A Deep Learning Decision Support Tool to Improve Risk Stratification and Reduce Unnecessary Biopsies in BI-RADS 4 Mammograms.

Purpose: To evaluate the performance of a biopsy decision support algorithmic model, the intelligent-augmented breast cancer risk calculator (iBRISK), on a multicenter patient dataset. Materials and Methods: iBRISK was previously developed by applying deep learning to clinical risk factors and mammographic descriptors from 9700 patient records at the primary institution and validated using another 1078 patients. All patients were seen from March 2006 to December 2016. In this multicenter study, iBRISK was further assessed on an independent, retrospective dataset (January 2015-June 2019) from three major health care institutions in Texas, with Breast Imaging Reporting and Data System (BI-RADS) category 4 lesions. Data were dichotomized and trichotomized to measure precision in risk stratification and probability of malignancy (POM) estimation. iBRISK score was also evaluated as a continuous predictor of malignancy, and cost savings analysis was performed. Results: The iBRISK model's accuracy was 89.5%, area under the receiver operating characteristic curve (AUC) was 0.93 (95% CI: 0.92, 0.95), sensitivity was 100%, and specificity was 81%. A total of 4209 women (median age, 56 years [IQR, 45-65 years]) were included in the multicenter dataset. Only two of 1228 patients (0.16%) in the "low" POM group had malignant lesions, while in the "high" POM group, the malignancy rate was 85.9%. iBRISK score as a continuous predictor of malignancy yielded an AUC of 0.97 (95% CI: 0.97, 0.98). Estimated potential cost savings were more than $420 million. Conclusion: iBRISK demonstrated high sensitivity in the malignancy prediction of BI-RADS 4 lesions. iBRISK may safely obviate biopsies in up to 50% of patients in low or moderate POM groups and reduce biopsy-associated costs.Keywords: Mammography, Breast, Oncology, Biopsy/Needle Aspiration, Radiomics, Precision Mammography, AI-augmented Biopsy Decision Support Tool, Breast Cancer Risk Calculator, BI-RADS 4 Mammography Risk Stratification, Overbiopsy Reduction, Probability of Malignancy (POM) Assessment, Biopsy-based Positive Predictive Value (PPV3) Supplemental material is available for this article. Published under a CC BY 4.0 license.See also the commentary by McDonald and Conant in this issue.

Financial toxicity in cancer patients and subsequent risk of repeat acute care utilization.

Background: Acute care (AC) visits by cancer patients are costly sources of healthcare resources and can exert a financial burden of oncology care both for individuals with cancer and healthcare systems. We sought to identify whether cancer patients who reported more severe initial financial toxicity (FT) burdens shouldered excess risks for acute care utilization. Methods: In 225 adult patients who participated in the Economic Strain and Resilience in Cancer (ENRICh) survey study of individuals receiving ambulatory cancer care between March and September 2019, we measured the baseline FT (a multidimensional score of 0-10 indicating the least to most severe global, material, and coping FT burdens). All AC visits, including emergency department (ED) and unplanned hospital admissions, within 1-year follow-up were identified. The association between the severity of FT and the total number of AC visits was tested using Poisson regression models. Results: A total of 18.6% (n = 42) of patients had any AC visit, comprising 64.3% hospital admissions and 35.7% ED visits. Global FT burden was associated with the risk of repeat AC visits within 1-year follow-up (RR = 1.17, 95% CI 1.07-1.29, P < 0.001 for every unit increase), even after adjusting for sociodemographic and disease covariates. When examining subdimensions of FT, the burden of depleted FT coping resources (coping FT) was strongly associated with the risk of repeat AC visits (RR = 1.27, 95% CI 1.15-1.40, P < 0.001) while material FT burden showed a trend toward association (RR = 1.07, 95% CI 0.99-1.15, P = 0.07). Conclusion: In this prospective study of acute oncology care utilization outcomes among adult cancer patients, FT was a predictor of a higher burden of acute care visits. Patients with severely depleted material and also practical and social coping resources were at particular risk for repeated visits. Future studies are needed to identify whether early FT screening and intervention efforts may help to mitigate urgent acute care utilization burdens.

