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Featured researches published by Aya Mitani.


Journal of the National Cancer Institute | 2008

Age-Related Crossover in Breast Cancer Incidence Rates Between Black and White Ethnic Groups

William F. Anderson; Philip S. Rosenberg; Idan Menashe; Aya Mitani; Ruth M. Pfeiffer

BACKGROUND Although breast cancer incidence is higher in black women than in white women among women younger than 40 years, the reverse is true among those aged 40 years or older. This crossover in incidence rates between black and white ethnic groups has been well described, has not been completely understood, and has been viewed as an artifact. METHODS To quantify this incidence rate crossover, we examined data for 440 653 women with invasive breast cancer from the National Cancer Institutes Surveillance, Epidemiology, and End Results database from January 1, 1975, through December 31, 2004. Data on invasive female breast cancers were stratified by race, age at diagnosis, year of diagnosis, and tumor characteristics. Standard descriptive analyses were supplemented with Poisson regression models, age-period-cohort models, and two-component mixture models. All statistical tests were two-sided. RESULTS We observed qualitative (ie, crossing or reversing) interactions between age and race. That is, age-specific incidence rates overall (expressed as number of breast cancers per 100 000 woman-years) were higher among black women (15.5) than among white women (13.1) younger than 40 years (difference = 2.4, 95% confidence interval [CI] = 2.4 to 2.4), and then, age-specific rates crossed with rates higher among white women (281.3) than among black women (239.5) aged 40 years or older (difference = 41.8, 95% CI = 41.7 to 41.9). The black-to-white incidence rate crossover was observed for all tumor characteristics assessed, although the crossover occurred at earlier ages of diagnosis for low-risk tumor characteristics than for high-risk tumor characteristics. The incidence rate crossover between ethnic groups was robust (ie, reliable and reproducible) to adjustment for calendar period and birth cohort effects in age-period-cohort models (P < .001 for difference by race). CONCLUSION Although this ecologic study cannot determine the individual-level factors responsible for the racial crossover in vital rates, it confirms that the age-related crossover in breast cancer incidence rates between black and white ethnic groups is a robust age-specific effect that is independent of period and cohort effects.


International Journal of Obstetric Anesthesia | 2011

General anesthesia for cesarean delivery at a tertiary care hospital from 2000 to 2005: a retrospective analysis and 10-year update

A. Palanisamy; Aya Mitani; Lawrence C. Tsen

BACKGROUND Complications from general anesthesia for cesarean delivery are a leading cause of anesthesia-related mortality. As a consequence, the overall use of general anesthesia in this setting is becoming less common. The impact and implications of this trend are considered in relation to a similar study performed at our institution 10 years ago. METHODS The hospital database for all cesarean deliveries performed during six calendar years (January 1, 2000 through December 31, 2005) was reviewed. The medical records of all parturients who received general anesthesia were examined to collect personal details and data pertinent to the indications for cesarean delivery and general anesthesia, mode of airway management and associated anesthetic complications. RESULTS Cesarean deliveries accounted for 23.65% to 31.51% of an annual total ranging from 8543 to 10091 deliveries. The percentage of cases performed under general anesthesia ranged from 0.5% to 1%. A perceived lack of time for neuraxial anesthesia accounted for more than half of the general anesthesia cases each year, with maternal factors accounting for 11.1% to 42.9%. Failures of neuraxial techniques accounted for less than 4% of the general anesthesia cases. There was only one case of difficult intubation and no anesthesia-related mortality was recorded. CONCLUSION The use of general anesthesia for cesarean delivery is low and declining. These trends may reflect the early and increasing use of neuraxial techniques, particularly in parturients with co-existing morbidities. A significant reduction in exposure of trainees to obstetric general anesthesia has been observed.


Clinical Journal of The American Society of Nephrology | 2013

Temporal Trends in the Incidence, Treatment, and Outcomes of Hip Fracture in Older Patients Initiating Dialysis in the United States

Sumi Sukumaran Nair; Aya Mitani; Benjamin A. Goldstein; Glenn M. Chertow; David W. Lowenberg; Wolfgang C. Winkelmayer

