Advancing Pharmacological Treatments for Opioid Use Disorder (ADaPT-OUD): an Implementation Trial in Eight Veterans Health Administration Facilities

BACKGROUND

Identifying effective strategies to improve access to medication treatments for opioid use disorder (MOUD) is imperative. Within the Veterans Health Administration (VHA), provision of MOUD varies significantly, requiring development and testing of implementation strategies that target facilities with low provision of MOUD.

OBJECTIVE

Determine the effectiveness of external facilitation in increasing the provision of MOUD among VHA facilities with low baseline provision of MOUD compared to matched controls.

DESIGN

Pre-post, block randomized study designed to compare facility-level outcomes in a stratified sample of eligible facilities. Four blocks (two intervention facilities in each) were defined by median splits of both the ratio of patients with OUD receiving MOUD and number of patients with OUD not currently receiving MOUD (i.e., number of actionable patients). Intervention facilities participated in a 12-month implementation intervention.

PARTICIPANTS

VHA facilities in the lowest quartile of MOUD provision (35 facilities), eight of which were randomly assigned to participate in the intervention (two per block) with twenty-seven serving as matched controls by block.

INTERVENTION

External facilitation included assessment of local barriers/facilitators, formation of a local implementation team, a site visit for action planning and training/education, cross-facility quarterly calls, monthly coaching calls, and consultation.

MAIN MEASURES

Pre- to post-change in the facility-level ratio of patients with an OUD diagnosis receiving MOUD compared to control facilities.

KEY RESULTS

Intervention facilities significantly increased the ratio of patients with OUD receiving MOUD from an average of 18% at baseline to 30% 1 year later, with an absolute difference of 12% (95% confidence interval [CI]: 6.6%, 17.0%). The difference in differences between intervention and control facilities was 3.0% (95% CI: - 0.2%. 6.7%). The impact of the intervention varied by block, with smaller, less complex facilities more likely to outperform matched controls.

CONCLUSIONS

Intensive external facilitation improved the adoption of MOUD in most low-performing facilities and may enhance adoption beyond other interventions less tailored to individual facility contexts.

Early impacts of a multi-faceted implementation strategy to increase use of medication treatments for opioid use disorder in the Veterans Health Administration

BACKGROUND

Despite the risk of negative sequelae from opioid use disorder (OUD) and clinical guidelines for the use of effective medication treatment for OUD (M-OUD), many Veterans Health Administration (VHA) providers and facilities lag in providing M-OUD. An intensive external facilitation intervention may enhance uptake in low-adopting VHA facilities by engaging stakeholders from multiple clinical settings within a facility (e.g., mental health, primary care, pain specialty clinic, substance use disorder clinics). Our study identified pre-intervention determinants of implementation through qualitative interviews, described strategies employed during the first 6 months of intensive external facilitation, and explored patterns of implementation determinants in relation to early outcomes.

METHODS

Guided by the integrated-Promoting Action on Research Implementation in Health Services (i-PARIHS) framework, we interviewed stakeholders at low-adopting VHA facilities prior to external facilitation, employed a rapid qualitative analytic process, presented findings during facility visits, and collaboratively created facilitation action plans to achieve goals set by the facilities that would increase M-OUD uptake. The primary outcome was the Substance Use Disorder (SUD)-16, which is a VHA facility-level performance metric consisting of the percent of patients receiving M-OUD among those with an OUD diagnosis. We examined the relationship between pre-implementation factors and 6-month SUD-16 outcomes.

RESULTS

Across eight VHA facilities, we interviewed 68 participants. Implementation determinants included barriers and facilitators across innovation, context, and recipients constructs of i-PARIHS. Each facility selected goals based on the qualitative results. At 6 months, two facilities achieved most goals and two facilities demonstrated progress. The SUD-16 from baseline to 6 months significantly improved in two facilities (8.4% increase (95 % confidence interval [CI] 4.4-12.4) and 9.9% increase (95% CI 3.6-16.2), respectively). Six-month implementation outcomes showed that the extent to which M-OUD aligns with existing clinical practices and values was a primary factor at all facilities, with six of eight facilities perceiving it as both a barrier and facilitator. External health system barriers were most challenging for facilities with the smallest change in SUD-16.

CONCLUSIONS

Early impacts of a multi-faceted implementation approach demonstrated a strong signal for positively impacting M-OUD prescribing in low-adopting VHA facilities. This signal indicates that external facilitation can influence adoption of M-OUD at the facility level in the early implementation phase. These short-term wins experienced by stakeholders may encourage continued adoption and long-term sustainability M-OUD.

Complementary, Integrative, and Nondrug Therapy Use for Pain Among US Military Veterans on Long-term Opioids

BACKGROUND

Long-term opioid therapy for chronic pain arose amid limited availability and awareness of other pain therapies. Although many complementary and integrative health (CIH) and nondrug therapies are effective for chronic pain, little is known about CIH/nondrug therapy use patterns among people prescribed opioid analgesics.

OBJECTIVE

The objective of this study was to estimate patterns and predictors of self-reported CIH/nondrug therapy use for chronic pain within a representative national sample of US military veterans prescribed long-term opioids for chronic pain.

RESEARCH DESIGN

National two-stage stratified random sample survey combined with electronic medical record data. Data were analyzed using logistic regressions and latent class analysis.

SUBJECTS

US military veterans in Veterans Affairs (VA) primary care who received ≥6 months of opioid analgesics.

MEASURES

Self-reported use of each of 10 CIH/nondrug therapies to treat or cope with chronic pain in the past year: meditation/mindfulness, relaxation, psychotherapy, yoga, t'ai chi, aerobic exercise, stretching/strengthening, acupuncture, chiropractic, massage; Brief Pain Inventory-Interference (BPI-I) scale as a measure of pain-related function.

RESULTS

In total, 8891 (65%) of 13,660 invitees completed the questionnaire. Eighty percent of veterans reported past-year use of at least 1 nondrug therapy for pain. Younger age and female sex were associated with the use of most nondrug therapies. Higher pain interference was associated with lower use of exercise/movement therapies. Nondrug therapy use patterns reflected functional categories (psychological/behavioral, exercise/movement, manual).

CONCLUSIONS

Use of CIH/nondrug therapies for pain was common among patients receiving long-term opioids. Future analyses will examine nondrug therapy use in relation to pain and quality of life outcomes over time.

The evaluating prescription opioid changes in veterans (EPOCH) study: Design, survey response, and baseline characteristics

In the United States (US), long-term opioid therapy has been commonly prescribed for chronic pain. Since recognition of the opioid overdose epidemic, clinical practice guidelines have recommended tapering long-term opioids to reduced doses or discontinuation. The Effects of Prescription Opioid Changes for veterans (EPOCH) study is a national population-based prospective observational study of US Veterans Health Administration primary care patients designed to assess effects of evolving opioid prescribing practice on patients treated with long-term opioids for chronic pain. A stratified random sampling design was used to identify a survey sample from the target population of patients treated with opioid analgesics for ≥ 6 months. Demographic, diagnostic, visit, and pharmacy dispensing data were extracted from existing datasets. A 2016 mixed-mode mail and telephone survey collected patient-reported data, including the main patient-reported outcomes of pain-related function (Brief Pain Inventory interference; BPI-I scores 0–10, higher scores = worse) and health-related quality of life. Data on survey participants and non-participants were analyzed to assess potential nonresponse bias. Weights were used to account for design. Linear regression models were used to assess cross-sectional associations of opioid treatment with patient-reported measures. Of 14,160 patients contacted, 9253 (65.4%) completed the survey. Participants were older than non-participants (63.9 ± 10.6 vs. 59.6 ± 13.0 years). The mean number of bothersome pain locations was 6.8 (SE 0.04). Effectiveness of pain treatment and quality of pain care were rated fair or poor by 56.1% and 45.3%, respectively. The opioid daily dosage range was 1.6 to 1038.2 mg, with mean = 50.6 mg (SE 1.1) and median = 30.9 mg (IQR 40.7). Among the 73.2% of patients who did not receive long-acting opioids, the mean daily dosage was 30.4 mg (SE 0.6) and mean BPI-I was 6.4 (SE 00.4). Among patients who received long-acting opioids, the mean daily dosage was 106.2 mg (SE 2.8) and mean BPI-I was 6.8 (SE 0.07). Higher daily dosage was associated with worse pain-related function and quality of life among patients without long-acting opioids, but not among patients with long-acting opioids. Future analyses will use follow-up data to examine effects of opioid dose reduction and discontinuation on patient outcomes.

