Ex ante, like ex-post, moral hazard reduces the efficiency of the insurance market. I use exogenous variation in risk protection associated with public catastrophic health insurance programs to test for ex-ante moral hazard. Using the introduction of and changes in these programs, I find large decreases in self-protection as the public program provides greater risk protection. Ex-ante moral hazard is stronger for women than for men and affects a variety of investments, including smoking, obesity, and cancer screening. Differences by gender in ex-ante moral hazard are consistent with greater returns to self-protection for women than for men.

I show that employees sort into firms on the basis of fringe benefits using laws mandating that employers provide a fringe benefit (insurance for mental illness) and a proxy for individual's demand for the benefit (mental distress). My estimates indicate that the mandate only affected less educated individuals, reduced labor demand, but increased labor supply for individuals who value mental health benefits; these results are driven by individuals switching into different jobs. I find no evidence for an aggregate welfare loss, but there is an increase in welfare for distressed individuals, at the expense of non-distressed individuals.

I examine the effects of public catastrophic insurance programs on enrollment and selection in private health insurance to supplement Medicare. Using variation over time in the availability and generosity of these programs I show that public catastrophic insurance crowds out private insurance coverage for individuals in worse health status, with little, if any, effect on healthier individuals. In addition, individuals for whom the public program is less generous are more likely to have private insurance coverage. The selective crowd-out of individuals in worse health induces advantageous selection in Medigap, one of two types of supplementary private insurance, and leads to lower insurance premiums. I also find that more cognitively able individuals are more likely to be crowded out if they are in bad health and that accounting for cognitive ability attenuates selection most strongly in states that provide public catastrophic insurance.

There is uncertainty about risk heterogeneity for venous thromboembolism (VTE) in olderpatients with advanced cancer and whether patients can be stratified according to VTE risk. We performed a retrospective cohort study of the linked Medicare-Surveillance, Epidemiology, and End Results cancer registry in older patients with advanced cancer of lung, breast, colon, prostate, or pancreas diagnosed between 1995–1999. We used survival analysis with demographics, comorbidities, and tumor characteristics/treatment as independent variables. Outcome was VTE diagnosed at least one month after cancer diagnosis. VTE rate was highest in the first year (3.4%). Compared to prostate cancer (1.4 VTEs/100 person-years), there was marked variability in VTE risk (hazard ratio (HR) for male-colon cancer 3.73 (95% CI 2.1–6.62), female-colon cancer HR 6.6 (3.83–11.38), up to female-pancreas cancer HR 21.57 (12.21–38.09). Stage IV cancer and chemotherapy resulted in higher risk (HRs 1.75 (1.44–2.12) and 1.31 (1.0–1.57), resp.). Stratifying the cohort by cancer type and stage using recursive partitioning analysis yielded five groups of VTE rates (nonlocalized prostate cancer 1.4 VTEs/100 person-years, to nonlocalized pancreatic cancer 17.4 VTEs/100 patient-years). In a high-risk population with advanced cancer, substantial variability in VTE risk exists, with notable differences according to cancer type and stage.

The purpose of this study was to determine whether racial disparities in cancer therapy had diminished since the time they were initially documented in the early 1990s.The authors identified a cohort of patients in the SEER-Medicare linked database who were ages 66 to 85 years and who had a primary diagnosis of colorectal, breast, lung, or prostate cancer during 1992 through 2002. The authors identified 7 stage-specific processes of cancer therapy by using Medicare claims. Candidate covariates in multivariate logistic regression included year, clinical, and sociodemographic characteristics, and physician access before cancer diagnosis.During the full study period, black patients were significantly less likely than white patients to receive therapy for cancers of the lung (surgical resection of early stage, 64.0% vs 78.5% for blacks and whites, respectively), breast (radiation after lumpectomy, 77.8% vs 85.8%), colon (adjuvant therapy for stage III, 52.1% vs 64.1%), and prostate (definitive therapy for early stage, 72.4% vs 77.2%, respectively). For both black and white patients, there was little or no improvement in the proportion of patients receiving therapy for most cancer therapies studied, and there was no decrease in the magnitude of any of these racial disparities between 1992 and 2002. Racial disparities persisted even after restricting the analysis to patients who had physician access before their diagnosis.There has been little improvement in either the overall proportion of Medicare beneficiaries receiving cancer therapies or the magnitude of racial disparity. Efforts in the last decade to mitigate cancer therapy disparities appear to have been unsuccessful. Cancer 2008. � 2008 American Cancer Society.

Context Medicare's reimbursement policy was changed in 1998 to provide coverage for screening colonoscopies for patients with increased colon cancer risk, and expanded further in 2001 to cover screening colonoscopies for all individuals. Objective To determine whether the Medicare reimbursement policy changes were associated with an increase in either colonoscopy use or early stage colon cancer diagnosis. Design, Setting, and Participants Patients in the Surveillance, Epidemiology, and End Results Medicare linked database who were 67 years of age and older and had a primary diagnosis of colon cancer during 1992-2002, as well as a group of Medicare beneficiaries who resided in Surveillance, Epidemiology, and End Results areas but who were not diagnosed with cancer. Main Outcome Measures Trends in colonoscopy and sigmoidoscopy use among Medicare beneficiaries without cancer were assessed using multivariate Poisson regression. Among the patients with cancer, stage was classified as early (stage I) vs all other (stages II-IV). Time was categorized as period 1 (no screening coverage, 1992-1997), period 2 (limited coverage, January 1998-June 2001), and period 3 (universal coverage, July 2001-December 2002). A multivariate logistic regression (outcome = early stage) was used to assess temporal trends in stage at diagnosis; an interaction term between tumor site and time was included. Results Colonoscopy use increased from an average rate of 285/100 000 per quarter in period 1 to 889 and 1919/100 000 per quarter in periods 2 (P<.001) and 3 (P vs 2<.001), respectively. During the study period, 44 924 eligible patients were diagnosed with colorectal cancer. The proportion of patients diagnosed at an early stage increased from 22.5% in period 1 to 25.5% in period 2 and 26.3% in period 3 (P<.001 for each pairwise comparison). The changes in Medicare coverage were strongly associated with early stage at diagnosis for patients with proximal colon lesions (adjusted relative risk period 2 vs 1, 1.19; 95% confidence interval, 1.13-1.26; adjusted relative risk period 3 vs 2, 1.10; 95% confidence interval, 1.02-1.17) but weakly associated, if at all, for patients with distal colon lesions (adjusted relative risk period 2 vs 1, 1.07; 95% confidence interval, 1.01-1.13; adjusted relative risk period 3 vs 2, 0.97; 95% confidence interval, 0.90-1.05). Conclusions Expansion of Medicare reimbursement to cover colon cancer screening was associated with an increased use of colonoscopy for Medicare beneficiaries, and for those who were diagnosed with colon cancer, an increased probability of being diagnosed at an early stage. The selective effect of the coverage change on proximal colon lesions suggests that increased use of whole-colon screening modalities such as colonoscopy may have played a pivotal role.