The relationship of individual comorbid chronic conditions to diabetes care quality

OBJECTIVE

Multimorbidity affects 26 million persons with diabetes, and care for comorbid chronic conditions may impact diabetes care quality. The aim of this study was to determine which chronic conditions were related to lack of achievement or achievement of diabetes care quality goals to determine potential targets for future interventions.

RESEARCH DESIGN AND METHODS

This is an exploratory retrospective analysis of electronic health record data for 23 430 adults, aged 18-75, with diabetes who were seen at seven Midwestern US health systems. The main outcome measures were achievement of six diabetes quality metrics in the reporting year, 2011 (glycated haemoglobin (HbA1c) control and testing, low-density lipoprotein control and testing, blood pressure control, kidney testing). Explanatory variables were 62 chronic condition indicators. Analyses were adjusted for baseline patient sociodemographic and healthcare utilization factors.

RESULTS

The 62 chronic conditions varied in their relationships to diabetes care goal achievement for specific care goals. Congestive heart failure was related to lack of achievement of cholesterol management goals. Obesity was related to lack of HbA1c and BP control. Mental health conditions were related to both lack of achievement and achievement of different care goals. Three conditions were related to lack of cholesterol testing, including congestive heart failure and substance-use disorders. Of 17 conditions related to achieving control goals, 16 were related to achieving HbA1c control. One-half of the comorbid conditions did not predict diabetes care quality.

CONCLUSIONS

Future interventions could target patients at risk for not achieving diabetes care for specific care goals based on their individual comorbidities.

Physician assistants and nurse practitioners perform effective roles on teams caring for Medicare patients with diabetes

One approach to the patient-centered medical home, particularly for patients with chronic illnesses, is to include physician assistants (PAs) and nurse practitioners (NPs) on primary care teams. Using Medicare claims and electronic health record data from a large physician group, we compared outcomes for two groups of adult Medicare patients with diabetes whose conditions were at various levels of complexity: those whose care teams included PAs or NPs in various roles, and those who received care from physicians only. Outcomes were generally equivalent in thirteen comparisons. In four comparisons, outcomes were superior for the patients receiving care from PAs or NPs, but in three other comparisons the outcomes were superior for patients receiving care from physicians only. Specific roles performed by PAs and NPs were associated with different patterns in the measure of the quality of diabetes care and use of health care services. No role was best for all outcomes. Our findings suggest that patient characteristics, as well as patients' and organizations' goals, should be considered when determining when and how to deploy PAs and NPs on primary care teams. Accordingly, training and policy should continue to support role flexibility for these health professionals.

Bivalirudin for the treatment of patients with confirmed or suspected heparin-induced thrombocytopenia

BACKGROUND

Heparin-induced thrombocytopenia (HIT) is an adverse immune-mediated response to unfractionated heparin and, less commonly, low molecular weight heparin. It is associated with a high thrombotic risk and the potential for limb and life-threatening complications. Argatroban is the only approved and currently available anticoagulant for HIT treatment in the USA.

OBJECTIVES

To report safety and efficacy outcomes with bivalirudin for HIT treatment.

METHODS

We retrospectively examined records from our registry of patients with a suspected, confirmed or previous history of HIT and who had received bivalirudin for anticoagulation in a single tertiary-care center over a 9-year period.

RESULTS

We identified 461 patients who received bivalirudin: 220 (47.7%) were surgical patients, and 241 (52.3%) were medical patients. Of this population, 107 (23.2%) were critically ill, and 109 (23.6%) were dialysis-dependent. Suspected, confirmed and previous history of HIT were reported in 262, 124 and 75 patients, respectively. Of 386 patients with suspected or confirmed HIT, 223 patients (57.8%) had thrombosis at HIT diagnosis. New thrombosis was identified in 21 patients (4.6%) while they were on treatment with therapeutic doses of bivalirudin. No patient required HIT-related amputation. Major bleeding occurred in 35 patients (7.6%). We found a significant increase in major bleeding risk in the critically ill population (13.1%; odds ratio 2.4, 95% confidence interval 1.2-4.9, P = 0.014). The 30-day all-cause mortality rate was 14.5% (67 patients), and eight of 67 (1.7%) deaths were HIT-related.