Cost-effectiveness of population-level proactive tobacco cessation outreach among socio-economically disadvantaged smokers: evaluation of a randomized control trial

AIMS

To estimate the cost-effectiveness at population-level of the OPT-IN proactive tobacco cessation outreach program for adult smokers enrolled in publicly funded health insurance plans for low-income persons (e.g. Medicaid).

DESIGN

Cost-effectiveness analysis using a state transition model based on data from the Offering Proactive Treatment Intervention (OPT-IN) randomized control trial.

SETTING

The trial was conducted in Minnesota, USA, and the economic analysis was conducted from the Medicaid program perspective.

PARTICIPANTS

Data were used from 2406 smokers who were randomized into the intervention or comparator groups.

INTERVENTION AND COMPARATOR

The intervention was comprised of proactive outreach (mailed invitation and telephone calls) and free cessation treatment (nicotine replacement therapy and intensive telephone counseling). The comparator was usual care, which comprised access to a primary care physician, insurance coverage of Food and Drug Administration (FDA)-approved smoking cessation medications and the state's telephone quitline.

MEASUREMENTS

Smoking status, quality of life and health-care use at varying times, including at baseline and 1 year.

FINDINGS

The OPT-IN program cost an average of $84 per participant greater than the comparator. One year after randomization, the population-level, 6-month prolonged smoking abstinence rate was 16.5% in the proactive outreach intervention group and 12.1% in the usual care group (P < 0.05). The model projected that the proactive outreach intervention added $78 in life-time cost and generated 0.005 additional quality-adjusted life-years (QALYs), with an expected incremental cost-effectiveness ratio of $4231 per QALY. Probabilistic sensitivity analysis found that the proactive outreach intervention would be cost-effective against a willingness-to-pay threshold of $50 000/QALY approximately 68% of the time.

CONCLUSIONS

Population-level proactive tobacco treatment with personal telephone outreach was effective in achieving higher population-level quit rates and was cost-effective at various willingness-to-pay thresholds, compared with usual care (i.e. reactive treatment). Taken together with prior research, population-level proactive tobacco cessation outreach programs are judged to be highly cost-effective over the long term.

A Proactive Smoking Cessation Intervention for Socioeconomically Disadvantaged Smokers: The Role of Smoking-Related Stigma

Introduction

Smoking denormalization has been paralleled by reduced smoking prevalence, but smoking rates among socioeconomically disadvantaged populations remain high. The social unacceptability of smoking has also led to increased perceptions of smoking-related stigma. By examining how smoking stigma influences cessation intervention effectiveness, we can better tailor interventions to socioeconomically disadvantaged smokers.

Aims and Methods

Data are from a randomized controlled trial evaluating the effectiveness of a proactive cessation intervention on abstinence. Current smokers enrolled in Minnesota Health Care Programs were randomized to proactive outreach (n = 1200) or usual care (n = 1206). The intervention included mailings, telephone outreach, counseling, and access to free cessation treatments. Using baseline measurements, groups with lower (n = 1227) and higher (n = 1093) perceived stigma were formed. Intervention, stigma, and their interaction term were added to a logistic regression modeling abstinence at 12 months.

Results

Lower perceived smoking-related stigma was associated with less support for quitting, lower rates of physician quitting advice, and less motivation for quitting. A logistic regression modeling abstinence found a significant intervention × stigma interaction. The proactive intervention was more effective among smokers with lower perceived smoking-related stigma (odds ratio 1.94, 95% confidence interval, 1.29 to 2.92) than those with higher perceived smoking-related stigma (odds ratio 1.04, 95% confidence interval, 0.70 to 1.55).

Discussion

Smokers with lower perceived smoking-related stigma had social environments that were conducive to smoking, received less physician advice to quit, and were less motivated to quit than higher stigma smokers. Despite these barriers, the intervention was more effective for lower stigma smokers, suggesting that proactive outreach is an efficient treatment for these hard-to-reach smokers.

Implications

Smoking denormalization has led to increased perceptions of smoking-related stigma among many smokers; however, little is known about how this stigma influences the cessation process. In the present study, smokers with lower levels of perceived smoking-related stigma lived in social environments that were more conducive to smoking and were less motivated to quit than higher stigma smokers. Despite these barriers, our proactive outreach cessation intervention was more effective for lower stigma smokers, suggesting that interventions which utilize proactive outreach to stimulate interest in quitting and offer facilitated access to free cessation treatments are an effective treatment approach for these hard-to-reach smokers. These strategies may be particularly effective for motivating smokers enrolled in government-subsidized health insurance programs to take advantage of cessation resources.

Which patients initiate cognitive processing therapy and prolonged exposure in department of veterans affairs PTSD clinics?

The United States Department of Veterans Affairs (VA) provides Cognitive Processing Therapy (CPT) and Prolonged Exposure therapy (PE) for PTSD at all of its facilities, but little is known about systematic differences between patients who do and do not initiate these treatments. VA administrative data were analyzed for 6,251 veterans receiving psychotherapy over one year in posttraumatic stress disorder (PTSD) specialty clinics at nine VA medical centers. CPT and PE were initiated by 2,173 (35%) patients. Veterans' probability of initiating either CPT or PE (considered together) was 29% lower (adjusted odds ratio = .61) if they had a psychiatric hospitalization within the same year, and 15% lower (AOR = .78) if they had service-connected disability for PTSD. Veterans' probability of starting CPT or PE was 19% lower (AOR = .74) if they were Hispanic or Latino, 10% lower (AOR = .84), if they were male rather than female, and 9% lower (AOR = .87) if they were divorced, separated or widowed rather than currently married. Probability of receiving CPT or PE was also lower if verans had more co-occurring psychiatric diagnoses (AOR per diagnosis = .88), were older (AOR per every five years = .95), or lived further away from the VA clinic (AOR per every ten miles = .98). Nonetheless, most patients initiating CPT or PE had two or more comorbidities and were service-connected for PTSD. Observed gender, age and ethnic differences in initiation of CPT and PE appear unrelated to clinical suitability and warrant further study.

The relationship between smoking cessation and binge drinking, depression, and anxiety symptoms among smokers with serious mental illness

INTRODUCTION

Concerns about the adverse effects of smoking cessation on alcohol use and mental health are a barrier to cessation for smokers with serious mental illness (SMI). The purpose of this study is to examine how incident smoking cessation affects binge drinking and symptoms of depression and anxiety among smokers with SMI.

METHODS

The present study is a secondary analysis of the OPTIN trial, which demonstrated the effectiveness of proactive outreach for smoking cessation among Minnesota Health Care Programs enrollees. Participants with ICD-9 codes indicating schizophrenia spectrum disorders, psychotic disorders, bipolar disorders, or severe/recurrent major depressive disorder were categorized as having SMI (n = 939); remaining smokers were categorized as non-SMI (n = 1382). Multivariable regressions modeled the association between incident smoking cessation and binge drinking, PHQ-2 depression scores, and PROMIS anxiety scores in the two groups.

RESULTS

Quitting smoking was not associated with binge drinking among those with SMI, but was associated with less binge drinking among those without SMI (p = 0.033). Quitting smoking was not associated with PHQ-2 depression scores among those with or without SMI. However, quitting smoking was associated with lower mean PROMIS anxiety scores for those with SMI (p = 0.031), but not those without SMI.

CONCLUSION

Quitting smoking was not associated with heightened binge drinking or symptoms of depression and anxiety among smokers with SMI. These findings suggest that quitting smoking is not detrimental for these patients, and provide evidential support for facilitating access to cessation resources for patients with serious mental illness who smoke.

