectiveness of sodium-glucose cotransporter 2 inhibitors (SGLT2is) on chronic heart failure, demand is emerging for further information on their effects in patients who are hospitalized for acute heart failure. However, there is still limited evidence about the class effect of SGLT2is on acute heart failure. We investigated whether initiating treatment with SGLT2is after an episode of acute heart failure reduces the risks of post-discharge heart failure readmission or cardiovascular mortality among patients with type 2 diabetes. METHODS: A retrospective cohort study was conducted in a cohort of patients with type 2 diabetes who hospitalized for heart failure, using Korean Health Insurance Review & Assessment database (2015-2020). The exposure was defined as initiation of SGLT2is during hospitalization or at discharge. We assessed hazards of post-discharge heart failure readmission and cardiovascular death at 1-year, and 30-, 60-, and 90-day from the date of discharge in the SGLT2is users and non-users. Cox proportional hazards models with propensity score-based inverse probability of treatment weighting were used to estimate hazard ratios and 95% confidence intervals. RESULTS: Among 56,343 patients with type 2 diabetes hospitalized for heart failure, 29,290 patients were included in the study cohort (mean [SD] age, 74.1 [10.8] years; 56.1% women); 818 patients (2.8%) were prescribed SGLT2is during index hospitalization or at discharge. Patients with a prescription for SGLT2i vs. those without prescription had lower rates of heart failure readmission or cardiovascular death at 1 year (22.4% vs. 25.3%; adjusted hazard ratio, 0.90 [95% confidence interval, 0.87-0.93]), and also at 30 days (7.0% vs. 7.7%%; 0.74 [0.69-0.79]). CONCLUSIONS: Among patients with type 2 diabetes, initiating SGLT2i treatment after an episode of acute heart failure was significantly associated with a reduced combined risk of heart failure readmission and cardiovascular mortality in a nationwide cohort reflecting routine clinical practice.

Safety of sodium-glucose co-transporter-2 inhibitors on amputation across categories of baseline cardiovascular disease and diuretics use in patients with type 2 diabetes.

AIM: To assess the risk of amputation associated with sodium-glucose co-transporter-2 inhibitors (SGLT2is) among patients with type 2 diabetes, across categories of baseline cardiovascular disease (CVD) and diuretic use (DU). MATERIALS AND METHODS: We conducted an active comparator, new-user cohort study using Korea's nationwide claims data (2015-2020). The study cohort consisted of patients with type 2 diabetes who initiated SGLT2is or dipeptidyl peptidase-4 inhibitors (DPP4is). Cohort entry was defined by first prescription date. We then classified patients into four discrete subcohorts based on their baseline status of CVD and DU as (1) CVD+/DU+, (2) CVD+/DU-, (3) CVD-/DU+ and (4) CVD-/DU-. We performed 1:1 propensity score (PS) matching within each cohort and estimated hazard ratios (HRs) with 95% confidence intervals (CIs) for the risk of amputation with SGLT2is versus DPP4is using Cox models. RESULTS: We identified 219 900 PS-matched pairs of SGLT2is and DPP4is (CVD+/DU+, n = 11 719; CVD+/DU-, n = 26 092; CVD-/DU+, n = 26 894; and CVD-/DU-, n = 155 195), with well-balanced baseline covariates across all cohorts. Significantly lower risks of amputation with SGLT2is versus DPP4is were found in CVD+/DU+ (HR 0.36, 95% CI 0.14-0.90), CVD+/DU- (0.45, 0.21-0.99) and CVD-/DU- (0.48, 0.33-0.70), but not in CVD-/DU+ (0.54, 0.26-1.12). Consistent trends in estimates were found across various sensitivity analyses. CONCLUSIONS: Initiating SGLT2is against DPP4is did not increase the risk of amputation across patient populations of varying vulnerability. These findings based on routine practice will reassure clinicians of the safety of SGLT2is with regard to amputation risk in selected high-risk patients with type 2 diabetes.

Immeasurable Time Bias in Self-controlled Designs: Case-crossover, Case-time-control, and Case-case-time-control Analyses.

