QOL Assessment in Rheumatoid Arthritis 833 pact of ther y and to aid in treatment decisions for lobal health The several advantages of the DAS28 include its ability to evaluate disease ac. practice,physicians primarily evaluate the succe tivity and response to treatment independent of pre treatment status:its ability to discriminate betweer high and low disease activity:its sensitivity to treat Several validated instruments are available for clinical trials and clinical practice. statu fic dim en 3.QOL Assessment tings for aid in healthcare policy decisions.This article re. 3.1 Generic Instruments views several instruments that measure health status and HR-QOL in RA and provides examples of their There is no universal fo RA G of approac 2.Clinical Assessment of RA and table While ideally adi。 specific Disease Activity instrument should be used for many dise such instruments have not yet been developed for all There is no'gold standard'for measuring disease activity and remission in RA:however,physical, Although generic HR-QOL radiographic and laboratory measurements have tra ments are usually designed for the broadest possible se across a var ety or diseases,dilferent J01 an sme dcdneandd pain and icular appro Clinicians often rely on the American Colleg of population.These HR-QOL in Rheumatology (ACR)20.ACR50 or ACR70 res- struments are not only important in providing a ponse criteria to monitor a patient's response to means of comparison of effectiveness,but are also treatment.The ACR20 criteria have been validated key parameters that are incorporated into economic for use in clinical trials to define clinically signif analyses by capturing both benefi cial and detrimen provement(i.e tal effects tment on the individual.They are so use on across disease ve to the nu nd" An ted out the following nt as s is that of the mi an sessment,physician assessm difference (MCID).Clinical trial endpoints are gen of disability,and the value for one acute r erally evaluated for statistically significant differ. reactant (i.e.erythrocyte sedimentation rate [ESR] ences between treatment groups.However.what is or C-reactive protein [CRPD). statistically significant may not necessarily reflect a Another measurement of disease clinic Disease Activity S albenefit to the patient fa large enouh core (DAS)v is the which has d,even sm ences b er goticacaichtwiCe4gnicatwiho dinde that is based on of the MCID vid that dis n statistical and and tender joints (of 28 joints).the ESR,and a visual clinical relevance The MCI refers to the small- analogue scale score (0-100)of patients'general or est difference in an outcome that is perceived by the 2008 Adis Data Information BV.All rights reservod. Pha conomics2008:26(10) QOL Assessment in Rheumatoid Arthritis 833 pact of therapy and to aid in treatment decisions for global health.[14] The several advantages of the the individual patient. However, in current clinical DAS28 include its ability to evaluate disease ac￾practice, physicians primarily evaluate the success tivity and response to treatment independent of pre￾of therapy from a clinical perspective and rarely treatment status; its ability to discriminate between assess HR-QOL.[10,11] high and low disease activity; its sensitivity to treat￾Several validated instruments are available for ment effects; as well as its validation for use both in clinical trials and clinical practice.[13] evaluation of HR-QOL, and while some of these instruments characterize the health status of an indi￾vidual or population with regard to specific dimen- 3. QOL Assessment sions or domains, others can be used to derive utility weightings for use in economic evaluations, and to 3.1 Generic Instruments aid in healthcare policy decisions. This article re￾views several instruments that measure health status There is no universally accepted definition of, or and HR-QOL in RA and provides examples of their method for measuring, disease-specific HR-QOL in use in clinical trials of the newest biological RA. General features of approaches utilized to mea- DMARDs for the treatment of RA. sure HR-QOL in RA are represented in figure 1[15,16] and table I.[15,17-20] While ideally a disease-specific 2. Clinical Assessment of RA instrument should be used for many diseases, such Disease Activity instruments have not yet been developed for all There is no ‘gold standard’ for measuring disease disease states, and generic instruments are often utilized.[15,20] activity and remission in RA; however, physical, Although generic HR-QOL instru￾radiographic and laboratory measurements have tra- ments are usually designed for the broadest possible ditionally been used, often in combination. use across a variety of diseases, different medical [8] These interventions and a wide range of populations, measures include counting of inflamed joints, as- [21] sessment of degree and duration of pain and stiff- specific or targeted instruments may be more appro￾ness, and clinician and patient global assessments. priate than generic measures for a particular setting, [8] or in a defined population.[21] Clinicians often rely on the American College of These HR-QOL in￾Rheumatology (ACR) 20, ACR50 or ACR70 res- struments are not only important in providing a ponse criteria to monitor a patient’s response to means of comparison of effectiveness, but are also treatment. The ACR20 criteria have been validated key parameters that are incorporated into economic for use in clinical trials to define clinically signif- analyses by capturing both beneficial and detrimen￾icant levels of improvement. tal effects of treatment on the individual. They are [12] Patients are required to have a minimum level of improvement (i.e. 20%, also useful for outcomes comparison across disease 50% or 70%) relative to baseline in the number of states and can aid in policy decisions. swollen joints and tender joints, and in any three of An important concept in patient-reported out￾the following disease-activity measures: patient as- comes is that of the minimal clinically important sessment, physician assessment, pain scale, degree difference (MCID). Clinical trial endpoints are gen￾of disability, and the value for one acute phase erally evaluated for statistically significant differ￾reactant (i.e. erythrocyte sedimentation rate [ESR] ences between treatment groups. However, what is or C-reactive protein [CRP]).[8] statistically significant may not necessarily reflect a Another measurement of disease activity is the clinical benefit to the patient (i.e. if a large enough Disease Activity Score 28 (DAS28), population is used, even small differences between [13] which has been more frequently used in Europe, but is gaining treatments may be statistically significant without being of actual clinical value).[25] wider acceptance in the US in clinical trials as well as in clinical practice. This scoring system is a The concept of the MCID was initiated to provide combined index that is based on a count of swollen a measure that distinguishes between statistical and and tender joints (of 28 joints), the ESR, and a visual clinical relevance.[26] The MCID refers to the small￾analogue scale score (0–100) of patients’ general or est difference in an outcome that is perceived by the © 2008 Adis Data Information BV. All rights reserved. Pharmacoeconomics 2008; 26 (10)