Two methods for modelling the propagation of terahertz radiation in a layered structure

Modelling the interaction of terahertz(THz) radiation with biological tissueposes many interesting problems. THzradiation is neither obviously described byan electric field distribution or anensemble of photons and biological tissueis an inhomogeneous medium with anelectronic permittivity that is bothspatially and frequency dependent making ita complex system to model.A three-layer system of parallel-sidedslabs has been used as the system throughwhich the passage of THz radiation has beensimulated. Two modelling approaches havebeen developed a thin film matrix model anda Monte Carlo model. The source data foreach of these methods, taken at the sametime as the data recorded to experimentallyverify them, was a THz spectrum that hadpassed though air only.Experimental verification of these twomodels was carried out using athree-layered in vitro phantom. Simulatedtransmission spectrum data was compared toexperimental transmission spectrum datafirst to determine and then to compare theaccuracy of the two methods. Goodagreement was found, with typical resultshaving a correlation coefficient of 0.90for the thin film matrix model and 0.78 forthe Monte Carlo model over the full THzspectrum. Further work is underway toimprove the models above 1 THz.

Catalogue of human tissue optical properties at terahertz frequencies

Recently published studies suggest thatterahertz pulsed imaging will have applications inmedicine and biology, but there iscurrently very little information about the opticalproperties of human tissue at terahertzfrequencies. Such information would be useful forpredicting the feasibility of proposedapplications, optimising acquisition protocols,providing information about variability ofhealthy tissue and supplying data for studies of theinteraction mechanisms. Research ethicscommittee approval was obtained, andmeasurements made from samples of freshlyexcised human tissue, using a broadbandterahertz pulsed imaging system comprisingfrequencies approximately 0.5 to 2.5 THz.Refractive index and linear absorptioncoefficient were found. Reproducibility wasdetermined using blood from one volunteer,which was drawn and measured on consecutivedays. Skin, adipose tissue, striatedmuscle, vein and nerve were measured (to date, from oneindividual). Water had a higher refractiveindex (2.04 ± 0.07) than any tissue.The linear absorption coefficient was higher formuscle than adipose tissue, as expectedfrom the higher hydration of muscle. As these samples camefrom a single subject, there is currentlyinsufficient statistical power to draw firmconclusions, but results suggest that in vivo clinical imaging will be feasible in certainapplications.

The mu/kappa agonist nalbuphine attenuates sensitization to the behavioral effects of cocaine

Sensitization refers to an increase in sensitivity to a drug and is believed to play a role in the etiology of substance use disorders. The purpose of the present study was to evaluate the ability of the mixed mu/kappa agonist nalbuphine to modulate sensitization to the locomotor and positive reinforcing effects of cocaine. Rats were habituated to a locomotor activity chamber and treated with saline (1.0 ml/kg, ip), cocaine (10 mg/kg, ip), or cocaine+nalbuphine (10 mg/kg, ip) every day for 10 days. Following locomotor activity testing, rats were implanted with intravenous catheters and cocaine self-administration was examined on fixed ratio (FR) and progressive ratio (PR) schedules of reinforcement. Rats treated with cocaine exhibited a progressive increase in locomotor activity over the 10-day treatment period, and this effect was significantly reduced in rats treated with cocaine+nalbuphine. In self-administration tests, rats treated with cocaine exhibited significantly higher levels of responding at a threshold dose of cocaine (0.03 mg/kg/infusion) on both FR and PR schedules than rats treated with saline. This increase in responding at a threshold dose of cocaine was blocked completely in rats treated with cocaine+nalbuphine. These data suggest that nalbuphine attenuates the development of sensitization to the behavioral effects of cocaine.

Predictors of short-term postoperative survival after elective colectomy in colon cancer patients ≥ 80 years of age

BACKGROUND

Individuals ≥ 80 years of age represent an increasing proportion of colon cancer diagnoses. Selecting these patients for elective surgery is challenging because of diminished overall health, functional decline, and limited data to guide decisions. The objective was to identify overall health measures that are predictive of poor survival after elective surgery in these oldest-old colon cancer patients.

METHODS

Medicare beneficiaries ≥ 80 years who underwent elective colectomy for stage I-III colon cancer from 1992-2005 were identified from the Surveillance, Epidemiology and End Results(SEER)-Medicare database. Kaplan-Meier survival analysis determined 90-day and 1-year overall survival. Multivariable logistic regression assessed factors associated with short-term postoperative survival.

