Dynamic change of lymphocytes associated with short-term prognosis in anti-MDA5-positive dermatomyositis with interstitial lung disease: a multicenter retrospective study.

Abstract

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 1month, then the differences in clinical features and outcomes were compared. Associations between lymphocytes and risk of death within 1month 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 1month 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 1month in the highest tertile were 0.497 (95% CI 0.26-0.949, P for trend = 0.033) after adjustment for potential confounders. GAMM analysis found a mean daily decrease of lymphocytes (0.034 × 10^9/L) after admission in death 1-month patients. Low baseline lymphocytes and gradually declined lymphocytes are both associated with a high risk of death within 1month. However dynamic changes in lymphocytes can better reflect the disease status and better predict the short-term prognosis than baseline lymphocytes in MDA5 + DM-ILD patients. Key points •Low baseline lymphocytes and gradually decreased trend along time correlated with poor short-term prognosis in MDA5 + DM-ILD patients. •Dynamic changes of lymphocytes can better reflect the disease status and better predict the 1-month prognosis than baseline lymphocytes in MDA5 + DM-ILD patients. •Generalized additive mixed model (GAMM) analysis found that in 1-month non-survivors, peripheral blood lymphocytes decreased by 0.034 × 10^9/L per day, while the lymphocytes in survivors gradually increased.