Table 3.
Factors associated with increasing convalescent antibody titers in COVID-19
| Geometric mean ratio (CI) P | |||
|---|---|---|---|
| n (%) | Unadjusted | Adjusted | |
| Total | 312 (100%) | ||
| Female sex | 160 (51%) | 0.63 (0.41–0.97) 0.036 | 0.81 (0.56–1.18) 0.276 |
| Older age (by 10-year intervals) | 1.50 (1.35–1.67) <0.001 | 1.23 (1.09–1.38) <0.001 | |
| BMI | 1.17 (1.12–1.23) <0.001 | 1.05 (1.00–1.11) 0.035 | |
| Comorbidity | |||
| Asthma/COPD | 38 (12%) | 1.70 (0.88–3.28) 0.111 | |
| Hypertension | 35 (11%) | 5.43 (2.82–10.46) <0.001 | 1.74 (0.89–3.43) 0.108 |
| Chronic heart disease | 22 (7%) | 4.68 (2.06–10.64) <0.001 | 0.94 (0.41–2.16) 0.891 |
| Rheumatic disease | 20 (6%) | 1.67 (0.70–4.01) 0.249 | |
| Diabetes | 13 (4%) | 3.57 (1.23–10.37) 0.020 | 1.47 (0.59–3.71) 0.409 |
| Immunosuppression | 11 (4%) | 1.51 (0.47–4.83) 0.488 | |
| Current or prior smoker | 96 (31%) | 1.57 (0.99–2.50) 0.055 | |
| Severity of initial illness | 2.12 (1.82–2.48) <0.001 | 1.67 (1.34–2.07) <0.001 | |
| Days in hospital | 1.10 (1.07–1.13) <0.001 | 1.01 (0.97–1.04) 0.679 | |
Associated factors were analyzed by linear regression with log-transformed antibody titers as response variables and reported as geometric mean ratios with 95% confidence intervals (CIs) and P values. Factors with significance level P < 0.1 in univariable analysis were included in the multivariable analyses. For factors with significance level P < 0.05, the P values are shown in bold.