CONCLUSION

Bivalirudin may be an effective and safe alternative option for the treatment of both suspected and confirmed HIT, and appears to reduce the rate of HIT-related amputation.

Impact of the American College of Surgeons Oncology Group (ACOSOG) Z0011 trial on clinical management of the axilla in older breast cancer patients: a SEER-medicare analysis

BACKGROUND

American College of Surgeons Oncology Group (ACOSOG) Z0011 demonstrated that eligible breast cancer patients with positive sentinel lymph nodes (SLN) could be spared an axillary lymph node dissection (ALND) without sacrificing survival or local control. Although heralded as a ‘‘practice-changing trial,’’ some argue that the stringent inclusion criteria limit the trial’s clinical significance. The objective was to assess the potential impact of ACOSOG Z0011 on axillary surgical management of Medicare patients and examine current practice patterns.

METHODS

Medicare beneficiaries aged C66 years with nonmetastatic invasive breast cancer diagnosed from 2001 to 2007 were identified from the Surveillance, Epidemiology and End Results-Medicare database (n = 59,431). Eligibility for ACOSOG Z0011 was determined: SLN mapping, tumor\5 cm, no neoadjuvant treatment, breast conservation; number of positive nodes was determined. Actual surgical axillary management for eligible patients was assessed.

RESULTS

Twelve percent (6,942/59,431) underwent SLN mapping and were node positive. Overall, 2,637 patients (4.4 % (2,637/59,431) of the total cohort, but 38 % (2,637/6,942) of patients with SLN mapping and positive nodes) met inclusion criteria for ACOSOG Z0011, had 1 or 2 positive lymph nodes, and could have been spared an ALND. Of these 2,637 patients, 46 % received a completion ALND and 54 % received only SLN biopsy.

CONCLUSIONS

Widespread implementation of ACOSOG Z0011 trial results could potentially spare 38 % of older breast cancer patients who undergo SLN mapping with positive lymph nodes an ALND. However, 54 % of these patients are already managed with SLN biopsy alone, lessening the impact of this trial on clinical practice in older breast cancer patients.

LIM proteins in actin cytoskeleton mechanoresponse

The actin cytoskeleton assembles into branched networks or bundles to generate mechanical force for critical cellular processes such as establishment of polarity, adhesion, and migration. Stress fibers (SFs) are contractile actomyosin structures that physically couple to the extracellular matrix through integrin-based focal adhesions (FAs), thereby transmitting force into and across the cell. Recently, LIN-11, Isl1, and MEC-3 (LIM) domain proteins have been implicated in mediating this cytoskeletal mechanotransduction. Among the more well-studied LIM domain adapter proteins is zyxin, a dynamic component of both FAs and SFs. Here we discuss recent research detailing the mechanisms by which SFs adjust their structure and composition to balance mechanical forces and suggest ways that zyxin and other LIM domain proteins mediate mechanoresponse.

High-power beam transport through a hollow-core photonic bandgap fiber

We investigate the use of a seven-cell hollow-core photonic bandgap fiber for transport of CW laser radiation from a single-mode, narrow-linewidth, high-power fiber laser amplifier. Over 90% of the amplifier output was coupled successfully and transmitted through the fiber in a near-Gaussian mode, with negligible backreflection into the source. 100 W of power was successfully transmitted continuously without damage and 160 W of power was transmitted briefly before the onset of thermal lensing in the coupling optics.

Antihypertensive medication initiation among young adults with regular primary care use

BACKGROUND

Young adults with hypertension have the lowest prevalence of controlled blood pressure compared to middle-aged and older adults. Uncontrolled hypertension, even among young adults, increases future cardiovascular event risk. However, antihypertensive medication initiation is poorly understood among young adults and may be an important intervention point for this group.

