Support Vector Machines and logistic regression to predict temporal artery biopsy outcomes.

OBJECTIVE: Support vector machines (SVM) is a newer statistical method that has been reported to be advantageous to traditional logistic regression for clinical classification. We determine if SVM can better predict the results of temporal artery biopsy (TABx) for giant cell arteritis compared to logistic regression. METHOD: A database of 530 TABx patients with 10 covariates was used and randomly split into training and test sets. The area under the receiving operating curve (AUC), misclassification rate (MCR), and false negative rate (FN) were compared for SVM and logistic regression. AUC and MCR were used to tune the SVM. RESULTS: The SVM model with optimal AUC had gamma = 0.01267 and cost = 26.466, with 133 support vectors. The AUC/MCR/FN for logistic regression and SVM respectively were 0.827/0.184/0.524 and 0.825/0.168/0.571. CONCLUSION: In our dataset of 530 TABx subjects, SVM did not offer any distinct advantage over the logistic regression prediction model.

Which literacy skills are associated with smoking?

BACKGROUND: Research has demonstrated associations between smoking and reading skills, but other literacy skills such as speaking, listening and numeracy are less studied despite our dependence on the use of numbers and the oral exchange to deliver information on the risks of smoking. METHODS: The authors used multivariable logistic regression to examine the effects of reading, numeracy, speaking and listening skills on: (1) becoming a regular smoker and (2) smoking cessation. Further, multivariable linear regression was used to examine the relation between literacy skills and amount smoked among current smokers. Models controlled for education, gender, age, race/ethnicity, income and, when relevant, age at which they became a regular smoker. RESULTS: For each grade equivalent increase in reading skills, the odds of quitting smoking increased by about 8% (OR=1.08, 95% CI 1.01 to 1.15). For every point increase in numeracy skills, the odds of quitting increased by about 24% (OR=1.24, 95% CI 1.06 to 1.46). No literacy skills were associated with becoming a regular smoker or current amount smoked. CONCLUSION: The ability to locate, understand and use information related to the risks of smoking may impact one's decision to quit. Messaging should be designed with the goal of being easily understood by all individuals regardless of literacy level.

Children's mental health care following Hurricane Katrina: a field trial of trauma-focused psychotherapies.

New Orleans school children participated in an assessment and field trial of two interventions 15 months after Hurricane Katrina. Children (N = 195) reported on hurricane exposure, lifetime trauma exposure, peer and parent support, posttraumatic stress disorder (PTSD), and depressive symptoms. Teachers reported on behavior. At baseline, 60.5% screened positive for PTSD symptoms and were offered a group intervention at school or individual treatment at a mental health clinic. Uptake of the mental health care was uneven across intervention groups, with 98% beginning the school intervention, compared to 37% beginning at the clinic. Both treatments led to significant symptom reduction of PTSD symptoms, but many still had elevated PTSD symptoms at posttreatment. Implications for future postdisaster mental health work are discussed.

Disparities in the treatment of patients with IL-2 for metastatic renal cell carcinoma.

OBJECTIVES: The incidence of metastatic renal cell cancer (mRCC) is rising. To date, interleukin-2 (IL-2) is the only treatment offering a complete response rate for mRCC. We wish to test the hypothesis that the combination of restricted availability and expense associated with IL-2 administration results in differential access to the medication based on race and sex, despite similar clinical indications for its use. METHODS: We used data from the Surveillance, Epidemiology, and End Results program and the Centers for Medicare Services (CMS) to clinically characterize subjects with mRCC diagnosed from 1992 through 2002. We linked these subjects to claims identified in the CMS databases. We then assigned subjects to cohorts receiving radical nephrectomy, IL-2, both, or neither. A logistic model was created to identify factors that had significant independent effects on the receipt of IL-2. RESULTS: Three thousand seven hundred thirty individuals were identified with mRCC. After controlling for other variables, female subjects were less likely to receive IL-2 (O.R. 0.80). African American subjects were also less likely to receive IL-2 (O.R 0.55). Married individuals were much more likely to receive IL-2 (O.R 1.9). CONCLUSIONS: African Americans and women were much less likely to be treated with IL-2 after controlling for relevant clinical variables. These data document that the only therapy offering a complete response to patients with mRCC is less frequently given to those who are African American or female. It is possible that the racial and gender-based disparities in treatment with IL-2 will be replicated with newer, expensive treatment options for mRCC. Further prospective investigation into mitigating barriers to receipt of effective care for mRCC is urgently needed.

Alcohol and tobacco marketing: evaluating compliance with outdoor advertising guidelines.

