Breast Cancer Conspicuity on Simultaneously Acquired Digital Mammographic Images versus Digital Breast Tomosynthesis Images.

Background Digital breast tomosynthesis (DBT) has been shown to improve screening outcomes compared with digital mammography (DM) alone. However, little is known about differences in breast cancer conspicuity between DM and DBT or by mammographic view. Purpose To compare conspicuity of breast cancers at DM versus DBT and by mammographic view, craniocaudal (CC) versus mediolateral oblique (MLO). Materials and Methods Lesion conspicuity was graded by three readers by using a 0-5 numerical scale on both DM and DBT images from combined DM and DBT studies for 197 consecutive screening-detected cancers in women (mean age, 60.4 years ± 11.1 [standard deviation]) from October 1, 2011, through December 31, 2014. Intermodality (ie, DM vs DBT) and intramodality (ie, CC vs MLO) analyses were performed. For intramodality analyses, conspicuity was analyzed by view, CC versus MLO, within the same modality. Conspicuity grades were dichotomized into low (scores 0-3) and high (scores 4 and 5) conspicuity. This binary result was assessed by using a generalized linear mixed-effects model with logit link function, random-effect intercept for reader, and compound symmetry covariance structure for lesion. Results Cancers were more likely to be high conspicuity at DBT than at DM (odds ratio [OR], 2.4; 95% confidence interval [CI]: 1.9, 3.0; P < .01). At both DM and DBT, cancers were more likely to be high conspicuity at the CC than the MLO view (DM vs DBT OR, 1.6 [95% CI: 1.3, 1.9] vs 1.7 [95% CI: 1.3, 2.1], respectively; P < .01 for both). Cancers seen at one view only were more often detected at CC than MLO for both DM and DBT (DM vs DBT OR, 1.6 [95% CI: 1.2, 2.0] vs 3.6 [95% CI: 1.9, 7.0], respectively; P < .01.). Conclusion Cancers were more conspicuous at digital breast tomosynthesis than at digital mammography. Cancers may only be detected at one of two views, and they are more likely to be seen at the craniocaudal view. © RSNA, 2019.

Effect of Mammographic Screening Modality on Breast Density Assessment: Digital Mammography versus Digital Breast Tomosynthesis.

Background Breast Imaging Reporting and Data System (BI-RADS) breast density categories assigned by interpreting radiologists often influence decisions surrounding supplemental breast cancer screening and risk assessment. The landscape of mammographic screening continuously evolves, and different mammographic screening modalities may result in different perception of density, reflected in different assignment of BI-RADS density categories. Purpose To investigate the effect of screening mammography modality on BI-RADS breast density assessments. Materials and Methods Data were retrospectively analyzed from 24 736 individual women (42.3% [10 455 of 24 736] white women, 57.7% [14 281 of 24 736] black women; mean age, 56.3 years; age range, 40.0-74.9 years) who underwent from one to seven mammographic screening examinations from September 2010 through February 2017 (60 766 examinations). Three screening modalities were used: digital mammography alone (8935 examinations); digital mammography with digital breast tomosynthesis (DBT; 30 779 examinations); and synthetic mammography with DBT (21 052 examinations). Random-effects logistic regression analysis was performed to estimate the likelihood of assignment to high versus low BI-RADS density category according to each modality, adjusted for ethnicity, age, body mass index (BMI), and radiologist. The interactions of modality with ethnicity and BMI on density categorization were also tested with the model. Results Women screened with DBT versus digital mammography alone had lower likelihood regarding categorization of high density breasts (digital mammography and DBT vs digital mammography: odds ratio, 0.69 [95% confidence interval: 0.61, 0.80], P < .001; synthetic mammography and DBT vs digital mammography: odds ratio, 0.43 [95% confidence interval: 0.37, 0.50], P < .001). Lower likelihood of high density was also observed at synthetic mammography and DBT compared with digital mammography and DBT (odds ratio, 0.62; 95% confidence interval: 0.56, 0.69; P < .001). There were interactions of modality with ethnicity (P = .007) and BMI (P = .003) on breast density assessment, with greater differences in density categorization according to modality observed for black women than for white women and groups with higher BMI. Conclusion Breast density categorization may vary by screening mammographic modality, and this effect appears to vary by ethnicity and body mass index. © RSNA, 2019 Online supplemental material is available for this article. See also the editorial by Philpotts in this issue.