Validating the use of veterans affairs tobacco health factors for assessing change in smoking status: accuracy, availability, and approach

BACKGROUND

Accurate smoking status is key for research purposes, but can be costly and difficult to measure. Within the Veteran's Health Administration (VA), smoking status is recorded as part of routine care as "health factors" (HF)-fields that researchers can query through the electronic health record (EHR). Many researchers are interested in using these fields to track changes in smoking status over time, however the validity of this measure for assessing change is unknown. The primary goal of this project was to examine whether HFs can be used to accurately measure change in tobacco status over time, with secondary goals of assessing the optimum timeframe for assessment and variation in accuracy by site.

METHODS

Secondary analysis of the Veterans VICTORY study, a pragmatic smoking cessation randomized controlled trial conducted from 2009 to 2011. Eligible subjects were identified via the EHR using a past 90-day HF indicating current tobacco use (for example: "CURRENT SMOKER", "CURRENTLY USES TOBACCO"). Participants were surveyed at 1 year to determine prolonged smoking abstinence. We identified HFs for tobacco status within +/- 120 days of the follow-up survey mailing date and recorded the temporally closest HF. Among subjects with both measures, we compared the two for agreement using kappa statistics and concordance.

RESULTS

1713 subjects (33%) had both follow-up survey and HF data, 1594 (31%) had only a survey response, 790 (15%) had only HF and 1026 (20%) had neither. For subjects with both measures, there was 90% concordance and moderate agreement (Kappa 0.48, 95%CI 0.41-0.55, Sensitivity 54.4, 95%CI 41.1-67.7, Specificity 94.3, 95%CI 87.5-100.0).

CONCLUSIONS

We found high concordance but only moderate agreement by kappa statistics between HFs and survey data. The difference is likely accounted for by the natural history of quit attempts, in which patients cycle in and out of quit attempts. HFs appear to provide an accurate measure of population level quit behavior utilizing data collected in the course of clinical care.

Proactive tobacco treatment for individuals with and without a mental health diagnosis: Secondary analysis of a pragmatic randomized controlled trial

INTRODUCTION

Individuals with (vs. without) mental illness use tobacco at higher rates and have more difficulty quitting. Treatment models for smokers with mental illness are needed.

METHODS

This secondary analysis of the Victory Over Tobacco study [a pragmatic randomized clinical trial (N=5123) conducted in 2009-2011 of Proactive Care (proactive outreach plus connection to smoking cessation services) vs. Usual Care] tests the effectiveness of treatment assignment in participants with and without a mental health diagnosis on population-level, 6month prolonged abstinence at one year follow-up.

RESULTS

Analyses conducted in 2015-6 found that there was no interaction between treatment group and mental health group on abstinence (F(1,3300=1.12, p=0.29)). Analyses stratified by mental health group showed that those without mental illness, assigned to Proactive Care, had a significantly higher population-level abstinence rate than those assigned to Usual Care (OR=1.40, 95% CI=1.17-1.67); in those with mental illness, assignment to Proactive Care produced a non-significant increase in abstinence compared to Usual Care (OR=1.18, 95% CI=0.98-1.41). Those with mental illness reported more medical visits, cessation advice and treatment (p<0.001), similar levels of abstinence motivation (p>0.05), but lower abstinence self-efficacy (p<0.001).

CONCLUSIONS

Those with a mental health diagnosis benefitted less from proactive outreach regarding tobacco use. VA primary care patients with mental illness may not need additional outreach because they are connected to cessation resources during medical appointments. This group may also require more intensive cessation interventions targeting self-efficacy to improve cessation rates. Clinicaltrials.gov registration # NCT00608426.

Treatment barriers among younger and older socioeconomically disadvantaged smokers

OBJECTIVES

Underutilization of smoking cessation treatments contributes to high rates of smoking in socioeconomically disadvantaged populations. Guided by a conceptual framework, the present study explored how healthcare provider factors, social environment characteristics, and cessation beliefs influence treatment utilization among low-income smokers and whether these associations vary by age.

STUDY DESIGN

Analyses were conducted on baseline data from 2406 participants enrolled in a randomized controlled trial that evaluated the effectiveness of a proactive outreach cessation intervention among a sample of younger (18-34 years) and older (35-64 years) smokers enrolled in public healthcare assistance programs.

METHODS

Multivariable logistic regression models predicted past year cessation treatment utilization (CTU) among younger and older smokers. Independent variables included measures of healthcare provider barriers, social environment characteristics, and cessation beliefs.

RESULTS

Younger smokers were less likely to have CTU than older smokers (27.2% vs 36.2%; P <.001). In both groups, number of cigarettes per day, more problems accessing healthcare, receiving medication-related cessation advice, and readiness to quit were positively associated with CTU (P <.05). Among younger smokers, living with another smoker was associated with lower odds of CTU while receipt of cessation advice was associated (P = .033) with higher odds of CTU.

CONCLUSIONS

In this sample of low-income smokers, interest in quitting was high but treatment utilization was low. Increasing utilization of cessation treatments via interventions that target issues specific to low-income smokers, including healthcare provider access and advice, the home environment, and motivation to quit, is an important step toward reducing smoking rates in this population.

What factors do patients consider most important in making lung cancer screening decisions? Findings from a demonstration project conducted in the Veterans Health Administration

INTRODUCTION

The National Lung Screening Trial recently reported that annual low-dose computed tomography screening is associated with decreased lung cancer mortality in high-risk smokers. This study sought to identify the factors patients consider important in making lung cancer screening (LCS) decisions, and explore variations by patient characteristics and LCS participation.

MATERIAL AND METHODS

This observational survey study evaluated the Minneapolis VA LCS Clinical Demonstration Project in which LCS-eligible Veterans (N=1388) were randomized to either Direct LCS Invitation (mailed with decision aid, N=926) or Usual Care (provider referral, N=462). We surveyed participants three months post-randomization (response rate 44%) and report the proportion of respondents rating eight decision-making factors (benefits, harms, and neutral factors) as important by condition, patient characteristics, and LCS completion.

RESULTS

Overall, the most important factor was personal risk of lung cancer and the least important factor was health risks from LCS. The reported importance varied by patient characteristics, including smoking status, health status, and education level. Overall, the potential harms of LCS were reported less important than the benefits or the neutral decision-making factors. Exposure to Direct LCS Invitation (with decision aid) increased Veterans' attention to specific decision-making factors; compared to Usual Care respondents, a larger proportion of Direct LCS Invitation respondents rated the chance of false-positive results, LCS knowledge, LCS convenience, and anxiety as important. Those completing LCS considered screening harms less important, with the exception of incidental findings.

CONCLUSION

Decision tools influence Veterans' perceptions about LCS decision-making factors. As the factors important to LCS decision making vary by patient characteristics, targeted materials for specific subgroups may be warranted. Attention should be paid to how LCS incidental findings are communicated.

Telehealth by an Interprofessional Team in Patients With CKD: A Randomized Controlled Trial

BACKGROUND

Telehealth and interprofessional case management are newer strategies of care within chronic disease management. We investigated whether an interprofessional team using telehealth was a feasible care delivery strategy and whether this strategy could affect health outcomes in patients with chronic kidney disease (CKD).

STUDY DESIGN

Randomized clinical trial.

SETTING & PARTICIPANTS

Minneapolis Veterans Affairs Health Care System (VAHCS), St. Cloud VAHCS, and affiliated clinics March 2012 to November 2013 in patients with CKD (estimated glomerular filtration rate < 60mL/min/1.73m(2)).

INTERVENTIONS

Patients were randomly assigned to receive an intervention (n=451) consisting of care by an interprofessional team (nephrologist, nurse practitioner, nurses, clinical pharmacy specialist, psychologist, social worker, and dietician) using a telehealth device (touch screen computer with peripherals) or to usual care (n=150).

OUTCOMES

The primary end point was a composite of death, hospitalization, emergency department visits, or admission to skilled nursing facilities, compared to usual care.

