Dynamic Change of Lymphocytes Associated with Short-Term Prognosis in Anti-Mda5-positive Dermatomyositis with Interstitial Lung Disease: a Multicenter Retrospective Study.

Lymphopenia is a unique manifestation of anti-MDA5 positive dermatomyositis with interstitial lung disease (MDA5 + DM-ILD). This study aimed to investigate the relationship between dynamic changes in peripheral lymphocytes and short-term prognosis in patients of MDA5 + DM-ILD. Two hundred sixty-three MDA5 + DM-ILD patients were divided into different groups according to lymphocyte count and death or survival within 1 month, then the differences in clinical features and outcomes were compared. Associations between lymphocytes and risk of death within 1 month were also investigated in different lymphocyte groups using Cox proportional hazard models. A generalized additive mixed model (GAMM) was established to analyze the dynamic changes of lymphocytes in the death 1-month group. Lymphocytes of the patients who died within 1 month were significantly lower than survivors by different lymphocyte grouping methods, and the total lymphocytes showed a gradually decreasing trend in non-survivors. And the difference between survivors and non-survivors was more obvious over time. The lowest tertile of baseline lymphocytes as a reference, the hazard ratios for death within 1 month in the highest tertile were 0.497 (95