Mammographic breast density decreases after bariatric surgery.

PURPOSE: Breast density (BD), an important risk factor for breast cancer, can change over time in some women, but the underlying mechanism is unclear. Very little is known about the impact of surgical weight loss on BD. Our hypothesis is that weight loss after bariatric surgery is associated with a significant and favorable change in mammographic BD. METHODS: We identified 1097 women 40 years of age or older who underwent gastric bypass or sleeve gastrectomy at our institution from 2010 to 2014. Women who did not have either pre- and post-bariatric surgery mammograms performed at our institution were excluded; 110 had both mammograms and comprised the cohort. Breast density was determined both qualitatively, using reported BI-RADS density, and quantitatively, using the Laboratory for Individualized Breast Radiodensity Assessment. RESULTS: Qualitative BI-RADS density, quantitative breast area, and percent BD significantly decreased in post-bariatric surgery mammograms (p = 0.009, <0.001, and <0.001, respectively). CONCLUSIONS: Our retrospective study demonstrated that surgical weight loss was associated with a significant decrease in breast density. Additional studies are warranted to validate our findings and elucidate the molecular mechanisms underlying breast density change after weight loss surgery.

Challenges With Identifying Indication for Examination in Breast Imaging as a Key Clinical Attribute in Practice, Research, and Policy.

PURPOSE: To assess indication for examination for four breast imaging modalities and describe the complexity and heterogeneity of data sources and ascertainment methods. METHODS: Indication was evaluated among the Population-based Research Optimizing Screening through Personalized Regimens (PROSPR) breast cancer research centers (PRCs). Indication data were reported overall and separately for four breast imaging modalities: digital mammography (DM), digital breast tomosynthesis (DBT), ultrasound (US), and magnetic resonance imaging (MRI). RESULTS: The breast PRCs contributed 236,262 women with 607,735 breast imaging records from 31 radiology facilities. We found a high degree of heterogeneity for indication within and across six data sources. Structured codes within a data source were used most often to identify indication for mammography (59% DM, 85% DBT) and text analytics for US (45%) and MRI (44%). Indication could not be identified for 17% of US and 26% of MRI compared with 2% of mammography examinations (1% DM, 3% DBT). CONCLUSIONS: Multiple and diverse data sources, heterogeneity of ascertainment methods, and nonstandardization of codes within and across data systems for determining indication were found. Consideration of data sources and standardized methodology for determining indication is needed to assure accurate measurement of cancer screening rates and performance in clinical practice and research.

Effect of a Financial Incentive for Colorectal Cancer Screening Adherence on the Appropriateness of Colonoscopy Orders.

Performance incentives for preventive care may encourage inappropriate testing, such as cancer screening for patients with short life expectancies. Defining screening colonoscopies for patients with a >50% 4-year mortality risk as inappropriate, the authors performed a pre-post analysis assessing the effect of introducing a cancer screening incentive on the proportion of screening colonoscopy orders that were inappropriate. Among 2078 orders placed by 23 attending physicians in 4 academic general internal medicine practices, only 0.6% (n = 6/1057) of screening colonoscopy orders in the preintervention period and 0.6% (n = 6/1021) of screening colonoscopy orders in the postintervention period were deemed "inappropriate." This study found no evidence that the incentive led to an increase in inappropriate screening colonoscopy orders.

Implementation of Synthesized Two-dimensional Mammography in a Population-based Digital Breast Tomosynthesis Screening Program.

Purpose To evaluate the early implementation of synthesized two-dimensional (s2D) mammography in a population screened entirely with s2D and digital breast tomosynthesis (DBT) (referred to as s2D/DBT) and compare recall rates and cancer detection rates to historic outcomes of digital mammography combined with DBT (referred to as digital mammography/DBT) screening. Materials and Methods This was an institutional review board-approved and HIPAA-compliant retrospective interpretation of prospectively acquired data with waiver of informed consent. Compared were recall rates, biopsy rates, cancer detection rates, and radiation dose for 15 571 women screened with digital mammography/DBT from October 1, 2011, to February 28, 2013, and 5366 women screened with s2D/DBT from January 7, 2015, to June 30, 2015. Two-sample z tests of equal proportions were used to determine statistical significance. Results Recall rate for s2D/DBT versus digital mammography/DBT was 7.1% versus 8.8%, respectively (P < .001). Biopsy rate for s2D/DBT versus digital mammography/DBT decreased (1.3% vs 2.0%, respectively; P = .001). There was no significant difference in cancer detection rate for s2D/DBT versus digital mammography/DBT (5.03 of 1000 vs 5.45 of 1000, respectively; P = .72). The average glandular dose was 39% lower in s2D/DBT versus digital mammography/DBT (4.88 mGy vs 7.97 mGy, respectively; P < .001). Conclusion Screening with s2D/DBT in a large urban practice resulted in similar outcomes compared with digital mammography/DBT imaging. Screening with s2D/DBT allowed for the benefits of DBT with a decrease in radiation dose compared with digital mammography/DBT. © RSNA, 2016 An earlier incorrect version of this article appeared online. This article was corrected on August 11, 2016.