RESULTS

Baseline characteristics of the overall study group: mean age, 75.1±8.1 (SD) years; men, 98.5%; white, 97.3%; and mean estimated glomerular filtration rate, 37±9mL/min/1.73m(2). Telehealth and interprofessional care were successfully implemented with meaningful engagement with the care system. One year after randomization, 208 (46.2%) patients in the intervention group versus 70 (46.7%) in the usual-care group had the primary composite outcome (HR, 0.98; 95% CI, 0.75-1.29; P=0.9). There was no difference between groups for any component of the primary outcome: all-cause mortality (HR, 1.46; 95% CI, 0.42-5.11), hospitalization (HR, 1.15; 95% CI, 0.80-1.63), emergency department visits (HR, 0.92; 95% CI, 0.68-1.24), or nursing home admission (HR, 3.07; 95% CI, 0.71-13.24).

LIMITATIONS

Older population, mostly men, potentially underpowered/wide CIs.

CONCLUSIONS

Telehealth by an interprofessional team is a feasible care delivery strategy in patients with CKD. There was no statistically significant evidence of superiority of this intervention on health outcomes compared to usual care.

Proactive tobacco treatment offering free nicotine replacement therapy and telephone counselling for socioeconomically disadvantaged smokers: a randomised clinical trial

Background

Evidenced-based tobacco cessation treatments are underused, especially by socioeconomically disadvantaged smokers. This contributes to widening socioeconomic disparities in tobacco-related morbidity and mortality.

Methods

The Offering Proactive Treatment Intervention trial tested the effects of a proactive outreach tobacco treatment intervention on population-level smoking abstinence and tobacco treatment use among a population-based sample of socioeconomically disadvantaged smokers. Current smokers (n=2406), regardless of interest in quitting, who were enrolled in the Minnesota Health Care Programs, the state's publicly funded healthcare programmes for low-income populations, were randomly assigned to proactive outreach or usual care. The intervention comprised proactive outreach (tailored mailings and telephone calls) and free cessation treatment (nicotine replacement therapy and intensive, telephone counselling). Usual care comprised access to a primary care physician, insurance coverage of Food and Drug Administration-approved smoking cessation medications, and the state's telephone quitline. The primary outcome was self-reported 6-month prolonged smoking abstinence at 1 year and was assessed by follow-up survey.

Findings

The proactive intervention group had a higher prolonged abstinence rate at 1 year than usual care (16.5% vs 12.1%, OR 1.47, 95% CI 1.12 to 1.93). The effect of the proactive intervention on prolonged abstinence persisted in selection models accounting for non-response. In analysis of secondary outcomes, use of evidence-based tobacco cessation treatments were significantly greater among proactive outreach participants compared with usual care, particularly combination counselling and medications (17.4% vs 3.6%, OR 5.69, 95% CI 3.85 to 8.40).

Interpretation

Population-based proactive tobacco treatment increases engagement in evidence-based treatment and is effective in long-term smoking cessation among socioeconomically disadvantaged smokers. Findings suggest that dissemination of population-based proactive treatment approaches is an effective strategy to reduce the prevalence of smoking and socioeconomic disparities in tobacco use.

Trial registration number

NCT01123967.

Smoking cessation among African American and white smokers in the Veterans Affairs health care system

OBJECTIVES

We examined whether a proactive care smoking cessation intervention designed to overcome barriers to treatment would be especially effective at increasing cessation among African Americans receiving care in the Veterans Health Administration.

METHODS

We analyzed data from a randomized controlled trial, the Veterans Victory over Tobacco study, involving a population-based electronic registry of current smokers (702 African Americans, 1569 whites) and assessed 6-month prolonged smoking abstinence at 1 year via a follow-up survey of all current smokers. We also examined candidate risk adjustors for the race effect on smoking abstinence.

RESULTS

The interaction between patient race and intervention condition (proactive care vs. usual care) was not significant. Overall, African Americans had higher quit rates than Whites (13% vs. 9%; P < .006) regardless of condition.

CONCLUSIONS

African Americans quit at higher rates than Whites. These findings may be a result of the large number of veterans receiving smoking cessation services and the lack of racial differences in receipt of these services as well as racial differences in smoking history, self-efficacy, and motivation to quit that favor African Americans.

Proactive tobacco treatment and population-level cessation: a pragmatic randomized clinical trial

IMPORTANCE

Current tobacco use treatment approaches require smokers to request treatment or depend on the provider to initiate smoking cessation care and are therefore reactive. Most smokers do not receive evidence-based treatments for tobacco use that include both behavioral counseling and pharmacotherapy.

OBJECTIVE

To assess the effect of a proactive, population-based tobacco cessation care model on use of evidence-based tobacco cessation treatments and on population-level smoking cessation rates (ie, abstinence among all smokers including those who use and do not use treatment) compared with usual care among a diverse population of current smokers.

DESIGN, SETTING, AND PARTICIPANTS

The Veterans Victory Over Tobacco Study, a pragmatic randomized clinical trial involving a population-based registry of current smokers aged 18 to 80 years. A total of 6400 current smokers, identified using the Department of Veterans Affairs (VA) electronic medical record, were randomized prior to contact to evaluate both the reach and effectiveness of the proactive care intervention.

INTERVENTIONS

Current smokers were randomized to usual care or proactive care. Proactive care combined (1) proactive outreach and (2) offer of choice of smoking cessation services (telephone or in-person). Proactive outreach included mailed invitations followed by telephone outreach to motivate smokers to seek treatment with choice of services.

MAIN OUTCOMES AND MEASURES

The primary outcome was 6-month prolonged smoking abstinence at 1 year and was assessed by a follow-up survey among all current smokers regardless of interest in quitting or treatment utilization.

RESULTS

A total of 5123 participants were included in the primary analysis. The follow-up survey response rate was 66%. The population-level, 6-month prolonged smoking abstinence rate at 1 year was 13.5% for proactive care compared with 10.9% for usual care (P = .02). Logistic regression mixed model analysis showed a significant effect of the proactive care intervention on 6-month prolonged abstinence (odds ratio [OR], 1.27 [95% CI, 1.03-1.57]). In analyses accounting for nonresponse using likelihood-based not-missing-at-random models, the effect of proactive care on 6-month prolonged abstinence persisted (OR, 1.33 [95% CI, 1.17-1.51]).

CONCLUSIONS AND RELEVANCE

Proactive, population-based tobacco cessation care using proactive outreach to connect smokers to evidence-based telephone or in-person smoking cessation services is effective for increasing long-term population-level cessation rates.

TRIAL REGISTRATION

clinicaltrials.gov Identifier: NCT00608426.

Is Policy Well-Targeted to Remedy Financial Strain among Caregivers of Severely Injured U.S. Service Members?

U.S. military service members have sustained severe injuries since the start of the wars in Iraq and Afghanistan. This paper aims to determine the factors associated with financial strain of their caregivers and establish whether recent federal legislation targets caregivers experiencing financial strain. In our national survey, 62.3% of caregivers depleted assets and/or accumulated debt, and 41% of working caregivers left the labor force. If a severely injured veteran needed intensive help, the primary caregiver faced odds 4.63 times higher of leaving the labor force, and used $27,576 more in assets and/or accumulated debt compared to caregivers of veterans needing little or no assistance.

Population-based tobacco treatment: study design of a randomized controlled trial

Background

Most smokers do not receive comprehensive, evidence-based treatment for tobacco use that includes intensive behavioral counseling along with pharmacotherapy. Further, the use of proven, tobacco treatments is lower among minorities than among Whites. The primary objectives of this study are to: (1) Assess the effect of a proactive care intervention (PRO) on population-level smoking abstinence rates (i.e., abstinence among all smokers including those who use and do not utilize treatment) and on utilization of tobacco treatment compared to reactive/usual care (UC) among a diverse population of smokers, (2) Compare the effect of PRO on population-level smoking abstinence rates and utilization of tobacco treatments between African American and White smokers, and (3) Determine the cost-effectiveness of the proactive care intervention.