RESULTS

Overall survival for the 12,979 oldest-old patients undergoing elective colectomy for colon cancer was 93.4 and 85.7 %, at 90 days and 1 year. Older age, male gender, frailty, increased hospitalizations in prior year, and dementia were most strongly associated with decreased survival. In addition, AJCC stage III (vs stage I) disease and widowed (vs married) were highly associated with decreased survival at 1 year. Although only 4.4 % of patients were considered frail, this had the strongest association with mortality, with an odds ratio of 8.4 (95 % confidence interval, 6.4-11.1).

CONCLUSIONS

Although most oldest-old colon cancer patients do well after elective colectomy, a significant proportion (6.6 %) die by postoperative day 90 and frailty is the strongest predictor. The ability to identify frailty through billing claims is intriguing and suggests the potential to prospectively identify, through the electronic medical record, patients at highest risk of decreased survival.

Cocaine-induced cardiotoxicity in vitro

A growing number of reports have related cocaine use with the onset of myocardial infarction in young otherwise healthy individuals. Although the cardiac effects of cocaine have traditionally been attributed to sympathomimetic stimulation, several studies have suggested that cocaine may be directly cardiotoxic. The purpose of this study was to evaluate the cardiotoxic effects of cocaine in an in vitro preparation devoid of sympathetic innervation. Primary cultures of rat cardiac muscle and non-muscle cells were prepared from hearts excised from 3-5-day-old Sprague-Dawley rats. Cultures were exposed to various cocaine concentrations (1 x 10(-7)-1 x 10(-3)m) for 1-24 hr. Beating activity, morphological status and lactate dehydrogenase (LDH) leakage were evaluated following cocaine exposure. A decrease in the beating activity of cultured muscle cells was observed 1 hr after exposure to the highest cocaine concentrations (1 x 10(-5)-1 x 10(-3)m) tested. Similar results were obtained 24 hr after exposure. Morphological alterations in muscle cells were evident only after exposure to the highest concentration (1 x 10(-3)m). Vacuoles appeared 1 hr after cocaine exposure and were replaced by dark granules within 24 hr. LDH release was significantly elevated in the muscle cell cultures exposed to 1 x 10(-3)m cocaine for 24 hr. The pattern of cocaine-induced morphological alterations and enzyme leakage was similar in non-muscle cells. These data suggest that cocaine induces direct toxic effects on both cardiac muscle and non-muscle cells maintained in an environment free of neuronal and hormonal influences.

Formation of amino acids and nucleotide bases in a Titan atmosphere simulation experiment

The discovery of large (>100 u) molecules in Titan's upper atmosphere has heightened astrobiological interest in this unique satellite. In particular, complex organic aerosols produced in atmospheres containing C, N, O, and H, like that of Titan, could be a source of prebiotic molecules. In this work, aerosols produced in a Titan atmosphere simulation experiment with enhanced CO (N(2)/CH(4)/CO gas mixtures of 96.2%/2.0%/1.8% and 93.2%/5.0%/1.8%) were found to contain 18 molecules with molecular formulae that correspond to biological amino acids and nucleotide bases. Very high-resolution mass spectrometry of isotopically labeled samples confirmed that C(4)H(5)N(3)O, C(4)H(4)N(2)O(2), C(5)H(6)N(2)O(2), C(5)H(5)N(5), and C(6)H(9)N(3)O(2) are produced by chemistry in the simulation chamber. Gas chromatography-mass spectrometry (GC-MS) analyses of the non-isotopic samples confirmed the presence of cytosine (C(4)H(5)N(3)O), uracil (C(5)H(4)N(2)O(2)), thymine (C(5)H(6)N(2)O(2)), guanine (C(5)H(5)N(5)O), glycine (C(2)H(5)NO(2)), and alanine (C(3)H(7)NO(2)). Adenine (C(5)H(5)N(5)) was detected by GC-MS in isotopically labeled samples. The remaining prebiotic molecules were detected in unlabeled samples only and may have been affected by contamination in the chamber. These results demonstrate that prebiotic molecules can be formed by the high-energy chemistry similar to that which occurs in planetary upper atmospheres and therefore identifies a new source of prebiotic material, potentially increasing the range of planets where life could begin.

Surgical treatment of colon cancer in patients aged 80 years and older : analysis of 31,574 patients in the SEER-Medicare database

BACKGROUND

Age-related disparities in colon cancer treatment exist, with older patients being less likely to receive recommended therapy. However, to the authors' knowledge, few studies to date have focused on receipt of surgery. The objective of the current study was to describe patterns of surgery in patients aged ≥ 80 years with colon cancer and examine outcomes with and without colectomy.

