Univariate analysis of the association between risk factors and any complication, percutaneous drainage of an abscess, reoperation, readmission, emergency department visit and lengthy hospital stay (> 7 d)
| Characteristic | RR (95% CI) | |||||
|---|---|---|---|---|---|---|
| Any complication | Percutaneous drainage of abscess | Reoperation | Readmission | Emergency department visit | Lengthy stay | |
| Age at appendectomy, yr | ||||||
| 18–30 | 1 (reference) | 1 (reference) | 1 (reference) | 1 (reference) | 1 (reference) | 1 (reference) |
| 31–50 | 1.15 (1.11–1.19) | 1.34 (1.11–1.62) | 1.44 (1.01–2.04) | 1.13 (1.02–1.25) | 0.98 (0.94–1.03) | 1.92 (1.66–2.23) |
| 51–70 | 1.41 (1.36–1.46) | 1.64 (1.34–2.01) | 1.84 (1.27–2.69) | 1.35 (1.21–1.52) | 1.01 (0.95–1.06) | 4.76 (4.15–5.46) |
| ≥ 71 | 2.20 (2.10–3.10) | 1.57 (1.13–2.20) | 4.16 (2.66–6.51) | 2.02 (1.72–2.37) | 1.13 (1.03–1.23) | 15.29 (13.30–17.6) |
| Sex | ||||||
| Female | 1 (reference) | 1 (reference) | 1 (reference) | 1 (reference) | 1 (reference) | 1 (reference) |
| Male | 0.86 (0.84–0.88) | 1.34 (1.15–1.56) | 1.08 (0.83–1.41) | 0.96 (0.88–1.04) | 0.83 (0.79–0.86) | 1.07 (0.99–1.17) |
| Neighbourhood income quintile | ||||||
| 1 | 1 (reference) | 1 (reference) | 1 (reference) | 1 (reference) | 1 (reference) | 1 (reference) |
| 2 | 0.93 (0.89–0.97) | 0.99 (0.78–1.25) | 1.16 (0.77–1.75) | 0.87 (0.76–1.00) | 0.85 (0.79–0.90) | 1.02 (0.90–1.17) |
| 3 | 0.93 (0.89–0.97) | 0.88 (0.69–1.12) | 0.82 (0.52–1.27) | 0.92 (0.81–1.05) | 0.87 (0.81–0.92) | 0.88 (0.77–1.00) |
| 4 | 0.92 (0.88–0.96) | 0.92 (0.73–1.16) | 1.01 (0.67–1.53) | 0.87 (0.76–0.99) | 0.86 (0.81–0.92) | 0.87 (0.76–0.99) |
| 5 | 0.86 (0.83–0.90) | 0.89 (0.70–1.13) | 0.86 (0.56–1.33) | 0.84 (0.74–0.96) | 0.78 (0.73–0.83) | 0.90 (0.79–1.03) |
| Missing | 0.98 (0.81–1.19) | 0.59 (0.15–2.38) | — | 0.92 (0.50–1.70) | 1.08 (0.83–1.40) | 1.13 (0.64–1.97) |
| Residence | ||||||
| Urban | 1 (reference) | 1 (reference) | 1 (reference) | 1 (reference) | 1 (reference) | 1 (reference) |
| Rural | 1.20 (1.16–1.25) | 0.72 (0.55–0.95) | 1.18 (0.79–1.75) | 1.08 (0.95–1.23) | 1.36 (1.29–1.44) | 1.37 (1.22–1.54) |
| Missing | 1.02 (0.52–2.00) | 3.48 (0.51–23.6) | — | 1.17 (0.17–7.91) | 0.63 (0.17–2.36) | 3.55 (1.25–10.10) |
| Perforation status | ||||||
| Nonperforated | 1 (reference) | 1 (reference) | 1 (reference) | 1 (reference) | 1 (reference) | 1 (reference) |
| Perforated | 1.41 (1.37–1.45) | 5.61 (4.72–6.66) | 4.45 (3.33–5.94) | 1.98 (1.82–2.16) | 1.21 (1.16–1.26) | 4.13 (3.77–4.51) |
| Time from triage to operating room, h | ||||||
| < 6 | 1 (reference) | 1 (reference) | 1 (reference) | 1 (reference) | 1 (reference) | 1 (reference) |
| 6–12 | 0.99 (0.95–1.04) | 1.05 (0.83–1.33) | 0.94 (0.63–1.39) | 1.09 (0.95–1.24) | 0.93 (0.87–0.99) | 1.09 (0.94–1.27) |
| > 12 | 1.09 (1.05–1.14) | 1.24 (0.99–1.56) | 0.93 (0.63–1.37) | 1.21 (1.06–1.37) | 0.96 (0.91–1.02) | 1.94 (1.68–2.24) |
| Missing | 1.67 (1.53–1.82) | 1.23 (0.66–2.28) | 3.00 (1.49–6.03) | 1.74 (1.29–2.34) | 1.18 (1.01–1.37) | 8.29 (6.88–10.00) |
| Time of appendectomy | ||||||
| 8 am–5 pm | 1 (reference) | 1 (reference) | 1 (reference) | 1 (reference) | 1 (reference) | 1 (reference) |
| 5 pm–12 am | 0.93 (0.90–0.95) | 0.81 (0.68–0.96) | 1.26 (0.93–1.70) | 0.91 (0.83–1.00) | 0.91 (0.87–0.96) | 0.76 (0.69–0.83) |
| 12 am–8 am | 0.94 (0.90–0.98) | 1.42 (1.15–1.77) | 0.59 (0.34–1.04) | 0.93 (0.81–1.07) | 0.93 (0.87–0.99) | 0.91 (0.79–1.03) |
| Surgical technique | ||||||
| Open | 1 (reference) | 1 (reference) | 1 (reference) | 1 (reference) | 1 (reference) | 1 (reference) |
| Laparoscopic | 0.65 (0.63–0.67) | 1.11 (0.91–1.36) | 0.57 (0.42–0.76) | 0.89 (0.77–0.95) | 0.83 (0.79–0.87) | 0.21 (0.20–0.23) |
CI = confidence interval; RR = relative risk.