Racial Differences in Quantitative Measures of Area and Volumetric Breast Density.

BACKGROUND: Increased breast density is a strong risk factor for breast cancer and also decreases the sensitivity of mammographic screening. The purpose of our study was to compare breast density for black and white women using quantitative measures. METHODS: Breast density was assessed among 5282 black and 4216 white women screened using digital mammography. Breast Imaging-Reporting and Data System (BI-RADS) density was obtained from radiologists' reports. Quantitative measures for dense area, area percent density (PD), dense volume, and volume percent density were estimated using validated, automated software. Breast density was categorized as dense or nondense based on BI-RADS categories or based on values above and below the median for quantitative measures. Logistic regression was used to estimate the odds of having dense breasts by race, adjusted for age, body mass index (BMI), age at menarche, menopause status, family history of breast or ovarian cancer, parity and age at first birth, and current hormone replacement therapy (HRT) use. All statistical tests were two-sided. RESULTS: There was a statistically significant interaction of race and BMI on breast density. After accounting for age, BMI, and breast cancer risk factors, black women had statistically significantly greater odds of high breast density across all quantitative measures (eg, PD nonobese odds ratio [OR] = 1.18, 95% confidence interval [CI] = 1.02 to 1.37, P = .03, PD obese OR = 1.26, 95% CI = 1.04 to 1.53, P = .02). There was no statistically significant difference in BI-RADS density by race. CONCLUSIONS: After accounting for age, BMI, and other risk factors, black women had higher breast density than white women across all quantitative measures previously associated with breast cancer risk. These results may have implications for risk assessment and screening.

Effectiveness of Digital Breast Tomosynthesis Compared With Digital Mammography: Outcomes Analysis From 3 Years of Breast Cancer Screening.

IMPORTANCE: Breast cancer screening with digital breast tomosynthesis (DBT) combined with digital mammography (DM) decreases false-positive examinations and increases cancer detection compared with screening with DM alone. However, the longitudinal performance of DBT screening is unknown. OBJECTIVES: To determine whether the improved outcomes observed after initial implementation of DBT screening are sustainable over time at a population level and to evaluate the effect of more than 1 DBT screening at the individual level. DESIGN, SETTING, AND PARTICIPANTS: Retrospective analysis of screening mammography metrics was performed for all patients presenting for screening mammography in an urban, academic breast center during 4 consecutive years (DM, year 0; DBT, years, 1-3). The study was conducted from September 1, 2010, to September 30, 2014 (excluding September 2011, which was the transition period from DM to DBT), for a total of 44 468 screening events attributable to a total of 23 958 unique women. Differences in screening outcomes between each DBT year and the DM year, as well as between groups of women with only 1, 2, or 3 DBT screenings, were assessed, and the odds of recall adjusted for age, race/ethnicity, breast density, and prior mammograms were estimated. Data analysis was performed between February 16 and October 26, 2015. EXPOSURE: Digital mammography screening supplemented with DBT. MAIN OUTCOMES AND MEASURES: Recall rates, cancer cases per recalled patients, and biopsy and interval cancer rates were determined. RESULTS: Screening outcome metrics were evaluated for a total of 44 468 examinations attributable to 23 958 unique women (mean [SD] age, 56.8 [11.0] years) over a 4-year period: year 0 cohort (DM0), 10 728 women; year 1 cohort (DBT1), 11 007; year 2 cohort (DBT2), 11 157; and year 3 cohort (DBT3), 11 576. Recall rates rose slightly for years 1 to 3 of DBT (88, 90, and 92 per 1000 screened, respectively) but remained significantly reduced compared with the DM0 rate of 104 per 1000 screened. Reported as odds ratios (95% CIs), the findings were DM vs DBT1, 0.83 (0.76-0.91, P < .001); DM vs DBT2, 0.85 (0.78-0.93, P < .001); and DM vs DBT3, 0.87 (0.80-0.95, P = .003). The cancer cases per recalled patients continued to rise from DM0 rate of 4.4% to 6.2% (P = .06), 6.5% (P = .03), and 6.7% (P = .02) for years 1 to 3 of DBT, respectively. Outcomes assessed for the most recent screening for individual women undergoing only 1, 2, or 3 DBT screenings during the study period demonstrated decreasing recall rates of 130, 78, and 59 per 1000 screened, respectively (P < .001). Interval cancer rates, determined using available follow-up data, decreased from 0.7 per 1000 women screened with the use of DM to 0.5 per 1000 screened with the use of DBT1. CONCLUSIONS AND RELEVANCE: Digital breast tomosynthesis screening outcomes are sustainable, with significant recall reduction, increasing cancer cases per recalled patients, and a decline in interval cancers.