BACKGROUND: Historically, the alcohol and tobacco industries have been the biggest users of outdoor advertising. However, the 1999 Master Settlement Agreement (MSA) outlawed tobacco billboards and transit furniture (e.g., bus, bench) ads, and the Outdoor Advertising Association of America (OAAA) has pledged to voluntarily eliminate ads for alcohol and tobacco within 500 feet of schools, playgrounds, and churches. METHODS: Outdoor advertisements were observed (2004-2005) in a sample of urban census tracts (106 in pre-Katrina southern Louisiana and 114 in Los Angeles County) to evaluate tobacco and alcohol advertisers' compliance with the MSA and the OAAA Code of Industry Principles. Data were analyzed in 2007-2008. RESULTS: More than one in four tobacco ads in Louisiana failed to comply with the MSA. In Los Angeles, 37% of alcohol ads and 25% of tobacco ads were located within 500 feet of a school, playground, or church; in Louisiana, roughly one in five ads promoting alcohol or tobacco fell within this distance. In Los Angeles, low-income status and the presence of a freeway in the tract were associated with 40% more alcohol and tobacco billboards near children. In Louisiana, each additional major roadway-mile was associated with 4% more tobacco ads-in violation of MSA-and 7% more small ads near schools, playgrounds, and churches; city jurisdiction accounted for 55% of MSA violations and more than 70% of the violations of OAAA guidelines. CONCLUSIONS: Cities must be empowered to deal locally with violations of the MSA. Legislation may be needed to force advertisers to honor their pledge to protect children from alcohol and tobacco ads.

Renal and cardiovascular morbidity after partial or radical nephrectomy.

BACKGROUND: To clarify the benefits of nephron-sparing surgery among patients with early-stage kidney cancer, the authors compared the frequency of renal and cardiovascular morbidity after partial or radical nephrectomy. METHODS: This retrospective cohort study was based on linked Surveillance, Epidemiology, and End Results-Medicare data. The authors identified 10,886 patients who underwent partial or radical nephrectomy between 1991 and 2002. Medical claims were examined for the occurrence of adverse renal and/or cardiovascular outcomes, and multivariate survival models were fit to estimate the association between type of surgery and each clinical outcome, using propensity scores to balance the treatment cohorts with respect to measured patient and disease characteristics. To control for secular trends in the indications for partial nephrectomy, separate analyses were performed based on treatment era (1991-1999 or 2000-2002). RESULTS: During the study interval, 10,123 patients (93%) and 763 patients (7%) underwent radical or partial nephrectomy, respectively. During 2000 to 2002, patients who underwent partial nephrectomy experienced fewer adverse renal outcomes (16.4% vs 21.8%; adjusted hazard ratio, 0.74; 95% confidence interval, 0.58-0.94), including a trend toward less frequent receipt of dialysis services, dialysis access surgery, or renal transplantation. The likelihood of adverse cardiovascular outcomes did not differ by treatment. CONCLUSIONS: Among contemporary patients, partial nephrectomy was associated with less clinically apparent renal morbidity than radical nephrectomy. This finding motivates expanded use of partial nephrectomy among patients with early-stage kidney cancer. Given the potential for selection bias and residual confounding in this observational cohort, additional prospective studies will be necessary to validate the current findings.

Androgen deprivation therapy increases cardiovascular morbidity in men with prostate cancer.

BACKGROUND: The use of androgen deprivation therapy (ADT) in the treatment of men with prostate cancer has risen sharply. Although cardiovascular disease is the most common reason for death among men with prostate cancer who do not die of the disease itself, data regarding the effect of ADT on cardiovascular morbidity and mortality in men with prostate cancer are limited. In the current study, the authors attempted to measure the risk for subsequent cardiovascular morbidity in men with prostate cancer who received ADT. METHODS: A cohort of newly diagnosed men in a population-based registry who were diagnosed between 1992 and 1996 were identified retrospectively. A total of 22,816 subjects were identified after exclusion criteria were applied. Using a multivariate model, the authors calculated the risk of subsequent cardiovascular morbidity in men with prostate cancer who were treated with ADT, as defined using Medicare claims. RESULTS: Newly diagnosed prostate cancer patients who received ADT for at least 1 year were found to have a 20% higher risk of serious cardiovascular morbidity compared with similar men who did not receive ADT. Subjects began incurring this higher risk within 12 months of treatment. However, Hispanic men were found to have a lowered risk for cardiovascular morbidity. CONCLUSIONS: ADT is associated with significantly increased cardiovascular morbidity in men with prostate cancer and may lower overall survival in men with low-risk disease. These data have particular relevance to decisions regarding the use of ADT in men with prostate cancer in settings in which the benefit has not been clearly established. For men with metastatic disease, focused efforts to reduce cardiac risk factors through diet, exercise, or the use of lipid-lowering agents may mitigate some of the risks of ADT.

Variations in reconstruction after radical cystectomy.

