Papers by Soko Setoguchi Iwata
Pharmacoepidemiology and drug safety, 2013
PurposeThe role of administrative databases for research on drug safety during pregnancy can be l... more PurposeThe role of administrative databases for research on drug safety during pregnancy can be limited by their inaccurate assessment of the timing of exposure, as the gestational age at birth is typically unavailable. Therefore, we sought to develop and validate algorithms to estimate the gestational age at birth using information available in these databases.The role of administrative databases for research on drug safety during pregnancy can be limited by their inaccurate assessment of the timing of exposure, as the gestational age at birth is typically unavailable. Therefore, we sought to develop and validate algorithms to estimate the gestational age at birth using information available in these databases.MethodsUsing a population-based cohort of 286,432 mother–child pairs in British Columbia (1998–2007), we validated an ICD-9/10-based preterm-status indicator and developed algorithms to estimate the gestational age at birth on the basis of this indicator, maternal age, singleton/multiple status, and claims for routine prenatal care tests. We assessed the accuracy of the algorithm-based estimates relative to the gold standard of the clinical gestational age at birth recorded in the delivery discharge record.Using a population-based cohort of 286,432 mother–child pairs in British Columbia (1998–2007), we validated an ICD-9/10-based preterm-status indicator and developed algorithms to estimate the gestational age at birth on the basis of this indicator, maternal age, singleton/multiple status, and claims for routine prenatal care tests. We assessed the accuracy of the algorithm-based estimates relative to the gold standard of the clinical gestational age at birth recorded in the delivery discharge record.ResultsThe preterm-status indicator had specificity and sensitivity of 98% and 91%, respectively. Estimates from an algorithm that assigned 35 weeks of gestational age at birth to deliveries with the preterm-status indicator and 39 weeks to those without them were within 2 weeks of the clinical gestational age at birth in 75% of preterm and 99% of term deliveries.The preterm-status indicator had specificity and sensitivity of 98% and 91%, respectively. Estimates from an algorithm that assigned 35 weeks of gestational age at birth to deliveries with the preterm-status indicator and 39 weeks to those without them were within 2 weeks of the clinical gestational age at birth in 75% of preterm and 99% of term deliveries.ConclusionsSubtracting 35 weeks (245 days) from the date of birth in deliveries with codes for preterm birth and 39 weeks (273 days) in those without them provided the optimal estimate of the beginning of pregnancy among the algorithms studied. Copyright © 2012 John Wiley & Sons, Ltd.Subtracting 35 weeks (245 days) from the date of birth in deliveries with codes for preterm birth and 39 weeks (273 days) in those without them provided the optimal estimate of the beginning of pregnancy among the algorithms studied. Copyright © 2012 John Wiley & Sons, Ltd.
Circulation. Arrhythmia and electrophysiology, 2013
Circulation, 2012
Background-One sixth of US dialysis patients 65 years of age have been diagnosed with atrial fibr... more Background-One sixth of US dialysis patients 65 years of age have been diagnosed with atrial fibrillation/flutter (AF).
BMJ (Clinical research ed.), 2013
Objective To determine whether use of serotonin or non-serotonin reuptake inhibitors near to deli... more Objective To determine whether use of serotonin or non-serotonin reuptake inhibitors near to delivery is associated with postpartum hemorrhage.
The American journal of cardiology, 2008
Conflicting evidence exists regarding gender differences in the management and outcomes of myocar... more Conflicting evidence exists regarding gender differences in the management and outcomes of myocardial infarctions (MIs). In this study, it was hypothesized that the management and outcomes of MIs would not differ by gender after proper adjustment for age, access to care, MI characteristics, and co-morbidities. Data from a published MI validation study, which sampled 2,200 MI hospitalizations in Medicare beneficiaries with the prescription drug benefit for detailed hospital chart review, were used. Gender differences in the use of MI-related procedures and recommended cardiovascular medications as well as short-and long-term mortality were assessed using multivariate regression. A total of 1,625 patients were identified (80% women) with confirmed MIs for whom complete clinical information was available. Compared with men, women were older and had higher body mass index. Women were more likely to have diabetes, renal dysfunction, and depression, but less likely to have had previous MIs, chronic lung disease, cancer, and to use tobacco. The characteristics of the index MIs were similar, except for non-Q-wave MIs being more common in men. The management of the MIs during admission was similar. During follow-up of up to 6.6 years, men were 40% more likely to die than women (95% confidence interval 21% to 62%), but no mortality difference was observed in patients aged 65 to 74 years (hazard ratio 0.92, 95% confidence interval 0.62 to 1.36), whereas in those aged >75 years, men were more likely to die than women (hazard ratio 1.54, 95% confidence interval 1.30 to 1.82). In conclusion, for older patients, the management of MIs did not significantly differ between men and women. Men, especially those aged >75 years, however, had worse short-and long-term prognoses compared with women of a similar age. The mortality was highest and the gender effect was more pronounced during the MI hospitalizations.