Baseline Screening Mammography: Performance of Full-Field Digital Mammography Versus Digital Breast Tomosynthesis.

OBJECTIVE: Baseline mammography studies have significantly higher recall rates than mammography studies with available comparison examinations. Digital breast tomosynthesis reduces recalls when compared with digital mammographic screening alone, but many sites operate in a hybrid environment. To maximize the effect of screening digital breast tomosynthesis with limited resources, choosing which patient populations will benefit most is critical. This study evaluates digital breast tomosynthesis in the baseline screening population. MATERIALS AND METHODS: Outcomes were compared for 10,728 women who underwent digital mammography screening, including 1204 (11.2%) baseline studies, and 15,571 women who underwent digital breast tomosynthesis screening, including 1859 (11.9%) baseline studies. Recall rates, cancer detection rates, and positive predictive values were calculated. Logistic regression estimated the odds ratios of recall for digital mammography versus digital breast tomosynthesis for patients undergoing baseline screening and previously screened patients, adjusted for age, race, and breast density. RESULTS: In the baseline subgroup, recall rates for digital mammography and digital breast tomosynthesis screening were 20.5% and 16.0%, respectively (p = 0.002); digital breast tomosynthesis screening in the baseline subgroup resulted in a 22% reduction in recall compared with digital mammography, or 45 fewer patients recalled per 1000 patients screened. Digital breast tomosynthesis screening in the previously screened patients resulted in recall reduction of 14.3% (p < 0.001; p for interaction = 0.21). The recall rate reduction for baseline screening was especially pronounced in women younger than 50 years (p = 0.005). DBT implementation resulted in an increase in cancer detection in the baseline subgroup of 40.5% versus an increase in the previously screened subgroup of 17.4%. DBT implementation resulted in an increase in PPV1 in the baseline subgroup of 85% versus 35.3% in the previously screened subgroup, although the p-interaction was not significant. CONCLUSION: If resources are limited, women younger than 50 years who are undergoing baseline screening or do not have prior available mammograms may benefit more from digital breast tomosynthesis than from digital mammography alone.

Screening outcomes following implementation of digital breast tomosynthesis in a general-population screening program.

BACKGROUND: Early data on breast cancer screening utilizing digital breast tomosynthesis (DBT) combined with digital mammography (DM) have shown improvements in false-positive and false-negative screening rates compared with DM alone. However, these trials were performed at sites where conventional mammographic screening was concurrently performed, possibly leading to selection biases or with complex, multireader algorithms not reflecting general clinical practice. Our study reports the impact on screening outcomes for DBT screening implemented in an entire clinic population. METHODS: Recall rates, cancer detection, and positive predictive values of screening were compared for 15571 women screened with DBT and 10728 screened with DM alone prior to DBT implementation at a single breast imaging center. Generalized linear mixed-effects models were used to estimate the odds ratio (OR) for recall rate adjusted for age, race, presence of prior mammograms, breast density and reader. All statistical tests were two-sided. RESULTS: DBT screening showed a statistically significant reduction in recalls compared to DM alone. For the entire population, there were 16 fewer recalls (8.8% vs 10.4%, P <.001, adjusted OR = 0.80, 95% confidence interval [CI] = 0.74 to 0.88, P < .001) and 0.9 additional cancers detected per 1000 screened with DBT compared to DM alone. There was a statistically significant increase in PPV1 (6.2% vs 4.4%, P = .047). In women younger than age 50 years screened with DBT, there were 17 fewer recalls (12.3% vs 14.0%, P = .02) and 3.6 additional cancer detected per 1000 screened (5.7 vs 2.2 per 1000, P = .02). CONCLUSIONS: Our data support the clinical implementation of DBT in breast cancer screening; however, larger prospective trials are needed to validate our findings in specific patient subgroups.

