Based on patient-reported outcomes, a diagnostic prediction model was used to differentiate juvenile idiopathic arthritis (JIA) from chronic musculoskeletal pain syndrome (CMPS), according to study results published in The Journal of Pediatrics.

A retrospective cohort study was conducted to explore how the Juvenile Arthritis Multidimensional Assessment Report (JAMAR) performs in distinguishing JIA from CMPS.

Researchers evaluated JAMAR items that were completed by 287 patients at their initial visit to the pediatric rheumatology department at Wilhelmina Children’s Hospital in Utrecht, The Netherlands. They used a penalized multivariable model to identify JAMAR items that were relevant for predicting a diagnosis of JIA in clinical application. New data from the same center were used to validate the model.


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A total of 196 JAMARs (97 JIA and 99 CMPS) were collected in the model development data; 91 JAMARs (48 JIA and 43 CMPS) were collected in the validation data. In the prediction model, variables with the strongest association with a JIA diagnosis, and not CMPS, included asymmetric pain/swelling in the shoulder (odds ratio [OR], 2.34); difficulty with self-care (OR, 2.41); skin rash (OR, 2.07); and asymmetric pain/swelling in the knee (OR, 2.29).

Predictions regarding validation data were calculated for 83 of the 91 participants. Calibration and discrimination (area under the curve [AUC], 0.83; 95% CI, 0.74-0.94) in the validation data were found to be good. At the cutoff threshold of 70% for the predicted probability of JIA, the model had a negative predictive value of 95% and a positive predictive value of 67%.

Researchers listed some major limitations of the current study. Because JAMAR has not been validated in other diagnoses, its use in patients with CMPS warrants additional investigation and validation.

The researchers concluded, “Several items from the JAMAR questionnaire can help distinguish JIA from CMPS in children with corresponding symptoms. We present an easy to use, adjusted and validated model with the aim to separate JIA and CMPS early at presentation based on patient-reported outcomes to [facilitate] proper referral and treatment. Physicians can utilize the model even without having access to the full JAMAR questionnaire.”

Reference

van Straalen JW, van Stigt Thans M, Wulffraat NM, de Roock S, Swart JF. A diagnostic prediction model for separating juvenile idiopathic arthritis and chronic musculoskeletal pain syndrome. J Pediatr. Published online April 20, 2022. doi:10.1016/j.jpeds.2022.04.029