BACKGROUND: Impact of immeasurable time bias (IMTB) is yet to be examined in self-controlled designs. METHODS: We conducted case-crossover, case-time-control, and case-case-time-control analyses using Korea's healthcare database. Two empirical examples among elderly patients were used: 1) benzodiazepines-hip fracture; 2) benzodiazepines-mortality. For cases, the date of hip fracture diagnosis or death was defined as the index date, and the inherited date of their matched cases for controls or future cases. Exposure was assessed in the 1-30 day (hazard) and 61-90 day (control) windows preceding the index date. A non-missing exposure setting included in- and outpatient prescriptions and the pseudo-outpatient setting included only the outpatients. Conditional logistic regression was done to estimate odds ratios (ORs) with 95% confidence intervals (CIs), where the relative difference in OR among the two settings was calculated to quantify the IMTB. RESULTS: The IMTB had negligible impacts in the hip fracture example in the case-crossover (non-missing exposure setting OR 1.27; 95% CI, 1.12-1.44; pseudo-outpatient setting OR 1.21; 95% CI, 1.06-1.39; magnitude 0.05), case-time-control (OR 1.18; 95% CI, 0.98-1.44; OR 1.13; 95% CI, 0.92-1.38; 0.04, respectively), and case-case-time-control analyses (OR 0.99; 95% CI, 0.80-1.23; OR 0.94; 95% CI, 0.75-1.18; 0.05, respectively). In the mortality example, IMTB had significant impacts in the case-crossover (non-missing exposure setting OR 1.44; 95% CI, 1.36-1.52; pseudo-outpatient setting OR 0.72; 95% CI, 0.67-0.78; magnitude 1.00), case-time-control (OR 1.38; 95% CI, 1.26-1.51; OR 0.68; 95% CI, 0.61-0.76; 1.03, respectively), and case-case-time-control analyses (OR 1.27; 95% CI, 1.15-1.40; OR 0.62; 95% CI, 0.55-0.69; 1.05, respectively). CONCLUSION: Although IMTB had negligible impacts on the drug's effect on acute events, as these are unlikely to be accompanied with hospitalizations, it negatively biased the drug's effect on mortality, an outcome with prodromal phases, in the three self-controlled designs.

Long-term clinical outcomes of oral antidiabetic drugs as fixed-dose combinations: A nationwide retrospective cohort study.

AIM: To compare treatment patterns and clinical outcomes of single-pill fixed-dose combination (FDC) and two-pill combination (TPC) therapies using real-world data. METHODS: We conducted a nationwide retrospective cohort study using South Korea's healthcare database (2002-2015). We identified two cohorts of incident patients with type 2 diabetes who initiated FDC or TPC therapy within 4 months of their first prescription for metformin or sulphonylurea. We examined persistence and adherence patterns and the clinical outcome of a composite endpoint of death or hospitalization for acute myocardial infarction, heart failure or stroke and compared the differences in treatment patterns and clinical outcomes using Cox models. RESULTS: Of 5143 and 10 973 patients who initiated FDC and TPC therapy, respectively, we identified 5143 patient pairs after propensity score matching. The FDC group exhibited greater median time to treatment discontinuation (163 vs. 146 days), and proportion of days covered at 12 months (mean 0.60 vs. 0.57, P < .0001) and at 24 months (0.53 vs. 0.51, P = .014) than the TPC group. The FDC group, compared with the TPC group, had reduced risks of the composite clinical outcome (hazard ratio 0.86, 95% confidence intervals 0.77-0.97) and hospitalization for stroke (0.80, 0.67-0.96). CONCLUSION: FDC therapy may provide favourable cardiovascular benefits, especially reducing the risk of hospitalization for stroke, and has better medication adherence among patients with type 2 diabetes.

Treatment pattern in postmenopausal women with osteoporosis: a population-based cohort study in South Korea.