Clinical predictors of urgent findings on abdominopelvic CT in emergency department patients with Crohn's disease.

BACKGROUND: Patients with Crohn's disease (CD) are frequently exposed to diagnostic radiation in emergency departments (EDs). We aimed to examine clinical predictors of urgent abdominopelvic computed tomography (APCT) findings in this population. METHODS: A retrospective cross-sectional study was performed among adults with CD presenting to 2 emergency departments with a gastrointestinal chief complaint. The outcome, APON (abscess, perforation, obstruction, new or worsening non-CD-related findings), included APCTs with new or worsening CD-related or non-CD-related urgent findings. Variables with P < 0.05 in bivariate analyses were included in a multivariable logistic regression model, which was also used to develop a risk score for APON. RESULTS: A total of 481 APCTs were performed and 166 (34.5%) identified APON. Variables retained in the final model were history of intestinal obstruction (odds ratio [OR]: 3.78, 95% confidence interval [CI]: 2.27-6.28), history of intraabdominal abscess (OR: 2.64, 95% CI: 1.43 to 4.88), current hematochezia (OR: 0.38, 95% CI: 0.21 to 0.68), and white blood cell count >12,000/µL (OR: 2.49, 95% CI: 1.63 to 3.84). The c-statistic was 0.72. The risk score subtracts 1 point for hematochezia, and adds 1 point for each of the other variables. Among patients with a risk score of -1, the predicted and observed risk for APON was 9% and 6%, respectively. Any score greater than -1 had a predicted and observed risk of 19.8% and higher. CONCLUSIONS: An APON risk score of -1 is associated with a low risk of urgent APCT findings in patients with CD in the emergency department. Implementation of such a tool may support clinical decision-making in the ED setting.

Use of abdominopelvic computed tomography in emergency departments and rates of urgent diagnoses in Crohn's disease.

BACKGROUND & AIMS: In the United States, the use of abdominopelvic computed tomography (APCT) by emergency departments for patients with abdominal pain has increased, despite stable admission rates and diagnosis requiring urgent intervention. We proposed that trends would be similar for patients with Crohn's disease (CD). METHODS: We conducted a retrospective study of data from 648 adults with CD who presented at 2 emergency departments (2001-2009; 1572 visits). Trends in APCT use were assessed with Spearman correlation coefficient. We compared patient characteristics and APCT findings during 2001-2003 and 2007-2009. RESULTS: APCT use increased from 2001 (used for 47% of encounters) to 2009 (used for 78% of encounters; P = .005), whereas admission rates were relatively stable at 68% in 2001 and 71% in 2009 (P = .06). The overall proportion of APCTs with findings of intestinal perforation, obstruction, or abscess was 29.0%; 34.9% of APCTs were associated with urgent diagnoses, including those unrelated to CD. Between 2001-2003 and 2007-2009, the proportions of APCTs that detected intestinal perforation, obstruction, or abscess were similar (30% vs 29%, P = .92), as were the proportions used to detect any diagnosis requiring urgent intervention, including those unrelated to CD (36% vs 34%, P = .91). CONCLUSIONS: Despite the increased use of APCT by emergency departments for patients with CD, there were no significant changes in admission rates between the periods of 2001-2003 and 2007-2009. The proportion of APCTs that detected intestinal perforation, obstruction, abscess, or other urgent conditions not related to CD remained high.

Evaluation of the use of electronic health data to classify four-year mortality risk for older adults undergoing screening colonoscopies.

Current cancer screening recommendations often apply coarse age cutoffs for screening requirements without regard to predicted life expectancy. Using these cutoffs, healthier older patients may be under-screened, and sicker younger patients may be screened too often. Mortality risk classification using EHR data could be used to tailor screening reminders to physicians in ways that better align screening recommendations with patients who are more likely to live long enough to benefit from early detection. We have evaluated the performance of an existing prognostic index for 4-year mortality using data readily available in the electronic health record (EHR), and investigated the effect of the index in retrospective cohorts of adults age 65 and older undergoing screening colonoscopy. Risk scores in this adaptation of a four-year prognostic index were found to be associated with actual death rates and consistent with mortality rates from a national sample. Our results demonstrate that data extracted from electronic health records can be used to classify mortality risk. With improvements, including extension to a 5-year mortality model with inclusion of additional variables and extension of variable definitions, informatics methods to implement mortality models may prove to be clinically useful in tailoring screening guidelines.