BACKGROUND: Most urologists specializing in the management of patients with bladder cancer consider continent urinary diversion the reconstructive technique that affords the best quality of life after radical cystectomy. The authors sought to evaluate factors that predict reconstructive technique after radical cystectomy. METHODS: Using linked data from Medicare and the National Cancer Institute's (NCI) Surveillance, Epidemiology, and End Results (SEER) program, 3611 subjects were identified who underwent radical cystectomy for bladder cancer between 1992 and 2000. Multivariate logistic regression was used to identify factors independently associated with utilization of continent reconstruction after radical cystectomy, incorporating patient and provider variables. RESULTS: In multivariate analysis, the likelihood of continent diversion was inversely associated with older age (odds ratio [OR] < or = 0.68, P <.002), African American race (OR 0.43, P = .003), and higher comorbidity index (OR 0.71, P = .03), and directly associated with male sex (OR 1.45, P = .002), higher education level (OR 1.54, P = .03), and year of surgery (OR > or = 1.56, P < .001 for all year categories vs. 1992-1994). Treatment at academic (OR 1.43, P = .003) and NCI-designated cancer centers (OR 5.50, P <.001) and by high-volume providers (OR 1.49, P <.001) was independently associated with continent reconstruction. CONCLUSIONS: Disparities in the utilization of continent urinary diversion after radical cystectomy suggest that demographic, socioeconomic, provider-based, and clinical variables predict the likelihood that those undergoing radical cystectomy will receive continent reconstruction. Regionalization of bladder cancer care may ameliorate many of the disparities noted but must be balanced against the risk imposed by a delay in care.

Patterns of care for men with prostate cancer after failure of primary treatment.

BACKGROUND: This study sought to determine trends in patterns of care after failure of primary prostate cancer treatment and to determine whether nonclinical factors influenced the receipt of secondary treatment. METHODS: The authors identified individuals treated for nonmetastatic prostate cancer in the years 1991-1999 from the linked databases of Medicare and the National Cancer Institute's Surveillance, Epidemiology, and End Results registry. The outcome of interest was receipt of secondary therapy. They performed Cox proportional hazard analyses to investigate the link between demographic and clinical characteristics and the likelihood of receiving secondary treatment after either surgery or radiation. RESULTS: Of 65,716 subjects who met our inclusion criteria, 10,200 (15%) received some form of secondary therapy. For men undergoing initial surgical or radiation therapy, tumor grade, year of diagnosis, and geographic region were associated with secondary therapy. No socioeconomic factors such as education, ethnicity, or income level were associated with secondary therapy. CONCLUSIONS: Patterns of care after primary prostate cancer therapy continue to vary regionally. Standardized clinical algorithms and utilization of prostate-specific antigen testing appear to have influenced secondary therapy rates.

Incremental treatment costs in national cancer institute-sponsored clinical trials.

CONTEXT: Concern about additional costs for direct patient care impedes efforts to enroll patients in clinical trials. But generalizable evidence substantiating these concerns is lacking. OBJECTIVE: To assess the additional cost of treating cancer patients in the National Cancer Institute (NCI)-sponsored clinical trials in the United States across a range of trial phases, treatment modalities, and patient care settings. DESIGN: Retrospective cost study using a multistage, stratified, random sample of patients enrolled in 1 of 35 active phase 3 trials or phase 1 or any phase 2 trials between October 1, 1998, and December 31, 1999. Unadjusted and adjusted costs were compared and related to trial phase, institution type, and vital status. SETTING AND PARTICIPANTS: A representative sample of 932 cancer patients enrolled in nonpediatric, NCI-sponsored clinical trials and 696 nonparticipants with a similar stage of disease not enrolled in a research protocol from 83 cancer clinical research institutions across the United States. MAIN OUTCOME MEASURES: Direct treatment costs as measured using a combination of medical records, telephone survey, and Medicare claims data. Administrative and other research costs were excluded. RESULTS: The incremental costs of direct care in trials were modest. Over approximately a 2.5-year period, adjusted costs were 6.5% higher for trial participants than nonparticipants (35,418 dollars vs 33,248 dollars; P =.11). Cost differences for phase 3 studies were 3.5% (P =.22), lower than for phase 1 or 2 trials (12.8%; P =.20). Trial participants who died had higher costs than nonparticipants who died (17.9%; 39,420 dollars vs 33,432 dollars, respectively; P =.15). CONCLUSIONS: Treatment costs for nonpediatric clinical trial participants are on average 6.5% higher than what they would be if patients did not enroll. This implies total incremental treatment costs for NCI-sponsored trials of 16 million dollars in 1999. Incremental costs were higher for patients who died and who were in early phase studies although these findings deserve further scrutiny. Overall, the additional treatment costs of an open reimbursement policy for government-sponsored cancer clinical trials appear minimal.