BACKGROUND AND OBJECTIVES Patients with ESRD experience a fivefold higher incidence of hip fracture than the age- and sex-matched general population. Despite multiple changes in the treatment of CKD mineral bone disorder, little is known about long-term trends in hip fracture incidence, treatment patterns, and outcomes in patients on dialysis. DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS Fourteen annual cohorts (1996-2009) of older patients (≥67 years) initiating dialysis in the United States were studied. Eligible patients had Medicare fee-for-service coverage for ≥2 years before dialysis initiation and were followed for ≤3 years for a first hip fracture. Type of treatment (internal fixation or partial or total hip replacement) was ascertained along with 30-day mortality. Cox and modified Poisson regressions were used to describe trends in study outcomes. RESULTS This study followed 409,040 patients over 607,059 person-years, during which time 17,887 hip fracture events were recorded (29.3 events/1000 person-years). Compared with patients incident for ESRD in 1996, adjusted hip fracture rates increased until the 2004 cohort (+41%) and declined thereafter. Surgical treatment included internal fixation in 56%, partial hip replacement in 29%, and total hip replacement in 2%, which remained essentially unchanged over time; 30-day mortality after hip fracture declined from 20% (1996) to 16% (2009). CONCLUSIONS Hip fracture incidence rates remain higher today than in patients reaching ESRD in 1996, despite multiple purported improvements in the management of CKD mineral bone disorder. Although recent declines in incidence and steady declines in associated short-term mortality are encouraging, hip fractures remain among the most common and consequential noncardiovascular complications of ESRD.


Clinical Journal of The American Society of Nephrology | 2013

Differences in Access to Kidney Transplantation between Hispanic and Non-Hispanic Whites by Geographic Location in the United States

Cristina M. Arce; Benjamin A. Goldstein; Aya Mitani; Colin R. Lenihan; Wolfgang C. Winkelmayer

BACKGROUND AND OBJECTIVES Hispanic patients undergoing chronic dialysis are less likely to receive a kidney transplant compared with non-Hispanic whites. This study sought to elucidate disparities in the path to receipt of a deceased donor transplant between Hispanic and non-Hispanic whites. DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS Using the US Renal Data System, 417,801 Caucasians who initiated dialysis between January 1, 1995 and December 31, 2007 with follow-up through 2008 were identified. This study investigated time from first dialysis to first kidney transplantation, time from first dialysis to waitlisting, and time from waitlisting to kidney transplantation. Multivariable Cox regression estimated cause-specific hazard ratios (HRCS) and subdistribution (competing risk) hazard ratios (HRSD) for Hispanics versus non-Hispanic whites. RESULTS Hispanics experienced lower adjusted rates of deceased donor kidney transplantation than non-Hispanic whites (HRCS, 0.77; 95% confidence interval [95% CI], 0.75 to 0.80) measured from dialysis initiation. No meaningful differences were found in time from dialysis initiation to placement on the transplant waitlist. Once waitlisted, Hispanics had lower adjusted rates of deceased donor kidney transplantation (HRCS, 0.66; 95% CI, 0.64 to 0.68), and the association attenuated once accounting for competing risks (HRSD, 0.79; 95% CI, 0.77 to 0.81). Additionally controlling for blood type and organ procurement organization further reduced the disparity (HRSD, 0.99; 95% CI, 0.96 to 1.02). CONCLUSIONS After accounting for geographic location and controlling for competing risks (e.g., Hispanic survival advantage), the disparity in access to deceased donor transplantation was markedly attenuated among Hispanics compared with non-Hispanic whites. To overcome the geographic disparities that Hispanics encounter in the path to transplantation, organ allocation policy revisions are needed to improve donor organ equity.


Gastrointestinal Endoscopy | 2013

Optical biopsy of sessile serrated adenomas: do these lesions resemble hyperplastic polyps under narrow-band imaging?

Sheila Kumar; Ann Fioritto; Aya Mitani; Manisha Desai; Naresh T. Gunaratnam; Uri Ladabaum

BACKGROUND Serrated colorectal lesions include hyperplastic polyps (HPs) and sessile serrated adenomas (SSAs). Optical biopsy could misclassify SSAs as unimportant if they resemble HPs. OBJECTIVE To explore the narrow-band imaging (NBI) features of SSAs. We hypothesized that SSAs resemble HPs under NBI. DESIGN Retrospective analysis of data from our prospective study of NBI in routine practice. SETTING Single specialty group. PATIENTS Patients undergoing colonoscopy. INTERVENTION Colonoscopy. MAIN OUTCOME MEASUREMENTS Polyp histology prediction by community gastroenterologists. Features of SSAs versus HPs and adenomas by using the Narrow-Band Imaging International Colorectal Endoscopic (NICE) Classification. RESULTS Among 2388 lesions, 141 were diagnosed on pathology as SSAs, 465 as HPs, and 1546 as adenomas. Each individual NICE feature of HPs was found in 38% to 42% of SSAs, 66% to 67% of HPs, and 15% to 20% of adenomas (P < .001 for each). Each individual NICE feature of adenomas was found in 57% to 62% of SSAs, 33% to 34% of HPs, and 80% to 84% of adenomas (P < .001 for each). Compared with HPs, SSAs were less likely (odds ratio [OR] 0.74; 95% confidence interval [CI], 0.69-0.79) and adenomas were even less likely (OR 0.62; 95% CI, 0.59-0.64) to have all 3 NICE features of HPs. SSAs >5 mm were more likely than smaller SSAs to have all 3 NICE features of adenomas. SSA location did not predict NBI features. Analyses restricted to high-confidence lesions showed similar results. LIMITATIONS The endoscopists were not NBI experts. CONCLUSION Community gastroenterologists observed a profile of NICE features among SSAs that was intermediate to the profiles observed for HPs and adenomas. These results require confirmation by NBI experts.


