Delayed care-seeking in international migrant workers with imported malaria in China

Abstract Background Imported malaria cases continue to pose major challenges in China as well as in other countries that have achieved elimination. Early diagnosis and treatment of each imported malaria case is the key to successfully maintaining malaria elimination success. This study aimed to build an easy-to-use predictive nomogram to predict and intervene against delayed care seeking among international migrant workers with imported malaria. Methods A prediction model was built based on migrant workers with imported malaria from 2012 to 2019, in Jiangsu Province, China. Routine surveillance information (e.g. sex, age, profession, symptoms, origin country and length of stay abroad), data on the place of initial care-seeking, and the gross-domestic product (GDP) of the destination city were extracted and incorporated. Multivariate logistic regression was performed to identify independent predictors and a nomogram was established to predict the risk of delayed care-seeking. The discrimination and calibration of the nomogram was performed using area under the curve (AUC) and calibration plots. In addition, four machine learning models were used to make a comparison. Results Of 2255 Chinese patients with imported malaria, 636 (28.2%) sought care within 24 hours after symptom onset, and 577 (25.6%) sought care three days after symptom onset. Development of symptoms before entry into China, initial care seeking from superior healthcare facilities, and a higher GDP level of the destination city were significantly associated with delayed care seeking among migrant workers with imported malaria. Based on these independent risk factors, an easy-to-use and intuitive nomogram was established. The calibration curves of the nomogram showed good consistency. Conclusions The tool provides public health practitioners with a method for the early detection of delayed care-seeking risk among international migrant workers with imported malaria, which may be of significance in improving post-travel healthcare for labour migrants, reducing the risk of severe malaria, preventing malaria reintroduction, and sustaining achievements in malaria elimination.