Seven Months Follow-Up Study on Pulmonary Function, Lung Radiographic, and Related Physiological Characteristics in Severe COVID-19 Survivors

ABSTRACT

RATIONALE The long-term impact of severe COVID-19 on pulmonary function, chest high-resolution CT (HRCT) pictures, and related physiological characteristics have not been understood clearly. METHODS: 25 survivors with confirmed severe COVID-19 were evaluated pulmonary function, HRCT, and health-related quality of life at seven months after discharge. The data during hospitalization were analyzed retrospectively. RESULTS: Table1 summarized the characteristics of all 25 patients at seven months after discharge. Patients with abnormal CT at seven months (n = 10) had lower albumin level (29.5[26.5-31.2] vs 32.4[30.0-36.5], p = 0.016), higher CT peak scores (24[15-24] vs 13[9-18], p = 0.002), longer cumulative days of receiving glucocorticoids (12[10-14] vs 6[0-11], p = 0.013) compared with patients with normal or basically normal CT. Then survivors were categorized as patients with abnormal DLCO and DLCO/VA, abnormal DLCO but normal DLCO/VA, and normal DLCO and DLCO/VA (n = 7, 5, and 13 respectively). Abnormal DLCO and DLCO/VA group had lower serum IL-2R level (433[326-514] vs 1218[581-1754] vs 710[562-927], p = 0.005), IL-8 level (7.20[3.15-13.25] vs 33.40[23.25-121.35] vs 17.50[6.63-47.48], p = 0.018), TNF-α level (5.80[4.80-7.80] vs 10.10[8.60-11.90] vs 9.00[7.73-12.70], p = 0.010), but higher PCT level (0.08[0.04-0.10] vs 0.03[0.03-0.10] vs 0.03[0-0.04], p = 0.036) compared with other two groups. Correlation analyses indicated that, CT scores after discharge positively correlated with age, PCT level, LDH level, cumulative days of receiving glucocorticoids, total dosage of glucocorticoids used, and CT peak scores (R = 0.409, 0.426, 0.479, 0.537, 0.528, and 0.738 respectively, p = 0.042, 0.043, 0.015, 0.007, 0.008, and < 0.001 respectively), negatively correlated with albumin level (R = -0.561, p = 0.004). DLCO% negatively correlated with total dosage of glucocorticoids used (R = -0.410, p = 0.047). DLCO/VA% positively correlated with BMI, serum IL-2R, and TNF-α level (R= 0.427, 0.560, and 0.525 respectively, p = 0.033, 0.016, and 0.025 respectively), negatively correlated with PCT level (R = -0.467, p = 0.025). Multiple linear regression analysis found that age, PCT level, and CT peak scores were associated with CT scores after discharge (β = 0.290, 0.302, and 0.428 respectively, p = 0.049, 0.030, and 0.036 respectively). BMI and PCT level were associated with DLCO/VA% (β = 0.536 and -0.463 respectively, p = 0.023 and 0.028 respectively). CONCLUSIONS: Radiological and functional impairment were still found in a considerable proportion of survivors with severe COVID-19. These statuses may be related to the severity of the disease and the level of inflammation.