A flexible quasi-likelihood model for microbiome abundance count data.

In this article, we present a flexible model for microbiome count data. We consider a quasi-likelihood framework, in which we do not make any assumptions on the distribution of the microbiome count except that its variance is an unknown but smooth function of the mean. By comparing our model to the negative binomial generalized linear model (GLM) and Poisson GLM in simulation studies, we show that our flexible quasi-likelihood method yields valid inferential results. Using a real microbiome study, we demonstrate the utility of our method by examining the relationship between adenomas and microbiota. We also provide an R package "fql" for the application of our method.

Pilot study of a Spanish language measure of financial toxicity in underserved Hispanic cancer patients with low English proficiency.

Background: Financial toxicity (FT) reflects multi-dimensional personal economic hardships borne by cancer patients. It is unknown whether measures of FT-to date derived largely from English-speakers-adequately capture economic experiences and financial hardships of medically underserved low English proficiency US Hispanic cancer patients. We piloted a Spanish language FT instrument in this population. Methods: We piloted a Spanish version of the Economic Strain and Resilience in Cancer (ENRICh) FT measure using qualitative cognitive interviews and surveys in un-/under-insured or medically underserved, low English proficiency, Spanish-speaking Hispanics (UN-Spanish, n = 23) receiving ambulatory oncology care at a public healthcare safety net hospital in the Houston metropolitan area. Exploratory analyses compared ENRICh FT scores amongst the UN-Spanish group to: (1) un-/under-insured English-speaking Hispanics (UN-English, n = 23) from the same public facility and (2) insured English-speaking Hispanics (INS-English, n = 31) from an academic comprehensive cancer center. Multivariable logistic models compared the outcome of severe FT (score > 6). Results: UN-Spanish Hispanic participants reported high acceptability of the instrument (only 0% responded that the instrument was "very difficult to answer" and 4% that it was "very difficult to understand the questions"; 8% responded that it was "very difficult to remember resources used" and 8% that it was "very difficult to remember the burdens experienced"; and 4% responded that it was "very uncomfortable to respond"). Internal consistency of the FT measure was high (Cronbach's α = 0.906). In qualitative responses, UN-Spanish Hispanics frequently identified a total lack of credit, savings, or income and food insecurity as aspects contributing to FT. UN-Spanish and UN-English Hispanic patients were younger, had lower education and income, resided in socioeconomically deprived neighborhoods and had more advanced cancer vs. INS-English Hispanics. There was a higher likelihood of severe FT in UN-Spanish (OR = 2.73, 95% CI 0.77-9.70; p = 0.12) and UN-English (OR = 4.13, 95% CI 1.13-15.12; p = 0.03) vs. INS-English Hispanics. A higher likelihood of severely depleted FT coping resources occurred in UN-Spanish (OR = 4.00, 95% CI 1.07-14.92; p = 0.04) and UN-English (OR = 5.73, 95% CI 1.49-22.1; p = 0.01) vs. INS-English. The likelihood of FT did not differ between UN-Spanish and UN-English in both models (p = 0.59 and p = 0.62 respectively). Conclusion: In medically underserved, uninsured Hispanic patients with cancer, comprehensive Spanish-language FT assessment in low English proficiency participants was feasible, acceptable, and internally consistent. Future studies employing tailored FT assessment and intervention should encompass the key privations and hardships in this population.

Short-form adaptive measure of financial toxicity from the Economic Strain and Resilience in Cancer (ENRICh) study: Derivation using modern psychometric techniques.

