The PRINTO criteria for clinically inactive disease in juvenile dermatomyositis.
OBJECTIVE
To develop data-driven criteria for clinically inactive disease on and off therapy for juvenile dermatomyositis (JDM).


METHODS
The Paediatric Rheumatology International Trials Organisation (PRINTO) database contains 275 patients with active JDM evaluated prospectively up to 24 months. Thirty-eight patients off therapy at 24 months were defined as clinically inactive and included in the reference group. These were compared with a random sample of 76 patients who had active disease at study baseline. Individual measures of muscle strength/endurance, muscle enzymes, physician's and parent's global disease activity/damage evaluations, inactive disease criteria derived from the literature and other ad hoc criteria were evaluated for sensitivity, specificity and Cohen's κ agreement.


RESULTS
The individual measures that best characterised inactive disease (sensitivity and specificity >0.8 and Cohen's κ >0.8) were manual muscle testing (MMT) ≥78, physician global assessment of muscle activity=0, physician global assessment of overall disease activity (PhyGloVAS) ≤0.2, Childhood Myositis Assessment Scale (CMAS) ≥48, Disease Activity Score ≤3 and Myositis Disease Activity Assessment Visual Analogue Scale ≤0.2. The best combination of variables to classify a patient as being in a state of inactive disease on or off therapy is at least three of four of the following criteria: creatine kinase ≤150, CMAS ≥48, MMT ≥78 and PhyGloVAS ≤0.2. After 24 months, 30/31 patients (96.8%) were inactive off therapy and 69/145 (47.6%) were inactive on therapy.


CONCLUSIONS
PRINTO established data-driven criteria with clearly evidence-based cut-off values to identify JDM patients with clinically inactive disease. These criteria can be used in clinical trials, in research and in clinical practice.
Pediatria II, Reumatologia, Istituto Giannina Gaslini, Genova, Italy.
Dragana
D
Lazarevic
Angela
A
Pistorio
Elena
E
Palmisani
Paivi
P
Miettunen
Angelo
A
Ravelli
Clarissa
C
Pilkington
Nico M
NM
Wulffraat
Clara
C
Malattia
Stella Maris
SM
Garay
Michael
M
Hofer
Pierre
P
Quartier
Pavla
P
Dolezalova
Inmaculada Calvo
IC
Penades
Virginia P L
VP
Ferriani
Gerd
G
Ganser
Ozgur
O
Kasapcopur
Jose Antonio
JA
Melo-Gomes
Ann M
AM
Reed
Malgorzata
M
Wierzbowska
Lisa G
LG
Rider
Alberto
A
Martini
Nicolino
N
Ruperto
D000305:Adrenal Cortex Hormones / Q000627:therapeutic use; D002648:Child; D002675:Child, Preschool; D016208:Databases, Factual / Q000592:standards* / Q000706:statistics & numerical data; D003882:Dermatomyositis / Q000175:diagnosis* / Q000188:drug therapy*; D019317:Evidence-Based Medicine / Q000592:standards* / Q000706:statistics & numerical data; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007166:Immunosuppressive Agents / Q000627:therapeutic use; D008137:Longitudinal Studies; D008297:Male; D011446:Prospective Studies; D016032:Randomized Controlled Trials as Topic; D012015:Reference Standards; D012219:Rheumatology / Q000592:standards* / Q000706:statistics & numerical data; D012680:Sensitivity and Specificity
D000305:Adrenal Cortex Hormones; D007166:Immunosuppressive Agents