American Journal of Kidney Diseases | 2013

Trends in Relative Mortality Between Hispanic and Non-Hispanic Whites Initiating Dialysis: A Retrospective Study of the US Renal Data System

Cristina M. Arce; Benjamin A. Goldstein; Aya Mitani; Wolfgang C. Winkelmayer

BACKGROUND Hispanic patients undergoing long-term dialysis experience better survival compared with non-Hispanic whites. It is unknown whether this association differs by age, has changed over time, or is due to differential access to kidney transplantation. STUDY DESIGN National retrospective cohort study. SETTING & PARTICIPANTS Using the US Renal Data System, we identified 615,618 white patients 18 years or older who initiated dialysis therapy between January 1, 1995, and December 31, 2007. PREDICTORS Hispanic ethnicity (vs non-Hispanic whites), year of end-stage renal disease incidence, age (as potential effect modifier). OUTCOMES All-cause and cause-specific mortality. RESULTS We found that Hispanics initiating dialysis therapy experienced lower mortality, but age modified this association (P < 0.001). Compared with non-Hispanic whites, mortality in Hispanics was 33% lower at ages 18-39 years (adjusted cause-specific HR [HRcs], 0.67; 95% CI, 0.64-0.71) and 40-59 years (HRcs, 0.67; 95% CI, 0.66-0.68), 19% lower at ages 60-79 years (HRcs, 0.81; 95% CI, 0.80-0.82), and 6% lower at 80 years or older (HRcs, 0.94; 95% CI, 0.91-0.97). Accounting for the differential rates of kidney transplantation, the associations were attenuated markedly in the younger age strata; the survival benefit for Hispanics was reduced from 33% to 10% at ages 18-39 years (adjusted subdistribution-specific HR [HRsd], 0.90; 95% CI, 0.85-0.94) and from 33% to 19% among those aged 40-59 years (HRsd, 0.81; 95% CI, 0.80-0.83). LIMITATIONS Inability to analyze Hispanic subgroups that may experience heterogeneous mortality outcomes. CONCLUSIONS Overall, Hispanics experienced lower mortality, but differential access to kidney transplantation was responsible for much of the apparent survival benefit noted in younger Hispanics.


Peritoneal Dialysis International | 2013

Determinants of Peritoneal Dialysis Technique Failure in Incident US Patients

Jenny I. Shen; Aya Mitani; Anjali B. Saxena; Benjamin A. Goldstein; Wolfgang C. Winkelmayer

♦ Objectives: Switching from peritoneal dialysis (PD) to hemodialysis (HD) is undesirable, because of complications from temporary vascular access, disruption of daily routine, and higher costs. Little is known about the role that social factors play in technique failure. ♦ Design, Setting, Participants, Measurements: We followed for 3 years a nationally representative cohort of US patients who initiated PD in 1996 - 1997. Technique failure was defined as any switch from PD to HD for 30 days or more. We used Cox regression to examine associations between technique failure and demographic, medical, social, and pre-dialysis factors. We estimated hazard ratios (HRs) with 95% confidence intervals (CIs). ♦ Results: We identified an inception cohort of 1587 patients undergoing PD. In multivariate analysis, female sex (HR: 0.78; 95% CI: 0.64 to 0.95) was associated with lower rates of technique failure, and black race [compared with white race (HR: 1.48; 95% CI: 1.20 to 1.82)] and receiving Medicaid (HR: 1.48; 95% CI: 1.17 to 1.86) were associated with higher rates. Compared with patients who worked full-time, those who were retired (HR: 1.49; 95% CI: 1.07 to 2.08) or disabled (HR: 1.38; 95% CI: 1.01 to 1.88) had higher rates of failure. Patients with a systolic blood pressure of 140 - 160 mmHg had a higher rate of failure than did those with a pressure of 120 - 140 mmHg (HR: 1.24; 95% CI: 1.00 to 1.52). Earlier referral to a nephrologist (>3 months before dialysis initiation) and the primary decision-maker for the dialysis modality (physician vs patient vs shared) were not associated with technique failure. ♦ Conclusions: This study confirms that several socio-demographic factors are associated with technique failure, emphasizing the potential importance of social and financial support in maintaining PD.