OBJECTIVES: This study sought to evaluate advanced psychometric properties of the 15-item Economic Strain and Resilience in Cancer (ENRICh) measure of financial toxicity for cancer patients. METHODS: We surveyed 515 cancer patients in the greater Houston metropolitan area using ENRICh from March 2019 to March 2020. We conducted a series of factor analyses alongside parametric and non-parametric item response theory (IRT) assessments using Mokken analysis and the graded response model (GRM). We utilized parameters derived from the GRM to run a simulated computerized adaptive test (CAT) assessment. RESULTS: Among participants, mean age was 58.49 years and 278 (54%) were female. The initial round factor analysis results suggested a one-factor scale structure. Negligible levels of differential item functioning (DIF) were evident between eight items. Three items were removed due to local interdependence (Q3>+0.4). The original 11-point numerical rating scale did not function well, and a new 3-point scoring system was implemented. The final 12-item ENRICh had acceptable fit to the GRM (p<0.001; TLI = 0.94; CFI = 0.95; RMSEA = 0.09; RMSR = 0.06) as well as good scalability and dimensionality. We observed high correlation between CAT version scores and the 12-item measure (r = 0.98). During CAT, items 2 (money you owe) and 4 (stress level about finances) were most frequently administered, followed by items 1 (money in savings) and 5 (ability to pay bills). Scores from these four items alone were strongly correlated with that of the 12-item ENRICh (r = 0.96). CONCLUSION: These CAT and 4-item versions provide options for quick screening in clinical practice and low-burden assessment in research.

Financial toxicity impact on younger versus older adults with cancer in the setting of care delivery.

BACKGROUND: Young adults and other working-age adults with cancer are at risk for cancer-related financial toxicity (FT), including material hardships, depletion of coping resources, and psychological burden. This study compares FT domains in young adults (18-39 years old) (YAs), other working-age adults (40-64 years old), and older adults (≥65 years old) receiving cancer care. METHODS: A total of 311 adults were surveyed using the multi-domain Economic Strain and Resilience in Cancer instrument measuring FT (0-10 score indicating least to greatest FT; score ≥5 severe FT). Participants were receiving ambulatory care from March-September 2019. Associations of age with overall FT and material hardship, coping resource depletion, and psychological burden FT domains were tested using Kruskal-Wallis and χ2 tests and multivariable generalized linear models with gamma distribution. RESULTS: YAs (median age, 31.5 years) comprised 9.6% of the sample; other working-age adults comprised 56.9%. Overall, material, coping, and psychological FT scores were worse in younger age adults versus older adults (P < .001 in all multivariable models). Compared with older adults, younger age adults demonstrated worse material hardship (median scores, 3.70 vs 4.80 vs 1.30 for YAs, other working-age, and older adults, respectively; P < .001), coping resource depletion (4.50 vs 3.40 vs 0.80; P < .001), and psychological burden (6.50 vs 7.00 vs 1.00; P < .001). Fifty percent of YAs had severe overall FT versus 40.7% of other working-age adults and 9.6% of older adults (P < .001). CONCLUSIONS: Younger age adults with cancer bore disproportionate FT. Interventions to address unmet needs are critical components for addressing FT in this population.

Sensitivity of Psychosocial Distress Screening to Identify Cancer Patients at Risk for Financial Hardship During Care Delivery.

PURPOSE: Patients with cancer frequently encounter financial hardship, yet systematic strategies to identify at-risk patients are not established in care delivery. We assessed sensitivity of distress-based screening to identify patients with cancer-related financial hardship and associated care delivery outcomes. METHODS: A survey of 225 patients at a large cancer center assessed cancer-related financial hardship (0-10 Likert scale; highest quintile scores ≥ 5 defined severe hardship). Responses were linked to electronic medical records identifying patients' distress screening scores 6 months presurvey (0-10 scale) and outcomes of missed cancer care visits and bad debt charges (unrecovered patient charges) within 6 months postsurvey. A positive screen for distress was defined as score ≥ 4. We analyzed screening test characteristics for identifying severe financial hardship within 6 months and associations between financial hardship and outcomes using logistic models. RESULTS: Although patients with positive distress screens were more likely to report financial hardship (odds ratio [OR], 1.21; 1.08-1.37; P < .001), a positive distress screen was only 48% sensitive and 70% specific for identifying severe financial hardship. Patients with worse financial hardship scores were more likely to miss oncology care visits within 6 months (for every additional point in financial hardship score from 0 to 10, OR, 1.28; 1.12-1.47; P < .001). Of patients with severe hardship, 72% missed oncology visits versus 35% without severe hardship (P = .006). Patients with worse hardship were more likely to incur any bad debt charges within 6 months (OR, 1.32; 1.13-1.54; P < .001). CONCLUSION: Systematic financial hardship screening is needed to help mitigate adverse care delivery outcomes. Existing distress-based screening lacks sensitivity.

