A chat with Daniel Polsky Mitra, Nandita
Health services and outcomes research methodology,
12/2020, Letnik:
20, Številka:
4
Journal Article
Dr. Daniel Polsky gave the opening Keynote Address at the 2020 ICHPS conference in San Diego, CA. In this interview, we highlight his career achievements in health economics and health policy that ...made him uniquely qualified to give this address. We also focus on his thoughts on bridging the gap between methodological health policy research and policy implementation. We end with his specific advice and recommendations for both junior investigators and leaders in statistics on ways to ensure that their research remains relevant, translatable, and impactful to policy makers.
A bronchial-airway gene-expression classifier that is used in combination with results on bronchoscopy helps to identify intermediate-risk patients who are unlikely to have lung cancer.
Lesions that ...are suspicious for lung cancer are frequently identified on chest imaging. The decision to pursue surveillance imaging or an invasive evaluation requires an assessment of the likelihood of cancer, the ability to biopsy, the surgical risk, and the patient’s preferences.
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When biopsy is required, the approach can include bronchoscopy, transthoracic needle biopsy, or surgical lung biopsy. The choice among these procedures is determined on the basis of considerations such as lesion size and location, the presence of adenopathy, the risk associated with the procedure, and local expertise. Bronchoscopy is relatively safe, with less than 1% of procedures complicated . . .
The goal of the study was to determine whether complications of diabetes well-known to be associated with death such as cardiovascular disease and renal failure fully explain the higher rate of death ...in those who have undergone a lower-extremity amputation (LEA).
This was a longitudinal cohort study of patients cared for in the Health Improvement Network. Our primary exposure was LEA and outcome was all-cause death. Our "risk factor variables" included a history of cardiovascular disease (a history of myocardial infarctions, cerebrovascular accident, and peripheral vascular disease/arterial insufficiency), Charlson index, and a history of chronic kidney disease. We estimated the effect of LEA on death using Cox proportional hazards models.
The hazard ratio (HR) for death after an LEA was 3.02 (95% CI 2.90, 3.14). The fully adjusted (all risk factor variables) LEA HR was diminished only by ∼22% to 2.37 (2.27, 2.48). Furthermore, LEA had an area under the receiver operating curve (AUC) of 0.51, which is poorly predictive, and the fully adjusted model had an AUC of 0.77, which is better but not strongly predictive. Sensitivity analysis revealed that it is unlikely that there exists an unmeasured confounder that can fully explain the association of LEA with death.
Individuals with diabetes and an LEA are more likely to die at any given point in time than those who have diabetes but no LEA. While some of this variation can be explained by known complications of diabetes, there remains a large amount of unexplained variation.
To examine practice patterns and compare survival outcomes between total laryngectomy (TL) and larynx preservation chemoradiation (LP-CRT) in the setting of T4a larynx cancer, using a large national ...cancer registry.
Using the National Cancer Database, we identified 969 patients from 2003 to 2006 with T4a squamous cell larynx cancer receiving definitive treatment with either initial TL plus adjuvant therapy or LP-CRT. Univariate and multivariable logistic regression were used to assess predictors of undergoing surgery. Survival outcomes were compared using Kaplan-Meier and propensity score-adjusted and inverse probability of treatment-weighted Cox proportional hazards methods. Sensitivity analyses were performed to account for unmeasured confounders.
A total of 616 patients (64%) received LP-CRT, and 353 (36%) received TL. On multivariable logistic regression, patients with advanced nodal disease were less likely to receive TL (N2 vs N0, 26.6% vs 43.4%, odds ratio OR 0.52, 95% confidence interval CI 0.37-0.73; N3 vs N0, 19.1% vs 43.4%, OR 0.23, 95% CI 0.07-0.77), whereas patients treated in high case-volume facilities were more likely to receive TL (46.1% vs 31.5%, OR 1.78, 95% CI 1.27-2.48). Median survival for TL versus LP was 61 versus 39 months (P<.001). After controlling for potential confounders, LP-CRT had inferior overall survival compared with TL (hazard ratio 1.31, 95% CI 1.10-1.57), and with the inverse probability of treatment-weighted model (hazard ratio 1.25, 95% CI 1.05-1.49). This survival difference was shown to be robust on additional sensitivity analyses.
Most patients with T4a larynx cancer receive LP-CRT, despite guidelines suggesting TL as the preferred initial approach. Patients receiving LP-CRT had more advanced nodal disease and worse overall survival. Previous studies of (non-T4a) locally advanced larynx cancer showing no difference in survival between LP-CRT and TL may not apply to T4a disease, and patients should be counseled accordingly.
