7support a claim in medical product labeling if the claim is consistent with the instru-
ment’s documented measurement capability.” [ 1 ] In fact, several new biologics for
treatment of RA have an approved PRO label claim. However, in rheumatology,
interest in PROs preceded these recent developments and PROs have had a promi-
nent role in clinical trials for several decades. For many years the primary applica-
tion of PROs was in this setting. For instance, 3 out of 7 endorsed outcome domains
for clinical trials in rheumatoid arthritis are PROs. Physical function, pain, and
patient global assessment of disease activity have been respectively used as out-
come measures in 90, 70, and 70 % of contemporary clinical trials [ 26 ]. In some
rheumatic diseases, such as acute gout and osteoarthritis, patient-reported pain fre-
quently is the primary outcome of clinical trials [ 27 ]. Like for any application,
PROs to be used in clinical trials should be valid and feasible. However, the primary
aim of clinical trials is to assess the within-subject change over time. The ability to
detect clinically relevant change, responsiveness, is therefore another key property
of PROs to be used in trials that may affect achieved statistical power of a trial (in
case it is the primary outcome [ 16 ]. The Outcome Measures in Rheumatology
(OMERACT) group has summarized relevant measurement properties of PROs to
be used in clinical trials in their OMERACT filter as respectively: truth, feasibility,
and discrimination [ 28 ].
Comparative Effectiveness Research
Comparative effectiveness studies involve evaluating costs and health outcomes
between competing treatment alternatives. Typically, cost–utility analyses are
employed in such studies, which involve calculating incremental (direct and indi-
rect) costs associated with incremental quality-adjusted life years gained. In these
studies, evidence is first needed for the overall effect of an intervention on perceived
health-related quality of life. However, this evidence should be presented in a way
that permits comparisons with other interventions within or across treatment areas
and patient populations. The most common way this is achieved is by tobtaining
Quality-Adjusted Life Years (QALY). Within the QALY methodology, the quality
and quantity of life gains are expressed as a single index that can be used to inform
decision-making relating to the allocation of healthcare resources. Specifically, it is
assumed that a year of life lived in perfect health is worth 1 QALY, while a year
lived in less than perfect health is worth less than 1. Different techniques are used to
obtain QALYs, including the time-trade-off (asking patients how many years of
their life they would be willing to give in order to be restored to full health) or by
visual analogue scale (VAS). However the most popular method is probably using
multi-item PROs such as the EuroQOL 5d or SF-6D questionnaires. Quality-
adjusted life years associated with an intervention are simply obtained by multiply-
ing the utility value associated with a health state (QALY) by the time spent in that
health state. The most important advantages of the QALY approach to health
1 PROMs and Quality of Care