Quality of life (QoL) improvement is important to demonstrate in RA clinical trials, but can be abstract. More meaningful measures of QoL include medical expenditure and job loss, aspects that have marked importance for RA patients, physicians and society. We re-examined previous positive QoL findings for abatacept over placebo by converting existing QoL measures into estimated medical expenditure and estimated likelihood of job loss.
Two double-blind, placebo-controlled, multicentre randomized clinical trials were undertaken: one for MTX failure (n = 652) and one for more severe anti-TNF failure patients (n = 391). Based on derived scores using previously published formulae, measures of monthly medical expenditure, current inability to work and job loss at 6 months, 1 yr and 2 yrs were analysed.
Abatacept led to greater reduction in medical expenditure over time in MTX failure ($152 lower) and anti-TNF failure patients ($122 lower) compared with placebo at end-point. Likewise, significantly more reduction in likelihood for current and future job loss was achieved with abatacept compared with placebo, which has 25-64% greater likelihood.
QoL changes provided greater reduction in medical expenditure and likelihood of an inability to work. The strong effect sizes obtained for all significant analyses suggest that the results are clinically meaningful. Moreover, given the nature of the variables, results should also be meaningful for patients, physicians, employers and health care insurance entities. Limitations are discussed regarding using estimated outcomes rather than analysis of actual outcomes.