Michael Darden

Are investments in disease prevention complements? The case of statins and health behaviors

We obtain estimates of associations between statin use and health behaviors. Statin use is associated with a small increase in BMI and moderate (20-33%) increases in the probability of being obese. Statin use was also associated with a significant (e.g., 15% of mean) increase in moderate alcohol use among men. There was no consistent evidence of a decrease in smoking associated with statin use, and exercise worsened somewhat for females. Statin use was associated with increased physical activity among males. Finally, there was evidence that statin use increased the use of blood pressure medication and aspirin for both males and females, although estimates varied considerably in magnitude. These results are consistent with the hypothesis that healthy diet is a strong substitute for statins, but there is only uneven evidence for the hypothesis that investments in disease prevention are complementary.

The Star Treatment: Estimating the Impact of Star Ratings on Medicare Advantage Enrollments

The Centers for Medicare and Medicaid Services (CMS) has calculated and disseminated an overall contract quality star rating system (from one to five stars) for all Medicare Advantage (MA) contracts since 2009. In this paper, we study the effect of CMS-reported star ratings on MA plan enrollment. We formulate a discrete choice demand model for differentiated MA plans and estimate the model with market-level plan enrollment data. We identify separate enrollment effects for each star level using a regression discontinuity research design that exploits plausibly random variation around star thresholds. The results suggest that the 2009 published star ratings directed beneficiaries away from low-rated plans more than actively toward high-rated plans. When we repeat the analysis for 2010 published quality stars, we find no significant effects. We present suggestive evidence that supply-side responses to the star rating system may explain the one-time enrollment response to CMS-published quality stars.

Amnion membrane in diabetic foot wounds: A meta-analysis

Background: Amniotic membrane is tissue obtained from human placenta rich in cytokines, growth factors, and stem cells that possess the ability to inhibit infection, improve healing, and stimulate regeneration. Methods: A meta-analysis was performed examining randomized controlled trials comparing amniotic tissue products with standard of care in nonhealing diabetic foot ulcers including PubMed, Cochrane Central Register of Controlled Trials, and the Cochrane Database of Systematic Reviews. Results: A search of 3 databases identified 596 potentially relevant articles. Application of selection criteria led to the selection of 5 randomized controlled trials. The 5 selected randomized controlled trials represented a total of 311 patients. The pooled relative risk of healing with amniotic products compared with control was 2.7496 (2.05725–3.66524, P < 0.001). Conclusions: The current meta-analysis indicates that the treatment of diabetic foot ulcers with amniotic membrane improves healing rates in diabetic foot ulcers. Further studies are needed to determine whether these products also decrease the incidence of subsequent complications, such as amputation or death, in diabetic patients.

Supply-Side Responses to Public Quality Ratings: Evidence from Medicare Advantage

Since 2009, the Centers for Medicare and Medicaid Services (CMS) has distributed quality star ratings for Medicare Advantage (MA) contracts to better inform Medicare-eligible individuals of MA plan quality. This paper examines the extent to which the quality star rating scheme affected insurer behavior in the MA market. We identify the causal effect of 2009 star ratings on 2010 MA premiums using a regression discontinuity design that exploits plausibly random variation around threshold values underlying the star rating calculations. We find that contracts with higher star ratings in 2009 significantly increased their average 2010 monthly premiums relative to contracts just below the respective threshold values, with increases of more than

Quality Ratings and Premiums in the Medicare Advantage Market

26 per month among 3.5- and 4-star contracts. We present additional evidence that the estimated premium increases in 2010 are not purely the result of demand shifts in the prior year. Furthermore, the 2009 star ratings have a significant effect on plan mix, where 3-star contracts disproportionately dropped their

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0 premium plans while 2.5-, 3.5-, and 4-star contracts disproportionately expanded plans into new markets, particularly plans with positive monthly premiums. Broadly, our analysis reveals a relatively large supply-side response to published quality ratings, suggesting some level of caution as policy makers extend quality rating systems into new health-care markets.

Effect of obesity on perioperative outcomes after laparoscopic hepatectomy

We examine the response of Medicare Advantage contracts to published quality ratings. We identify the effect of star ratings on premiums using a regression discontinuity design that exploits plausibly random variation around rating thresholds. We find that 3, 3.5, and 4-star contracts in 2009 significantly increased their 2010 monthly premiums by

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20 or more relative to contracts just below the respective threshold values. High quality contracts also disproportionately dropped

Comprehensive Indoor Smoking Bans and Smoking Prevalence: Evidence from the BRFSS

0 premium plans or expanded their offering of positive premium plans. Welfare results suggest that the estimated premium increases reduced consumer welfare by over

The Effects of Parental Health Shocks on Adult Offspring Smoking Behavior and Self‐Assessed Health

250 million among the affected beneficiaries.