OBJECTIVE

The purpose of this study was to compare rates and predictors of antihypertensive medication initiation between young adults and middle-aged and older adults with incident hypertension and regular primary care contact.

DESIGN

A retrospective analysis

PARTICIPANTS

Adults ≥ 18 years old (n = 10,022) with incident hypertension and no prior antihypertensive prescription, who received primary care at a large, Midwestern, academic practice from 2008-2011.

MAIN MEASURES

The primary outcome was time from date of meeting hypertension criteria to antihypertensive medication initiation, or blood pressure normalization without medication. Kaplan-Meier analysis was used to estimate the probability of antihypertensive medication initiation over time. Cox proportional-hazard models (HR; 95% CI) were fit to identify predictors of delays in medication initiation, with a subsequent subpopulation analysis for young adults (18-39 years old).

KEY RESULTS

After a mean follow-up of 20 (±13) months, 34% of 18-39 year-olds with hypertension met the endpoint, compared to 44% of 40-59 year-olds and 56% of ≥ 60 year-olds. Adjusting for patient and provider factors, 18-39 year-olds had a 44% slower rate of medication initiation (HR 0.56; 0.47-0.67) than ≥ 60 year-olds. Among young adults, males, patients with mild hypertension, and White patients had a slower rate of medication initiation. Young adults with Medicaid and more clinic visits had faster rates.

CONCLUSIONS

Even with regular primary care contact and continued elevated blood pressure, young adults had slower rates of antihypertensive medication initiation than middle-aged and older adults. Interventions are needed to address multifactorial barriers contributing to poor hypertension control among young adults.

Determining breast cancer axillary surgery within the surveillance epidemiology and end results-Medicare database

BACKGROUND

Use of sentinel lymph node biopsy (SLNB) is under-reported by cancer registries' "Scope of Regional Lymph Node Surgery" variable. In 2011, the Surveillance Epidemiology and End Results (SEER) Program recommended against its use to determine extent of axillary surgery, leaving a gap in the utilization of claims data for breast cancer research. The objective was to develop an algorithm using SEER registry and claims data to classify extent of axillary surgery for breast cancer.

METHODS

We analyzed data for 24,534 breast cancer patients. CPT codes and number of examined lymph nodes classified the extent of axillary surgery. The final algorithm was validated by comparing the algorithm derived extent of axillary surgery to direct chart review for 100 breast cancer patients treated at our breast center.

RESULTS

Using the algorithm, 13% had no axillary surgery, 56% SLNB and 31% axillary lymph node dissection (ALND). SLNB was performed in 77% of node negative patients and ALND in 72% of node positive. In our validation study, concordance between algorithm and direct chart review was 97%.

CONCLUSIONS

Given recognized inaccuracies in cancer registries' "Scope of Regional Lymph Node Surgery" variable, these findings have high utility for health services researchers studying breast cancer treatment.

Adjuvant chemotherapy for stage II right-sided and left-sided colon cancer: analysis of SEER-medicare data

BACKGROUND

Survival benefit from adjuvant chemotherapy is established for stage III colon cancer; however, uncertainty exists for stage II patients. Tumor heterogeneity, specifically microsatellite instability (MSI), which is more common in right-sided cancers, may be the reason for this observation. We examined the relationship between adjuvant chemotherapy and overall 5-year mortality for stage II colon cancer by location (right- vs left-side) as a surrogate for MSI.

METHODS

Using Surveillance, Epidemiology, and End Results (SEER)-Medicare data, we identified Medicare beneficiaries from 1992 to 2005 with AJCC stage II (n = 23,578) and III (n = 17,148) primary adenocarcinoma of the colon who underwent surgery for curative intent. Overall 5-year mortality was examined with Kaplan-Meier survival analysis and Cox proportional hazards regression with propensity score weighting.