American journal of kidney diseases : the official journal of the National Kidney Foundation, 2011
Clinical journal of the American Society of Nephrology : CJASN, 2013
The lack of evidence on the effectiveness and safety of interventions in chronic dialysis patient... more The lack of evidence on the effectiveness and safety of interventions in chronic dialysis patients has been a subject of continuing criticism. New technologies are often introduced into the market without having specifically studied or even included patients with advanced kidney disease. Therefore, the need to generate valid effectiveness and safety data in this vulnerable subpopulation is of utmost importance. The US Food and Drug Administration has recently placed an increased focus on safety surveillance, and sponsors must now meet this additional postmarketing commitment. In patients with ESRD, the unique data collection environment in the United States allows for creative and efficient study designs to meet the needs of patients, providers, and sponsors. The purpose of this manuscript is to review the methodological and practical aspects of the different options for postmarketing study design in this field, with critical appraisal of their advantages and disadvantages.
Journal of clinical epidemiology, 2013
Objectives: To assess the extent of immortal time bias in estimating the clinical effectiveness o... more Objectives: To assess the extent of immortal time bias in estimating the clinical effectiveness of implantable cardioverter-defibrillators (ICDs) and the impact of methods of handling immortal time bias.
Heart failure clinics, 2013
Comparative effectiveness research Randomized trials Observational data Statistical methods Epide... more Comparative effectiveness research Randomized trials Observational data Statistical methods Epidemiologic methods
Pharmacoepidemiology and drug safety, 2012
PurposeTo examine the performance of propensity score-based methods for estimating relative risks... more PurposeTo examine the performance of propensity score-based methods for estimating relative risks when exposed and comparison subjects are selected from different data sources.To examine the performance of propensity score-based methods for estimating relative risks when exposed and comparison subjects are selected from different data sources.MethodsWe conducted Monte Carlo simulations to assess the performance of propensity score methods under various scenarios in which exposed and comparison subjects were selected from different data sources for a comparative effectiveness study of a medical device.We conducted Monte Carlo simulations to assess the performance of propensity score methods under various scenarios in which exposed and comparison subjects were selected from different data sources for a comparative effectiveness study of a medical device.ResultsThe use of propensity score methods in our simulated data scenarios often yielded estimates of relative risk that were close to the true effect, unless the comparison group differed from the exposed group systematically on a factor associated with the outcome. This situation caused severe bias regardless of which method was used but could be overcome if the exposed group could be restricted similarly to the comparison group. Mean square error of relative risk estimates was lowest for similarly restricted study groups and when the comparison group could be considered a random sample of the source population that generated the exposed group.The use of propensity score methods in our simulated data scenarios often yielded estimates of relative risk that were close to the true effect, unless the comparison group differed from the exposed group systematically on a factor associated with the outcome. This situation caused severe bias regardless of which method was used but could be overcome if the exposed group could be restricted similarly to the comparison group. Mean square error of relative risk estimates was lowest for similarly restricted study groups and when the comparison group could be considered a random sample of the source population that generated the exposed group.ConclusionsWhen exposed and comparison groups originated from different data sources, all propensity score methods yielded relatively unbiased and consistent estimates of relative risk in most situations reflected in our simulation study. Copyright © 2012 John Wiley & Sons, Ltd.When exposed and comparison groups originated from different data sources, all propensity score methods yielded relatively unbiased and consistent estimates of relative risk in most situations reflected in our simulation study. Copyright © 2012 John Wiley & Sons, Ltd.