Methods/Design

This prospective randomized controlled trial identifies a population-based sample of current smokers from the Department of Veterans Affairs (VA) electronic medical record health factor dataset. The proactive care intervention combines: (1) proactive outreach and (2) offer of choice of smoking cessation services (telephone or face-to-face). Proactive outreach includes mailed invitation materials followed by an outreach call that encourages smokers to seek treatment with choice of services. Proactive care participants who choose telephone care receive VA telephone counseling and access to pharmacotherapy. Proactive care participants who choose face-to-face care are referred to their VA facility's smoking cessation clinic. Usual care participants have access to standard smoking cessation services from their VA facility (e.g., pharmacotherapy, smoking cessation clinic) and from their state telephone quitline. Baseline data is collected from VA administrative databases and participant surveys. Outcomes from both groups are collected 12 months post-randomization from participant surveys and from VA administrative databases. The primary outcome is self-reported smoking abstinence, which is assessed at the population-level (i.e., among those who utilize and those who do not utilize tobacco treatment). Primary analyses will follow intention-to-treat methodology.

Discussion

This randomized trial is testing proactive outreach strategies offering choice of smoking cessation services, an innovation that if proven effective and cost-effective, will transform the way tobacco treatment is delivered. National dissemination of proactive treatment strategies could dramatically reduce tobacco-related morbidity, mortality, and health care costs.

Clinical trials registration

ClinicalTrials.gov: NCT00608426.

Effect of nurse case management compared with usual care on controlling cardiovascular risk factors in patients with diabetes: a randomized controlled trial

OBJECTIVE

To determine whether nurse case management with a therapeutic algorithm could effectively improve rates of control for hypertension, hyperglycemia, and hyperlipidemia compared with usual care among veterans with diabetes.

RESEARCH DESIGN AND METHODS

A randomized controlled trial of diabetic patients that had blood pressure (BP) >140/90 mmHg, hemoglobin A(1c) (HbA(1c)) >9.0%, or LDL >100 mg/dL. Intervention patients received case management (n = 278) versus usual care (n = 278) over a 1-year period. The primary outcome was the percentage of patients achieving simultaneous control of all three parameters (defined by BP <130/80 mmHg, HbA(1c) <8.0%, and LDL <100 mg/dL) at 1 year. Secondary outcomes included improvements within each individual component of the composite primary outcome. Differences between groups were analyzed using t tests, Pearson χ(2) tests, and linear and logistic regression.

RESULTS

A greater number of individuals assigned to case management achieved the primary study outcome of having all three outcome measures under control (61 [21.9%] compared with 28 [10.1%] in the usual care group [P < 0.01]). In addition, a greater number of individuals assigned to the intervention group achieved the individual treatment goals of HbA(1c) <8.0% (73.7 vs. 65.8%, P = 0.04) and BP <130/80 mmHg (45.0 vs. 25.4%, P < 0.01), but not for LDL <100 mg/dL (57.6 vs. 55.4%, P = 0.61), compared with those in the usual care group.

CONCLUSIONS

In patients with diabetes, nurse case managers using a treatment algorithm can effectively improve the number of individuals with control of multiple cardiovascular risk factors at 1 year.

The magnitude of acute serum creatinine increase after cardiac surgery and the risk of chronic kidney disease, progression of kidney disease, and death

BACKGROUND

Long-term outcomes after acute kidney injury remain poorly defined. We determined the association between the magnitude of creatinine increase after cardiac surgery and the risk of incident chronic kidney disease (CKD), CKD progression, and death.

METHODS

We identified 29,388 individuals who underwent cardiac surgery at Veterans Affairs hospitals between November 1999 and September 2005. The magnitude of creatinine increase was defined by the percent change from baseline to peak creatinine levels after cardiac surgery and categorized as none (≤0%) or as class I, (1%-24%), II (25%-49%), III (50%-99%), or IV (≥100%). Cox proportional hazard models were used to examine the association between the magnitude of creatinine increase and outcomes.

RESULTS

The relative hazards for outcomes increased monotonically with greater increases in creatinine levels compared with no change in creatinine levels. The relative hazards for adverse outcomes were significantly higher immediately after the creatinine increase and attenuated over time. Three months after surgery, creatinine increase classes I, II, III, and IV were associated with a greater risk of incident CKD (hazard ratios [HRs] 2.1, 4.0, 5.8, and 6.6, respectively; all P<.01), progression of CKD stage (HRs 2.5, 3.8, 4.4, and 8.0; all P<.01), and long-term mortality (HRs 1.4, 1.9, 2.8, and 5.0; all P<.01). At 5 years, the associations were lower in magnitude: incident CKD (HRs 1.4, 1.9, 2.3, and 2.3; all P<.01), CKD progression (HRs 1.5, 1.7, 1.7, and 2.4; all P<.01), and mortality (HRs 1.0, 1.2, 1.4, and 1.8; all P<.01, except class I).

CONCLUSION

The magnitude of creatinine increase after cardiac surgery is associated in a graded manner with an increased risk of incident CKD, CKD progression, and mortality.

Periodontal infection and preterm birth: successful periodontal therapy reduces the risk of preterm birth

OBJECTIVE

This study tested the hypothesis that successful periodontal treatment was associated with a reduction in the incidence of spontaneous preterm birth (PTB).

DESIGN

This was a randomised, controlled, blinded clinical trial.

SETTING

Hospital outpatient clinic.

POPULATION

Pregnant women of 6-20 weeks of gestation were eligible.

METHODS

Of 322 pregnant women with periodontal disease, 160 were randomly assigned to receive scaling and root planing (SRP, cleaning above and below the gum line), plus oral hygiene instruction, whereas the remaining 162 received only oral hygiene instruction and served as an untreated control group. Subjects received periodontal examinations before and 20 weeks after SRP, and were classified blindly according to the results of treatment into two groups: successful ('non-exposure') and unsuccessful ('exposure') treatment. Groups were compared using standard inferential statistics; dichotomous variables were compared using the chi-square test or logistic regression. Results are presented in terms of odds ratios.

MAIN OUTCOME MEASURE

The main outcome measure was spontaneous preterm birth before 35 weeks of gestation.

RESULTS

No significant difference was found between the incidence of PTB in the control group (52.4%; n = 162) and the periodontal treatment group (45.6%; n = 160) (P < 0.13, Fisher's exact test). The incidence of PTB was compared within the periodontal treatment group, considering the success of therapy. A logistic regression analysis showed a strong and significant relationship between successful periodontal treatment and full-term birth (adjusted odds ratio 6.02; 95% CI 2.57-14.03). Subjects refractory to periodontal treatment were significantly more likely to have PTB.

CONCLUSIONS

A beneficial effect on PTB may be dependent on the success of periodontal treatment.

Periodontal disease and pregnancy outcomes: exposure, risk and intervention

Despite the many advances in medicine, the rate of preterm birth has not significantly decreased in the United States over the past several decades. In fact, the rate rose in 2003 to more than 12% of all births in the United States. This equates to over half a million premature births in the United States alone. Consequently, the identification of risk factors for preterm birth which are amenable to intervention would have far-reaching and long-lasting effects. There is emerging evidence of a relationship between periodontal health and adverse pregnancy outcomes, particularly preterm birth/preterm low-birth-weight infants. Therefore this chapter explores the putative association between periodontal disease and infant prematurity, as well as the results of intervention studies which treated periodontal disease in order to reduce the incidence of prematurity. Of 31 published studies, 22 show a positive association between premature birth and periodontal disease. Ongoing studies are addressing the efficacy of periodontal treatment for decreasing the incidence of infant prematurity.