RESULTS

It was found that 18 % of stage II patients (n = 2941) with right-sided cancer and 22 % (n = 1693) with left-sided cancer received adjuvant chemotherapy. After adjustment, overall 5-year survival benefit from chemotherapy was observed only for stage III patients (right-sided: hazard ratio [HR], 0.64; 95 % CI, 0.59-0.68; p < .001 and left-sided: HR, 0.61; 95 % CI, 0.56-0.68; p < .001). No survival benefit was observed for stage II patients with either right-sided (HR, 0.97; 95 % CI, 0.87-1.09; p = .64) or left-sided cancer (HR, 0.97; 95 % CI, 0.84-1.12; p = .68).

CONCLUSIONS

Among Medicare patients with stage II colon cancer, a substantial number receive adjuvant chemotherapy. Adjuvant chemotherapy did not improve overall 5-year survival for either right- or left-sided colon cancers. Our results reinforce existing guidelines and should be considered in treatment algorithms for older adults with stage II colon cancer.

Rehospitalization to primary versus different facilities following abdominal aortic aneurysm repair

OBJECTIVE

Reducing readmissions represents a unique opportunity to improve care and reduce health care costs and is the focus of major payers. A large number of surgical patients are readmitted to hospitals other than where the primary surgery was performed, resulting in clinical decisions that do not incorporate the primary surgeon and potentially alter outcomes. This study characterizes readmission to primary vs different hospitals after abdominal aortic aneurysm (AAA) repair and examines the implications with regard to mortality and cost.

METHODS

Patients who underwent open or endovascular aneurysm repair for AAA were identified from the Centers for Medicare and Medicaid Services Chronic Conditions Warehouse, a random 5% national sample of Medicare beneficiaries from 2005 to 2009. Outcomes for patients who underwent AAA repair and were readmitted within 30 days of initial discharge were compared based on readmission location (primary vs different hospital).

RESULTS

A total of 885 patients underwent AAA repair and were readmitted within 30 days. Of these, 626 (70.7%) returned to the primary facility, and 259 (29.3%) returned to a different facility. Greater distance from patient residence to the primary hospital was the strongest predictor of readmission to a different facility. Patients living 50 to 100 miles from the primary hospital were more likely to be readmitted to a different hospital compared with patients living <10 miles away (odds ratio, 8.50; P < .001). Patients with diagnoses directly related to the surgery (eg, wound infection) were more likely to be readmitted to the primary hospital, whereas medical diagnoses (eg, pneumonia and congestive heart failure) were more likely to be treated at a different hospital. There was no statistically significant difference in mortality between patients readmitted to a different or the primary hospital. Median total 30-day payments were significantly lower at different vs primary hospitals (primary, $11,978 vs different, $11,168; P = .04).

CONCLUSIONS

Readmission to a different facility after AAA repair is common and occurs more frequently than for the overall Medicare population. Patients travelling a greater distance for AAA repair are more likely to return to different vs the primary hospital when further care is required. For AAA repair, quality healthcare may be achieved at marginally lower cost and with greater patient convenience for selected readmissions at hospitals other than where the initial procedure was performed.

Publicly reported quality-of-care measures influenced Wisconsin physician groups to improve performance

Public reporting of how physicians and hospitals perform on certain quality of care measures is increasingly common, but little is known about whether such disclosures have an impact on the quality of care delivered to patients. We analyzed fourteen publicly reported quality of ambulatory care measures from 2004 to 2009 for the Wisconsin Collaborative for Healthcare Quality, a voluntary consortium of physician groups. We also fielded a survey of the collaborative's members and analyzed Medicare billing data to independently compare members' performance to that of providers in the rest of Wisconsin, neighboring states, and the rest of the United States. We found that physician groups in the collaborative improved their performance during the study period on many measures, such as cholesterol control and breast cancer screening. Physician groups reported on the survey that publicly reported performance data motivated them to act on some, but not all, of the quality measures. Our study suggests that large group practices will engage in quality improvement efforts in response to public reporting, especially when comparative performance is displayed, as it was in this case on the collaborative's website.

