Cut-Offs and Response Criteria for the Hospital Universitario La Princesa Index (HUPI) and Their Comparison to Widely-Used Indices of Disease Activity in Rheumatoid Arthritis.
OBJECTIVE
To estimate cut-off points and to establish response criteria for the Hospital Universitario La Princesa Index (HUPI) in patients with chronic polyarthritis.


METHODS
Two cohorts, one of early arthritis (Princesa Early Arthritis Register Longitudinal [PEARL] study) and other of long-term rheumatoid arthritis (Estudio de la Morbilidad y Expresión Clínica de la Artritis Reumatoide [EMECAR]) including altogether 1200 patients were used to determine cut-off values for remission, and for low, moderate and high activity through receiver operating curve (ROC) analysis. The areas under ROC (AUC) were compared to those of validated indexes (SDAI, CDAI, DAS28). ROC analysis was also applied to establish minimal and relevant clinical improvement for HUPI.


RESULTS
The best cut-off points for HUPI are 2, 5 and 9, classifying RA activity as remission if ≤2, low disease activity if >2 and ≤5), moderate if >5 and <9 and high if ≥9. HUPI's AUC to discriminate between low-moderate activity was 0.909 and between moderate-high activity 0.887. DAS28's AUCs were 0.887 and 0.846, respectively; both indices had higher accuracy than SDAI (AUCs: 0.832 and 0.756) and CDAI (AUCs: 0.789 and 0.728). HUPI discriminates remission better than DAS28-ESR in early arthritis, but similarly to SDAI. The HUPI cut-off for minimal clinical improvement was established at 2 and for relevant clinical improvement at 4. Response criteria were established based on these cut-off values.


CONCLUSIONS
The cut-offs proposed for HUPI perform adequately in patients with either early or long term arthritis.
Rheumatology Department, Hospital Universitario la Princesa, IIS-IP, Madrid, Spain.
Isidoro
http://orcid.org/0000-0001-9614-5199
I
González-Álvaro
Division of Rheumatology, Rush University Medical Center, Chicago, Illinois, United States of America.
Isabel
I
Castrejón
Rheumatology Department, Hospital Universitario la Princesa, IIS-IP, Madrid, Spain.
Ana M
AM
Ortiz
Rheumatology Department. Hospital Clínico San Carlos, IdISSC, Madrid, Spain.
Esther
E
Toledano
Rheumatology Department, Hospital Universitario la Princesa, IIS-IP, Madrid, Spain.
Santos
S
Castañeda
Rheumatology Department, Hospital Universitario la Princesa, IIS-IP, Madrid, Spain.
Alberto
A
García-Vadillo
Instituto de Salud Musculoesquelética, Madrid, Spain.
Loreto
L
Carmona
D000368:Aged; D018501:Antirheumatic Agents / Q000008:administration & dosage*; D019540:Area Under Curve; D001172:Arthritis, Rheumatoid / Q000097:blood / Q000188:drug therapy* / Q000473:pathology; D001799:Blood Sedimentation; D002097:C-Reactive Protein / Q000378:metabolism*; D004912:Erythrocytes / Q000473:pathology; D005260:Female; D017408:Guidelines as Topic; D006785:Hospitals, University; D006801:Humans; D008297:Male; D008875:Middle Aged; D012074:Remission Induction; D012720:Severity of Illness Index; D057170:Translational Research, Biomedical
D018501:Antirheumatic Agents; D002097:C-Reactive Protein