Validation of the EQ-5D-5L and psychosocial bolt-ons in a large cohort of people living with multiple sclerosis in Australia.

BACKGROUND: Multiple sclerosis (MS) is an inflammatory, neurodegenerative disease of the central nervous system which results in disability over time and reduced quality of life. To increase the sensitivity of the EQ-5D-5L for psychosocial health, four bolt-on items from the AQoL-8D were used to create the nine-item EQ-5D-5L-Psychosocial. We aimed to externally validate the EQ-5D-5L-Psychosocial in a large cohort of people with MS (pwMS) and explore the discriminatory power of the new instrument with EQ-5D-5L/AQoL-8D. METHODS: A large representative sample from the Australian MS Longitudinal Study completed the AQoL-8D and EQ-5D-5L (including EQ VAS) and both instruments health state utilities (HSUs) were scored using Australian tariffs. Sociodemographic/clinical data were also collected. External validity of EQ-5D-5L-Psychosocial scoring algorithm was assessed with mean absolute errors (MAE) and Spearman's correlation coefficient. Discriminatory sensitivity was assessed with an examination of ceiling/floor effects, and disability severity classifications. RESULTS: Among 1683 participants (mean age: 58.6 years; 80% female), over half (55%) had moderate or severe disability. MAE (0.063) and the distribution of the prediction error were similar to the original development study. Mean (± standard deviation) HSUs were EQ-5D-5L: 0.58 ± 0.32, EQ-5D-5L-Psychosocial 0.62 ± 0.29, and AQoL-8D: 0.63 ± 0.20. N = 157 (10%) scored perfect health (i.e. HSU = 1.0) on the EQ-5D-5L, but reported a mean HSU of 0.90 on the alternative instruments. The Sleep bolt-on dimension was particularly important for pwMS. CONCLUSIONS: The EQ-5D-5L-Psychosocial is more sensitive than the EQ-5D-5L in pwMS whose HSUs approach those reflecting full health. When respondent burden is taken into account, the EQ-5D-5L-Psychosocial is preferential to the AQoL-8D. We suggest a larger confirmatory study comparing all prevalent multi-attribute utility instruments for pwMS.

Theoretical studies of the oxidative addition of azolium salts to a model Wilkinson's catalyst.

The oxidative addition of 1,3-dimethylimidazolium to a model Wilkinson's catalyst (RhCl(PH(3))(3)) has been studied with density functional calculations (B3LYP). According to our free energy calculations, the octahedral rhodium carbene hydride product forms from initial predissociation of a phosphine molecule to subsequently form a 5 ligand intermediate; however, results indicate that a six ligand, associative route with a concerted three-centred transition structure may also be competitive. Exchange of the phosphine molecule on the metal centre with trimethylphosphine had a significant effect in lowering the barrier to oxidative addition and decreasing the endothermicity of the reaction. Solvation was found to have a moderate effect on the overall reaction. Bulk solvent calculations reflected a relative stabilisation of reactants for both pathways, resulting in an endothermic overall reaction. A study of alternative azolium salts revealed the saturated 1,3-dimethyl-4,5-dihydroimidazolium resulted in little change to the reaction geometries or energies, while the use of 3-methylthiazolium salt significantly reduced the barrier to addition and increased the exothermicity of the reaction considerably.