Bayesian learning and predictability in a stochastic nonlinear dynamical model.

Bayesian inference methods are applied within a Bayesian hierarchical modeling framework to the problems of joint state and parameter estimation, and of state forecasting. We explore and demonstrate the ideas in the context of a simple nonlinear marine biogeochemical model. A novel approach is proposed to the formulation of the stochastic process model, in which ecophysiological properties of plankton communities are represented by autoregressive stochastic processes. This approach captures the effects of changes in plankton communities over time, and it allows the incorporation of literature metadata on individual species into prior distributions for process model parameters. The approach is applied to a case study at Ocean Station Papa, using particle Markov chain Monte Carlo computational techniques. The results suggest that, by drawing on objective prior information, it is possible to extract useful information about model state and a subset of parameters, and even to make useful long-term forecasts, based on sparse and noisy observations.

Integrating buprenorphine treatment into office-based practice: a qualitative study.

BACKGROUND: Despite the availability and demonstrated effectiveness of office-based buprenorphine maintenance treatment (BMT), the systematic examination of physicians' attitudes towards this new medical practice has been largely neglected. OBJECTIVE: To identify facilitators and barriers to the potential or actual implementation of BMT by office-based medical providers. DESIGN: Qualitative study using individual and group semi-structured interviews. PARTICIPANTS: Twenty-three practicing office-based physicians in New England. APPROACH: Interviews were audiotaped, transcribed, and entered into a qualitative software program. The transcripts were thematically coded using the constant comparative method by a multidisciplinary team. RESULTS: Eighty percent of the physicians were white; 55% were women. The mean number of years since graduating medical school was 14 (SD = 10). The primary areas of clinical specialization were internal medicine (50%), infectious disease (20%), and addiction medicine (15%). Physicians identified physician, patient, and logistical factors that would either facilitate or serve as a barrier to their integration of BMT into clinical practice. Physician facilitators included promoting continuity of patient care, positive perceptions of BMT, and viewing BMT as a positive alternative to methadone maintenance. Physician barriers included competing activities, lack of interest, and lack of expertise in addiction treatment. Physicians' perceptions of patient-related barriers included concerns about confidentiality and cost, and low motivation for treatment. Perceived logistical barriers included lack of remuneration for BMT, limited ancillary support for physicians, not enough time, and a perceived low prevalence of opioid dependence in physicians' practices. CONCLUSIONS: Addressing physicians' perceptions of facilitators and barriers to BMT is crucial to supporting the further expansion of BMT into primary care and office-based practices.

The impact of race as a risk factor for symptom severity and age at diagnosis of uterine leiomyomata among affected sisters.

OBJECTIVE: The objective of the study was to identify risk factors for uterine leiomyomata (UL) in a racially diverse population of women with a family history of UL, and to evaluate their contribution to disease severity and age at diagnosis. STUDY DESIGN: We collected and analyzed epidemiologic data from 285 sister pairs diagnosed with UL. Risk factors for UL-related outcomes were compared among black (n = 73) and white (n = 212) sister pairs using univariate and multivariate regression models. RESULTS: Black women reported an average age at diagnosis of 5.3 years younger (SE, 1.1; P < .001) and were more likely to report severe disease (odds ratio, 5.22; 95% confidence interval, 1.99-13.7, P < .001) than white women of similar socioeconomic status. CONCLUSION: Self-reported race is a significant factor in the severity of UL among women with a family history of UL. Differences in disease presentation between races likely reflect underlying genetic heterogeneity. The affected sister-pair study design can address both epidemiological and genetic hypotheses about UL.

HIV testing and sexual risk reduction counseling in office-based buprenorphine/naloxone treatment.

OBJECTIVES: We assessed the feasibility and preliminary efficacy of human immunodeficiency virus (HIV) testing with sexual risk reduction counseling for opioid-dependent patients initiating office-based buprenorphine/naloxone treatment. METHODS: We conducted a 14-week randomized, controlled trial with 30 patients (original target of 114) assigned to receive buprenorphine/naloxone induction/stabilization and HIV testing with Brief Sexual Risk Management (BSRM) or Enhanced Sexual Risk Management (ESRM). We evaluated process measures and compared outcomes at baseline and during the 3-month follow-up. RESULTS: Similar proportions of patients receiving BSRM and ESRM underwent HIV testing (93% vs 80%; P = 0.28) and completed counseling sessions (80% vs 67%; P = 0.40). Brief Sexual Risk Management sessions were shorter than ESRM sessions (15.4 vs 23.4 minutes), with comparable manual adherence (P = 0.80). Outcomes did not vary by BSRM versus ESRM. CONCLUSIONS: Although the recruitment of opioid-dependent patients with sexual risk behaviors is challenging, HIV testing with sexual risk reduction counseling in office-based buprenorphine/naloxone treatment practice is feasible. Interventions to decrease sexual risk behaviors among a segment of this population are necessary.

Opioids, chronic pain, and addiction in primary care.

