Laura A. Hatfield

Early Performance of Accountable Care Organizations in Medicare

BACKGROUND In the Medicare Shared Savings Program (MSSP), accountable care organizations (ACOs) have financial incentives to lower spending and improve quality. We used quasi-experimental methods to assess the early performance of MSSP ACOs. METHODS Using Medicare claims from 2009 through 2013 and a difference-in-differences design, we compared changes in spending and in performance on quality measures from before the start of ACO contracts to after the start of the contracts between beneficiaries served by the 220 ACOs entering the MSSP in mid-2012 (2012 ACO cohort) or January 2013 (2013 ACO cohort) and those served by non-ACO providers (control group), with adjustment for geographic area and beneficiary characteristics. We analyzed the 2012 and 2013 ACO cohorts separately because entry time could reflect the capacity of an ACO to achieve savings. We compared ACO savings according to organizational structure, baseline spending, and concurrent ACO contracting with commercial insurers. RESULTS Adjusted Medicare spending and spending trends were similar in the ACO cohorts and the control group during the precontract period. In 2013, the differential change (i.e., the between-group difference in the change from the precontract period) in total adjusted annual spending was -

Predictors of HIV disclosure to secondary partners and sexual risk behavior among a high-risk sample of HIV-positive MSM: results from six epicenters in the US

144 per beneficiary in the 2012 ACO cohort as compared with the control group (P=0.02), consistent with a 1.4% savings, but only -

Dynamic MR perfusion and proton MR spectroscopic imaging in Sturge-Weber syndrome: correlation with neurological symptoms.

3 per beneficiary in the 2013 ACO cohort as compared with the control group (P=0.96). Estimated savings were consistently greater in independent primary care groups than in hospital-integrated groups among 2012 and 2013 MSSP entrants (P=0.005 for interaction). MSSP contracts were associated with improved performance on some quality measures and unchanged performance on others. CONCLUSIONS The first full year of MSSP contracts was associated with early reductions in Medicare spending among 2012 entrants but not among 2013 entrants. Savings were greater in independent primary care groups than in hospital-integrated groups.

Comparison of Substance Use and Risky Sexual Behavior Among a Diverse Sample of Urban, HIV-Positive Men Who Have Sex with Men

Abstract This study sought to identify predictors of HIV disclosure and serodiscordant unprotected anal intercourse (SDUAI) among HIV-positive men who have sex with men (MSM). Between January 2005 and April 2006, 675 HIV-positive MSM were recruited into the Positive Connections intervention trial held in six US cities with intentional over-sampling of HIV-positive MSM of Color (74%) and men engaging in unprotected anal intercourse (UAI) in the previous year. Baseline survey data showed 30 and 31%, respectively, of participants disclosed to none or some of their secondary sex partners in the last 90 days. Greater disclosure to secondary partners was associated with having fewer sexual partners, being extremely out as MSM, longer HIV diagnosis, knowledge of CD4 count, detectable viral load and being white. Disclosure to all secondary partners was associated with lower SDUAI. Recommendations for prevention for HIV-positive MSM include the promotion of serodisclosure to all secondary partners and increasing comfort with, and outness about, ones sexuality.

Comorbidity of Epilepsy and Headache in Patients With Sturge-Weber Syndrome

To investigate physiological alterations in Sturge‐Weber syndrome (SWS) using MR perfusion imaging (PWI) and proton spectroscopic imaging (MRSI), and their association with neurological status.

Quantitative analysis of cerebral cortical atrophy and correlation with clinical severity in unilateral Sturge-Weber syndrome.

ABSTRACT The purpose of this study was to examine substance use among a racially and ethnically diverse group of HIV-positive men who have sex with men (MSM) living in six U.S. cities, model associations between drug use and serodiscordant unprotected anal intercourse (SDUAI), and characterize users of the substances strongly associated with risky sexual behavior. Baseline questionnaire data from 675 participants of the Positive Connections intervention trial were analyzed. Overall, substance use was common; however, the highest percentage of stimulant (30%), methamphetamine (27%), and popper (i.e., amyl nitrite) (46%) use was reported among white MSM and crack/cocaine (38%) use was highest among African American MSM. Popper use versus non-use (odds ratio = 2.46; 95% confidence interval = 1.55–3.94) and condom self-efficacy (1 standard deviation (sd) increase on scale; odds ratio = .58; 95% confidence interval = .46–.73) were significantly associated with SDUAI after adjusting for key demographic and psychosocial factors. These results highlight the importance of addressing drug use in the context of sex for possible HIV transmission risk.