ObjectiveNudges are interventions that alter the way options are presented, enabling individuals to more easily select the best option. Health systems and researchers have tested nudges to shape ...clinician decision-making with the aim of improving healthcare service delivery. We aimed to systematically study the use and effectiveness of nudges designed to improve clinicians’ decisions in healthcare settings.DesignA systematic review was conducted to collect and consolidate results from studies testing nudges and to determine whether nudges directed at improving clinical decisions in healthcare settings across clinician types were effective. We systematically searched seven databases (EBSCO MegaFILE, EconLit, Embase, PsycINFO, PubMed, Scopus and Web of Science) and used a snowball sampling technique to identify peer-reviewed published studies available between 1 January 1984 and 22 April 2020. Eligible studies were critically appraised and narratively synthesised. We categorised nudges according to a taxonomy derived from the Nuffield Council on Bioethics. Included studies were appraised using the Cochrane Risk of Bias Assessment Tool.ResultsWe screened 3608 studies and 39 studies met our criteria. The majority of the studies (90%) were conducted in the USA and 36% were randomised controlled trials. The most commonly studied nudge intervention (46%) framed information for clinicians, often through peer comparison feedback. Nudges that guided clinical decisions through default options or by enabling choice were also frequently studied (31%). Information framing, default and enabling choice nudges showed promise, whereas the effectiveness of other nudge types was mixed. Given the inclusion of non-experimental designs, only a small portion of studies were at minimal risk of bias (33%) across all Cochrane criteria.ConclusionsNudges that frame information, change default options or enable choice are frequently studied and show promise in improving clinical decision-making. Future work should examine how nudges compare to non-nudge interventions (eg, policy interventions) in improving healthcare.
Unmeasured confounding is a common concern when researchers attempt to estimate a treatment effect using observational data or randomized studies with nonperfect compliance. To address this concern, ...instrumental variable methods, such as 2‐stage predictor substitution (2SPS) and 2‐stage residual inclusion (2SRI), have been widely adopted. In many clinical studies of binary and survival outcomes, 2SRI has been accepted as the method of choice over 2SPS, but a compelling theoretical rationale has not been postulated. We evaluate the bias and consistency in estimating the conditional treatment effect for both 2SPS and 2SRI when the outcome is binary, count, or time to event. We demonstrate analytically that the bias in 2SPS and 2SRI estimators can be reframed to mirror the problem of omitted variables in nonlinear models and that there is a direct relationship with the collapsibility of effect measures. In contrast to conclusions made by previous studies (Terza et al, 2008), we demonstrate that the consistency of 2SRI estimators only holds under the following conditions: (1) when the null hypothesis is true; (2) when the outcome model is collapsible; or (3) when estimating the nonnull causal effect from Cox or logistic regression models, the strong and unrealistic assumption that the effect of the unmeasured covariates on the treatment is proportional to their effect on the outcome needs to hold. We propose a novel dissimilarity metric to provide an intuitive explanation of the bias of 2SRI estimators in noncollapsible models and demonstrate that with increasing dissimilarity between the effects of the unmeasured covariates on the treatment versus outcome, the bias of 2SRI increases in magnitude.
This trial tested the safety and efficacy of a novel, deintensified radiation therapy (RT) approach after initial surgical resection for patients with human papilloma virus (HPV)-associated ...oropharyngeal squamous cell carcinoma (OPSCC).
This single-arm phase 2 prospective clinical trial enrolled 60 patients with stage pT1-pT2 N1-3 HPV-associated OPSCC treated with transoral robotic surgery (TORS) and selective neck dissection at a single institution between May 2014 and September 2017. Patients had favorable features at the primary site (negative surgical margins ≥2 mm, no perineural invasion, and no lymphovascular invasion) but required adjuvant therapy based on lymph node involvement. Surgeries were all performed at a high-volume head and neck cancer center with expertise in TORS. Patients received postoperative RT to at-risk areas in the involved neck (60-66 Gy) and uninvolved neck (54 Gy). The resected primary site was treated as an active avoidance structure in the treatment planning of postoperative RT. Concurrent chemotherapy was administered for patients with extranodal extension.
