CRP and Pleural effusion: First, univariate logistic regression was performed for the above variables with statistically significant differences, and 14 potential risk factors for SMPP were screened out, including WBC, N%, L%, NLR, AGR, CRP, ESR, MPV, age, primary disease, coinfection, pleural effusion, fever days ≥ 7 and wheeze (Table 4).