Meta-regression of the variables potentially associated with the prevalence of COVID-19
| Variables | Number of studies | Coefficient | SE | Lower 95% CI | Upper 95% CI | Z value | P value |
| Age (mean/median) | 42 | 0.043 | 0.024 | −0.003 | 0.089 | 1.82 | 0.069 |
| Male (%) | 44 | −0.018 | 0.011 | −0.040 | 0.004 | −1.64 | 0.101 |
| HTN (%) | 12 | 0.025 | 0.029 | −0.031 | 0.081 | 0.88 | 0.377 |
| DM (%) | 13 | 0.060 | 0.099 | −0.134 | 0.253 | 0.60 | 0.546 |
| Obesity (%) | <10 | NA | NA | NA | NA | NA | NA |
| Comorbidities (≥1) (%) | <10 | NA | NA | NA | NA | NA | NA |
| Glucocorticoids (%) | 26 | 0.020 | 0.010 | 0.001 | 0.040 | 2.04 | 0.042 |
| csDMARDs (%) | 24 | 0.005 | 0.010 | −0.015 | 0.025 | 0.47 | 0.637 |
| b/tsDMARDs (%, mono) | 31 | −0.006 | 0.008 | −0.021 | 0.010 | −0.72 | 0.469 |
| b/tsDMARDs (%, combo) | <10 | NA | NA | NA | NA | NA | NA |
| b/tsDMARDs (%, mono/combo) | 34 | −0.004 | 0.007 | −0.019 | 0.010 | −0.56 | 0.574 |
| TNF antagonists (%, mono/combo) | 30 | −0.020 | 0.013 | −0.045 | 0.004 | −1.63 | 0.104 |
| Non-TNF antagonists (% mono/combo) | 29 | −0.006 | 0.012 | −0.029 | 0.018 | −0.47 | 0.641 |
b/tsDMARDs, biologic or targeted synthetic DMARDs (abatacept, belimumab, CD-20, IL-1, IL-6, IL-12/23, IL-23, IL-17, α4β7 integrin, TNF and Janus kinase (JAK) inhibitors); combo, combination therapy with csDMARDs; csDMARDs, conventional synthetic disease-modifying antirheumatic drugs (hydroxychloroquine, chloroquine, thiopurines, cyclophosphamide, cyclosporine, tacrolimus, leflunomide, methotrexate, mycophenolate mofetil/mycophenolic acid and sulfasalazine); DM, diabetes; HTN, hypertension; mono, monotherapy; NA, not available; TNF, tumour necrosis factor.