Irina Degtiar

While much of the causal inference literature has focused on addressing internal validity biases, both internal and external validity are necessary for unbiased estimates in a target population of interest. However, few generalizability approaches exist for estimating causal quantities in a target population that is not well-represented by a randomized study but is reflected when additionally incorporating observational data. To generalize to a target population represented by a union of these data, we propose a novel class of conditional cross-design synthesis estimators that combine randomized and observational data, while addressing their estimates' respective biases—lack of overlap and unmeasured confounding. These methods enable estimating the causal effect of managed care plans on health care spending among Medicaid beneficiaries in New York City, which requires obtaining estimates for the 7% of beneficiaries randomized to a plan and 93% who choose a plan, who do not resemble randomized beneficiaries. Our new estimators include outcome regression, propensity weighting, and double robust approaches. All use the covariate overlap between the randomized and observational data to remove potential unmeasured confounding bias. Applying these methods, we find substantial heterogeneity in spending effects across managed care plans. This has major implications for our understanding of Medicaid, where this heterogeneity has previously been hidden. Additionally, we demonstrate that unmeasured confounding rather than lack of overlap poses a larger concern in this setting.

Rationale: The predominant cause of chronic lung allograft failure is small airway obstruction arising from bronchiolitis obliterans. However, clinical methodologies for evaluating presence and degree of small airway disease are lacking. Objectives: To determine if parametric response mapping (PRM), a novel computed tomography voxel-wise methodology, can offer insight into chronic allograft failure phenotypes and provide prognostic information following spirometric decline. Methods: PRM-based computed tomography metrics quantifying functional small airways disease (PRMfSAD) and parenchymal disease (PRMPD) were compared between bilateral lung transplant recipients with irreversible spirometric decline and control subjects matched by time post-transplant (n = 22). PRMfSAD at spirometric decline was evaluated as a prognostic marker for mortality in a cohort study via multivariable restricted mean models (n = 52). Measurements and Main Results: Patients presenting with an isolated decline in FEV1 (FEV1 First) had significantly higher PRMfSAD than control subjects (28% vs. 15%; P = 0.005), whereas patients with concurrent decline in FEV1 and FVC had significantly higher PRMPD than control subjects (39% vs. 20%; P = 0.02). Over 8.3 years of follow-up, FEV1 First patients with PRMfSAD greater than or equal to 30% at spirometric decline lived on average 2.6 years less than those with PRMfSAD less than 30% (P = 0.004). In this group, PRMfSAD greater than or equal to 30% was the strongest predictor of survival in a multivariable model including bronchiolitis obliterans syndrome grade and baseline FEV1% predicted (P = 0.04). Conclusions: PRM is a novel imaging tool for lung transplant recipients presenting with spirometric decline. Quantifying underlying small airway obstruction via PRMfSAD helps further stratify the risk of death in patients with diverse spirometric decline patterns.

Objective. The multibiomarker disease activity (MBDA) blood test has been clinically validated as a measure of disease activity in patients with RA. We aimed to estimate the effect of the MBDA test on physical function for patients with RA (based on HAQ), quality-adjusted life years and costs over 10 years. Methods. A decision analysis was conducted to quantify the effect of using the MBDA test on RA-related outcomes and costs to private payers and employers. Results of a clinical management study reporting changes to anti-rheumatic drug recommendations after use of the MBDA test informed clinical utility. The effect of treatment changes on HAQ was derived from 5 tight-control and 13 treatment-switch trials. Baseline HAQ scores and the HAQ score relationship with medical costs and quality of life were derived from published National Data Bank for Rheumatic Diseases data. Results. Use of the MBDA test is projected to improve HAQ scores by 0.09 units in year 1, declining to 0.02 units after 10 years. Over the 10 year time horizon, quality-adjusted life years increased by 0.08 years and costs decreased by US$457 (cost savings in disability-related medical costs, US$659; in productivity costs, US$2137). The most influential variable in the analysis was the effect of the MBDA test on clinician treatment recommendations and subsequent HAQ changes. Conclusion. The MBDA test aids in the assessment of disease activity in patients with RA by changing treatment decisions, improving the functional status of patients and cost savings. Further validation is ongoing and future longitudinal studies are warranted.