Factors Associated With Hospital Decisions to Purchase Robotic Surgical Systems.

Background. Robotic surgical systems are expensive to own and operate, and the purchase of such technology is an important decision for hospital administrators. Most prior literature focuses on the comparison of clinical outcomes between robotic surgery and other laparoscopic or open surgery. There is a knowledge gap about what drives hospitals' decisions to purchase robotic systems. Objective. To identify factors associated with a hospital's acquisition of advanced surgical systems. Method. We used 2002 to 2011 data from the State of California Office of Statewide Health Planning and Development to examine robotic surgical system purchase decisions of 476 hospitals. We used a probit estimation allowing heteroscedasticity in the error term including a set of two equations: one binary response equation and one heteroscedasticity equation. Results. During the study timeframe, there were 78 robotic surgical systems purchased by hospitals in the sample. Controlling for hospital characteristics such as number of available beds, teaching status, nonprofit status, and patient mix, the probit estimation showed that market-level directly relevant surgery volume in the previous year (excluding the hospital's own volume) had the largest impact. More specifically, hospitals in high volume (>50,000 surgeries v. 0) markets were 12 percentage points more likely to purchase robotic systems. We also found that hospitals in less competitive markets (i.e., Herfindahl index above 2500) were 2 percentage points more likely to purchase robotic systems. Limitations. This study has limitations common to observational database studies. Certain characteristics such as cultural factors cannot be accurately quantified. Conclusions. Our findings imply that potential market demand is a strong driver for hospital purchase of robotic surgical systems. Market competition does not significantly increase the adoption of new expensive surgical technologies.

Racial Differences in the Incidence and Survival of Patients With Neuroendocrine Tumors.

OBJECTIVES: The incidence of neuroendocrine tumors (NETs) has been steadily increasing. Racial differences in the incidence and survival are mostly unknown. This study examines the racial differences and the underlying causes. METHODS: We conducted a retrospective, population-based study using datasets from Surveillance, Epidemiology, and End Results (SEER) cancer registry and SEER data linked with Medicare claims (SEER-Medicare). We examined the incidence rates and the effects of patient demographics, clinical characteristics, and socioeconomic factors on survival. RESULTS: Of the 15,786 and 1731 cases from SEER and SEER-Medicare, 1991 and 163 were blacks, respectively. We found that blacks had higher NET incidence for all stages, with the largest difference noted in the local stage (4.3 vs 2.6 per 100,000 in whites). We found worse survival for distant-stage black patients, although they more often had clinical factors typically associated with better prognosis in NETs. However, they were also found to have significant unfavorable differences in socioeconomic and sociodemographic factors. CONCLUSIONS: Blacks have higher incidence of NETs and worse survival compared with other races, especially whites. The influences of neighborhood socioeconomic, sociodemographic, and marital status suggest that social determinants, support mechanisms, and access to health care may be contributing factors.

The concomitant use of tyrosine kinase inhibitors and proton pump inhibitors: Prevalence, predictors, and impact on survival and discontinuation of therapy in older adults with cancer.

BACKGROUND: The concomitant use of tyrosine kinase inhibitors (TKIs) and proton pump inhibitors (PPIs) is a significant concern because of potential drug-drug interaction that reduces TKI absorption, thus potentially reducing the effectiveness of TKIs. The objective of this study was to evaluate the prevalence and predictors of concomitant TKI-PPI receipt and its impact on survival and therapy discontinuation in older adults with cancer. METHODS: This retrospective study used linked Surveillance, Epidemiology, and End Results-Medicare data for the years 2007 through 2012. In total, 12,538 patients with lung cancer, renal cell cancer, chronic myelogenous leukemia, liver cancer, or pancreatic cancer were included. The primary exposure variable was concomitant receipt of TKI-PPI, defined as at least 30 days of PPI use in the first 90 days from the start of the TKI (exposure period). The outcomes measured were overall survival and discontinuation of therapy in 90 days and 1 year after the end of the exposure period. Cox proportional-hazards regression with inverse probability of treatment weighting was used to evaluate the association between exposure and outcome. RESULTS: The overall prevalence of TKI-PPI receipt was 22.7%. Predictors that were associated with increased use included polypharmacy and prior PPI receipt. TKI-PPI use decreased survival in 90 days (hazard ratio, 1.16; 95% confidence interval, 1.05-1.28) and in 1 year (hazard ratio, 1.10; 95% confidence interval, 1.04-1.18) but was not associated with discontinuation. CONCLUSIONS: Nearly 1 in 4 older adults with cancer who receive TKIs also receive PPIs concomitantly, and concomitant use is associated with an increased risk of death. Concerted efforts to manage medications are needed to identify and reduce the receipt of PPIs when TKIs are initiated.