INTRODUCTION: The treatment landscape of postmenopausal osteoporosis (OP) in an Asian population is yet to be explored. MATERIALS AND METHODS: We conducted a retrospective cohort study to explore treatment patterns and characteristics associated with treatment interruption in postmenopausal women diagnosed with OP between 2008 and 2014. Treatment pattern assessment included the initial distribution of OP medications and treatment interruption rate according to the treatment groups during a 3-year follow-up period. We used multivariate logistic regression to estimate odds ratio (OR) and 95% confidence interval (CI) to identify factors associated with treatment interruption. RESULTS: Of 21,813 patients, 87.9% initiated oral bisphosphonates (BP), followed by ibandronate intravenous (IV; 5.4%), selective estrogen receptor modulators (SERMs; 5.2%), pamidronate IV (1.4%) and zoledronic acid (0.06%). Treatment interruption was most notable in the first year of treatment, with cumulative treatment interruption rates highest for oral BP (76.3%) and lowest for pamidronate IV (50.5%). Compared to oral BP users, users of ibandronate IV (OR 0.34, 95% CI 0.30-0.39), pamidronate IV (0.49, 0.39-0.63), zoledronic acid (0.26, 0.09-0.77), and SERMs (0.50, 0.44-0.57) were less likely to interrupt treatment. Of characteristics assessed, presence of rheumatoid arthritis increased the odds of treatment interruption in ibandronate IV group (3.94, 2.12-7.33), and concomitant use of glucocorticoids for oral BP (1.11, 1.03-1.19) and pamidronate IV (2.04, 1.06-3.93) groups, respectively. CONCLUSION: Given the frequent treatment interruptions across all OP medications, our findings on the factors associated with treatment interruption will serve to implement targeted interventions in reinforcing persistence to OP treatment.

Association Between Nonsteroidal Antiinflammatory Drug Use and Adverse Clinical Outcomes Among Adults Hospitalized With Coronavirus 2019 in South Korea: A Nationwide Study.

BACKGROUND: Nonsteroidal antiinflammatory drugs (NSAIDs) may exacerbate coronavirus disease 2019 (COVID-19) and worsen associated outcomes by upregulating the enzyme that severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) binds to in order to enter cells. METHODS: We conducted a cohort study using South Korea's nationwide healthcare database, which contains data for all individuals who received a COVID-19 test (n = 69 793) as of 8 April 2020. We identified adults hospitalized with COVID-19, where cohort entry was the date of hospitalization. NSAID users were those prescribed NSAIDs in the 7 days before and including cohort entry, and nonusers were those not prescribed NSAIDs during this period. Our primary outcome was a composite of in-hospital death, intensive care unit admission, mechanical ventilation use, and sepsis; our secondary outcomes were cardiovascular complications and acute renal failure. We conducted logistic regression analysis to estimate odds ratio (OR) with 95% confidence intervals (CIs) using inverse probability of treatment weighting to minimize confounding. RESULTS: Of 1824 adults hospitalized with COVID-19 (mean age, 49.0 years; female, 59%), 354 were NSAID users and 1470 were nonusers. Compared with nonuse, NSAID use was associated with increased risks of the primary composite outcome (OR, 1.54; 95% CI, 1.13-2.11) but insignificantly associated with cardiovascular complications (OR, 1.54; 95% CI, 0.96-2.48) or acute renal failure (OR, 1.45; 95% CI, 0.49-4.14). CONCLUSIONS: While awaiting the results of confirmatory studies, we suggest NSAIDs be used with caution for COVID-19 patients as the harms associated with their use may outweigh their benefits.

Cardiovascular safety of evogliptin in patients with type 2 diabetes: A nationwide cohort study.

AIM: To assess whether the use of evogliptin, a novel dipeptidyl peptidase-4 inhibitor (DPP-4i), was associated with an increased risk of cardiovascular events compared with glimepiride in patients with type 2 diabetes (T2D). METHODS: We conducted a population-based cohort study using South Korea's nationwide healthcare database from 1 January 2014 to 31 December 2018. We identified a base cohort of patients with T2D who newly initiated metformin monotherapy, from which we identified a study cohort of patients who either added or switched to glimepiride or DPP-4is (including evogliptin). Patients were followed up from initiation of DPP-4is or glimepiride until the earliest of either outcome occurrence or 31 December 2018. Our primary outcome was hospitalization or an emergency visit for cardiovascular events, a composite endpoint comprised of cerebrovascular events, heart failure, myocardial infarction, transient ischaemic attack, angina pectoris and revascularization procedures; secondary outcomes were the individual components of the primary outcome. A multivariable Cox proportional hazards model was used to estimate adjusted hazard ratios (aHRs) with 95% confidence intervals (CIs) for the risk of study outcomes associated with evogliptin compared with glimepiride. RESULTS: Our base and study cohorts had 317,307 and 128,788 patients, respectively, of which 100,038 were DPP-4i users (2946 were evogliptin users) and 28,750 were glimepiride users within the study cohort. The median follow-up was 195 days for evogliptin and 113 days for glimepiride users. Compared with glimepiride, evogliptin was associated with a reduced risk of the primary outcome (aHR 0.67, 95% CI 0.48-0.95) and cerebrovascular events (aHR 0.41, 95% CI 0.22-0.78) but showed non-significant associations for myocardial infarction (aHR 0.63, 95% CI 0.27-1.46), heart failure (aHR 0.35, 95% CI 0.09-1.47), transient ischaemic attack (aHR 0.23, 95% CI 0.03-1.72) and angina pectoris (aHR 1.35, 95% CI 0.82-2.21). CONCLUSIONS: Findings from this population-based cohort study provide novel real-world evidence that the use of evogliptin, compared with glimepiride, did not increase the risk of cardiovascular events, including cerebrovascular events, myocardial infarction, heart failure, transient ischaemic attack and angina pectoris.