METHODS

Medicare beneficiaries aged ≥ 80 years with colon cancer who were diagnosed between 1992 and 2005 were identified from the Surveillance, Epidemiology, and End Results-Medicare database. Multivariable logistic regression analysis was used to assess factors associated with nonoperative management. Kaplan-Meier survival analysis determined 1-year overall and colon cancer-specific survival.

RESULTS

Of 31,574 patients, 80% underwent colectomy. Approximately 46% were diagnosed during an urgent/emergent hospital admission, with decreased 1-year overall survival (70% vs 86% for patients diagnosed during an elective admission) noted among these individuals. Factors found to be most predictive of nonoperative management included older age, black race, more hospital admissions, use of home oxygen, use of a wheelchair, being frail, and having dementia. For both operative and nonoperative patients, the 1-year overall survival rate was lower than the colon cancer-specific survival rate (operative patients: 78% vs 89%; nonoperative patients: 58% vs 78%).

CONCLUSIONS

The majority of older patients with colon cancer undergo surgery, with improved outcomes noted compared with nonoperative management. However, many patients who are not selected for surgery die of unrelated causes, reflecting good surgical selection. Patients undergoing surgery during an urgent/emergent admission have an increased short-term mortality risk. Because the earlier detection of colon cancer may increase the percentage of older patients undergoing elective surgery, the findings of the current study may have policy implications for colon cancer screening and suggest that age should not be the only factor driving cancer screening recommendations.

Monitoring diabetes in patients with and without rheumatoid arthritis: a Medicare study

Introduction

Diabetes mellitus is a key predictor of mortality in rheumatoid arthritis (RA) patients. Both RA and diabetes increase the risk of cardiovascular disease (CVD), yet understanding of how comorbid RA impacts the receipt of guideline-based diabetes care is limited. The purpose of this study was to examine how the presence of RA affected hemoglobin A1C (A1c) and lipid measurement in older adults with diabetes.

Methods

Using a retrospective cohort approach, we identified beneficiaries ≥65 years old with diabetes from a 5% random national sample of 2004 to 2005 Medicare patients (N = 256,331), then examined whether these patients had comorbid RA and whether they received guideline recommended A1c and lipid testing in 2006. Multivariate logistic regression was used to examine the effect of RA on receiving guideline recommended testing, adjusting for baseline sociodemographics, comorbidities and health care utilization.

Results

Two percent of diabetes patients had comorbid RA (N = 5,572). Diabetes patients with comorbid RA were more likely than those without RA to have baseline cardiovascular disease (such as 17% more congestive heart failure), diabetes-related complications including kidney disease (19% higher), lower extremity ulcers (77% higher) and peripheral vascular disease (32% higher). In adjusted models, diabetes patients with RA were less likely to receive recommended A1c testing (odds ratio (OR) 0.84, CI 0.80 to 0.89) than those without RA, but were slightly more likely to receive lipid testing (OR 1.08, CI 1.01 to 1.16).

Conclusions

In older adults with diabetes, the presence of comorbid RA predicted lower rates of A1c testing but slightly improved lipid testing. Future research should examine strategies to improve A1c testing in patients with diabetes and RA, in light of increased CVD and microvascular risks in patients with both conditions.

Outpatient diverticulitis: mild or myth?

BACKGROUND

Diverticulitis is considered common in the outpatient population, with mild variants of described diagnostic criteria: left lower quadrant pain, fever, and leukocytosis. Here, expected criteria utilization among outpatients with a possible diagnosis of diverticulitis is assessed.

STUDY DESIGN

Primary care acute clinic visits in 2008 for diverticulitis (ICD-9 562.11/562.13) or left lower quadrant pain (789.04) were identified among patients ≥ 40 years old. Encounters were reviewed through structured manual chart abstraction and evaluated for diagnostic accuracy compared to expected criteria. Analysis included inter-rater reliability (kappa tests) and descriptive frequencies by diagnosis code and diverticulitis rating (χ (2) tests).

RESULTS

A total of 376 acute visits were identified with codes for diverticulitis (n=97) or left lower quadrant pain (n=279). High inter-rater reliability was demonstrated for key clinical variables (kappa=0.84-1.0). Left lower quadrant pain was reported in >75% of patients, while temperature and white blood cell count data were frequently unavailable. Lack of these expected criteria resulted in low diagnostic accuracy ratings ("No/unlikely"-53.6% diverticulitis, 88.2% left lower quadrant pain, p<0.001).