A flexible quantile regression model for medical costs with application to Medical Expenditure Panel Survey Study.

Medical costs are often skewed to the right and heteroscedastic, having a sophisticated relation with covariates. Mean function regression models with low-dimensional covariates have been extensively considered in the literature. However, it is important to develop a robust alternative to find the underlying relationship between medical costs and high-dimensional covariates. In this paper, we propose a new quantile regression model to analyze medical costs. We also consider variable selection, using an adaptive lasso penalized variable selection method to identify significant factors of the covariates. Simulation studies are conducted to illustrate the performance of the estimation method. We apply our method to the analysis of the Medical Expenditure Panel Survey dataset.

A flexible model for correlated medical costs, with application to medical expenditure panel survey data.

We propose a flexible model for correlated medical cost data with several appealing features. First, the mean function is partially linear. Second, the distributional form for the response is not specified. Third, the covariance structure of correlated medical costs has a semiparametric form. We use extended generalized estimating equations to simultaneously estimate all parameters of interest. B-splines are used to estimate unknown functions, and a modification to Akaike information criterion is proposed for selecting knots in spline bases. We apply the model to correlated medical costs in the Medical Expenditure Panel Survey dataset. Simulation studies are conducted to assess the performance of our method.

Variation in Intensity and Costs of Care by Payer and Race for Patients Dying of Cancer in Texas: An Analysis of Registry-linked Medicaid, Medicare, and Dually Eligible Claims Data.

PURPOSE: To investigate end-of-life care for Medicaid, Medicare, and dually eligible beneficiaries dying of cancer in Texas. METHODS: We analyzed the Texas Cancer Registry (TCR)-Medicaid and TCR-Medicare linked databases' claims data for 69,572 patients dying of cancer in Texas from 2000 to 2008. We conducted regression models in adjusted analyses of cancer-directed and acute care and total costs of care (in 2014 dollars) in the last 30 days of life. RESULTS: Medicaid patients were more likely to receive chemotherapy and radiation therapy. Medicaid patients were more likely to have >1 emergency room (ER) [odds ratio (OR)=5.27; 95% confidence interval (CI), 4.76-5.84], and were less likely to enroll in hospice (OR=0.59; 95% CI, 0.55-0.63) than Medicare patients. Dual eligibles were more likely to have >1 ER visit than Medicare-only beneficiaries (OR=1.19; 95% CI, 1.07-1.33). Black and Hispanic patients were more likely to experience >1 ER visit and >1 hospitalization than whites. Costs were higher for nonwhite Medicare, Medicaid, and dually eligible patients compared with white Medicare enrollees. CONCLUSIONS: Variation in acute care utilization and costs by race and payer suggest efforts are needed to address palliative care coordination at the end of life for Medicaid and dually eligible beneficiaries and minority patients dying of cancer.

Metformin for primary colorectal cancer prevention in patients with diabetes: a case-control study in a US population.

