Table 2 Univariate and multivariate associations with the stratified outcomes “SSI”, "non-infectious wound healing disorders" and "other non-infectious complications" (Cox regression analyses; results expressed as hazard ratios with 95% confidence intervals)

Female sex

1.0, 0.6–1.8

1.1, 0.6–2.0

0.7, 0.3–1.3

0.6, 0.3–1.3

1.0, 0.8–1.3

1.0, 0.8–1.4

Age (continuous)

1.0, 1.0–1.0

1.0, 1.0–1.0

1.0, 1.0–1.0

1.0, 1.0–1.0

1.0, 1.0–1.0

1.0, 1.0–1.0

Diabetes mellitus

2.7, 1.3–5.7

2.1, 0.9–4.9

2.6, 1.2–5.8

1.4, 0.5–3.7

1.2, 0.7–1.8

0.8, 0.5–1.3

Body mass index (continuous)

1.0, 1.0–1.1

1.0, 0.9–1.1

1.1, 1.1–1.2

1.1, 1.0–1.1

1.0, 1.0–1.1

1.0, 1.0–1.0

 ASA (continuous)

1.7, 1.1–2.6

-

2.2, 1.4–3.4

-

1.4, 1.2–1.7

-

 ASA 2 compared to Score 1

1.4, 0.5–3.8

1.4, 0.5–3.9

3.0, 0.7–13.0

2.1, 0.4–9.9

1.1, 0.8–1.7

1.1, 0.7–1.7

 ASA 3 compared to Score 1

2.7, 1.0–7.5

2.4, 0.7–8.5

8.2, 1.9–35.1

3.3, 0.6–19.0

2.0, 1.3–3.0

1.7, 1.0–3.0

 ASA 4 compared to Score 1

3.9, 0.8–20.6

3.9, 0.6–26.9

4.9, 0.4–54.5

3.0, 0.2–44.1

1.8, 0.7–4.3

1.8, 0.6–5.2

Revision surgery

0.3, 0.1–2.0

-

0.5, 0.2–1.8

0.6, 0.2–2.1

1.0, 0.6–1.4

0.7, 0.3–1.5

Duration of surgery

1

-

1

-

1

-

 0.5–0.8 h compared to < 0.5 h

1.9,0.8–4.3

1.9, 0.8–4.6

5.1, 2.0–12.6

5.5, 1.8–16.6

2.0, 1.4–2.8

1.7, 1.2–2.5

 > 0.8 h compared to < 0.5 h

3.8, 1.8–8.2

3.6, 1.6–8.0

3.8, 1.4–10.1

3.5, 1.1–11.5

2.9, 2.0–4.0

2.3, 1.6–3.3

Study period

1

-

1

-

1

-

 Lockdown vs. Pre-Lockdown

1.8, 0.6–5.2

1.6, 0.6–4.8

0.6, 0.1–4.6

0.7, 0.1–5.7

0.7, 0.3–1.4

0.7, 0.3–1.5

 Post-lockdown vs. Pre-Lockdown

0.5, 0.2–0.9

0.4, 0.2–0.8

0.9, 0.5–1.8

0.9, 0.4–1.9

0.5, 0.4–0.7

0.5, 0.3–0.6