CONCLUSIONS

This investigation raises concern for low accuracy in the outpatient diagnosis of diverticulitis due to inconsistent use of expected criteria, suggesting a smaller population with true diverticulitis than previously anticipated, or lack of criteria applicability in this setting.

Number of first-contact access components required to improve preventive service receipt in primary care homes

BACKGROUND

A fundamental aim of primary care redesign and the patient-centered medical home is improving access to care. Patients who report having a usual site of care and usual provider are more likely to receive preventive services, but less is known about the influence of specific components of first-contact access (e.g., availability of appointments, advice by telephone) on preventive services receipt.

OBJECTIVE

To examine the relationship between number of first-contact access components and receipt of recommended preventive services.

DESIGN

Secondary survey data analysis.

PARTICIPANTS

Five thousand five hundred and seven insured adults who had continuity with a usual primary care physician and participated in the 2003-2006 round of the Wisconsin Longitudinal Survey.

MAIN MEASURES

Using multivariable logistic regression, we calculated adjusted risk ratios, adjusted predicted probabilities and 95% confidence intervals for each preventive service.

KEY RESULTS

Experiencing more first-contact access components was significantly associated with a higher rate of receiving cholesterol tests, flu shots and prostate exams but not mammography. There was variation in the number of components needed (between two and seven) to achieve a significant difference.

CONCLUSIONS

Having an increasing number of first-access components in a primary care office may improve preventive services receipt, and more components may be required for those services requiring greater provider contact (e.g., prostate exam) versus those that require less (e.g., mammography). In primary care redesign, the largest gains in preventive services receipt likely will come with redesign of multiple components simultaneously. While our study is a necessary step towards broadly understanding the relationship between first-contact access and preventive service receipt, other important questions remain. Certain components may drive greater improvements in the receipt of different services, and the effect of some of these components may depend on individual patient characteristics. Further research is critical for understanding redesign strategies that may optimize preventive service delivery.

Receipt of monitoring of diabetes mellitus in older adults with comorbid dementia

OBJECTIVES

To examine the extent to which receipt of recommended monitoring of diabetes mellitus (DM) differed for participants with and without comorbid dementia, as well as the effect of other comorbidities on monitoring of DM in individuals with comorbid dementia.

DESIGN

Retrospective cohort study.

SETTING

Secondary analysis of 2005/2006 claims and enrollment data for a 5% national random sample of Medicare beneficiaries.

PARTICIPANTS

Two hundred eighty-eight thousand eight hundred five Medicare fee-for-service beneficiaries with a diagnosis of DM before 2006, 44,717 (16%) of whom had evidence of comorbid dementia in claims.

MEASUREMENTS

Established algorithms were used to determine whether patients received at least one glycosylated hemoglobin (HbA1c) test, one low-density lipoprotein cholesterol (LDL-C) test, and one annual eye examination in 2006 and to construct variables representing comorbidities common in DM, sociodemographic characteristics, and patterns of healthcare utilization.

RESULTS

In unadjusted and fully adjusted models, the presence of dementia reduced the likelihood of receiving HbA1c tests, LDL-C tests, and eye examinations, with effects being smallest for HbA1c tests. The effects of other comorbidities on DM monitoring in participants with dementia varied according to the nature of the comorbidity and the specific test.

CONCLUSION

Dementia reduces the likelihood that individuals with DM will receive recommended annual monitoring for DM. More research is needed to understand reasons for lower monitoring in this subgroup and how this affects functioning, adverse events, and quality of life.

Lipid testing in patients with rheumatoid arthritis and key cardiovascular-related comorbidities: a medicare analysis

OBJECTIVE

For patients with rheumatoid arthritis (RA) and comorbid cardiovascular disease (CVD), diabetes, or hyperlipidemia, annual lipid testing is recommended to reduce morbidity and mortality from comorbidities. Given trends encouraging complex patients to receive care in "medical homes," we examined associations between regularly seeing a primary care provider (PCP) and lipid testing in RA patients with cardiovascular-related comorbidities.

METHODS

We performed a retrospective cohort study examining a 5% random USA Medicare sample (2004-06) of beneficiaries over 65 years old with RA and concomitant CVD, diabetes, or hyperlipidemia (n = 16,893). We examined the relationship between receiving lipid testing in 2006 and having at least 1 PCP visit per year in 2004, 2005, and 2006 using multivariate regression.

RESULTS

Ninety percent of patients had prevalent CVD; 46% had diabetes, and 64% had hyperlipidemia. However, annual lipid testing was only performed in 63% of these RA patients. Thirty percent of patients saw a PCP less than once per year, despite frequent visits (mean >9) with other providers. Patients without at least 1 annual PCP visit were 16% less likely to have lipid testing. Increased age, complexity scores, hospitalization, and large town residence predicted decreased lipid testing.