Clinical Journal of The American Society of Nephrology | 2012

Hispanic Ethnicity and Vascular Access Use in Patients Initiating Hemodialysis in the United States

Cristina M. Arce; Aya Mitani; Benjamin A. Goldstein; Wolfgang C. Winkelmayer

BACKGROUND AND OBJECTIVES Hispanics are the largest minority in the United States (comprising 16.3% of the US population) and have 1.5 times the age-, sex-, and race-adjusted incidence of ESRD compared with non-Hispanics. Poor health care access and low-quality care generally received by Hispanics are well documented. However, little is known regarding dialysis preparation of Hispanic patients with progressive CKD. DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS Using data from Medical Evidence Report form CMS-2728-U3, 321,996 adult patients of white or black race were identified who initiated hemodialysis (HD) between July 1, 2005 and December 31, 2008. The form captures Hispanic ethnicity, vascular access use at first outpatient HD, sociodemographic characteristics, and comorbidities. This study also examined whether use of an arteriovenous fistula (AVF) or graft (AVG) was reported. RESULTS AVF/AVG use was reported in 14.5% of Hispanics and 17.6% in non-Hispanics (P<0.001). The unadjusted prevalence ratio (PR) was 0.85 (95% confidence interval [95% CI], 0.83-0.88), indicating that Hispanics were 15% less likely to use AVG/AVF for their first outpatient HD. Adjustment for age, sex, and race, as well as a large number of comorbidities and frailty indicators, did not change this association (PR, 0.85; 95% CI, 0.83-0.88). Further adjustment for timing of first predialysis nephrology care, however, attenuated the PR by two-thirds (PR, 0.94; 95% CI, 0.92-0.97). CONCLUSIONS Hispanics are less likely to use arteriovenous access for first outpatient HD compared with non-Hispanics, which seems to be explained by variation in the access to predialysis nephrology care.


Cancer | 2014

Breast cancer treatment across health care systems: Linking electronic medical records and state registry data to enable outcomes research

Allison W. Kurian; Aya Mitani; Manisha Desai; Peter Paul Yu; Tina Seto; Susan C. Weber; Cliff Olson; Pragati Kenkare; Scarlett Lin Gomez; Monique A. de Bruin; Kathleen C. Horst; Jeffrey Belkora; Suepattra G. May; Dominick L. Frosch; Douglas W. Blayney; Harold S Luft; Amar K. Das

Understanding of cancer outcomes is limited by data fragmentation. In the current study, the authors analyzed the information yielded by integrating breast cancer data from 3 sources: electronic medical records (EMRs) from 2 health care systems and the state registry.


Journal of The American Society of Nephrology | 2014

State Medicaid Coverage, ESRD Incidence, and Access to Care

Manjula Kurella-Tamura; Benjamin A. Goldstein; Yoshio N. Hall; Aya Mitani; Wolfgang C. Winkelmayer

The proportion of low-income nonelderly adults covered by Medicaid varies widely by state. We sought to determine whether broader state Medicaid coverage, defined as the proportion of each states low-income nonelderly adult population covered by Medicaid, associates with lower state-level incidence of ESRD and greater access to care. The main outcomes were incidence of ESRD and five indicators of access to care. We identified 408,535 adults aged 20-64 years, who developed ESRD between January 1, 2001, and December 31, 2008. Medicaid coverage among low-income nonelderly adults ranged from 12.2% to 66.0% (median 32.5%). For each additional 10% of the low-income nonelderly population covered by Medicaid, there was a 1.8% (95% confidence interval, 1.0% to 2.6%) decrease in ESRD incidence. Among nonelderly adults with ESRD, gaps in access to care between those with private insurance and those with Medicaid were narrower in states with broader coverage. For a 50-year-old white woman, the access gap to the kidney transplant waiting list between Medicaid and private insurance decreased by 7.7 percentage points in high (>45%) versus low (<25%) Medicaid coverage states. Similarly, the access gap to transplantation decreased by 4.0 percentage points and the access gap to peritoneal dialysis decreased by 3.8 percentage points in high Medicaid coverage states. In conclusion, states with broader Medicaid coverage had a lower incidence of ESRD and smaller insurance-related access gaps.

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Gyorgy Frendl

Brigham and Women's Hospital

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