Pediatrics, 2013
The proven effectiveness of biologics and other immunomodulatory products in inflammatory rheumat... more The proven effectiveness of biologics and other immunomodulatory products in inflammatory rheumatic diseases has resulted in their widespread use as well as reports of potential short-and longterm complications such as infection and malignancy. These complications are especially worrisome in children who often have serial exposures to multiple immunomodulatory products. Post-marketing surveillance of immunomodulatory products in juvenile idiopathic arthritis (JIA) and pediatric systemic lupus erythematosus is currently based on product-specific registries and passive surveillance, which may not accurately reflect the safety risks for children owing to low numbers, poor long-term retention, and inadequate comparators. In collaboration with the US Food and Drug Administration (FDA), patient and family advocacy groups, biopharmaceutical industry representatives and other stakeholders, the Childhood Arthritis and Rheumatology Research Alliance (CARRA) and the Duke Clinical Research Institute (DCRI) have developed a novel pharmacosurveillance model (CARRA Consolidated Safety Registry [CoRe]) based on a multicenter longitudinal pediatric rheumatic diseases registry with over 8000 participants. The existing CARRA infrastructure provides access to much larger numbers of subjects than is feasible in single-product registries. Enrollment regardless of medication exposure allows more accurate detection and evaluation of safety signals. Flexibility built into the model allows the addition of specific data elements and safety outcomes, and designation of appropriate disease comparator groups relevant to each product, fulfilling post-marketing requirements and commitments. The proposed model can be applied to other pediatric and adult diseases, potentially transforming the paradigm of pharmacosurveillance in response to the growing public mandate for rigorous post-marketing safety monitoring.
Arthritis care & research, 2014
BackgroundLinkages between registries and administrative data may provide a valuable resource for... more BackgroundLinkages between registries and administrative data may provide a valuable resource for comparative effectiveness research. However, personal identifiers that uniquely identify individuals are not always available. We describe methods to link a de-identified arthritis registry and U.S. Medicare data. The linked dataset was also used to evaluate the generalizability of the registry to the U.S. Medicare population.MethodsRheumatoid arthritis (RA) patients participating in the Consortium of Rheumatology Researchers of North America (CORRONA) registry were linked to Medicare data restricted to rheumatology claims or claims for RA. Deterministic linkage was performed using age, sex, provider identification number, and geographic location of the CORRONA site. We then searched for visit dates in Medicare matching visit dates in CORRONA, requiring at least 1 exact matching date. Linkage accuracy was quantified as a positive predictive value (PPV) in a sub-cohort (n=1581) with more precise identifiers.ResultsCORRONA participants with self-reported Medicare (n=11,001) were initially matched to 30,943 Medicare beneficiaries treated by CORRONA physicians. A total of 8,431 CORRONA participants matched on at least 1 visit; 5,317 matched uniquely on all visits. The number of patients who linked and linkage accuracy (from the subcohort) was high for patients with >2 visits (n=3458, 98% accuracy), exactly 2 visits (n=822, 96% accuracy) visits, and 1 visit (n=1037, 79% accuracy) visit that matched exactly on calendar date. Demographics and comorbidity profiles of registry participants were similar to non-participants, except participants were more likely to use DMARDs and biologics.ConclusionLinkage between a national, de-identified outpatient arthritis registry and Medicare data on multiple non-unique identifiers appears feasible and valid. © 2014 American College of Rheumatology.
Journal of the American Society of Nephrology : JASN, 2011
A half million Americans have ESRD, which puts them at high risk for cardiovascular disease and p... more A half million Americans have ESRD, which puts them at high risk for cardiovascular disease and poor outcomes. Little is known about the epidemiology of atrial fibrillation among patients with ESRD. We analyzed data from annual cohorts (1992 to 2006) of prevalent hemodialysis patients from the United States Renal Data System. In each cohort, we searched 1 year of medical claims for relevant diagnosis codes to determine the prevalence of atrial fibrillation. Among 2.5 million patient observations, 7.7% had atrial fibrillation, with the prevalence increasing 3-fold from 3.5% (1992) to 10. 7% (2006). The number of affected patients increased from 3620 to 23,893 (6.6-fold) during this period. Older age, male gender, and several comorbid conditions were associated with increased risk for atrial fibrillation. Compared with otherwise similar Caucasians, the prevalence of atrial fibrillation rates was substantially lower for blacks, Asians, and Native Americans. One-year mortality was twice as high among hemodialysis patients with atrial fibrillation compared with those without (39% versus 19%), and this increased risk was constant during the 15 years of the study. In conclusion, the prevalence of diagnosed atrial fibrillation among patients receiving hemodialysis in the United States is increasing, varies by race, and remains associated with substantially increased mortality. Identifying potentially modifiable risk factors for incident atrial fibrillation requires further investigation.