CONCLUSIONS

Despite comorbid CVD, diabetes, or hyperlipidemia, 30% of Medicare RA patients saw a PCP less than once per year, and 1 in 3 lacked annual lipid testing. Findings support advocating primary care visits at least once per year. Remaining gaps in lipid testing suggest the need for additional strategies to improve lipid testing in at-risk RA patients.

Public reporting helped drive quality improvement in outpatient diabetes care among Wisconsin physician groups

Public reporting on the quality of ambulatory health care is growing, but knowledge of how physician groups respond to such reporting has not kept pace. We examined responses to public reporting on the quality of diabetes care in 409 primary care clinics within seventeen large, multispecialty physician groups. We determined that a focus on publicly reported metrics, along with participation in large or externally sponsored projects, increased a clinic's implementation of diabetes improvement interventions. Clinics were also more likely to implement interventions in more recent years. Public reporting helped drive both early implementation of a single intervention and ongoing implementation of multiple simultaneous interventions. To fully engage physician groups, accountability metrics should be structured to capture incremental improvements in quality, thereby rewarding both early and ongoing improvement activities.

Provider characteristics, clinical-work processes and their relationship to discharge summary quality for sub-acute care patients

BACKGROUND

Discharge summaries play a pivotal role in the transitional care of patients discharged to sub-acute care facilities, but the best ways to facilitate document completeness/quality remain unknown.

OBJECTIVE

To examine the relationship among clinical-work processes, provider characteristics, and discharge summary content to identify approaches that promote high-quality discharge documentation.

DESIGN

Retrospective cohort study.

SUBJECTS

All hip fracture and stroke patients discharged to sub-acute care facilities during 2003-2005 from a large Midwestern academic medical center (N = 489). Patients on hospice/comfort care were excluded.

MAIN MEASURES

We abstracted 32 expert-recommended components in four categories ('patient's medical course,' 'functional/cognitive ability at discharge,' 'future plan of care,' and 'name/contact information') from the discharge summaries of sample patients. We examined predictors for the number of included components within each category using Poisson regression models. Predictors included work processes (document completion in relation to discharge day; completion time of day) and provider characteristics (training year; specialty).

KEY RESULTS

Historical components (i.e., 'patient's medical course' category) were included more often than components that directly inform the admission orders in the sub-acute care facility (i.e., 'future plan of care'). In this latter category, most summaries included a discharge medication list (99%), disposition (90%), and instructions for follow-up (91%), but less frequently included diet (68%), activity instructions (58%), therapy orders (56%), prognosis/diagnosis communication to patient/family (15%), code status (7%), and pending studies (6%). 'Future plan of care' components were more likely to be omitted if a discharge summary was created >24 h after discharge (incident rate ratio = 0.91, 95% confidence interval = 0.84-0.98) or if an intern created the summary (0.90, 0.83-0.97).

CONCLUSION

Critical component omissions in discharge summaries were common, and were associated with delayed document creation and less experienced providers. More research is needed to understand the impact of discharge documentation quality on patient/system outcomes.

Hearing loss and older adults' perceptions of access to care

We investigated whether hard-of-hearing older adults were more likely to report difficulties and delays in accessing care and decreased satisfaction with healthcare access than those without hearing loss. The Wisconsin Longitudinal Study (2003-2006 wave, N = 6,524) surveyed respondents regarding hearing, difficulties/delays in accessing care, satisfaction with healthcare access, socio-demographics, chronic conditions, self-rated health, depression, and length of relationship with provider/site. We used multivariate regression to compare access difficulties/delays and satisfaction by respondents' hearing status (hard-of-hearing or not). Hard-of-hearing individuals comprised 18% of the sample. Compared to those not hard-of-hearing, hard-of-hearing individuals were significantly more likely to be older, male and separated/divorced. They had a higher mean number of chronic conditions, including atherosclerotic vascular disease, diabetes and depression. After adjustment for potential confounders, hard-of-hearing individuals were more likely to report difficulties in accessing healthcare (Odds Ratio 1.85; 95% Confidence Interval 1.19-2.88). Satisfaction with healthcare access was similar in both groups. Our findings suggest healthcare access difficulties will be heightened for more of the population because of the increasing prevalence of hearing loss. The prevalence of hearing loss in this data is low and our findings from a telephone survey likely underestimate the magnitude of access difficulties experienced by hard-of-hearing older adults. Further research which incorporates accessible surveys is needed. In the meantime, clinicians should pay particular attention to assessing barriers in healthcare access for hard-of-hearing individuals. Resources should be made available to proactively address these issues for those who are hard-of-hearing and to educate providers about the specific needs of this population.