BACKGROUND: Emerging evidence from observational studies has suggested that metformin may be beneficial in the primary prevention of colorectal cancer (CRC). However, to the authors' knowledge, none of these studies was conducted in a US population. Because environmental factors such as Western diet and obesity are implicated in the causation of CRC, a large case-control study was performed to assess the effects of metformin on the incidence of CRC in a US population. METHODS: MarketScan databases were used to identify diabetic patients with CRC. A case was defined as having an incident diagnosis of CRC. Up to 2 controls matched for age, sex, and geographical region were selected for each case. Metformin exposure was assessed by prescription tracking within the 12-month period before the index date. Conditional logistic regression was used to adjust for multiple potential confounders and to calculate adjusted odds ratios (AORs). RESULTS: The mean age of the study participants was 55 years and 57 years, respectively, in the control and case groups (P = 1.0). Approximately 60% of the study participants were male and 40% were female in each group. In the multivariable model, any metformin use was associated with a 15% reduction in the odds of CRC (AOR, 0.85; 95% confidence interval, 0.76-0.95 [P = .007]). After adjusting for health care use, the beneficial effect of metformin was reduced to 12% (AOR, 0.88; 95% confidence interval, 0.77-1.00 [P = .05]). The dose-response analyses demonstrated no significant association with metformin dose, duration, or total exposure. CONCLUSIONS: Metformin use appears to be associated with a reduced risk of developing CRC among diabetic patients in the United States.

The role of statins for primary prevention in non-elderly colorectal cancer patients.

BACKGROUND: There is conflicting evidence for the role of statins in the primary prevention of colorectal cancer (CRC). We conducted a case control study (N=357,702) in the non-elderly adult US population (age=18-64 years) with the primary objective to examine the association between CRC and statin use. PATIENTS AND METHODS: MarketScan® databases were used to identify patients with CRC. A case was defined as having an incident diagnosis of CRC. Up to ten individually matched controls (age, sex, region and date of diagnosis) were selected per case. Statin exposure was assessed by prescription tracking in the 12 months prior to the index date. Conditional logistic regression was used to adjust for multiple potential confounders and calculate adjusted odds ratios (AOR). RESULTS: The mean age of participants was 54 years; 52% males and 48% females. In a multivariable model, any statin use was associated with 26% reduced odds of CRC (AOR, 0.74, 95% confidence interval (CI), 0.72-0.77, p<0.001). Age-stratified analyses showed a stronger effect of statins on CRC in participants aged 55 years or younger (AOR, 0.67, 95% CI, 0.63-0.71, p<0.001) than in participants aged above 55 years (AOR, 0.79, 95% CI, 0.76-0.82, p<0.001); the age-by-statin interaction was statistically significant (p<0.001). The dose-response analyses performed with simvastatin only showed a trend towards significance between the duration of simvastatin exposure and odds of developing CRC (p=0.06). CONCLUSIONS: Statins appears to reduce the risk of CRC in non-elderly US population. Chemoprevention with statin might be more effective in non-elderly US population.

A review of economic impact of targeted oral anticancer medications.

There has been a rapid increase in the use of targeted oral anticancer medications (OAMs) in the past decade. As OAMs are often expensive, economic consideration play a significant role in the decision to prescribe, receive or cover them. This paper performs a systematic review of costs or budgetary impact of targeted OAMs to better understand their economic impact on the healthcare system, patients as well as payers. We present our review in a summary table that describes the method and main findings, take into account multiple factors, such as country, analytical approach, cost type, study perspective, timeframe, data sources, study population and care setting when we interpret the results from different papers, and discuss the policy and clinical implications. Our review raises a concern regarding the role of sponsorship on findings of economic analyses as the vast majority of pharmaceutical company-sponsored studies reported cost advantages toward the sponsor's drugs.

Population-based determinants of radical prostatectomy operative time.

OBJECTIVES: To determine factors that influence radical prostatectomy (RP) operative times. Operative time assessment is inherent to defining surgeon learning curves and evaluating quality of care. SUBJECTS/PATIENTS AND METHODS: Population-based observational cohort study using USA Surveillance, Epidemiology, and End Results (SEER)-Medicare linked data of men diagnosed with prostate cancer during 2003-2007 who underwent robot-assisted radical prostatectomy (RARP, 3458 men) and retropubic RP (RRP, 6993) through to 2009. We obtained median operative time using anaesthesia administrative data for RP and used median regression to assess the contribution of patient, surgeon, and hospital factors to operative times. RESULTS: The median RARP operative time decreased from 315 to 247 min from 2003 to 2008-2009 (P < 0.001), while the median RRP operative time remained similar (195 vs 197 min, P = 0.90). In adjusted analysis, RARP vs RRP (parameter estimate [PE] 70.9; 95% confidence interval [CI] 58, 84; P < 0.001) and obesity (PE 15; 95% CI 7, 23; P < 0.001) were associated with longer operative times while higher surgeon volumes were associated with shorter operative times (P < 0.001). RPs performed by surgeons employed by group (parameter estimate [PE] -22.76; 95% CI -38, -7.49; P = 0.004) and non-government (PE -35.59; 95% CI -68.15, -3.03; P = 0.032) vs government facilities and non-profit vs government hospital ownership (PE -21.85; 95% CI -32.28, -11.42; P < 0.001) were associated with shorter operative times. CONCLUSIONS: During our study period, RARP operative times decreased by 68 min while RRP operative times remained stagnant. Higher surgeon volume was associated with shorter operative times, and selective referral or improved efficiency to the level of high-volume surgeons would net almost $15 million (USA dollars) in annual savings.

