IRRs and HRs for 30-day, 90-day, and 1-year mortality as well as severe complications after hip fracture surgery, comparing patients having spinal with those having general anesthesia.
| Population | 30-day mortality IRR (95% CI) | P value | 90-day mortality IRR (95% CI) | P value | 1-year mortality HR (95% CI) | P value | Severe complication* IRR (95% CI) | P value |
| All patients N=2437 | 0.99 (0.72 to 1.36) | 0.952 | 0.88 (0.70 to 1.11) | 0.281 | 0.98 (0.83 to 1.15) | 0.773 | 1.24 (0.85 to 1.82) | 0.273 |
| Patients who underwent internal fixation N=1769 | 1.03 (0.73 to 1.47) | 0.858 | 0.83 (0.64 to 1.08) | 0.160 | 0.96 (0.79 to 1.16) | 0.677 | 1.27 (0.79 to 2.05) | 0.322 |
| Patients who underwent an arthroplasty N=668 | 0.92 (0.45 to 1.91) | 0.839 | 1.15 (0.7 to 1.89) | 0.603 | 1.06 (0.75 to 1.5) | 0.735 | 1.16 (0.61 to 2.18) | 0.670 |
| Patients with an extended surgical duration† N=221 | 1.8 (0.54 to 5.97) | 0.344 | 1.15 (0.43 to 3.09) | 0.796 | 1.24 (0.57 to 2.68) | 0.573 | 0.77 (0.22 to 2.65) | 0.692 |
| Patients with reduced surgical fitness‡ N=1244 | 0.98 (0.68 to 1.4) | 0.908 | 0.88 (0.68 to 1.14) | 0.327 | 0.96 (0.79 to 1.17) | 0.712 | 1.33 (0.86 to 2.06) | 0.194 |
| Patients with an elevated RCRI§ N=447 | 0.71 (0.37 to 1.34) | 0.292 | 0.86 (0.56 to 1.32) | 0.500 | 0.94 (0.69 to 1.29) | 0.717 | 1.01 (0.50 to 2.06) | 0.972 |
| Patients with an elevated CCI¶ N=735 | 1.02 (0.68 to 1.53) | 0.937 | 1.01 (0.75 to 1.36) | 0.954 | 1.1 (0.88 to 1.38) | 0.414 | 1.3 (0.80 to 2.11) | 0.292 |
| Patients with dementia N=571 | 0.87 (0.53 to 1.41) | 0.582 | 0.91 (0.65 to 1.29) | 0.620 | 0.99 (0.76 to 1.3) | 0.957 | 0.86 (0.40 to 1.84) | 0.705 |
| Patients who underwent out-of-hours surgery** N=956 | 1.09 (0.66 to 1.8) | 0.750 | 0.8 (0.55 to 1.16) | 0.243 | 0.89 (0.68 to 1.17) | 0.390 | 0.68 (0.32 to 1.44) | 0.320 |
| Geriatric patients†† N=2295 | 0.99 (0.72 to 1.36) | 0.965 | 0.88 (0.70 to 1.11) | 0.286 | 0.97 (0.82 to 1.15) | 0.745 | 1.26 (0.85 to 1.85) | 0.249 |
The reference group in each analysis is patients who received spinal anesthesia. IRRs are calculated using Poisson regression models with robust SEs. HRs are calculated using Cox proportional hazards model. The analyses are adjusted for age, sex, CCI, ASA classification, type of fracture, and type of surgery. Multiple imputation by chained equations was used to manage missing values.
*A complication was classified as severe if it had a Clavien-Dindo classification ≥3a.
†An extended surgical duration was defined as a surgery lasting >100 min, which constitute 90th percentile of the operative time in the current study cohort.
‡Patients were deemed to have a reduced fitness for surgery, if they had an ASA classification ≥3.
§An elevated RCRI was defined as RCRI ≥2.
¶An elevated CCI was defined as CCI ≥7.
**Out-of-hours surgery was defined as surgery between 17:00 and 08:00 hours.
††Geriatric patients were defined as ≥65 years old.
ASA, American Society of Anesthesiologists; CCI, Charlson Comorbidity Index; IRR, incident rate ratio; RCRI, Revised Cardiac Risk Index.