TY - JOUR
T1 - Incidence and outcomes for children with idiopathic inflammatory myopathy in Western Australia—a long-term population-based study
AU - Nossent, Johannes
AU - Keen, Helen
AU - Preen, David B.
AU - Inderjeeth, Charles A.
PY - 2024/10
Y1 - 2024/10
N2 - Aim: To determine the incidence and health outcomes for juvenile idiopathic inflammatory myopathy (JIIM) in a long-term whole-population study. Methods: We included patients under 18 years hospitalized in Western Australia (WA) from 1985 and 2015 with incident JIIM as defined by pertinent diagnostic codes for dermatomyositis (JDM) polymyositis (JPM), other JIIM and overlap myositis (JOM). We compared clinical outcomes and modified Charlson comorbidity scores with age and gender matched (2:1 ratio) patients with new onset juvenile idiopathic arthritis (JIA). Trends over time for annual incidence rate per million child-population (AIR) were analyzed by least square regression and survival by Kaplan–Meier curves. Results: We included 40 patients with JIIM (63% female, median age 8.5 years) for an average AIR of 2.52 per million (CI 1.09–5.57). AIR was stable over time leading to a point prevalence of 52.61 (CI 40.57–67.06) in 2015. Most patients (80%) were classified as JDM with an AIR for JDM of 2.02 (CI 1.09–5.58) and AIR for the combined other JIIM at 0.51 (CI 0.24–1.15). There was female preponderance (62.5%) in both JIIM groups, but no evidence of seasonality. Over a median follow-up of 13 years, one- and ten-year survival was 94.1%. Compared to JIA patients, readmission (80.4 vs. 63.7, p =.02) and infection rates (15.2 vs. 9.6, p <.01) per 100 person-years were higher for JIIM, with similar frequency of interstitial lung disease, fractures, and thrombotic events. At last observation, nearly all patients in both JIIM cohorts (97.5 vs. 92.5%) had accrued some form of comorbidity. Conclusions: The overall incidence of JIIM leading to hospitalization in WA was stable over 30 years. JIIM prognosis remains suboptimal due to early mortality and accrual of long-term comorbidity.
AB - Aim: To determine the incidence and health outcomes for juvenile idiopathic inflammatory myopathy (JIIM) in a long-term whole-population study. Methods: We included patients under 18 years hospitalized in Western Australia (WA) from 1985 and 2015 with incident JIIM as defined by pertinent diagnostic codes for dermatomyositis (JDM) polymyositis (JPM), other JIIM and overlap myositis (JOM). We compared clinical outcomes and modified Charlson comorbidity scores with age and gender matched (2:1 ratio) patients with new onset juvenile idiopathic arthritis (JIA). Trends over time for annual incidence rate per million child-population (AIR) were analyzed by least square regression and survival by Kaplan–Meier curves. Results: We included 40 patients with JIIM (63% female, median age 8.5 years) for an average AIR of 2.52 per million (CI 1.09–5.57). AIR was stable over time leading to a point prevalence of 52.61 (CI 40.57–67.06) in 2015. Most patients (80%) were classified as JDM with an AIR for JDM of 2.02 (CI 1.09–5.58) and AIR for the combined other JIIM at 0.51 (CI 0.24–1.15). There was female preponderance (62.5%) in both JIIM groups, but no evidence of seasonality. Over a median follow-up of 13 years, one- and ten-year survival was 94.1%. Compared to JIA patients, readmission (80.4 vs. 63.7, p =.02) and infection rates (15.2 vs. 9.6, p <.01) per 100 person-years were higher for JIIM, with similar frequency of interstitial lung disease, fractures, and thrombotic events. At last observation, nearly all patients in both JIIM cohorts (97.5 vs. 92.5%) had accrued some form of comorbidity. Conclusions: The overall incidence of JIIM leading to hospitalization in WA was stable over 30 years. JIIM prognosis remains suboptimal due to early mortality and accrual of long-term comorbidity.
KW - incidence
KW - juvenile idiopathic myositis
KW - outcomes
UR - http://www.scopus.com/inward/record.url?scp=85206833832&partnerID=8YFLogxK
U2 - 10.1111/1756-185X.15379
DO - 10.1111/1756-185X.15379
M3 - Article
C2 - 39420796
AN - SCOPUS:85206833832
SN - 1756-1841
VL - 27
JO - International Journal of Rheumatic Diseases
JF - International Journal of Rheumatic Diseases
IS - 10
M1 - e15379
ER -