Stability of clinical outcome measures in rheumatoid arthritis patients with stable disease defined on the basis of the EULAR response criteria

TY - JOUR

T1 - Stability of clinical outcome measures in rheumatoid arthritis patients with stable disease defined on the basis of the EULAR response criteria

AU - Madsen, Ole Rintek

PY - 2016/10/1

Y1 - 2016/10/1

N2 - Natural variation also known as measurement error is assessed in individuals in "steady state." The study aimed to examine inter-visit variations in clinical outcome measures in rheumatoid arthritis (RA) patients with stable disease defined on the basis of the EULAR response criteria. Two hundred thirty-three RA patients with stable disease defined as a change in Disease Activity Score (DAS28-CRP) ≤0.6 between two consecutive visits were identified in the Danish rheumatology registry for biological treatment (DANBIO). Clinical data from a single set of such two visits were extracted for each patient. Using the Bland-Altman method, lower and upper 95 % limits of agreement (LLoA; ULoA) between the consecutive assessments and the bias were calculated for each measure. Associations were characterized by Pearson's r-values and standard errors of estimation (SEE). The mean change in DAS28-CRP was 0.0 ± 0.3. Agreements between the assessments were close on the group level but poor on the individual level. For example, LLoA; ULoA [bias] for patient global assessment (0-100) was -28.3; 29.7 [0.7], for fatigue (0-100) -38.1; 36.3 [-0.9] and for 28 swollen joint count -3.3; 3.3 [0.0]. Inter-visit differences were poorly explained by the baseline values (r [SEE] ranging from 0.15 [12.6] for fatigue to 0.58 [1.4] for 28 tender joint count) and by changes in other outcome variables. In conclusion, outcome measures fluctuated substantially and unpredictably in individual RA patients considered in steady state. The observed between-visit differences may be interpreted to reflect natural variation or measurement error that should be taken into account when monitoring patients in the daily clinic.

AB - Natural variation also known as measurement error is assessed in individuals in "steady state." The study aimed to examine inter-visit variations in clinical outcome measures in rheumatoid arthritis (RA) patients with stable disease defined on the basis of the EULAR response criteria. Two hundred thirty-three RA patients with stable disease defined as a change in Disease Activity Score (DAS28-CRP) ≤0.6 between two consecutive visits were identified in the Danish rheumatology registry for biological treatment (DANBIO). Clinical data from a single set of such two visits were extracted for each patient. Using the Bland-Altman method, lower and upper 95 % limits of agreement (LLoA; ULoA) between the consecutive assessments and the bias were calculated for each measure. Associations were characterized by Pearson's r-values and standard errors of estimation (SEE). The mean change in DAS28-CRP was 0.0 ± 0.3. Agreements between the assessments were close on the group level but poor on the individual level. For example, LLoA; ULoA [bias] for patient global assessment (0-100) was -28.3; 29.7 [0.7], for fatigue (0-100) -38.1; 36.3 [-0.9] and for 28 swollen joint count -3.3; 3.3 [0.0]. Inter-visit differences were poorly explained by the baseline values (r [SEE] ranging from 0.15 [12.6] for fatigue to 0.58 [1.4] for 28 tender joint count) and by changes in other outcome variables. In conclusion, outcome measures fluctuated substantially and unpredictably in individual RA patients considered in steady state. The observed between-visit differences may be interpreted to reflect natural variation or measurement error that should be taken into account when monitoring patients in the daily clinic.

KW - Adult

KW - Aged

KW - Antirheumatic Agents

KW - Arthritis, Rheumatoid

KW - Biological Products

KW - Female

KW - Humans

KW - Male

KW - Middle Aged

KW - Outcome Assessment (Health Care)

KW - Registries

KW - Remission Induction

KW - Severity of Illness Index

KW - Treatment Outcome

KW - Journal Article

U2 - 10.1007/s10067-016-3322-x

DO - 10.1007/s10067-016-3322-x

M3 - Journal article

C2 - 27283868

SN - 0770-3198

VL - 35

SP - 2403

EP - 2409

JO - Clinical Rheumatology

JF - Clinical Rheumatology

IS - 10

ER -