This literature review assessed the burden of treatment-resistant depression in the United States by compiling published data about the clinical, societal, and economic outcomes associated with failure to respond to one or more adequate trials of drug therapy. PubMed and the Tufts Cost-Effectiveness Analyses Registry were searched for English-language articles published between January 1996 and August 2013 that collected primary data about treatment-resistant depression. Two researchers independently assessed study quality and extracted data. Sixty-two articles were included (N=59,462 patients). Patients with treatment-resistant depression had 3.8±2.1 prior depressive episodes and illness duration of 4.4±3.3 years and had completed 4.7±2.7 unsuccessful drug trials involving 2.1±.3 drug classes. Response rates for treatment-resistant depression were 36%±1%. A total of 17%±6% of patients had prior suicide attempts (1.1±.2 attempts per patient). Quality-of-life scores (scale of 0-1, with 0 indicating death and 1 indicating perfect health) for patients with treatment-resistant depression were .41±.8 and .26±.8 points lower, respectively, than for patients who experienced remission or response. Annual costs for health care and lost productivity were $5,481 and $4,048 higher, respectively, for patients with treatment-resistant versus treatment-responsive depression. Treatment-resistant depression exacts a substantial toll on patients' quality of life. At current rates of 12%-20% among all depressed patients, treatment-resistant depression may present an annual added societal cost of $29-$48 billion, pushing up the total societal costs of major depression by as much as $106-$118 billion. These findings underscore the need for research on the mechanisms of depression, new therapeutic targets, existing and new treatment combinations, and tests to improve the efficacy of and adherence to treatments for treatment-resistant depression.

Patients with schizophrenia often fail to respond to an initial course of therapy. This study systematically reviewed the societal and economic burden of treatment-resistant schizophrenia (TRS). Studies that described patients with TRS published 1996-2012 were included if they collected primary data on clinical, social, or economic outcomes. All studies were independently reviewed and extracted by at least two investigators. Sixty-five studies were identified. Almost 60% (SD 18%) of patients failed to achieve response after 23 weeks on antipsychotic drug therapy. Patients with TRS had high rates of smoking (56%), alcohol abuse (51%), substance abuse (51%), and suicide ideation (44%). The incidence of severe adverse events to treatment was 4% (SD 7%). Mean quality of life for patients who were unresponsive or intolerant to treatment was ∼20% lower than that of patients in remission. Annual costs for patients with schizophrenia are $15 500-$22 300 and are 3-11-fold higher for patients with TRS. TRS remains common and costly, despite availability of many treatment options, and contributes to a significant loss in patient quality of life. Although estimates in the literature vary greatly, TRS conservatively adds more than $34 billion in annual direct medical costs in the USA.

Background: Gene expression profiling (GEP) reliably supplements traditional clinicopathological information on the tissue of origin (TOO) in metastatic or poorly differentiated cancer. A cost-effectiveness analysis of GEP TOO testing versus usual care was conducted from a third-party payer perspective in the United States. Methods: A retrospective, observational study examined treatment changes in patients whose physicians had received the GEP TOO test results to help diagnose the tissue-site of their patient's malignancy and to guide appropriate therapy. Changes in planned chemotherapy, surgery, radiation therapy, added blood tests, imaging investigations, and referral to hospice care before and after the GEP TOO test results were recorded. The effect of changes in chemotherapy on survival were based on randomized controlled trials informing appropriate use of chemotherapy cited in National Comprehensive Cancer Network (NCCN) and Up-to-Date guidelines. Drug and administration costs were based on average doses reported in NCCN guidelines. Centers for Medicare and Medicaid Services (CMS) fee schedules were used to obtain other unit costs. Quality-of-life weights were obtained from literature sources. Changes in overall survival, costs, and cost per quality-adjusted life year (QALY) gained were estimated using bootstrap methods. Results: Use of chemotherapy regimens consistent with guidelines for the final tumor-site diagnosis increased significantly from 42% to 65% (net difference 23%; p< 0.001). Overall survival was projected to increase from 15.9 months to 19.5 months (mean difference 3.6 months, 95%CI [2.0, 5.1]). The average increase in survival adjusted for quality of life was 2.7 months (95%CI [1.4, 3.9]), and average third-party payer costs per patient increased by $10,360 (95% CI [$5,668, $15,053]). The cost per QALY gained was $46,858 (95% CI [$17,995, $75,718]). Conclusions: GEP TOO testing significantly altered clinical practice patterns for treating metastatic cancer of uncertain primary. It is projected to increase overall survival, QALYs, and costs, resulting in an expected cost per QALY of less than $50,000.