UNLABELLED: Research has largely ignored the systematic examination of physicians' attitudes towards providing care for patients with chronic noncancer pain. The objective of this study was to identify barriers and facilitators to opioid treatment of chronic noncancer pain patients by office-based medical providers. We used a qualitative study design using individual and group interviews. Participants were 23 office-based physicians in New England. Interviews were audiotaped, transcribed, and systematically coded by a multidisciplinary team using the constant comparative method. Physician barriers included absence of objective or physiological measures of pain; lack of expertise in the treatment of chronic pain and coexisting disorders, including addiction; lack of interest in pain management; patients' aberrant behaviors; and physicians' attitudes toward prescribing opioid analgesics. Physician facilitators included promoting continuity of patient care and the use of opioid agreements. Physicians' perceptions of patient-related barriers included lack of physician responsiveness to patients' pain reports, negative attitudes toward opioid analgesics, concerns about cost, and patients' low motivation for pain treatment. Perceived logistical barriers included lack of appropriate pain management and addiction referral options, limited information regarding diagnostic workup, limited insurance coverage for pain management services, limited ancillary support for physicians, and insufficient time. Addressing these barriers to pain treatment will be crucial to improving pain management service delivery. PERSPECTIVE: This article demonstrates that perceived barriers to treating patients with chronic noncancer pain are common among office-based physicians. Addressing these barriers in physician training and in existing office-based programs might benefit both noncancer chronic pain patients and their medical providers.

Cost analysis of clinic and office-based treatment of opioid dependence: results with methadone and buprenorphine in clinically stable patients.

The cost of providing and receiving treatment for opioid dependence can determine its adoption. To compare the cost of clinic-based methadone (MC, n=23), office-based methadone (MO, n=21), and office-based buprenorphine (BO, n=34) we performed an analysis of treatment and patient costs over 6 months of maintenance in patients who had previously been stabilized for at least 1 year. We performed statistical comparisons using ANOVA and chi-square tests and performed a sensitivity analysis varying cost estimates and intensity of clinical contact. The cost of providing 1 month of treatment per patient was $147 (MC), $220 (MO) and $336 (BO) (p<0.001). Mean monthly medication cost was $93 (MC), $86 (MO) and $257 (BO) (p<0.001). The cost to patients was $92 (MC), $63 (MO) and $38 (BO) (p=0.102). Sensitivity analyses, varying cost estimates and clinical contact, result in total monthly costs of $117 to $183 (MC), $149 to $279 (MO), $292 to $499 (BO). Monthly patient costs were $84 to $133 (MC), $55 to $105 (MO) and $34 to $65 (BO). We conclude that providing clinic-based methadone is least expensive. The price of buprenorphine accounts for a major portion of the difference in costs. For patients, office-based treatment may be less expensive.

Women and opioid dependence treatment: office-based versus opioid treatment program-based care?

Women are under-represented in opioid dependency treatment, yet national statistics indicate that, as the non-medical use of prescription pain relievers rises, more women will require this treatment. Important considerations for the treatment of opioid-dependency in women include high rates of psychiatric illness, concerns regarding substance abuse and treatment in pregnancy, high rates of history of trauma, relationship dynamics that put women at risk for sexually transmitted diseases, and social factors such as lower economic status and responsibilities as care givers. Traditional approaches to opioid-dependency treatment, such as methadone maintenance programs (MMPs), have not consistently addressed these needs and do not provide flexible care and anonymity. Recent data suggest that, in comparison to MMPs, a greater percentage of women are entering office-based treatment. Yet it is unclear whether physicians' offices will be equipped to adequately handle women's treatment needs. Nonetheless office-based treatment may provide a solution for women concerned about anonymity, stigma, and the requirement of daily visits to a MMP.

Use of N-acetylcholine and sodium bicarbonate to protect renal transplant function during endovascular renal artery aneurysm exclusion.

We describe the successful use of hydration with sodium bicarbonate and N-acetylcholine to prevent contrast-induced nephrophathy in a patient with a kidney transplant undergoing endovascular native renal artery aneurysm exclusion. The implications for surveillance studies for endovascular procedures are discussed.

Involvement of fumarate hydratase in nonsyndromic uterine leiomyomas: genetic linkage analysis and FISH studies.

Recently, germline mutations of the fumarate hydratase (FH) gene, in 1q42.1, have been found to be involved in syndromes associated with uterine leiomyomas (ULs). Compelling evidence also supports a genetic liability to develop nonsyndromic UL, although susceptibility genes have not been reported to date. Loss of heterozygosity (LOH) studies have found no or rare evidence of LOH of FH in nonsyndromic UL. However, the karyotypes of these tumors were not reported, and cytogenetic aberrations of 1q42-44 have been observed infrequently in UL. To determine whether FH mutations also may predispose women to developing nonsyndromic UL, we performed a genetic linkage study with DNA from 123 families containing at least one affected sister pair. In addition, to assess the frequency of FH loss specifically in UL with 1q rearrangements, we performed a fluorescence in situ hybridization (FISH) analysis of UL with 1q rearrangements. Analysis of the genotyping data revealed evidence suggestive of linkage to the FH region among study participants who were less than 40 years of age at diagnosis (Zlr 1.7 at D1S547, P = 0.04). FISH results showed that one copy of FH was absent in 9 of 11 ULs. These data indicate that loss of FH might be a significant event in the pathogenesis of a subset of nonsyndromic ULs.