Mortality by stage for right- versus left-sided colon cancer: analysis of surveillance, epidemiology, and end results--Medicare data

PURPOSE

Recent studies have reported increased mortality for right-sided colon cancers but had limited adjustment for patient characteristics and conflicting results by stage. We examined the relationship between colon cancer location (right- v left-side) and 5-year mortality by stage.

PATIENTS AND METHODS

We identified Medicare beneficiaries from 1992 to 2005 with American Joint Commission on Cancer stages I to III primary adenocarcinoma of the colon who underwent surgery for curative intent through Surveillance, Epidemiology, and End Results (SEER) -Medicare data. Adjusted hazard ratios (HRs) and 95% CIs for predictors of all-cause 5-year mortality were obtained by using Cox proportional hazards regression.

RESULTS

Of 53,801 patients, 67% had right-sided colon cancer. Patients with right-sided cancer were more likely to be older, to be women, to be diagnosed with a more advanced stage, and to have more poorly differentiated tumors. Adjusted Cox regression showed no significant difference in mortality between right- and left-sided cancers for all stages combined (HR, 1.01; 95% CI, 0.98 to 1.04; P = .598) or for stage I cancers (HR, 0.95; 95% CI, 0.88 to 1.03; P = .211). Stage II right-sided cancers had lower mortality than left-sided cancers (HR, 0.92; 95% CI, 0.87 to 0.97; P = .001), and stage III right-sided cancers had higher mortality (HR, 1.12; 95% CI, 1.06 to 1.18; P < .001).

CONCLUSION

When analysis was adjusted for multiple patient, disease, comorbidity, and treatment variables, no overall difference in 5-year mortality was seen between right- and left-sided colon cancers. However, within stage II disease, right-sided cancers had lower mortality; within stage III, right-sided cancers had higher mortality.

Adjuvant chemotherapy for stage II colon cancer with poor prognostic features

PURPOSE

Adjuvant chemotherapy is typically considered for patients with stage II colon cancer characterized by poor prognostic features, including obstruction, perforation, emergent admission, T4 stage, resection of fewer than 12 lymph nodes, and poor histology. Despite frequent use, the survival advantage conferred on patients with stage II disease by chemotherapy is yet unproven. We sought to determine the overall survival benefit of chemotherapy among patients with stage II colon cancer having poor prognostic features.

PATIENTS AND METHODS

A total of 43,032 Medicare beneficiaries who underwent colectomy for stage II and III primary colon adenocarcinoma diagnosed from 1992 to 2005 were identified from the Surveillance, Epidemiology, and End Results (SEER) -Medicare database. χ(2) and two-way analysis of variance were used to assess differences in patient- and disease-related characteristics. Five-year overall survival was examined using Kaplan-Meier survival analysis and Cox proportional hazards regression with propensity score weighting.

RESULTS

Of the 24,847 patients with stage II cancer, 75% had one or more poor prognostic features. Adjuvant chemotherapy was received by 20% of patients with stage II disease and 57% of patients with stage III disease. After adjustment, 5-year survival benefit from chemotherapy was observed only for patients with stage III disease (hazard ratio[HR], 0.64; 95% CI, 0.60 to 0.67). No survival benefit was observed for patients with stage II cancer with no poor prognostic features (HR, 1.02; 95% CI, 0.84 to 1.25) or stage II cancer with any poor prognostic features (HR, 1.03; 95% CI, 0.94 to 1.13).

CONCLUSION

Among Medicare patients identified with stage II colon cancer, either with or without poor prognostic features, adjuvant chemotherapy did not substantially improve overall survival. This lack of benefit must be considered in treatment decisions for similar older adults with colon cancer.

Preventive service gains from first contact access in the primary care home

BACKGROUND

The patient-centered medical home (PCMH) concept recently has garnered national attention as a means of improving the quality of primary care. Preventive services are one area in which the use of a PCMH is hoped to achieve gains, though there has been limited exploration of PCMH characteristics that can assist with practice redesign. The purpose of this study was to examine whether first-contact access characteristics of a medical home (eg, availability of appointments or advice by telephone) confer additional benefit in the receipt of preventive services for individuals who already have a longitudinal relationship with a primary care physician at a site of care.