Pain physician, 2013
While the use of opioids for chronic non-cancer pain (CNCP) has increased dramatically in the pas... more While the use of opioids for chronic non-cancer pain (CNCP) has increased dramatically in the past 2 decades, concern exists about the safety of opioids, particularly with the extensive use among individuals with CNCP. To assess the risk of type 2 diabetes (T2D) among adults exposed to opioids for non-cancer pain. Nested case-control study. United Kingdom-based General Practice Research Database (GPRD). Among 1.7 million opioid users with at least one prescription for an opioid to treat non-cancer pain in the GPRD (1990 - 2008), we identified all incident T2D cases with at least 2 years of medical history before their first diagnosis (index date). For each case we randomly selected up to 2 controls matched on age, gender, index date, and general practice. The same eligibility requirements were applied to controls as to cases. We defined "any exposure" as at least 2 prescriptions for an opioid within 2 years before the index date and defined "nonuse" as no use or only one prescription within 2 years (reference). For any exposure to opioids we further evaluated timing of use, cumulative use, and individual opioid type. Conditional logistic regression was used to estimate adjusted odds ratios (AORs) and 95% confidence intervals (CIs) controlling for confounders. We identified 50,468 T2D cases to which we matched 100,415 controls. Cases were more likely than controls to be former smokers, heavier, and to have more co-morbidities, co-medications, and visits to their general practitioners. After adjusting for important confounders there was no increased risk for T2D among those exposed to any opioid compared to nonusers (AOR = 1.03, 95% CI 1.00 - 1.06). The results did not change when we evaluated timing of use, cumulative use, or individual opioid type. Misclassification of exposure may have occurred; limited data for some individual opioid types. This study found no association between use of opioids and risk of T2D among non-cancer adults.
Clinical cardiology, 2012
Background:Warfarin use and associated outcomes in patients with heart failure and atrial fibrill... more Background:Warfarin use and associated outcomes in patients with heart failure and atrial fibrillation and a cardiovascular implantable electronic device have not been described previously.Warfarin use and associated outcomes in patients with heart failure and atrial fibrillation and a cardiovascular implantable electronic device have not been described previously.Hypothesis:We hypothesized that warfarin is underused and is associated with lower risks of mortality, thromboembolic events, and myocardial infarction.We hypothesized that warfarin is underused and is associated with lower risks of mortality, thromboembolic events, and myocardial infarction.Methods:Using data from a clinical registry linked with Medicare claims, we examined warfarin use at discharge and 30-day and 1-year Kaplan-Meier estimates of all-cause mortality and cumulative incidence rates of mortality, thromboembolic events, myocardial infarction, and bleeding events in patients 65 years or older, with a history of atrial fibrillation and a cardiovascular implantable electronic device admitted with heart failure between 2001 and 2006, who were naïve to anticoagulation therapy at admission. We compared outcomes between patients who were or were not prescribed warfarin at discharge and tested associations between treatment and outcomes.Using data from a clinical registry linked with Medicare claims, we examined warfarin use at discharge and 30-day and 1-year Kaplan-Meier estimates of all-cause mortality and cumulative incidence rates of mortality, thromboembolic events, myocardial infarction, and bleeding events in patients 65 years or older, with a history of atrial fibrillation and a cardiovascular implantable electronic device admitted with heart failure between 2001 and 2006, who were naïve to anticoagulation therapy at admission. We compared outcomes between patients who were or were not prescribed warfarin at discharge and tested associations between treatment and outcomes.Results:Of 2586 eligible patients in 252 hospitals, 2049 were discharged without a prescription for warfarin. At 1 year, the group discharged without warfarin had a higher mortality rate after discharge (37.4% vs 28.8%; P < 0.001) but similar rates of thromboembolism, myocardial infarction, and bleeding events. After adjustment, treatment with warfarin was associated with lower risk of all-cause death 1 year after discharge (hazard ratio: 0.76, 95% confidence interval: 0.63–0.92).Of 2586 eligible patients in 252 hospitals, 2049 were discharged without a prescription for warfarin. At 1 year, the group discharged without warfarin had a higher mortality rate after discharge (37.4% vs 28.8%; P < 0.001) but similar rates of thromboembolism, myocardial infarction, and bleeding events. After adjustment, treatment with warfarin was associated with lower risk of all-cause death 1 year after discharge (hazard ratio: 0.76, 95% confidence interval: 0.63–0.92).Conclusions:Among older patients with heart failure and atrial fibrillation and a cardiovascular implantable electronic device, 4 of 5 were discharged without a prescription for warfarin. Warfarin nonuse was associated with a higher risk of death 1 year after discharge. Clin. Cardiol. 