Health plan enrollment and mortality in the Medicare program

Abstract

Prior studies have found that Medicare health maintenance organization (HMO) enrollees have lower mortality (over a fixed observation period) than beneficiaries in traditional fee-for-service (FFS) Medicare. We use Medicare Current Beneficiary Survey (MCBS) data to compare 2-year predicted mortality for Medicare enrollees in the HMO and FFS sectors using a sample selection model to control for observed beneficiaries characteristics and unobserved confounders. The difference in raw, unadjusted mortality probabilities was 0.5% (HMO lower). Correcting for numerous observed confounders resulted in a difference of -0.6% (HMO higher). Further adjustment for unobserved confounders resulted in an estimated difference of 3.7 and 4.2% (HMO lower), depending on the specification of geographic-fixed effects. The latter result (4.2%) was statistically significant and consistent with prior studies that did not adjust for unobserved confounding. Our findings suggest there may be unobserved confounders associated with adverse selection in the HMO sector, which had a large effect on our mortality estimates among HMO enrollees. An important topic for further research is to identify such confounders and explore their relationship to mortality. The methods presented in this paper represent a promising approach to comparing outcomes between the HMO and FFS sectors, but further research is warranted.

Mortality, Hospitalizations, and Expenditures for the Medicare Population Aged 65 Years or Older, 1999-2013

“…21 Moreover, since 2003 both groups have experienced similar declines in overall mortality, lending support to the conclusion that the observed changes among the Fee-for-Service population are not the result of changes in the risks of the groups relative to each other and do represent true improvement. Moreover, other studies have found that healthier people are likely to shift enrollment from Fee-for-Service to Medicare Advantage, which may have led to an underestimation of the improvement over time, 22,23 because we observed increasing enrollment in Medicare Advantage over time.…”

Association of Medicare Part D Medication Out‐of‐Pocket Costs with Utilization of Statin Medications

“…However, the generosity of competitor plans should not directly influence the drug therapy utilization of the beneficiary, making it a valid instrument. Previous studies on health plan enrollment have used information from competitor plans as the instrumental variable to account for endogenous plan selection (Mello, Stearns, and Norton 2002;Dowd et al 2010). While a potential alternative instrument could be based on the market shares of competitor plans, the 5 percent sample cannot support such an approach.…”

Better Quality of Care or Healthier Patients? Hospital Utilization by Medicare Advantage and Fee-for-Service Enrollees

“…This makes it difficult to determine whether managed care improves health or simply attracts the healthy. Those studies that used econometric approaches to correct for this bias have focused on a limited number of self-report and mortality outcomes (Mello et al, 2002; Rizzo, 2005; Balsa et al, 2007; Huesch, 2010; Dowd et al, 2011). This study uses administrative data covering the universe of hospitalizations in Arizona, Florida, New Jersey and New York from 1999 through 2005, states where nearly a quarter of MMC enrollees lived during the study period.…”