Combining Dynamic Predictions From Joint Models for Longitudinal and Time-to-Event Data Using Bayesian Model Averaging

Sturge-Weber syndrome is associated with leptomeningeal angioma, trigeminal port-wine stain, epilepsy, and glaucoma. Clinically, many patients with Sturge-Weber syndrome are observed to have both seizures and headaches, but this has never been described in the literature. A questionnaire was mailed to 190 patients with reported comorbid epilepsy and headache as identified by the Sturge-Weber Foundation. Sixty-eight surveys were returned anonymously; 55 reported both seizures and headaches. The median age at headache onset was 8 years, with a median of three headaches per month. Fifty-eight percent felt that headaches were an equal or greater problem. Ibuprofen and acetaminophen were the most frequently tried abortive medications; 22% had tried sumatriptan. Only 22% reported a neurologist suggesting the use of an anticonvulsant as a preventive agent. Subjects with a family history of headaches had an earlier age at headache onset (7.5 vs 11 years; P = .02), and those with a family history of seizures were more likely to report behavior problems (69% vs 33%; P = .02). Subjects reporting learning problems or hemiparesis had an earlier age at seizure onset. Migraine-like headaches can be as significant a problem as epilepsy for patients with Sturge-Weber syndrome. Despite this, triptans and prophylactic medications (including anticonvulsants) were used in less than half of the patients. Correlations of family history with both age at symptom onset and behavior problems suggest that genetic substrate could be one factor determining the variable neurologic manifestations seen in Sturge-Weber syndrome. (J Child Neurol 2005;20:678—682). From the Departments of Neurology and Pediatrics (Drs Kossoff and Comi and Ms Hatfield), The Johns Hopkins Medical Institutions, Baltimore, MD, and The Sturge-Weber Foundation (Ms Ball), Mt. Freedom, NJ.

Multilevel Bayesian Models for Survival Times and Longitudinal Patient-Reported Outcomes With Many Zeros

Sturge-Weber syndrome is a neurocutaneous disorder with vascular malformations of the skin, brain, and eye. The objective of this study was to determine whether cortical atrophy in patients with Sturge-Weber syndrome correlates with clinical severity. Eighteen subjects (age 4 months—35 years) with unilateral Sturge-Weber syndrome received a neurologic examination and submitted previous magnetic resonance imaging (MRI) films. A blinded investigator assigned clinical severity scores based on seizures, hemiparesis, visual field cut, and cognitive impairments. Computer-aided analysis of MRIs produced laterality scores for cortical volume asymmetry. A significant relationship existed between clinical severity and laterality scores (Spearmans rho = —0.804; P < .001). Laterality scores also correlated well with hemiparesis subscores and weakly with cognitive impairment subscores (Kendalls tau b; P < .05). Using this simple, computer-aided analysis, cortical volume asymmetry correlated with clinical status. This method offers the advantages of relative simplicity, objectivity, and wide applicability to films from outside institutions, as would be encountered in clinical practice. (J Child Neurol 2005;20:867—870).

Quantitative EEG asymmetry correlates with clinical severity in unilateral Sturge-Weber syndrome.

The joint modeling of longitudinal and time-to-event data is an active area of statistics research that has received a lot of attention in recent years. More recently, a new and attractive application of this type of model has been to obtain individualized predictions of survival probabilities and/or of future longitudinal responses. The advantageous feature of these predictions is that they are dynamically updated as extra longitudinal responses are collected for the subjects of interest, providing real time risk assessment using all recorded information. The aim of this article is two-fold. First, to highlight the importance of modeling the association structure between the longitudinal and event time responses that can greatly influence the derived predictions, and second, to illustrate how we can improve the accuracy of the derived predictions by suitably combining joint models with different association structures. The second goal is achieved using Bayesian model averaging, which, in this setting, has the very intriguing feature that the model weights are not fixed but they are rather subject- and time-dependent, implying that at different follow-up times predictions for the same subject may be based on different models. Supplementary materials for this article are available online.

Association Between Availability of a Price Transparency Tool and Outpatient Spending

Regulatory approval of new therapies often depends on demonstrating prolonged survival. Particularly when these survival benefits are modest, consideration of therapeutic benefits to patient-reported outcomes (PROs) may add value to the traditional biomedical clinical trial endpoints. We extend a popular class of joint models for longitudinal and survival data to accommodate the excessive zeros common in PROs, building hierarchical Bayesian models that combine information from longitudinal PRO measurements and survival outcomes. The model development is motivated by a clinical trial for malignant pleural mesothelioma, a rapidly fatal form of pulmonary cancer usually associated with asbestos exposure. By separately modeling the presence and severity of PROs, using our zero-augmented beta (ZAB) likelihood, we are able to model PROs on their original scale and learn about individual-level parameters from both presence and severity of symptoms. Correlations among an individuals PROs and survival are modeled using latent random variables, adjusting the fitted trajectories to better accommodate the observed data for each individual. This work contributes to understanding the impact of treatment on two aspects of mesothelioma: patients’ subjective experience of the disease process and their progression-free survival times. We uncover important differences between outcome types that are associated with therapy (periodic, worse in both treatment groups after therapy initiation) and those that are responsive to treatment (aperiodic, gradually widening gap between treatment groups). Finally, our work raises questions for future investigation into multivariate modeling, choice of link functions, and the relative contributions of multiple data sources in joint modeling contexts.