Colon Cancer Staging in Vulnerable Older Adults: Adherence to National Guidelines and Impact on Survival

BACKGROUND

There is concern that elders are not adequately evaluated prior to colon cancer surgery. We sought to determine adherence with ACOVE-3 (Assessing Care of Vulnerable Elders) quality indicators for pre-operative staging prior to colectomy for colon cancer utilizing the Surveillance, Epidemiology and End Results (SEER)-Medicare linked database (1992-2005).

METHODS

We determined the proportion of patients aged 75 and older who had preoperative staging prior to colectomy for colon adenocarcinoma. Preoperative staging was defined as abdominopelvic computed tomography or magnetic resonance imaging scan (SCAN) and colonoscopy or flexible sigmoidoscopy (SCOPE). Multivariate logistic regression identified predictors of adherence. Odds ratios were adjusted for comorbidity, socioeconomic status, and disease severity. The association of adherence to ACOVE-3 and survival was quantified.

RESULTS

Of the 37,862 patients, the majority were 75-84 years, 28% of the patients were ≥85 years. Regarding preoperative staging in the 6-month interval prior to surgical resection, 8% had neither SCAN nor SCOPE, 6% had only SCAN, 43% had only SCOPE, and 43% had both SCAN and SCOPE. Compared to patients who were not staged, those evaluated with either SCOPE alone or SCAN plus SCOPE had lower odds of 3-year mortality. Patients who were staged with SCAN alone had an increased odds of death compared to those who had neither SCAN or SCOPE.

CONCLUSIONS

These data demonstrate that the majority of vulnerable elders with colon cancer did not receive appropriate preoperative staging prior to resection. The findings also confirm that adherence to ACOVE-3 guidelines is associated with improved long-term survival.

Low-cost transitional care with nurse managers making mostly phone contact with patients cut rehospitalization at a VA hospital

The Coordinated-Transitional Care (C-TraC) Program was designed to improve care coordination and outcomes among veterans with high-risk conditions discharged to community settings from the William S. Middleton Memorial Veterans Hospital, in Madison, Wisconsin. Under the program, patients work with nurse case managers on care and health issues, including medication reconciliation, before and after hospital discharge, with all contacts made by phone once the patient is at home. Patients who received the C-TraC protocol experienced one-third fewer rehospitalizations than those in a baseline comparison group, producing an estimated savings of $1,225 per patient net of programmatic costs. This model requires a relatively small amount of resources to operate and may represent a viable alternative for hospitals seeking to offer improved transitional care as encouraged by the Affordable Care Act. In particular, the model may be attractive for providers in rural areas or other care settings challenged by wide geographic dispersion of patients or by constrained resources.

External community review committee: a new strategy for engaging community stakeholders in research funding decisions

BACKGROUND

Major gaps exist between what we know and what we do in clinical practice and community health programs and narrowing this gap will require substantive partnerships between academic researchers and the communities they serve.

OBJECTIVES

We describe a research pilot award program that makes a unique commitment to community engagement through the addition of an External Community Review Committee to the typical research review process that gives external stakeholders decision-making power over research funding.

METHODS

Whereas engaging community reviewers in discussion and rating of research proposals is not novel, the ICTR ECRC review process is distinct in that it is subsequent to peer review and uses different criteria and methodology. This method of engagement allows for the community review panel to re-rank scientifically meritorious proposals-such that proposals funded do not necessarily follow the rank order from scientific peer review. The approach taken by UW ICTR differs from those discussed in the literature that present a model of community-academic co-review.

RESULTS

This article provides guidance for others interested in this model of community engagement and reviews insights gained during the evolution of this strategy; including how we addressed conflict, how the committee was able to change the pilot award program over time, and individual roles that were crucial to the success of this approach.

CONCLUSIONS

The advantages of this approach include success through traditional academic metrics while achieving an innovative shared-power mechanism for community engagement which we believe is critical for narrowing the gap between knowledge and practice.

