Change in end-of-life care for Medicare beneficiaries: site of death, place of care, and health care transitions in 2000, 2005, and 2009.

IMPORTANCE: A recent Centers for Disease Control and Prevention report found that more persons die at home. This has been cited as evidence that persons dying in the United States are using more supportive care. OBJECTIVE: To describe changes in site of death, place of care, and health care transitions between 2000, 2005, and 2009. DESIGN, SETTING, AND PATIENTS: Retrospective cohort study of a random 20% sample of fee-for-service Medicare beneficiaries, aged 66 years and older, who died in 2000 (n = 270,202), 2005 (n = 291,819), or 2009 (n = 286,282). A multivariable regression model examined outcomes in 2000 and 2009 after adjustment for sociodemographic characteristics. Based on billing data, patients were classified as having a medical diagnosis of cancer, chronic obstructive pulmonary disease, or dementia in the last 180 days of life. MAIN OUTCOME MEASURES: Site of death, place of care, rates of health care transitions, and potentially burdensome transitions (eg, health care transitions in the last 3 days of life). RESULTS: Our random 20% sample included 848,303 fee-for-service Medicare decedents (mean age, 82.3 years; 57.9% female, 88.1% white). Comparing 2000, 2005, and 2009, the proportion of deaths in acute care hospitals decreased from 32.6% (95% CI, 32.4%-32.8%) to 26.9% (95% CI, 26.7%-27.1%) to 24.6% (95% CI, 24.5%-24.8%), respectively. However, intensive care unit (ICU) use in the last month of life increased from 24.3% (95% CI, 24.1%-24.5%) to 26.3% (95% CI, 26.1%-26.5%) to 29.2% (95% CI, 29.0%-29.3%). (Test of trend P value was <.001 for each variable.) Hospice use at the time of death increased from 21.6% (95% CI, 21.4%-21.7%) to 32.3% (95% CI, 32.1%-32.5%) to 42.2% (95% CI, 42.0%-42.4%), with 28.4% (95% CI, 27.9%-28.5%) using a hospice for 3 days or less in 2009. Of these late hospice referrals, 40.3% (95% CI, 39.7%-40.8%) were preceded by hospitalization with an ICU stay. The mean number of health care transitions in the last 90 days of life increased from 2.1 (interquartile range [IQR], 0-3.0) to 2.8 (IQR, 1.0-4.0) to 3.1 per decedent (IQR, 1.0-5.0). The percentage of patients experiencing transitions in the last 3 days of life increased from 10.3% (95% CI, 10.1%-10.4%) to 12.4% (95% CI, 12.3%-2.5%) to 14.2% (95% CI, 14.0%-14.3%). CONCLUSION AND RELEVANCE: Among Medicare beneficiaries who died in 2009 and 2005 compared with 2000, a lower proportion died in an acute care hospital, although both ICU use and the rate of health care transitions increased in the last month of life.

Theoretical investigation of the gas-phase reactions of CrO(+) with ethylene.

The potential energy surfaces associated with the reactions of chromium oxide cation (CrO(+)) with ethylene have been characterized using density functional, coupled-cluster, and multireference methods. Our calculations show that the most probable reaction involves the formation of acetaldehyde and Cr(+) via a hydride transfer involving the metal center. Our calculations support previous experimental hypotheses that a four-membered ring intermediate plays an important role in the reactivity of the system. We have also characterized a number of viable reaction pathways that lead to other products, including ethylene oxide. Due to the experimental observation that CrO(+) can activate carbon-carbon bonds, a reaction pathway involving C-C bond cleavage has also been characterized. Since many of the reactions involve a change in the spin state in going from reactants to products, locations of these spin surface crossings are presented and discussed. The applicability of methods based on Hartree-Fock orbitals is also discussed.

Theoretical evidence for the nucleophilic addition of sulfur dioxide to 1,2-bridged chloronium and bromonium ions.

The nucleophilic addition of SO2, SO2ClF, and SO2F2 to carbenium ions and the nucleophilic addition of SO2 to 1,2-bridged halonium ions are theoretically investigated by using B3LYP/6-311+G(d,p). On the basis of geometric changes in ion-solvent complexes compared to isolated molecules, the theoretical data for the addition of solvent to carbenium ions uniformly agree with experiments by Olah and Donovan. The relative reactivity of carbenium ions (methyl > ethyl > iso-propyl > tert-butyl) follows the familiar trend based on electron demand at the carbenium center. The theoretical data for the addition of SO2 to 1,2-bridged halonium ions with use of similar methods indicate that this addition exhibits a reversed trend on the basis of the electron demand; SO2 adds to 2,2-dimethylethylene chloronium and bromonium ions but does not add to the fluoronium analogue. Furthermore, the addition depends on the stereochemistry of the approaching SO2. When SO2 approaches syn to the halogen atom on the halonium ion, addition is observed. When SO2 is anti, addition is not observed. The reversed reactivity and stereochemistry of the addition of SO2 to halonium ions can be explained by electron donation from the halogen atom to the sulfur atom of the approaching SO2. This sulfur-halogen interaction activates the nucleophilicity of the approaching SO2 and makes a normally unreactive tertiary carbenium carbon susceptible to addition. The theoretical evidence for covalently bound halonium ion-SO2 complexes is discussed in the context of previously reported experimental evidence for the existence of equilibria involving beta-halocarbenium ions.