Impact of antimicrobial stewardship programme changes on unnecessary double anaerobic coverage therapy.

BACKGROUND: Concern has been raised over the practice of unnecessary double anaerobic coverage therapy (DACT) in the hospital setting. However, the incidence of and risk factors for unnecessary DACT are not well studied. On 8 September 2008, the antimicrobial stewardship programme (ASP) at our institution was modified such that several antibiotics, including ampicillin/sulbactam and metronidazole, no longer required pre-approval. We anticipated that this change would increase both unnecessary DACT and target antibiotic consumption. METHODS: A nested case-control study was conducted to determine the cumulative incidence of and risk factors for unnecessary DACT. Cases were subjects who received unnecessary DACT while controls were subjects who did not receive DACT or who received necessary DACT. Segmented regression analysis was subsequently performed to evaluate the impact of ASP changes on unnecessary DACT and consumption of target antibiotics. RESULTS: From October 2007 to September 2009, the cumulative incidence of unnecessary DACT was 2.3% [95% confidence interval (CI) 1.7-3.1]. Independent risk factors for unnecessary DACT [adjusted odds ratio (95% CI); P value] included hospitalization on a surgical ward [3.51 (1.03-12.02); P = 0.002], hospitalization on an obstetrics and gynaecology ward [9.07 (2.54-32.40); P = 0.002] and underlying metastatic malignancy [3.18 (1.38-7.09); P = 0.006]. The ASP change was associated with an increase in ampicillin/sulbactam and metronidazole consumption. However, there was no significant impact on unnecessary DACT prescribing. CONCLUSIONS: Although uncommon, unnecessary DACT is more prevalent in specific services. Future qualitative studies focusing on these specific subgroups would be useful in elucidating this problem more clearly. The ASP changes were not associated with increases in unnecessary DACT.

Cefepime-resistant Pseudomonas aeruginosa.

Resistance to extended-spectrum cephalosporins complicates treatment of Pseudomonas aeruginosa infections. To elucidate risk factors for cefepime-resistant P. aeruginosa and determine its association with patient death, we conducted a case-control study in Philadelphia, Pennsylvania. Among 2,529 patients hospitalized during 2001-2006, a total of 213 (8.4%) had cefepime-resistant P. aeruginosa infection. Independent risk factors were prior use of an extended-spectrum cephalosphorin (p<0.001), prior use of an extended-spectrum penicillin (p = 0.005), prior use of a quinolone (p<0.001), and transfer from an outside facility (p = 0.01). Among those hospitalized at least 30 days, mortality rates were higher for those with cefepime-resistant than with cefepime-susceptible P. aeruginosa infection (20.2% vs. 13.2%, p = 0.007). Cefepime-resistant P. aeruginosa was an independent risk factor for death only for patients for whom it could be isolated from blood (p = 0.001). Strategies to counter its emergence should focus on optimizing use of antipseudomonal drugs.

Emergency department lactate is associated with mortality in older adults admitted with and without infections.

OBJECTIVES: Serum lactate values in the emergency department (ED) have been associated with mortality in diverse populations of critically ill patients. This study investigates whether serum lactate values measured in the ED are associated with mortality in older patients admitted to the hospital, both with and without infections. METHODS: This is a retrospective cohort study performed at two urban teaching hospitals. The study population includes 1,655 older ED patients (age>or=65 years) over a 3-year period (2004-2006) who had serum lactate measured prior to admission. The presence or absence of infection was determined by review of International Classification of Diseases Ninth Revision (ICD-9) admission diagnosis codes. Mortality during hospitalization was determined by review of inpatient records. Mortality at 30 and at 60 days was determined using a state death registry. RESULTS: In patients with infections, increasing serum lactate values of >or=2.0 mmol/L were linearly associated with relative risk (RR) of mortality during hospitalization (RR=1.9 to 3.6 with increasing lactate), at 30 days (RR=1.7 to 2.6), and at 60 days (RR=1.4 to 2.3) when compared to patients with serum lactate levels of <2.0 mmol/L. In patients without infections, a similar association was observed (RR=1.1 to 3.9 during hospitalization, RR=1.2 to 2.6 at 30 days, RR=1.1 to 2.4 at 60 days). In both groups of patients, serum lactate had a greater magnitude of association with mortality than either of two other commonly ordered laboratory tests, leukocyte count and serum creatinine. CONCLUSIONS: Higher ED lactate values are associated with greater mortality in a broad cohort of admitted patients over age 65 years, regardless of the presence or absence of infection.