2011 DOI: 10.1002/clc.22064Damon M. Seils, MA, Duke University, assisted with manuscript preparation. Mr. Seils did not receive compensation for his assistance apart from his employment at the institution where the study was conducted.This study was supported by a research agreement between Duke University and Janssen Pharmaceuticals.The authors have no other funding, financial relationships, or conflicts of interest to disclose.Among older patients with heart failure and atrial fibrillation and a cardiovascular implantable electronic device, 4 of 5 were discharged without a prescription for warfarin. Warfarin nonuse was associated with a higher risk of death 1 year after discharge. Clin. Cardiol. 2011 DOI: 10.1002/clc.22064Damon M. Seils, MA, Duke University, assisted with manuscript preparation. Mr. Seils did not receive compensation for his assistance apart from his employment at the institution where the study was conducted.This study was supported by a research agreement between Duke University and Janssen Pharmaceuticals.The authors have no other funding, financial relationships, or conflicts of interest to disclose.
The American journal of medicine, 2008
Background-Histamine may play an important role in bone turnover. The data regarding histamine re... more Background-Histamine may play an important role in bone turnover. The data regarding histamine receptor antagonists (H1RA, H2RA) and bone mineral density in humans are sparse. We examined bone mineral density in subjects using histamine receptor antagonists in a representative U.S. population-based sample from The Third National Health and Nutrition Examination Survey (NHANES III: 1988-1994). Methods-Adult subjects 60 years and older using H1RA or H2RA who underwent dual energy X-ray absorptiometry scanning in NHANES III were identified. We compared the femoral neck bone mineral density among users of these agents to non-users in adjusted linear regression models that included known demographic, anthropometric, and medical risk factors for osteoporosis. The mean age of study subjects was 72.6 years old, 52 % were women and 59 % were Caucasian. Among subjects with femoral neck bone mineral density measured, 199 used H1RAs, 297 used H2RAs, and 4,162 subjects were nonusers of histamine receptor antagonists. Femoral neck bone mineral density adjusting for age and gender and other covariates was higher in H1RA users (0.74 g/cm 2 ) versus nonusers (0.72 g/cm 2 ; p=0.037). H2RA users showed lower adjusted bone mineral density compared to non-users (0.69 g/cm 2 versus 0.72 g/cm 2 ; p =0.003), but bone densities were similar between H2RA users and nonusers when daily calcium intake exceeded 800mg per day. Conclusions-Femoral neck bone mineral density may be higher in H1RA users than non-users among older adults. H2RA users with more reduced calcium intake had lower bone mineral density than non-users.
Journal of cardiovascular pharmacology, 2002
Reactive hyperemic blood flow (RHBF) response has been suggested to be important for increasing n... more Reactive hyperemic blood flow (RHBF) response has been suggested to be important for increasing nutritive blood flow and maintaining exercise capacity. However, little is yet known about the time course of changes in limb vasodilatory reserve capacity and how this relates to exercise capacity after recovery of chronic heart failure (CHF). The purpose of the study was to evaluate upper and lower extremity RHBF before and after cardiac surgery and to determine whether these responses relate to changes in exercise capacity, Forearm and calf blood flow was measured in 16 )atients with CHF due to valvular heart disease before and after (at 1 and 3 months) open-chest cardiac surgery. Venous occlusion plethysmography was used to measure basal flow, 5 rain limb arterial occlusion-induced peak RHBF and total debt repayment (TDR) flow in the forearm and calf. All patients undenNent a cardiopulmonary exercise test before and after surgery (at 1 and 3 months). Exercise time remained unchanged at 1 month, but significantly increased at 3 months (from 291.1+89.4 to 320.6+107.0 sec; p<0.05). In upper limb, resting blood flow, peak RHBF and TDR flow remained unchanged throughout the study oeriod. However, in the lower !imb, although peak RHBF and TDR Flow did not change 1 month after surgery, these vascular response were increased significantly 3 months after surgery (RHBF; from 14.3±5.8 to 17.6±5.7 ml/min/dl, TDR; from 62.6:1:24.3 to 82.0±28,9 ml/dl, both p<0.05). In conclusion, increase in exercise capacity after recovery from CHF is associated with improvement in vasodilatory reserve capacity of the lower limb, but not of the upper limb. Changes in lower limb vasodilatory reserve may be an important factor to improve exercise capacity after recovery from CHF.