A flexible model for the mean and variance functions, with application to medical cost data.

Medical cost data are often skewed to the right and heteroscedastic, having a nonlinear relation with covariates. To tackle these issues, we consider an extension to generalized linear models by assuming nonlinear associations of covariates in the mean function and allowing the variance to be an unknown but smooth function of the mean. We make no further assumption on the distributional form. The unknown functions are described by penalized splines, and the estimation is carried out using nonparametric quasi-likelihood. Simulation studies show the flexibility and advantages of our approach. We apply the model to the annual medical costs of heart failure patients in the clinical data repository at the University of Virginia Hospital System.

Disparity implications of the Medicare medication therapy management eligibility criteria: a literature review.

The emphasis on eliminating racial and ethnic disparities in healthcare has received national attention, with various policy initiatives addressing this problem and proposing solutions. However, in the current economic era requiring tight monetary constraints, emphasis is increasingly being placed on economic efficiency, which often conflicts with the equality doctrine upon which many policies have been framed. The authors' review aims to highlight the disparity implications of one such policy provision - the predominantly utilization-based eligibility criteria for medication therapy management services under Medicare Part D - by identifying studies that have documented racial and ethnic disparities in health status and the use of and spending on prescription medications. Future design and evaluation of various regulations and legislations employing utilization-based eligibility criteria must use caution in order to strike an equity-efficiency balance.

Adoption of intensity-modulated radiation therapy for breast cancer in the United States.

BACKGROUND: Although intensity modulation of the radiation beam has been shown to lower toxic effects for patients receiving whole-breast irradiation, relatively simple techniques may suffice. It is thus controversial whether such treatment justifies billing for intensity-modulated radiation therapy (IMRT). METHODS: We used the claims data to determine billing for IMRT from Surveillance, Epidemiology, and End Results-Medicare records from 2001 to 2005 for 26,163 women aged 66 years or older with nonmetastatic breast cancer treated with surgery and radiotherapy. The impact of individual covariates (demographic, health services, tumor, and treatment factors) on cost of treatment was assessed using the Wilcoxon two-sample test. Two-sided multivariable logistic regression was used to identify predictors for IMRT use. Cost of radiation was calculated in 2005 dollars. All statistical tests were two-sided. RESULTS: The number of patients with IMRT billing claims increased from 0.9% (49 of 5196) of patients diagnosed in 2001 to 11.2% (564 of 5020) in 2005. In multivariable analysis, IMRT billing was more likely for patients with left-sided tumors (odds ratio [OR] = 1.30, 95% confidence interval [CI] = 1.16 to 1.45), for those residing in a health service area with high radiation oncologist density (OR = 2.32, 95% CI = 1.47 to 3.68), for those treated at freestanding radiation centers (OR = 1.36, 95% CI = 1.20 to 1.53), or for those residing in regions where the Medicare intermediary allowed breast IMRT (OR = 10.87, 95% CI = 9.26 to 12.76, all P < .001). The mean cost of radiation was $7179 without IMRT and $15 230 with IMRT. IMRT adoption contributed to an increase in the mean cost of breast radiation from $6334 in 2001 to $8473 in 2005. CONCLUSIONS: IMRT billing increased 10-fold from 2001 through 2005, contributing to a 33% increase in the cost of breast radiation. These findings suggest that reimbursement policy and practice setting strongly influenced adoption of IMRT billing for breast cancer.