Postdischarge adverse events for 1-day hospital admissions in older adults admitted from the emergency department.

STUDY OBJECTIVE: We assess hospital readmission and death within 60 days in older adults admitted from the emergency department (ED) and discharged by an inpatient service within 24 hours. METHODS: This was a retrospective review of ED patients aged 64 years or older, admitted from 2 hospitals (2004 to 2006), who were discharged home within 24 hours. Excluded were in-hospital deaths, observation admissions, transfers to other facilities, patients who left against medical advice, and hospice patients. Outcomes were 72-hour and 30-day readmissions and postdischarge deaths that occurred within 60 days of ED admission. Logistic regression was used to assess for predictors of readmission. A chart review of deaths after discharge was performed to assess for potential contributors to adverse outcomes. RESULTS: A total of 1,470 admissions met inclusion criteria as 1-day admissions. Of those, 22 (1.5%) patients returned for hospital readmission within 72 hours and 156 (10.6%) within 30 days of discharge. In the multivariable analysis, previous admissions (odds ratio [OR] 1.3; 95% confidence interval [CI] 1.1 to 1.4) and an admission diagnosis of heart failure (OR 2.2; 95% CI 1.0 to 5.0) were associated with 30-day readmission. In 841 individual patients with greater than or equal to one 1-day admission, there were 15 deaths (1.8%) within 60 days. Of those, 11 (73%) patients had abnormal ED ECG results, 6 (40%) were ruled out for acute myocardial infarction while hospitalized, and 3 (20%) had definitive follow-up arranged at discharge. CONCLUSION: One-day admissions in hospitalized older adults through the ED do not represent a group at low risk for postdischarge adverse outcomes.

Imipenem resistance in Pseudomonas aeruginosa: emergence, epidemiology, and impact on clinical and economic outcomes.

BACKGROUND: Pseudomonas aeruginosa is one of the most common gram-negative hospital-acquired pathogens. Resistance of this organism to imipenem complicates treatment. OBJECTIVE: To elucidate the risk factors for imipenem-resistant P. aeruginosa (IRPA) infection or colonization and to identify the effect of resistance on clinical and economic outcomes. METHODS: Longitudinal trends in prevalence of IRPA from 2 centers were characterized during the period from 1989 through 2006. For P. aeruginosa isolates obtained during the period from 2001 through 2006, a case-control study was conducted to investigate the association between prior carbapenem use and IRPA infection or colonization, and a cohort study was performed to identify the effect of IRPA infection or colonization on mortality, length of stay after culture, and hospital cost after culture. RESULTS: From 1989 through 2006, the proportion of P. aeruginosa isolates demonstrating resistance to imipenem increased from 13% to 20% (P < .001, trend). During the period from 2001 through 2006, there were 2,542 unique patients with P. aeruginosa isolates, and 253 (10.0%) had IRPA isolates. Prior carbapenem use was independently associated with IRPA infection or colonization (adjusted odds ratio [OR], 7.92 [95% confidence interval {CI}, 4.78-13.11]). Patients with an IRPA isolate recovered had higher in-hospital mortality than did patients with an imipenem-susceptible P. aeruginosa isolate (17.4% vs 13.4%; P = .01). IRPA infection or colonization was an independent risk factor for mortality among patients with isolates recovered from blood (adjusted OR, 5.43 [95% CI, 1.72-17.10]; P = .004) but not among patients with isolates recovered from other anatomic sites (adjusted OR, 0.78 [95% CI, 0.51-1.21]; P = .27). Isolation of IRPA was associated with longer hospital stay after culture (p < .001) and greater hospital cost after culture (P < .001) than was isolation of an imipenem-susceptible strain. In multivariable analysis, IRPA infection or colonization remained an independent risk factor for both longer hospital stay after culture (coefficient, 0.20 [95% CI, 0.04-0.36]; P = .02) and greater hospital cost after culture (coefficient, 0.30 [95% CI, 0.06-0.54]; P = .02). CONCLUSIONS: The prevalence of IRPA infection or colonization has increased significantly, with important implications for both clinical and economic outcomes. Interventions to curb this continued increase and strategies to optimize therapy are urgently needed.