Patient demographic and tumor characteristics influencing oncologist follow-up frequency in older breast cancer survivors

BACKGROUND

Although recommendations for breast cancer follow-up frequency exist, current follow-up guidelines are standardized, without consideration of individual patient characteristics. Some studies suggest oncologists are using these characteristics to tailor follow-up recommendations, but it is unclear how this is translating into practice. The objective of this study was to examine current patterns of oncologist breast cancer follow-up and determine the association between patient and tumor characteristics and follow-up frequency.

METHODS

The Surveillance, Epidemiology, and End Results (SEER)-Medicare database was used to identify stage I-III breast cancer patients diagnosed 2000-2007 (n = 39,241). Oncologist follow-up visits were defined using Medicare specialty provider codes and the linked AMA Masterfile. Multinomial logistic regression determined the association between patient and tumor characteristics and oncologist follow-up visit frequency.

RESULTS

Younger age (p < 0.001), positive nodes (p < 0.001), estrogen receptor/progesterone receptor positivity (p < 0.001), and increasing treatment intensity (p < 0.001) were most strongly associated with more frequent follow-up. However, after accounting for these characteristics, significant variation in follow-up frequency was observed. In addition to patient factors, the number and types of oncologists involved in follow-up were associated with follow-up frequency (p < 0.001). Types of oncologists providing follow-up varied, with medical oncologists the sole providers of follow-up for 19-51 % of breast cancer survivors. Overall, 58 % of patients received surgical oncology, and 51 % undergoing radiation received radiation oncology follow-up, usually in combination with medical oncology.

CONCLUSIONS

Significant variation in breast cancer follow-up frequency exists. Developing follow-up guidelines tailored for patient, tumor, and treatment characteristics while also providing guidance on who should provide follow-up has the potential to increase clinical efficiency.

Synergistic activities of a silver(I) glutamic acid complex and reactive oxygen species (ROS): a novel antimicrobial and chemotherapeutic agent

The antimicrobial and chemotherapeutic activities of a silver(I) glutamic acid complex with the synergistic concomitant generation of reactive oxygen species (ROS) were investigated here. The ROS generation system employed was via Fenton chemistry. The antimicrobial and chemotherapeutic activities were investigated on Staphylococcus aureus ATCC 43300 and Escherichia coli bacteria, and Vero and MCF-7 tumor cell lines, respectively. Antimicrobial activities were conducted by determining minimum inhibitory concentration (MIC), while chemotherapeutic efficacies were done by serial dilution using standard techniques to determine the half maximal inhibitory concentration (IC50). The antimicrobial and chemotherapeutic results obtained were compared with positive control drugs gentamicin, oxacillin, penicillin, streptomycin and cisplatin, a ubiquitously used platinum-based antitumor drug, and with the silver(I) glutamic acid complex and hydrogen peroxide separately. Based on MIC and IC50 values, it was determined that this synergistic approach was very effective at extremely low concentrations, especially when compared with the other drugs evaluated here. This finding might be of great significance regarding metronomic dosing when this synergistic approach is clinically implemented. Since silver at low concentrations exhibits no toxic, mutagenic and carcinogenic activities, this might offer an alternative approach for the development of safer silver-based antimicrobial and chemotherapeutic drugs, thereby reducing or even eliminating the toxicity associated with current drugs. Accordingly, the present approach might be integrated into the systemic clinical treatment of infectious diseases and cancer.

Division of primary care services between physicians, physician assistants, and nurse practitioners for older patients with diabetes

Team-based care involving physician assistants and/or nurse practitioners (PA/NPs) in the patient-centered medical home is one approach to improving care quality. However, little is known about how to incorporate PA/NPs into primary care teams. Using data from a large physician group, we describe the division of patients and services (e.g., acute, chronic, preventive, other) between primary care providers for older diabetes patients on panels with varying levels of PA/NP involvement (i.e., no role, supplemental provider, or usual provider of care). Panels with PA/NP usual providers had higher proportions of patients with Medicaid, disability, and depression. Patients with physician usual providers had similar probabilities of visits with supplemental PA/NPs and physicians for all service types. However, patients with PA/NP usual providers had higher probabilities of visits with a supplemental physician. Understanding how patients and services are divided between PA/NPs and physicians will assist in defining provider roles on primary care teams.