Median follow-up of the 60 patients enrolled was 2.4 years (range, 8.5-53.8 months). A single patient recurred at the primary site, for 2-year local control of 98.3%. One patient (1.7%) developed a regional neck recurrence, and 2 patients (3.3%) developed distant metastases. Measured 2-year local recurrence-free survival was 97.9% (95% confidence interval, 86.1%-99.7%). Overall survival was 100% at the time of analysis. The mean radiation dose to the primary site was 36.9 Gy (standard deviation, 10.3 Gy). Two patients (3.3%) experienced late soft tissue necrosis in the primary site surgical bed that resolved within 2 months. Feeding tube dependence rates were 0% during RT, 3.3% temporarily during follow-up, and 0% at last follow-up.
Deintensified postoperative RT that avoids the resected primary tumor site and targets only the at-risk neck after TORS for selected patients with HPV-associated OPSCC may be safe and is worthy of further study.
Background Atopic dermatitis (AD) is a common skin disease that is characterized by recurrent episodes of itching. Filaggrin ( FLG ) loss-of-function ( FLG null) mutations have been associated with ...an increased risk of AD. Objective We sought to evaluate the effect of individual FLG null mutations on the persistence of AD over time. Methods We evaluated a multiyear prospective cohort study of children with AD with respect to FLG null mutations (R501X, 2282del4, R2447X, and S3247X). We evaluated the association of these mutations with the persistence of AD symptoms over time with respect to reports of no symptoms of AD and whether topical medication was needed for symptom resolution. Results Eight hundred fifty-seven subjects were followed for 3684 person-years. One or more FLG null mutations were noted in 16.3% of subjects and specifically in 27.5% of white subjects and 5.8% of African American subjects. Subjects with an FLG null mutation were less likely (odds ratio OR, 0.54; 95% CI, 0.41-0.71) to report that their skin was symptom free at any time compared with those without an FLG null mutation. The effect of these mutations was similar in white subjects (OR, 0.42; 95% CI, 0.31-0.57) and African-American subjects (OR, 0.53; 95% CI, 0.25-1.12; P = .62). Children with the R501X mutation (OR, 0.44; 95% CI, 0.22-0.88) were the least responsive to therapy. Conclusions In a US cohort with AD, FLG null mutations were common. Children with FLG null mutations were more likely to have persistent AD. Although these mutations were more common in those of European ancestry, their effect on persistence was similar in those of African ancestry. Response to therapy was not uniform among children with FLG null mutations.
Propensity score methods are commonly used to adjust for observed confounding when estimating the conditional treatment effect in observational studies. One popular method, covariate adjustment of ...the propensity score in a regression model, has been empirically shown to be biased in non-linear models. However, no compelling underlying theoretical reason has been presented. We propose a new framework to investigate bias and consistency of propensity score-adjusted treatment effects in non-linear models that uses a simple geometric approach to forge a link between the consistency of the propensity score estimator and the collapsibility of non-linear models. Under this framework, we demonstrate that adjustment of the propensity score in an outcome model results in the decomposition of observed covariates into the propensity score and a remainder term. Omission of this remainder term from a non-collapsible regression model leads to biased estimates of the conditional odds ratio and conditional hazard ratio, but not for the conditional rate ratio. We further show, via simulation studies, that the bias in these propensity score-adjusted estimators increases with larger treatment effect size, larger covariate effects, and increasing dissimilarity between the coefficients of the covariates in the treatment model versus the outcome model.
Objective
To identify prevalences and predictors of nonfinancial barriers that lead to unmet need or delayed care among U.S. adults.
Data Source
2007 Health Tracking Household Survey.
Study Design
...Reasons for unmet need or delayed care in the previous 12 months were assigned to one of five dimensions in the Penchansky and Thomas model of access to care. Prevalences of barriers in each nonfinancial dimension were estimated for all adults and for adults with affordability barriers. Multivariable logistic regression models were used to estimate associations between individual, household, and insurance characteristics and barriers in each access dimension.
Principal Findings
Eighteen percent of U.S. adults experienced affordability barriers and 21 percent experienced nonfinancial barriers that led to unmet need or delayed care. Two‐thirds of adults with affordability barriers also reported nonfinancial barriers. Young adults, women, individuals with lower incomes, parents, and persons with at least one chronic illness had higher adjusted prevalences of nonfinancial barriers.
Conclusions
Nonfinancial barriers are common reasons for unmet need or delayed care among U.S. adults and frequently coincide with affordability barriers. Failure to address nonfinancial barriers may limit the impact of policies that seek to expand access by improving the affordability of health care.
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