Association between methylphenidate and risk of myocardial infarction: A multinational self-controlled case series study.

PURPOSE: To investigate the association between use of methylphenidate and risk of myocardial infarction among Asians. METHODS: We conducted a multinational self-controlled case series study using nationwide healthcare databases of South Korea (2002-2018), Taiwan (2004-2015), and Hong Kong (2001-2016). Of patients with myocardial infarction who were also prescribed methylphenidate within the observation period, methylphenidate use was classified into four mutually exclusive periods by each person-day: exposed (exposed to methylphenidate), pre-exposure (prior to the first methylphenidate prescription), washout (after the end of methylphenidate treatment), and baseline (unexposed to methylphenidate). Risk of myocardial infarction among the three periods of methylphenidate use was compared to the baseline period using conditional Poisson regression analysis to estimate incidence rate ratios (IRRs) with 95% confidence intervals (CIs). RESULTS: We identified 2104, 484, and 30 patients from South Korea, Taiwan, and Hong Kong, respectively. Risk of myocardial infarction was the highest during the pre-exposure period in all three populations: South Korea, pre-exposure (IRR 3.17, 95% CI 3.04-3.32), exposed (1.05, 1.00-1.11), washout (1.92, 1.80-2.04); Taiwan, pre-exposure (1.97, 1.78-2.17), exposed (0.72, 0.65-0.80), washout (0.56, 0.46-0.68); Hong Kong, pre-exposure (18.09, 8.19-39.96), exposed (9.32, 3.44-25.28), washout (7.69, 1.72-34.41). Following stratification for age and sex, the trends remained analogous to the main findings across all three populations. CONCLUSIONS: Although a positive association between initiating methylphenidate and the onset of myocardial infarction was observed, the risk was the highest in the period before its initiation. Thus, this multinational study suggests there was no causal relationship between methylphenidate and myocardial infarction among Asians.

Risk of mortality associated with concomitant antidepressant and benzodiazepine therapy among patients with depression: a population-based cohort study.

BACKGROUND: With antidepressants (ADs) having minimal therapeutic effects during the initial weeks of treatment, benzodiazepines (BZDs) are concomitantly used to alleviate depressive symptoms of insomnia or anxiety. However, with mortality risks associated with this concomitant use yet to be examined, it remains unclear as to whether this concomitant therapy offers any benefits in treating depression. METHODS: We conducted a population-based cohort study using South Korea's nationwide healthcare database from 2002 to 2017. Of 2.6 million patients with depression, we identified 612,729 patients with incident depression and newly prescribed ADs or BZDs, by excluding those with a record of diagnosis or prescription within the 2 years prior to their incident diagnosis. We classified our study cohort into two discrete groups depending on the type of AD treatment received within 6 months of incident diagnosis-AD monotherapy and AD plus BZD (AD+BZD) therapy. We matched our study cohort in a 1:1 ratio using propensity scores to balance baseline characteristics and obtain comparability among groups. The primary outcome was all-cause mortality, and patients were followed until the earliest of outcome occurrence or end of the study period. We conducted multivariable Cox proportional hazards regression analysis to estimate adjusted hazards ratios (HRs) with 95% confidence intervals (CIs) for the risk of mortality associated with AD+BZD therapy versus AD monotherapy. RESULTS: The propensity score-matched cohort had 519,780 patients with 259,890 patients in each group, where all baseline characteristics were well-balanced between the two groups. Compared to AD monotherapy, AD+BZD therapy was associated with an increased risk of all-cause mortality (adjusted HR, 1.04; 95% CI, 1.02 to 1.06). CONCLUSIONS: Concomitantly initiating BZDs with ADs was associated with a moderately increased risk of mortality. Clinicians should therefore exercise caution when deciding to co-prescribe BZDs with ADs in treating depression, as associated risks were observed.