Predictors of colorectal cancer screening variation among primary-care providers and clinics

OBJECTIVES

Colorectal cancer (CRC) screening is underutilized. To effect change, we must understand reasons for underuse at multiple levels of the health-care system. We evaluated patient, provider, and clinic factors that predict variation in CRC screening among primary-care clinics and primary-care providers (PCPs).

METHODS

We analyzed electronic medical record (EMR) data for 34,319 adults eligible for CRC screening, 19 clinics, and 97 PCPs in a large, academic physician group. Detailed data on potential patient, provider, and clinic predictors of CRC screening were obtained from the EMR. PCP perceptions of CRC screening barriers were measured via survey. The outcome was completion of CRC screening at the patient level. Multivariate logistic regression with clustering on clinics obtained adjusted odds ratios and 95% confidence intervals for potential predictors of CRC screening at each level.

RESULTS

Seventy-one percentage of patients completed CRC screening. Variation in screening rates was seen among clinics (51-80%) and among PCPs (51-82%). Significant predictors of completing CRC screening were identified at all levels: patient (older age, white race, being married, primarily English-speaking, having commercial insurance plans vs. Medicare or Medicaid, and higher health-care resource utilization), provider (larger panel size of patients eligible for CRC screening), and clinic (hospital-owned, shorter distance to nearest optical colonoscopy center).

CONCLUSIONS

Variation in CRC screening exists among primary-care clinics and providers within a single clinic. Predictors of variation can be identified at patient, provider, and clinic levels. Quality improvement interventions addressing CRC screening need to be directed at multiple levels of the health-care system.

Mechanism of allopurinol induced TPMT inhibition

Up to 1/5 of patients with wildtype thiopurine-S-methyltransferase (TPMT) activity prescribed azathioprine (AZA) or mercaptopurine (MP) demonstrate a skewed drug metabolism in which MP is preferentially methylated to yield methylmercaptopurine (MeMP). This is known as thiopurine hypermethylation and is associated with drug toxicity and treatment non-response. Co-prescription of allopurinol with low dose AZA/MP (25-33%) circumvents this phenotype and leads to a dramatic reduction in methylated metabolites; however, the biochemical mechanism remains unclear. Using intact and lysate red cell models we propose a novel pathway of allopurinol mediated TPMT inhibition, through the production of thioxanthine (TX, 2-hydroxymercaptopurine). In red blood cells pre-incubated with 250 μM MP for 2h prior to the addition of 250 μM TX or an equivalent volume of Earle's balanced salt solution, there was a significant reduction in the concentration of MeMP detected at 4h and 6h in cells exposed to TX (4 h, 1.68, p=0.0005, t-test). TX acts as a direct TPMT inhibitor with an apparent Ki of 0.329 mM. In addition we have confirmed that the mechanism is relevant to in vivo metabolism by demonstrating raised urinary TX levels in patients receiving combination therapy. We conclude that the formation of TX in patients receiving combination therapy with AZA/MP and allopurinol, likely explains the significant reduction of methylated metabolites due to direct TPMT inhibition.

Neurofilaments are the major neuronal target of hydroxynonenal-mediated protein cross-links

Lipid peroxidation generates reactive aldehydes, most notably hydroxynonenal (HNE), which covalently binds amino acid residue side chains leading to protein inactivation and insolubility. Specific adducts of lipid peroxidation have been demonstrated to be intimately associated with pathological lesions of Alzheimer's disease (AD), suggesting that oxidative stress is a major component in the disease. Here, we examined the HNE-cross-linking modifications by using an antibody specific for a lysine-lysine cross-link. Since in a prior study we noted no immunolabeling of neuritic plaques or neurofibrillary tangles but instead found strong labeling of axons, we focused this study on axons. Axonal labeling was examined in mouse sciatic nerve, and immunoblotting showed the cross-link was restricted to neurofilament heavy and medium subunits, which while altering migration, did not indicate larger NF aggregates, indicative of intermolecular cross-links. Examination of mice at various ages showed the extent of modification remaining relatively constant through the life span. These findings demonstrate lipid-cross-linking peroxidation primarily involves lysine-rich neurofilaments and is restricted to intramolecular cross-links.

