Table 4

Incidence rate ratio (IRR) for 30-day and 90-day mortality after hip fracture surgery

Variable30-day
IRR (95% CI)		P value*90-day
IRR (95% CI)		P value†
Revised Cardiac Risk Index (RCRI)
 0Ref.Ref.
 11.5 (1.43 to 1.58)<0.0011.35 (1.30 to 1.40)<0.001
 22.08 (1.96 to 2.21)<0.0011.75 (1.67 to 1.83)<0.001
 32.68 (2.46 to 2.91)<0.0012.18 (2.05 to 2.33)<0.001
 ≥43.13 (2.72 to 3.60)<0.0012.54 (2.28 to 2.84)<0.001
Age1.08 (1.08 to 1.08)<0.0011.07 (1.07 to 1.07)<0.001
Sex
 FemaleRef.Ref.
 Male1.92 (1.84 to 2.00)<0.0011.62 (1.57 to 1.67)<0.001
Peripheral vascular disease
 NoRef.Ref.
 Yes1.13 (1.03 to 1.23)0.0081.16 (1.09 to 1.24)<0.001
Dementia
 NoRef.Ref.
 Yes1.79 (1.71 to 1.87)<0.0011.77 (1.71 to 1.82)<0.001
Chronic obstructive pulmonary disease
 NoRef.Ref.
 Yes1.36 (1.28 to 1.44)<0.0011.27 (1.22 to 1.33)<0.001
Connective tissue disease
 NoRef.Ref.
 Yes0.97 (0.87 to 1.07)0.5090.97 (0.90 to 1.05)0.438
Liver disease
 NoRef.Ref.
 Yes1.88 (1.55 to 2.29)<0.0011.68 (1.45 to 1.95)<0.001
Cancer
 NoneRef.Ref.
 Local tumor1.09 (1.02 to 1.16)0.0071.14 (1.09 to 1.20)<0.001
 Metastatic1.99 (1.78 to 2.22)<0.0012.54 (2.36 to 2.73)<0.001
Type of surgery
 Pins or screwsRef.Ref.
 Pins or screws with sideplate1.05 (0.98 to 1.12)0.1381.03 (0.98 to 1.08)0.294
 Intramedullary rod1.03 (1.97 to 1.11)0.3380.98 (0.93 to 1.03)0.345
 Hemiarthroplasty1.08 (1.01 to 1.15)0.0260.97 (0.93 to 1.02)0.214
 Total hip replacement0.64 (0.54 to 0.75)<0.0010.53 (0.47 to 0.60)<0.001

  • Poisson regression model with robust SEs. Model adjusted for age, sex, comorbidities and type of surgery.

  • *The linear trend of the IRRs for 30-day mortality for the RCRI was tested using the LR test (p<0.001), the BIC score was reduced by 12.3 and the p value for the trend is <0.001.

  • †The linear trend of IRRs for 90-day mortality for RCRI was tested using the LR test (p=0.014), the BIC score was reduced by 28.3 and the p value for the trend is <0.001.

  • BIC, Bayesian Information Criterion; LR, likelihood ratio; Ref., reference.