METHODS

This was a secondary analysis examining data from 5507 insured adults with a usual physician who participated in the 2003 to 2006 round of the Wisconsin Longitudinal Study. Using logistic regression, we calculated the odds of receiving each preventive service, comparing individuals who had first-contact access with those without first-contact access.

RESULTS

Eighteen percent of the sample received care with first-contact access. In multivariable analyses, after adjustment, individuals who had first-contact access had higher odds of having received a prostate examination (odds ratio [OR], 1.62; 95% CI, 1.20-2.18), a flu shot (OR, 1.36; 95% CI, 1.01-1.82), and a cholesterol test (OR, 1.36; 95% CI, 1.01-1.82) during the past year. There was no significant difference in receipt of mammograms (OR, 1.23; 95% CI, 0.94-1.61).

CONCLUSIONS

In the primary care home, first-contact accessibility adds benefit, beyond continuity of care with a physician, in improving receipt of preventive services. Amid increasing primary care demands and finite resources available to translate the PCMH into clinic settings, there is a need for further studies of the interplay between specific PCMH principles and how they perform in practice.

Minority status and diabetes screening in an ambulatory population

OBJECTIVE

Ethnicity has been identified as a risk factor not only for having type 2 diabetes but for increased morbidity and mortality with the disease. Current American Diabetes Association (ADA) guidelines advocate screening high-risk minorities for diabetes. This study investigates the effect of minority status on diabetes screening practices in an ambulatory, insured population presenting for yearly health care.

RESEARCH DESIGN AND METHODS

This is a retrospective population-based study of patients in a large, Midwestern, academic group practice. Included patients were insured, had ≥1 primary care visit yearly from 2003 to 2007, and did not have diabetes but met ADA criteria for screening. Odds ratios (ORs), 95% confidence intervals (CI), and predicted probabilities were calculated to determine the relationship between screening with fasting glucose, glucose tolerance test, or hemoglobin A(1c) and patient and visit characteristics.

RESULTS

Of the 15,557 eligible patients, 607 (4%) were of high-risk ethnicity, 61% were female, and 86% were ≥45 years of age. Of the eight high-risk factors studied, after adjustment, ethnicity was the only factor not associated with higher diabetes screening (OR = 0.90 [95% CI 0.76-1.08]) despite more primary care visits in this group. In overweight patients <45 years, where screening eligibility is based on having an additional risk factor, high-risk ethnicity (OR 1.01 [0.70-1.44]) was not associated with increased screening frequency.

CONCLUSIONS

In an insured population presenting for routine care, high-risk minority status did not independently lead to diabetes screening as recommended by ADA guidelines. Factors other than insurance or access to care appear to affect minority-preventive care.

Building a diabetes screening population data repository using electronic medical records

There has been a rapid advancement of information technology in the area of clinical and population health data management since 2000. However, with the fast growth of electronic medical records (EMRs) and the increasing complexity of information systems, it has become challenging for researchers to effectively access, locate, extract, and analyze information critical to their research. This article introduces an outpatient encounter data framework designed to construct an EMR-based population data repository for diabetes screening research. The outpatient encounter data framework is developed on a hybrid data structure of entity-attribute-value models, dimensional models, and relational models. This design preserves a small number of subject-specific tables essential to key clinical constructs in the data repository. It enables atomic information to be maintained in a transparent and meaningful way to researchers and health care practitioners who need to access data and still achieve the same performance level as conventional data warehouse models. A six-layer information processing strategy is developed to extract and transform EMRs to the research data repository. The data structure also complies with both Health Insurance Portability and Accountability Act regulations and the institutional review board's requirements. Although developed for diabetes screening research, the design of the outpatient encounter data framework is suitable for other types of health service research. It may also provide organizations a tool to improve health care quality and efficiency, consistent with the "meaningful use" objectives of the Health Information Technology for Economic and Clinical Health Act.

Failure to rescue and mortality after reoperation for abdominal aortic aneurysm repair

OBJECTIVES

Complications after abdominal aortic aneurysm (AAA) repair resulting in reintervention increase mortality risk, but have not been well studied. Mortality after reintervention is termed failure to rescue and may reflect differences related to quality management of the complication. This study describes the relationship between reoperation and mortality and examines the effect of physician speciality on reintervention rates and failure to rescue after AAA repair.

METHODS

Data were extracted for 2616 patients who underwent intact AAA repair in 2005 to 2006 from a standard 5% random sample of all Medicare beneficiaries. Patient demographics, comorbidities, hospital characteristics, repair type, and speciality of operating surgeon were collected. Primary outcomes were 30-day reoperation and 30-day mortality. Logistic regression analysis identified characteristics predicting reoperation.