American Journal of Transplantation, 2007
Numerous studies have shown that protocol biopsies have predictive power. We retrospectively exam... more Numerous studies have shown that protocol biopsies have predictive power. We retrospectively examined the histologic findings and C4d staining in 89 protocol biopsies from 48 ABO-incompatible (ABO-I) transplant recipients, and compared the results with those of 250 controls from 133 ABO-compatible (ABO-C) transplant recipients given equivalent maintenance immunosuppression. Others have shown that subclinical rejection (borderline and grade I) in ABO-C grafts decreased gradually after transplantation. In our study, however, subclinical rejection in the ABO-I grafts was detected in 10%, 14% and 28% at 1, 3 and 6–12 months, respectively. At 6–12 months, mild tubular atrophy was more common in the ABO-C grafts whereas the incidence of transplant glomerulopathy did not differ between the two groups (ABO-C: 7%; ABO-I: 15%; p = 0.57). In the ABO-I transplants, risk factors for transplant glomerulopathy in univariate analysis were positive panel reactivity (relative risk, 45.0; p < 0.01) and a prior history of antibody-mediated rejection (relative risk, 17.9; p = 0.01). Furthermore, C4d deposition in the peritubular capillaries was detected in 94%, with diffuse staining in 66%. This deposition, however, was not linked to antibody-mediated rejection. We conclude that, in the ABO-I kidney transplantation setting, detection of C4d alone in protocol biopsies might not have any diagnostic or therapeutic relevance.
Journal of Clinical Oncology, 2008
To compare prospectively and retrospectively defined benchmarks for the quality of end-of-life ca... more To compare prospectively and retrospectively defined benchmarks for the quality of end-of-life care, including a novel indicator for the use of opiate analgesia.
Circulation, 2006
Background-Although most randomized trials and meta-analyses suggest a slight or no increase in t... more Background-Although most randomized trials and meta-analyses suggest a slight or no increase in the risk of cancer in statin users, results from observational studies have been conflicting, and some have even suggested a large protective effect of statins on certain cancers. Long-term statin users tend to be healthier, less frail, and more adherent to therapy than nonusers, however. This could explain such apparent "protective" effects. Methods and Results-We conducted the present cohort study by linking data from a large state drug benefit program with cancer registry data and Medicare healthcare utilization data. We identified all initiators of statins; initiators of glaucoma medications, another preventive drug, served as a comparison group. Outcomes included all registry-identified cases of colorectal, lung, and breast cancer. Multivariable Cox proportional models were used to adjust for confounding. Patient characteristics were similar in both groups, but statin initiators (nϭ24 439) were slightly younger and used some services more frequently than glaucoma drug initiators (nϭ7284). The mean follow-up was 2.9 years, with the longest follow-up being 8.4 years. Incidence rates of colorectal, lung, and breast cancers in both groups were very similar to rates in the general population. Adjusted hazard ratios were 0.96 (95% CI, 0.70 to 1.31) for colorectal cancer, 1.11 (95% CI, 0.77 to 1.60) for lung cancer, and 0.99 (95% CI, 0.74 to 1.33) for breast cancer. Conclusions-These data from a large population of typical older patients who began using statins indicate that it is unlikely that statins confer a clinically important decrease or increase in the risk of colorectal, lung, or breast cancer over the durations studied. (Circulation. 2007;115:27-33.)
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Papers by Soko Setoguchi Iwata