Association between domperidone use and adverse cardiovascular events: A nested case-control and case-time-control study.

PURPOSE: To assess the association between domperidone and adverse cardiovascular events. METHODS: We conducted nested case-control and case-time-control studies using Korea's healthcare database (2002-2015). We identified patients without history of hospitalization, cancer, or cardiovascular diseases in 2002. From our cohort, those diagnosed with an adverse cardiovascular event (case), composite of arrhythmia, hypertension, or acute myocardial infarction were matched to two controls using risk-set sampling on various sociodemographic variables. Exposure was assessed in the 1 to 7 days, or in the 1 to 7 days (hazard period) and 91 to 97 days (control period) prior to index date, in nested case-control and case-time control studies, respectively. We compared domperidone to metoclopramide or non-use and estimated odds ratios (OR) with 95% confidence intervals (CI) using conditional logistic regression. RESULTS: From 627 799 patients, we identified 71 555 cases and 141 833 controls. In the nested case-control study, while the risk of cardiovascular events was increased with domperidone (OR 1.38, 95% CI 1.28-1.47) compared to non-use, the risk was reduced (0.64, 0.57-0.72) compared to metoclopramide. In the case-time-control study, similar increased risk was found when compared to non-use (1.40, 1.29-1.52) but a reduced risk as compared with metoclopramide (0.63, 0.54-0.72). Risk of myocardial infarction associated with domperidone was highest (nested case-control: 1.94, 1.33-2.83; case-time-control: 1.91, 1.01-3.62) when compared to non-use but did not indicate an increased risk when compared to metoclopramide (nested case-control: 0.60, 0.32-1.13; case-time-control: 0.70, 0.25-1.98). CONCLUSION: Our findings support a positive association between domperidone and adverse cardiovascular events. However, domperidone may have a safer cardiovascular profile than metoclopramide.

An empirical assessment of immeasurable time bias in the setting of nested case-control studies: Statins and all-cause mortality among patients with heart failure.

PURPOSE: Immeasurable time bias exaggerates drug benefits in pharmacoepidemiologic studies due to exposure misclassification that occurs due to the lack of inpatient drug data in many healthcare databases. METHODS: To estimate the magnitude of immeasurable time bias and assess potential approaches to minimize it, we conducted a nested case-control study of statin use and mortality among heart failure patients using the South Korean nationwide healthcare database, which contains both inpatient and outpatient medication data. Using both inpatient and outpatient medication data to define the gold standard exposure definition, we assessed 10 different analytical methods in which exposure was defined using outpatient medication data only. We compared different methodological approaches to reduce immeasurable time bias: restricting to nonhospitalized patients, adjusting for hospitalization, weighting by either measurable time (nonhospitalized time during 90-d period) or outpatient time, and computing the odds ratios (ORs) using 90-day cumulative probability of exposure produced by the Kaplan-Meier product-limit estimator for cases and controls. RESULTS: The three approaches that most closely approximated the gold standard (hazard ratio [HR] 1.20; 95% confidence interval [CI], 1.05-1.37) were weighting by either measurable (HR 1.09; 95% CI, 0.92-1.28) or outpatient time (HR 1.14; 95% CI, 0.96-1.34) in the unexposed or by estimating the 90-day exposure probability (HR 1.31; 95% CI, 1.11-1.51). CONCLUSION: The use of one of these three methods may be suggested as an approach to minimize immeasurable time bias in nested case-control studies.

Current status of pharmacovigilance regulatory structures, processes, and outcomes in the Asia-Pacific region: Survey results from 15 countries.

PURPOSE: Regulatory discrepancies may exist in pharmacovigilance (PV) structure, process, and outcome status worldwide. Our study's objective was to survey the current status of PV in each regulatory body in the Asia-Pacific Economic Cooperation (APEC) region. METHODS: A modified questionnaire was sent to the PV team heads of 21 PV agencies based in the APEC countries, between June 28 and September 12, 2017, to gather information on the structure, process, and outcome of PV status in these countries. RESULTS: Of the 21 APEC countries, 15 responded. We found harmonized laws and regulations for general PV and risk management systems. However, variations were found in PV structure: for example, 11 out of 15 countries had national regulatory representatives responsible for PV in pharmaceutical companies, while four did not. For PV process, discrepancies were also found in the source type of adverse drug reaction (ADR) reports and reporting of medication errors and therapeutic ineffectiveness in cumulative ADR reports. With respect to PV outcomes, among countries that performed active surveillance, the United States of America was more active, with hundreds of projects including additional pharmacoepidemiological studies etc. Among the nine countries that responded, Japan had the greatest number of product label changes followed by Taiwan, Malaysia, and Korea. CONCLUSION: We have identified substantial variations in the structures, processes, and outcomes of PV status among the countries of the APEC region. Therefore, efforts to reduce variations in the PV administration and regulation are warranted for harmonization of PV within the APEC region.