Use of mental health treatment among veterans filing claims for posttraumatic stress disorder

This study examines predictors of current mental health service use in a sample of 154 veterans filing claims for Veterans Affairs (VA) disability benefits based on Posttraumatic Stress Disorder (PTSD). Our conceptual framework was the behavioral model that classifies predictors of service utilization into predisposing (background), enabling (e.g., insurance) and need (e.g., symptoms) factors. Slightly more than half of the PTSD claimants were receiving mental health treatment at the time of claim initiation. Mean symptom levels were clinically significant in both users and nonusers of mental health treatment. In a multivariate logistic regression analysis, mental health treatment use was associated with younger age, marriage, and dependence on public insurance. Implications for future research are discussed.

The impact of CCA-treated posts in vineyards on soil and ground water

Grapes in Marlborough are typically grown on a vertical shoot positioned trellis system (VSP). For this purpose Pinus radiata posts are treated with CCA, a mixture of copper (Cu), chromium (Cr) and arsenic (As), giving a wood concentration of 1,730, 3,020 and 2,410 mg/kg, respectively on a dry matter basis. The CCA levels around the posts in different soils were investigated and assessed for the potential leaching of CCA into ground water. An initial survey showed leaching of all three heavy metals from the treated posts into the soil surrounding the posts (0.2% of the total vineyard area) compared with the control, depending on vineyard age and soil type. The rate of movement out of the posts was calculated from posts placed in lysimeters. HortResearch's Soil Plant Atmosphere Model (SPASMO) was used to predict the leaching rate of CCA. For As, leaching was found to be 5 mg/post/month, with the Cr rate being about twice that. Further modelling revealed a steady plume of As moving downwards after about 200-300 years. However, long-term hydrogeological modelling showed that sufficient aquifer water flow prevented the accumulation of CCA in the ground water. The modelling approaches are discussed.

Promoting repeat tobacco dependence treatment: are relapsed smokers interested?

BACKGROUND

Promotion of repeat tobacco dependence treatment among relapsed smokers interested in "recycling" (repeat quit attempt) may be a promising approach to increase quit rates.

OBJECTIVE

To report relapsed smokers' interest in recycling and their treatment preferences.

STUDY DESIGN

Descriptive analysis of a population of relapsed smokers who were randomized to receive a recycling intervention strategy to increase tobacco dependence treatment rates, as part of a randomized controlled trial at 5 Veterans Affairs medical centers.

METHODS

Individuals prescribed a tobacco dependence medication in 2002 were eligible and were identified from the Department of Veterans Affairs Pharmacy Benefits Management database. Intervention group participants (n = 951) were contacted for a standardized telephone interview approximately 6 months after the prescription fill date to assess smoking status, interest in recycling, and treatment preferences. Bivariate analyses and generalized linear mixed-model regressions were used to describe outcomes.

RESULTS

The response rate to the intervention telephone call was 62% (586/951), at which 61% (357/586) of respondents had relapsed. Almost two thirds of relapsed smokers were interested in recycling within 30 days. Of these, 91% wanted behavioral or pharmacologic smoking cessation treatment, and 64% wanted behavioral and pharmacologic treatment. In multivariate analyses, independent predictors of interest in recycling within 30 days included black race, lower smoking level, and greater number of smoking-related medical conditions.

CONCLUSION

Most smokers who attempt to quit but relapse want to quit again right away, and most are interested in receiving behavioral and pharmacologic treatment.

Regulated deficit irrigation (RDI) to save water and improve Sauvignon Blanc quality?

With a fast change of land use in Marlborough from extensive pastoral farming to intensive irrigated viticulture, a need has risen to investigate the sustainable use of the available water. In 2001 a 5 ha irrigation research project was installed in a Marlborough Sauvignon Blanc vineyard. Irrigation treatments installed were control (compensate 100% for crop evapotranspiration (ET(O)), 80%, 70% and 60% of ET(O). During the two years that the Regulated Deficit Irrigation (RDI) trial has run so far, very different climatic conditions created much greater differences in yield and vegetative growth, than up to 40% reduction in irrigation, none of which were significant. The use of sap flow in the vines has been fine-tuned and is now giving reliable results on which to base vine water need.

Protection of the Cyp1a2(-/-) null mouse against uroporphyria and hepatic injury following exposure to 2,3,7,8-tetrachlorodibenzo-p-dioxin

The effect of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) on the liver of C57BL/6J mice is a model for clinical sporadic porphyria cutanea tarda (PCT). There is massive uroporphyria, inhibition of uroporphyrinogen decarboxylase (UROD) activity, and hepatocellular damage. A variety of evidence implicates the CYP1A2 enzyme as necessary for mouse uroporphyria. Here we report that, 5 weeks after a single oral dose of TCDD (75 microg/kg), Cyp1a2(+/+) wild-type mice showed severe uroporphyria and greater than 90% decreases in UROD activity; in contrast, despite exposure to this potent agent Cyp1a2(-/-) knockout mice displayed absolutely no increases in hepatic porphyrin levels, even after prior iron overload, and no detectable inhibition of UROD activity. Plasma levels of alanine-aminotransferase (ALT) and aspartate aminotransferase (AST)-although elevated in both genotypes after TCDD exposure-were significantly less in Cyp1a2(-/-) than in Cyp1a2(+/+) mice, suggesting that the absence of CYP1A2 also affords partial protection against TCDD-induced liver toxicity. Histological examination confirmed a decrease in hepatocellular damage in TCDD-treated Cyp1a2(-/-) mice; in particular, there was no bile duct damage or proliferation that in the Cyp1a2(+/+) mice might be caused by uroporphyrin. We conclude that CYP1A2 is both necessary and essential for the potent uroporphyrinogenic effects of TCDD in mice, and that CYP1A2 also plays a role in contributing to TCDD-induced hepatocellular injury. This study has implications for both the toxicity assessment of TCDD and the hepatic injury seen in PCT patients.

The controversy surrounding indomethacin for tocolysis

Indomethacin is a prostaglandin synthetase inhibitor sometimes used for tocolysis. Several placebo-controlled trials and trials comparing indomethacin to other potential first-line tocolytic agents support its efficacy for delaying delivery for >48 hours. Recent observational studies, however, have raised concerns about the safety of indomethacin, implicating it with increased rates of intraventricular hemorrhage and necrotizing enterocolitis. Careful analysis of these observational studies suggests that these results should be viewed with caution, because of uncontrolled confounding by indication. A recent decision analysis supports the risk/benefit analysis of indomethacin in this setting. Still, the future of indomethacin in preterm labor should be guided by well-designed prospective clinical trials. Such studies are underway.

Mutation frequency in the lacI gene of liver DNA from lambda/lacI transgenic mice following the interaction of PCBs with iron causing hepatic cancer and porphyria

The synergistic interaction of iron overload, AHR: genotype and exposure to a mixture of polychlorinated biphenyls (PCBs) (Aroclor 1254) in mice leads to hepatic porphyria, oxidative DNA damage and cancer. In humans, hepatocellular cancer is associated with iron overload and hepatic porphyria. Neither the mechanism of hepatic carcinogenesis induced by PCBs in rodents nor hepatocellular cancer induced by iron and porphyria in humans are understood. To test the hypothesis that chronic interaction of iron and PCBs may induce mutagenesis in liver DNA, lambda /lacI transgenic C57BL/6 mice were given iron dextran (600 mg iron/kg) and then administered Aroclor 1254 in the diet (0.01%) for 7 weeks. Hepatic iron, CYP1A activity and CYP1A1/1A2 protein were elevated >20-fold as a result of iron or Aroclor treatments, respectively, but porphyria with associated histological changes only developed in the combined iron/Aroclor treatment group. lambda/lacI shuttle vectors were isolated from liver genomic DNA and the mutational frequency (MF) in the lacI gene determined. Both iron and Aroclor treatments alone caused significant small increases in MF (1.5- and 1.4-fold, respectively), however, the MF following the combined iron and Aroclor treatment (1. 6-fold) was not greater than the additive effects. In contrast, the MF was significantly elevated (4.7-fold) in liver DNA of mice 2 weeks following five daily doses of N-nitrosodimethylamine (4 mg/kg). These studies demonstrate that neither PCBs nor iron overload caused marked point mutations even in a combination regime that leads to oxidative damage and cancer. There was also no strong evidence either that porphyrins or chronic CYP1A1 expression induced by the PCBs after this period caused marked point mutagens or simple deletions. Hence, to understand the PCBs-iron synergism more complex scenarios than point mutations or simple deletions must be invoked.

