Alternative approaches to derive disability weights in injuries: do they make a difference?

BACKGROUND: In burden of disease studies, several approaches are used to assess disability weights, a scaling factor necessary to compute years lived with disability (YLD). The aim of this study was to quantify disability weights for injury consequences with two competing approaches, (a) standard QALY/DALY model (SQM) which derives disability weights from patient survey data and (b) the annual profile model (APM) which derives weights for the same patient data valued by a panel.
METHODS: Disability weights were assessed using (a) EQ-5D data from a postal survey among 8,564 injury patients 2(1/2), 5, and 9 months after attending the Emergency Department, and (b) preferences of 143 laymen elicited with the time trade-off method.
RESULTS: Compared with APM, SQM disability weights were consistently higher. YLD calculated with SQM disability weights was more than three times higher compared with YLD calculated with APM disability weights, for mild injuries with short duration, this increase was six fold.
CONCLUSIONS: The APM seems the preferred method in burden of injury studies that includes mild conditions with a rapid course, since the SQM approach might overestimate the impact of the latter. The APM, however, might underestimate the impact of injury consequences, especially in case of severe injuries.