Epidemiology and impact of imipenem resistance in Acinetobacter baumannii.

BACKGROUND: Acinetobacter baumannii is an emerging gram-negative pathogen that can cause healthcare-acquired infections among patients. Treatment is complicated for cases of healthcare-acquired infection with A. baumannii resistant to imipenem. OBJECTIVE: To elucidate the risk factors for imipenem-resistant A. baumannii (IRAB) infection or colonization and to identify the effect of resistance on clinical and economic outcomes. METHODS: We analyzed data from 2 medical centers of the University of Pennsylvania. Longitudinal trends in the prevalence of IRAB clinical isolates were characterized during the period from 1989 through 2004. For A. baumannii isolates obtained from 2001 through 2006, a case-control study was conducted to investigate the association between prior carbapenem use and IRAB infection or colonization, and a cohort study was performed to identify the effect of IRAB infection or colonization on mortality, length of stay after culture, and hospital cost after culture. RESULTS: From 1989 through 2004, the annual prevalence of IRAB isolates ranged from 0% to 21%. During the period from 2001 through 2006, there were 386 unique patients with A. baumannii isolates, and 89 (23.1%) had IRAB isolates. Prior carbapenem use was independently associated with IRAB infection or colonization (adjusted odds ratio, 3.04 [95% confidence interval, 1.07-8.65]). There was a borderline significant association between IRAB infection or colonization and mortality, although this association was limited to isolates recovered from blood samples (adjusted odds ratio, 5.30 [95% confidence interval, 0.81-34.59]). Compared with patients with imipenem-susceptible A. baumannii infection or colonization, patients with IRAB infection or colonization had a longer hospital stay after culture (median, 21 vs 16 days; P = .07) and greater hospital charges after culture (mean, $334,516 vs $276,059; P = .03). After controlling for patient location in an intensive care unit, transfer from another facility, and length of hospital stay before culture, there was no longer an independent association between IRAB infection or colonization and higher cost after culture and length of stay after positive culture result. CONCLUSIONS: Many A. baumannii isolates exhibit imipenem resistance, which is strongly associated with prior use of carbapenems. Given the high mortality rate associated with A. baumannii infection or colonization, interventions to curb further emergence of cases of IRAB infection and strategies to optimize therapy are needed.

Risk factors and clinical impact of Klebsiella pneumoniae carbapenemase-producing K. pneumoniae.

BACKGROUND: Klebsiella pneumoniae carbapenemase (KPC)-producing K. pneumoniae is an emerging pathogen with serious clinical and infection control implications. To our knowledge, no study has specifically examined risk factors for KPC-producing K. pneumoniae or its impact on mortality. METHODS: To identify risk factors for infection or colonization with KPC-producing K. pneumoniae, a case-control study was performed. Case patients with KPC-producing K. pneumoniae were compared with control subjects with carbapenem-susceptible K. pneumoniae. A cohort study evaluated the association between KPC-producing K. pneumoniae and in-hospital mortality. RESULTS: Fifty-six case patients and 863 control subjects were identified. In multivariable analysis, independent risk factors for KPC-producing K. pneumoniae were (1) severe illness (adjusted odds ratio [AOR], 4.31; 95% confidence interval [CI], 2.25-8.25), (2) prior fluoroquinolone use (AOR, 3.39; 95% CI, 1.50, 7.66), and (3) prior extended-spectrum cephalosporin use (AOR, 2.55; 95% CI, 1.18, 5.52). Compared with samples from other anatomic locations, K. pneumoniae isolates from blood samples were less likely to harbor KPC (AOR, 0.33; 95% CI, 0.12, 0.86). KPC-producing K. pneumoniae was independently associated with in-hospital mortality (AOR, 3.60; 95% CI, 1.87-6.91). CONCLUSIONS: KPC-producing K. pneumoniae is an emerging pathogen associated with significant mortality. Our findings highlight the urgent need to develop strategies for prevention and infection control. Limiting use of certain antimicrobials, specifically fluoroquinolones and cephalosporins, use may be effective strategies.