Genetic variation of basal iron status, ferritin and iron regulatory protein in mice: potential for modulation of oxidative stress

Toxic and carcinogenic free radical processes induced by drugs and other chemicals are probably modulated by the participation of available iron. To see whether endogenous iron was genetically variable in normal mice, the common strains C57BL/10ScSn, C57BL/6J, BALB/c, DBA/2, and SWR were examined for major differences in their hepatic non-heme iron contents. Levels in SWR mice were 3- to 5-fold higher than in the two C57BL strains, with intermediate levels in DBA/2 and BALB/c mice. Concentrations in kidney, lung, and especially spleen of SWR mice were also greater than those in C57BL mice. Non-denaturing PAGE of hepatic ferritin from all strains showed a major holoferritin band at approximately 600 kDa, with SWR mice having > 3-fold higher levels than C57BL strains. SDS PAGE showed a band of 22 kDa, mainly representing L-ferritin subunits. A trace of a subunit at 18 kDa was also detected in ferritin from SWR mice. The 18 kDa subunit and a 500 kDa holoferritin from which it originates were observed in all strains after parenteral iron overload, and there was no major variation in ferritin patterns. Although iron uptake studies showed no evidence for differential duodenal absorption between strains to explain the variation in basal iron levels, acquisition of absorbed iron by the liver was significantly higher in SWR mice than C57BL/6J. As with iron and ferritin contents, total iron regulatory protein (IRP-1) binding capacity for mRNA iron responsive element (IRE) and actual IRE/IRP binding in the liver were significantly greater in SWR than C57BL/6J mice. Cytosolic aconitase activity, representing unbound IRP-1, tended to be lower in the former strain. SWR mice were more susceptible than C57BL/10ScSn mice to the toxic action of diquat, which is thought to involve iron catalysis. If extrapolated to humans, the findings could suggest that some people might have the propensity for greater basal hepatic iron stores than others, which might make them more susceptible to iron-catalysed toxicity caused by oxidants.

Low levels of p53 are associated with resistance to tetrachlorodibenzo-p-dioxin toxicity in DBA/2 mice

We show here that DBA/2 strain mice have a complex mutation/polymorphism in the promoter region of the Trp53 locus (the mouse p53 locus). This region has previously been shown to be essential for p53 expression. We further show that the DBA/2 mutation is associated with approximately fourfold lower p53 levels in thymocytes treated with the DNA-damaging agent etoposide in-vitro, and with relative resistance of these thymocytes to apoptosis induced by the DNA-damaging agent etoposide compared with C57BL/6 mice. When part of the promoter containing this mutation was inserted into a plasmid containing a luciferase reporter gene but lacking eukaryote promoter sequences and transfected into MCF-7 human breast cell line cells, the mean luciferase activity was slightly less with the DBA/2 than with the C57BL/6 promoter-reporter construct (p < 0.01). We found that DBA/2xC57BL/6 F2 hybrid mice with the DBA/2 genotype at the Trp53 locus were relatively resistant to tetrachlorodibenzo-p-dioxin toxicity, and this resistance was additive with resistance associated with the Ahr locus. DBA/2 mice are long-lived and do not have particularly high levels of cancer, suggesting either that they carry other compensatory tumour resistance alleles (such as Ahr(d)), or that, while there may be a p53 protein dosage effect for acute toxicity, lower than normal levels of p53 may still be sufficient to protect against cancer. In evolutionary terms, it may be better to maintain low levels of p53 in order to avoid death from acute toxicity, even at the expense of a higher incidence of cancer in later life.

Interaction between iron metabolism and 2,3,7,8-tetrachlorodibenzo-p-dioxin in mice with variants of the Ahr gene: a hepatic oxidative mechanism

The binding of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) with the aryl hydrocarbon (AH) receptor and subsequent changes in gene expression have been studied intensively, but the mechanisms by which these lead to toxicity are unclear. We investigated the influence of iron, previously implicated in TCDD-induced hepatic porphyria, in mice with alleles of Ahr that encode receptors with varied affinity for TCDD. The administration of iron to Ahrb-1 C57BL/6J (AH-responsive) mice before a single dose of TCDD (75 micrograms/kg) markedly potentiated not only the hepatic porphyria but also general hepatocellular damage and elevation of plasma hepatic enzymes. The formation of hydroxylated and peroxylated derivatives of uroporphyrins formed from uroporphyrinogen and the induction of a mu-glutathione transferase (GST) were consistent with the operation of an oxidative mechanism. In a comparison of C57BL/6J mice with Ahrb-2 BALB/c (AH-responsive) and Ahrd SWR and DBA/2 (AH-nonresponsive) mice, iron overcame the weak hepatic porphyria and toxicity responses in BALB/c and SWR strains but not in DBA/2. CYP1A isoforms are strongly implicated in the mechanism of porphyria, but activities were lowered by 20-30% with iron treatment, and a comparison of levels between strains did not fully account for the resistance of DBA/2 mice. Studies with the use of gel shift assays and cytosolic aconitase of the capacity of the iron regulatory protein controlling the translation of some iron metabolism proteins showed a significant difference between C57BL/6J and DBA/2 mice after the administration of TCDD. We conclude that iron potentiates both the hepatic porphyria and toxicity of TCDD in susceptible mice in an oxidative process with disturbance of iron regulatory protein capacity. Iron even overcomes the AH-nonresponsive Ahrd allele in the SWR strain but not in DBA/2 mice, which remain resistant.

Protoporphyria induced by the orally active iron chelator 1,2-diethyl-3-hydroxypyridin-4-one in C57BL/10ScSn mice

Administration in the drinking water of the orally-active iron chelator 1,2-diethyl-3-hydroxypyridin-4-one (CP94) to C57BL/10ScSn mice caused the development of hepatic protoporphyria. This was detected after 1 week and continued as long as the chelator was given (15 weeks). The more hydrophilic 1,2-dimethyl- and 1-hydroxyethyl,2-ethyl-analogues (CP20 and CP102) were also tested, but they were both inactive in inducing accumulation of protoporphyrin in the liver. Restriction of in vivo iron supply for ferrochelatase seemed a likely mode of action, but an approximately 30% decrease in activity of this enzyme was also observed when measured in vitro. Extracts of livers from mice given CP20, CP94, and CP102 showed no potential to inhibit mouse ferrochelatase, in contrast to the findings with an extract from mice treated with the known porphyrogenic chemical 4-ethyl-3, 5-diethoxycarbonyl-2,6-dimethyl-1,4-dihydropyridine, indicating that ferrochelatase inhibition did not occur by the formation of an N-ethyl-protoporphyrin derived from metabolism by cytochrome P450, CP20, CP94, CP102, and CP117 (the pivoyl ester of CP102) all caused significant depression of the levels of ferritin-iron and total nonheme iron, but only CP94 caused the significant accumulation of protoporphyrin. Protoporphyria did not occur with iron overloaded C57BL/10ScSn mice or in SWR mice that had elevated basal iron status. Although the protoporphyrin had only a small effect on the total levels of the hemoprotein cytochrome P450 in C57BL/10ScSn mice, the activity of the CYP2B isoforms of cytochrome P450 was actually induced in both strains. The results show that CP94 could cause protoporphyria in individuals of low iron status, perhaps through specifically targeting particular iron pools available to ferrochelatase and by concomitantly stimulating heme synthesis.