Association between use of antiemetics, antipsychotics, or antidepressants and the risk of Parkinson's disease
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OBJECTIVE: Antipsychotics, antidepressants, and antiemetics are well-known causative agents of parkinsonism. However, it is not certain that the use of these medications increases the risk of Parkinson's disease (PD). We aim to define the risk of PD associated with use of antipsychotic, antidepressant, or antiemetic therapy. MATERIALS AND METHODS: We conducted a population-based nested case-control study using data from the South Korean health insurance database. For each PD case, we randomly selected sex, age group, cohort entry date, duration of follow-up, and Charlson comorbidity score-matched controls (up to 3). Exposure was categorized into six groups based on treatments received 1 - 90 days before the index date (separate use of either: antiemetics; antipsychotics; or antidepressants; combined use of antiemetics with either: antipsychotics; or antidepressants; and combined use of all three). We used conditional logistic regression to estimate odds ratios (ORs) and 95% confidence intervals (CIs) for PD. RESULTS: Final subjects included 31,428 cases and 94,284 matched controls. We observed an increased risk of PD with the separate use of antiemetics (adjusted OR, 1.08; 95% CI, 1.05 - 1.11) and that of antipsychotics (1.31; 1.12 - 1.52), and the combined use of antiemetics and antipsychotics (1.42; 1.15 - 1.75). Both antidepressants alone and with antipsychotics were not associated with higher risk of PD. CONCLUSIONS: Separate or concurrent use of antiemetics and antipsychotics showed increased risks of PD. Although statistical significance was observed, when taking into account that there still lie unmeasured, unconsidered confounders, there may be no clinical association present. Caution will be needed in prescribing these drugs in patients who have prognostic factors for PD. 
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The Zuellig Pharma Korea Consortium Database: An on-site drug wholesales database for pharmacoepidemiological studies using real-world data
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OBJECTIVE: To assess the value and representativeness of the Zuellig Pharma Korea Consortium (ZPK-C) database, which contains drug wholesales data collected in a weekly interval, for its prospective use as a data source for pharmacoepidemiology studies. MATERIALS AND METHODS: Wholesales and nationwide claims data of antidiabetic and antihypertensive products were compared in 17 administrative regions using the defined daily dose per 100,000 inhabitants per day (DID) and its proportion for standardized evaluation. RESULTS: We found regional concordance in 12 and 13 regions (out of 17) for antidiabetic and antihypertensive products, respectively, of which concordance was higher in rural than metropolitan regions. CONCLUSION: The ZPK-C showed potential as a valuable data source for pharmacoepidemiology research.

Regulatory effect of decreasing therapeutic duplication of respiratory drugs using a prescription database between 2012 and 2015.

Duplicative drug use increases the risk of adverse drug reactions and expends healthcare resources unnecessarily. No epidemiological evidence of the prevalence of therapeutic duplication (TD) involving respiratory system drugs exists. Therefore, we describe the prescription patterns of these drugs and estimate changes in TD rates following implementation of a new regulation in 2013. A time-series analysis using national healthcare data was conducted, involving eight classes, and patients prescribed any of these drugs between 2012 and 2015. We used two definitions of TD; duplicative prescriptions overlapped for more than 30 days by the same prescriber and for more than 1 day by different prescribers. We calculated relative and absolute difference in TD rates after the regulation. TD by the same prescriber decreased for respiratory drugs of six classes, but increased more than 10% for antihistamines (+10.28, +0.05). TD by a different prescriber decreased only for xanthine bronchodilators, but increased more than 10% for beta-receptor agonists (+27.07, +1.42), leukotriene receptor antagonists (+16.10, +0.44), cough suppressants (+15.64, +0.52), mucolytic agents (+11.16, +0.67). The 2013 regulation regarding respiratory drugs did not have the anticipated effect of reducing TD prevalence; more effective interventions are needed.