RESULTS

A total of 156 reoperations were required in 142 (4.2%) patients. Early mortality was far more likely for patients requiring reintervention than for those who did not (22.5% vs 1.5%; P < .0001). Of patients requiring reoperation, those requiring two or more interventions had an even higher mortality (54% vs 20%; P = .0007). Despite equivalent reoperation rates between specialities (vascular surgeons, 5.2%; others, 5.6%, P = .67), the mortality after reoperation was nearly half for vascular surgeons compared with other specialities (16.2% vs 32.3%; P = .04). The most common reason for reoperation was arterial complications (35.8%) accounting for the largest difference in mortality between vascular surgeons (30.7%) and other specialities (52.0%).

CONCLUSIONS

Postoperative complications requiring reoperation dramatically increase mortality after AAA repair. Despite similar complication rates, vascular surgeons showed lower mortality rates after reoperation.

Preclinical pharmacology of AZD2327: a highly selective agonist of the δ-opioid receptor

In the present article, we summarize the preclinical pharmacology of 4-{(R)-(3-aminophenyl)[4-(4-fluorobenzyl)-piperazin-1-yl]methyl}-N,N-diethylbenzamide (AZD2327), a highly potent and selective agonist of the δ-opioid receptor. AZD2327 binds with sub-nanomolar affinity to the human opioid receptor (K(i) = 0.49 and 0.75 nM at the C27 and F27 isoforms, respectively) and is highly selective (>1000-fold) over the human μ- and κ-opioid receptor subtypes as well as >130 other receptors and channels. In functional assays, AZD2327 shows full agonism at human δ-opioid receptors ([(35)S]GTPγ EC(50) = 24 and 9.2 nM at C27 and F27 isoforms, respectively) and also at the rat and mouse δ-opioid receptors. AZD2327 is active in a wide range of models predictive of anxiolytic activity, including a modified Geller-Seifter conflict test and social interaction test, as well as in antidepressant models, including learned helplessness. In animals implanted with microdialysis probes and then given an acute stressor by pairing electric shock delivery with a flashing light, there is an increase in norepinephrine release into the prefrontal cortex associated with this acute anxiety state. Both the benzodiazepine anxiolytic standard diazepam and AZD2327 blocked this norepinephrine release equally well, and there was no evidence of tolerance to these effects of AZD2327. Overall, these data support the role of the δ-opioid receptor in the regulation of mood, and data suggest that AZD2327 may possess unique antidepressant and anxiolytic activities that could make a novel contribution to the pharmacotherapy of psychiatric disorders.

Formation of NH3 and CH2NH in Titan's upper atmosphere

The large abundance of NH3 in Titan's upper atmosphere is a consequence of coupled ion and neutral chemistry. The density of NH3 is inferred from the measured abundance of NH4+. NH3 is produced primarily through reaction of NH2 with H2CN, a process neglected in previous models. NH2 is produced by several reactions including electron recombination of CH2NH2+. The density of CH2NH2+ is closely linked to the density of CH2NH through proton exchange reactions and recombination. CH2NH is produced by reaction of N(2D) and NH with ambient hydrocarbons. Thus, production of NH3 is the result of a chain of reactions involving non-nitrile functional groups and the large density of NH3 implies large densities for these associated molecules. This suggests that amine and imine functional groups may be incorporated as well in other, more complex organic molecules.

Intention to receive cancer screening in Native Americans from the Northern Plains

BACKGROUND

Native Americans are disproportionately affected by cancer morbidity and mortality. This study examined intention to receive cancer screening in a large sample of Native Americans from the Northern Plains, a region with high cancer mortality rates.

METHODS

A survey was administered orally to 975 individuals in 2004-2006 from three reservations and among the urban Native American community in the service region of the Rapid City Regional Hospital. Data analysis was conducted in 2009.

RESULTS

About 63% of the sample planned to receive cancer screening. In multivariate analyses, individuals who planned to receive cancer screening were women, responsible for four or more people, received physical examinations at least yearly and had received prior cancer screening. They also were more likely to hold the belief that most people would go through cancer treatment even though these treatments can be emotionally or physically uncomfortable. About 90% of those who did not plan to receive cancer screening would be more likely to intend to receive cancer screening if additional resources were available.

CONCLUSIONS

In an area of high cancer morbidity and mortality, over one-third of screening eligible individuals did not plan to receive cancer screening. Future research should evaluate the potential for improving cancer screening rates through interventions that seek to facilitate increased knowledge about cancer screening and access to cancer screening services in the community.