Uroporphyria induced by 5-aminolaevulinic acid alone in Ahrd SWR mice

In mice, depression of hepatic uroporphyrinogen decarboxylase (UROD) leading to porphyrin accumulation (uroporphyria) occurs with chlorinated ligands of the aryl hydrocarbon (AH) receptor especially after iron overload. However, in the absence of chlorinated ligands, iron itself will eventually cause uroporphyria, but this response is not associated with the Ahr genotype. These effects are potentiated by administration of the haem precursor 5-aminolaevulinate (ALA). The aim of this study was to investigate the effects of ALA alone. Prolonged administration of 2 mg ALA/mL in the drinking water to SWR mice also led to decarboxylase insufficiency (11% of control) and uroporphyria by 8 weeks, whereas DBA/2 mice did not show reduced enzyme activity. Both strains are considered AH nonresponsive and analysis of the Ahr gene using restriction fragment length polymorphism was consistent with SWR, like DBA/2, possessing the Ahrd allele. Exposure of isolated hepatocytes to ALA (150-500 microM) for up to 48 hr showed a significant accumulation of both uroporphyrin and coproporphyrin in the medium, which for uroporphyrin particularly was significantly greater with SWR than with DBA/2 cells. Basal in vivo CYP1A2 activity, measured as microsomal methoxyresorufin dealkylation, was significantly greater in SWR than in DBA/2 mice (1.3-fold), but it was unclear whether this was sufficient to explain the marked difference in sensitivities of the two strains. Despite SWR mice being AH nonresponsive, uroporphyria and decarboxylase depression after an initial iron overload and ALA for 3 weeks were greatly potentiated by a single dose (100 mg/kg) of hexachlorobenzene (a weak AH ligand). The results demonstrate that there is a genetic difference in mice independent of the Ahr genotype and response to iron, which influences the susceptibility to ALA-induced uroporphyria. Thus chemicals, iron and ALA can act independently, but also together, to cause porphyria in susceptible individuals.

Synergy of iron in the toxicity and carcinogenicity of polychlorinated biphenyls (PCBs) and related chemicals

In Ah-responsive C57BL/10ScSn mice a single dose of iron significantly potentiated the property of the polychlorinated biphenyl (PCB) mixture Aroclor 1254 to induce porphyria by inhibition at the uroporphyrinogen decarboxylase stage of hepatic haem biosynthesis. The induction of liver tumors and other lesions were also enhanced markedly by iron overload suggesting a link between porphyria and cancer. The cellular, molecular and biochemical processes involved have been investigated in attempts to explain these phenomena by an iron-catalysed 'oxidative stress' mechanism.

Interaction of some trialkyl phosphorothiolates with acetylcholinesterase. Characterization of inhibition, aging and reactivation

The reaction of bovine erythrocyte acetylcholinesterase (acetylcholine acetylhydrolase, EC 3.1.1.7) with a set of structurally related phosphorothiolates was studied in order to investigate the properties of the phosphorylated enzymes and to identify the leaving group. OOS- and OOS-trimethyl phosphorothiolates and their triethyl analogues inhibit acetylcholinesterase reversibly and by progressive inhibition, and the phosphorylated enzymes undergo both spontaneous reactivation and aging. For each compound the enzyme-inhibitor dissociation constant, and the rate constants for inhibition (ka), reactivation and aging have been derived. The OOS-compounds are more potent inhibitors than the OOS-compounds, and the derived inhibited enzymes reactivate and age faster. By comparing reactivation and aging rate constants with those obtained from phosphorylated enzymes of known structure it was concluded that the leaving group of during phosphorylation is the S-alkyl. SSS-trimethyl and -triethyl phosphorothiolates also form reversible complexes and inhibit the enzyme progressively. With these inhibitors the phosphorylated enzymes did not reactivate either spontaneously or in response to oximes under conditions successful for the other inhibitors. The ka values (37 degrees C, pH 7.4) range from 30 M-1 X min-1 (OOS-trimethyl phosphorothiolate) to 6.7 X 10(3) M-1 X min-1 (OOS-triethyl phosphorothiolate) as compared to 1.25 X 10(5) M-1 X min-1 determined for isomalathion (O, S-dimethyl S-(1,2-dicarbethoxyethyl)-phoshporodithioate), which was used as one of the reference compounds. If the inhibitory potency of the trialkyl phosphorothiolates is calculated from measurements made after a fixed preincubation time the results in ka values will be misleading.

Reactivation and aging of neurotoxic esterase inhibited by a variety of organophosphorus esters

1. It was proposed [Johnson (1974) J. Neurochem. 23, 785--789] that both inhibition of neurotoxic esterase of nervous tissue and subsequent 'aging' of the inhibited esterase are necessary events in the pathogenesis of organophosphate-induced delayed neuropathy: aging has now been demonstrated with a number of neurotoxic compounds. 2. Reactivation by KF was observed for hen brain neurotoxic esterase inhibited by 14 organophosphates and phosphonates, and time-dependent loss of reactivatibility (aging) occurred in every case. 3. For five other compounds no reactivation occurred and aging could not therefore be established, but independent evidence for two compounds suggests that aging was rapid. 4. Half-lives of aging of neurotoxic esterase inhibited by phosphates ranged from less than 1 min to 10 min, and for phosphonates the range was 3--600 min. 5. The relationship of these findings to the mechanism of toxicity and to the prospects of therapy are considered. 6. Aging occurred rapidly with aryloxy and linear alkoxy groups attached to phosphorus and slowly with a highly branched alkoxy substituent: these effects seem incompatible with an SN1 (dealkylation) mechanism.

Biochemical events in delayed neurotoxicity: is aging of chymotrypsin inhibited by saligenin cyclic phosphates a model for aging of neurotoxic esterase?

Chymotrypsin and neurotoxic esterase (NTE) have some similarities. After inhibition of concentrated (80-800 micro M) chymotrypsin by aryl saligenin cyclic phosphates it is known that aging occurs and some phenolic material becomes attached to protein. This binding has now been shown to be a manifestation of non-specific reaction with any available electrophile such as Tris, reduced glutathione (GSH), or protein. The reaction is therefore not a model for the 100% efficient transfer of alkyl groups to protein which occurs during aging of NTE inhibited by dialkyl phosphates.

Rapid aging of neurotoxic esterase after inhibition by di-isopropyl phosphorofluoridate

1. It was proposed [Johnson (1974) J. Neurochem.23, 785-789] that an essential step in the genesis of delayed neuropathy caused by some organophosphorus esters was aging of phosphorylated neurotoxic esterase, involving generation of a charged monosubstituted phosphoric acid residue on the protein. 2. Neurotoxic esterase of hen brain was inhibited with di-isopropyl phosphorofluoridate either unlabelled or mixed-labelled with (3)H and (32)P. 3. Reactivation of inhibited enzyme by KF was possible only immediately after a brief inhibition:aging at pH8.0 and 37 degrees C occurred with a half-life of about 2-4min. 4. When the radiolabelled enzyme was studied no loss of label was observed during the expected aging period, but a change in the nature of the bound radioisotopes occurred (half-life=3.25min). 5. Alkaline hydrolysis of labelled enzyme liberated di-isopropyl phosphate at early times after labelling, but increasing amounts of monoisopropyl phosphate plus a volatile tritiated compound (possibly propan-2-ol) at later times. 6. Treatment of labelled enzyme with KF released di-isopropyl phosphate and caused reactivation of enzyme to similar degrees. It is concluded that the chemical change from di-isopropyl phosphoryl-enzyme to mono-isopropyl phosphoryl-enzyme and the loss of reactivatibility are related. 7. The rate of aging is similar at pH5.2, 6.5 and 8. Aging is unaffected by addition of reduced glutathione and imidazole at pH5.2 or 8, and none of the transferred (3)H is trapped by these reagents. The mechanism of aging must be different from the better-known dealkylation aging of the cholinesterases.

Haptoglobin Phenotype Frequencies in Mentally Retarded Persons

Haptoglobin phenotype frequencies for 887 unselected mentally retarded patients were within the range reported for normal European populations. Of these sera, 2% initially classified as anhaptoglobinemic by subjective appraisal of starch-gel electropherograms were subsequently shown to be hypohaptoglobinemic. This frequency of hypohaptoglobinemia is similar to that reported for normal populations. Sixteen of the hypohaptoglobinemic cases were reinvestigated, and all but one showed some evidence of hepatic dysfunction.