Table 3 Factors associated with mortality due to COVID-19. Uni- and multivariable analysis

Country, n (%)

 Argentina (ref)

2433 (96.0)

101 (4.0)

–

–

 Brazil

1000 (95.8)

44 (4.2)

1.06 (0.73–1.51, p = 0.752)

0.67 (0.41–1.07, p = 0.095)

 México

1056 (90.6)

110 (9.4)

2.51 (1.90–3.32, p<0.001)

1.29 (0.82–2.01, p = 0.259)

Age, mean (SD)

49.1 (14.0)

60.3 (14.7)

1.06 (1.05–1.07, p<0.001)

1.07 (1.06–1.08, p<0.001)

Male sex, n (%)

782 (93.0)

59 (7.0)

1.43 (1.05–1.92, p = 0.021)

1.60 (1.13–2.23, p = 0.007)

Glucocorticoid use, n (%)

1660 (91.6)

153 (8.4)

2.56 (1.98–3.32, p<0.001)

2.02 (1.50–2.72, p<0.001)

Rituximab use, n (%)

130 (79.3)

34 (20.7)

5.16 (3.41–7.62, p<0.001)

4.82 (3.03–7.52, p<0.001)

Diabetes, n (%)

387 (86.4)

61 (13.6)

3.33 (2.44–4.50, p<0.001)

2.38 (1.67–3.34, p<0.001)

Chronic kidney disease, n (%)

118 (79.2)

31 (20.8)

5.13 (3.33–7.69, p<0.001)

4.22 (2.56–6.81, p<0.001)

Rheumatic disease activity, n (%)

 Remission (ref)

1556 (95.6)

72 (4.4)

–

–

 Low

1518 (96.4)

56 (3.6)

0.80 (0.56–1.14, p = 0.213)

0.83 (0.59–1.17, p = 0.300)

 Moderate

803 (95.1)

41 (4.9)

1.10 (0.74–1.63, p = 0.623)

1.10 (0.74–1.62, p = 0.641)

 High

133 (82.1)

29 (17.9)

4.71 (2.92–7.44, p<0.001)

4.91 (2.92–8.14, p<0.001)

Immune-mediated inflammatory disease, n (%)

 IJD (ref)

2502 (95.4)

120 (4.6)

–

–

 CTD/Vasculitis

1680 (94.0)

108 (6.0)

1.34 (1.03–1.75, p = 0.032)

1.98 (1.45–2.70, p<0.001)

 Other Diseases

307 (91.9)

27 (8.1)

1.83 (1.17–2.79, p = 0.006)

2.58 (1.57–4.14, p<0.001)

Number of comorbidities, n (%)

 0 (ref)

2595 (97.1)

77 (2.9)

–

–

 1

1133 (94.1)

71 (5.9)

2.11 (1.52–2.94, p<0.001)

 2

549 (89.3)

66 (10.7)

4.05 (2.87–5.70, p<0.001)

 3

162 (87.6)

23 (12.4)

4.78 (2.87–7.71, p<0.001)

 ≥4

50 (73.5)

18 (26.5)

12.13 (6.62–21.44, p<0.001)

Physicians per 1000 inhabitants, n (%)

 1.06–8.8 (ref)

4134 (94.4)

246 (5.6)

–

–

 8.85–16.6

353 (97.5)

9 (2.5)

0.43 (0.20–0.79, p = 0.014)

0.23 (0.09–0.51, p = 0.001)

Average Income (USD per month), n (%)

 169 437 (ref)

2978 (95.7)

135 (4.3)

–

–

 438–707

1509 (92.6)

120 (7.4)

1.75 (1.36–2.26, p<0.001)

1.64 (1.11–2.45, p = 0.014)

GINI index, n (%)

 0.297–0.421 (ref)

1082 (95.2)

54 (4.8)

–

–

 0.422–0.548

3405 (94.4)

201 (5.6)

1.18 (0.88–1.62, p = 0.285)

Unemployment (%), n (%)

 1.56–10.1 (ref)

2790 (94.4)

167 (5.6)

–

–

 10.2–18.8

1697 (95.1)

88 (4.9)

0.87 (0.66–1.13, p = 0.289)

MHDI, n (%)

 0.690–0.786

1208 (92.8)

94 (7.2)

–

–

 0.787–0.884

3279 (95.3)

161 (4.7)

0.63 (0.49–0.82, p = 0.001)

Population density (habitants/km²), n (%)

 (0.2, 3131.0] (ref)

4084 (95.2)

205 (4.8)

–

–

 (3131.1–6262.8]

403 (89.0)

50 (11.0)

2.47 (1.77–3.40, p<0.001)

SARS-CoV-2 infection during vaccination period, n (%)

1739 (96.1)

70 (3.9)

0.60 (0.45–0.79, p<0.001)

0.68 (0.49–0.93, p = 0.019)

Predominant SARS-CoV-2 viral variant, n (%)

 Delta (ref)

165 (91.7)

15 (8.3)

–

–

 Gamma

602 (96.2)

24 (3.8)

0.44 (0.23–0.87, p = 0.016)

 Omicron

298 (96.4)

11 (3.6)

0.41 (0.18–0.90, p = 0.027)

 Other

3424 (94.4)

205 (5.6)

0.66 (0.39–1.18, p = 0.135)

Stringency Index, mean (SD)

71.3 (18.4)

71.5 (18.7)

1.00 (0.99–1.01, p = 0.817)