Abstract 351: Predictors of Delays to Antihypertensive Medication Initiation Among Young Adults with Regular Primary Care Use

Background: In the U.S., young adults (18-39 years old) continue to have low rates of hypertension control (38%) compared to middle-aged and older adults (54%). Although lifestyle modification counseling is a critical step in hypertension treatment, antihypertensive medication initiation is crucial for young adults who remain hypertensive, especially with Stage 2 hypertension (≥160/100 mmHg). However, young adults have low rates of antihypertensive medication initiation and the factors driving delays in medication initiation among young adults who are regular users of primary care are not well understood. The purpose of this study is to compare the rates of antihypertensive medication initiation among age groups and determine predictors of delays in antihypertensive medication initiation among young adults.

Methods: This is a retrospective analysis of 14,974 patients, ≥18 years old, receiving regular primary care in a large, Midwestern, academic group practice from 2008 - 2011. Patients were included upon meeting JNC7 clinical criteria for Stage 1 (≥140-159/90-99 mmHg) or Stage 2 hypertension and followed up to 4 years. Patients with a previous antihypertensive prescription were excluded. Cox proportional hazard models (HR; 95% CI) stratified by hypertension stage, were fit overall and separately for young adults 18-39 years old to identify predictors of delays in antihypertensive medication initiation.

Results: After 4 years, 51% overall (4,149 of 8,125) were prescribed antihypertensive medication and 69% (1,650 of 2,403) among those with Stage 2 hypertension; 43% of hypertensive young adults (18-39 yrs; 846 of 1,988) were prescribed medication, 62% (339 of 547) among those with Stage 2. Among age groups, 43% of 18-39 year olds (846 of 1,988) received antihypertensive treatment within 4 years, compared to 53% (40-59 yrs; 2,223 of 4,216) and 56% (≥60 yrs; 1,080 of 1,921). Adjusting for patient factors, blood pressure lability (i.e., intermittently normal blood pressures), and provider factors, adults 18-24 years old had a 50% slower rate of medication initiation (HR 0.5; 0.4-0.7) than ≥60 year olds. Adults 25-31 years (HR 0.6; 0.5-0.7) and 32-39 years (HR 0.8; 0.7-0.9) also had slower rates of medication initiation. When analyses were limited to young adults, higher urgent care use, White race, labile blood pressures, and non-English primary language were associated with slower rates of medication initiation. Young adults with diabetes, Medicaid and more specialty visits had faster rates.

Conclusions: There are delays in antihypertensive medication initiation for young adults with multifactorial causes. Addressing poor hypertension control rates among young adults should target key factors related to delays, while continuing lifestyle modification counseling.

B vitamins and cognitive performance in older adults: review

A copious amount of scientific scrutiny has been dedicated to documenting typical and atypical human ageing, with a substantial body of work focusing upon the impact of lifestyle choices. One such lifestyle choice is that of diet and, in particular, micronutrient ingestion. Epidemiological studies have reported positive associations between B vitamin status and cognitive function, including negative associations between biological markers (i.e., homocysteine) of dysregulated one-carbon metabolism and cognitive function. This has led to a surge of randomised control trials (RCTs) investigations into B vitamin therapy. However, results have continuingly failed to show beneficial behavioural effects. Despite this, results reliably show treatment-related increases in B vitamin level and decreases in homocysteine level—both of which have been identified as risk factors for atypical ageing. In this paper we argue that it would be premature to conclude that B vitamin therapy has no potential and that more research is needed to systematically investigate the optimal dose, the therapeutic “window,” and individual differences in therapy responders and nonresponders. We start with a brief look at one-carbon metabolism and then consider the evidence from epidemiological studies and RCTs in relation to three specific B vitamins: folic acid (B9), pyridoxine (B6), and cobamides (B12).