Table 4.
Univariate and multivariate regression models predicting DHD. Results are presented as ORs where an OR of >1 indicates an increased chance of DHD compared with the reference category and an OR of <1 indicates a reduced chance of DHD. All results from the univariate analysis are presented but for clarity, only the statistically significant results from the multivariate regression are presented. Non-significant results (p>0.05) are represented by an asterisk.
| Univariate analysis | Multivariate analysis | |||
| OR | p-value | OR | p-value | |
| Patient / co-morbid characteristics | ||||
| Age group <65 years 65–75 years 75.01–85 years >85 years |
9.2 (95% CI: 7.6–11.1) 3.9 (95% CI: 3.3–4.5) 2.1 (95% CI: 1.9–2.4) Reference |
<0.001 <0.001 <0.001 – |
5.5 (95% CI: 4.4–6.8) 2.7 (95% CI: 2.3–3.2) 1.7 (95% CI: 1.5–1.9) Reference |
<0.001 <0.001 <0.001 – |
| Sex Male Female |
Reference 1.0 (95% CI: 0.9–1.1) |
– 0.56 |
Reference 1.3 (95% CI: 1.1–1.5) |
– <0.001 |
| Preinjury AMTS 10 ≤9 |
2.6 (95% CI: 2.4–2.9) Reference |
<0.001 – |
1.7 (95% CI: 1.5–1.9) Reference |
<0.001 – |
| Preinjury co-morbidities (Reference = Yes) CVD = No CVA = No COPD = No Renal disease = No Diabetes = No Rheumatoid arthritis = No Parkinson’s disease = No Malignancy = No |
1.6 (95% CI: 1.5–1.8) 1.9 (95% CI: 1.6–2.1) 1.3 (95% CI: 1.2–1.5) 2.4 (95% CI: 2.0–3.0) 1.4 (95% CI: 1.2–1.6) 0.9 (95% CI: 0.7–1.2) 2.3 (95% CI: 1.7–3.1) 1.1 (95% CI: 0.9–1.2) |
<0.001 <0.001 <0.001 <0.001 <0.001 0.59 <0.001 0.36 |
* 1.4 (95% CI: 1.1–1.6) 1.2 (95% CI: 1.1–1.4) 1.7 (95% CI: 1.3–2.1) * * 2.0 (95% CI: 1.5–2.8) * |
* <0.001 0.003 <0.004 * * <0.001 * |
| Smoking Yes No |
Reference 0.6 (95% CI: 0.5–0.7) |
– <0.001 |
* |
* |
| Preinjury medication (Reference = Yes) Clopidogrel = No Warfarin = No Polypharmacy (≥4 medications) = No |
1.5 (95% CI: 1.2–2.0) 2.2 (95% CI: 1.5–3.3) 1.6 (95% CI: 1.5–1.8) |
<0.001 <0.001 <0.001 |
* * * |
* * * |
| Social characteristics | ||||
| Living alone prior to injury Yes No Unknown |
Reference 1.7 (95% CI: 1.5–1.9) 3.0 (95% CI: 1.5–6.1) |
– <0.001 0.002 |
Reference 1.5 (95% CI: 1.3–1.6) 1.5 (95% CI: 0.7–3.3) |
– <0.001 0.29 |
| Preinjury walking ability Alone outdoors Alone indoors Accompanied outdoors Accompanied indoors Unable / transfers only Unknown |
Reference 0.3 (95% CI: 0.3–0.3) 0.4 (95% CI: 0.4–0.5) 0.3 (95% CI: 0.2–0.4) 0.3 (95% CI: 0.2–0.4) 0.6 (95% CI: 0.4–0.9) |
– <0.001 <0.001 <0.001 0.008 <0.001 |
Reference 0.6 (95% CI: 0.5–0.7) 0.7 (95% CI: 0.6–0.9) 0.7 (95% CI: 0.4–1.0) 0.7 (95% CI: 0.4–1.3) 0.6 (59% CI: 0.4–0.8) |
– <0.001 0.003 0.040 0.31 0.002 |
| Walking aids used prior to injury No aids One aid Two aids Frame / walker Wheelchair / bed bound Unknown |
Reference 0.4 (95% CI: 0.4–0.5) 0.4 (95% CI: 0.3–0.5) 0.3 (95% CI: 0.2–0.3) 0.6 (95% CI: 0.4–0.8) 0.3 (95% CI: 0.2–0.4) |
– <0.001 <0.001 <0.001 0.003 <0.001 |
Reference 0.7 (95% CI: 0.6–0.8) 0.6 (95% CI: 0.4–0.8) 0.6 (95% CI: 0.5–0.8) 1.0 (95% CI: 0.6–1.8) 0.7 (95% CI: 0.5–1.2) |
– <0.001 0.001 <0.001 0.90 0.21 |
| Preinjury assistance with basic care ADLs
(washing, dressing, feeding, toileting etc) Yes No |
Reference 2.5 (95% CI: 2.2–2.9) |
– <0.001 |
Reference 1.3 (95% CI: 1.1–1.6) |
– 0.002 |
| Admission characteristics | ||||
| Fracture type Intracapsular Basicervical Intertrochanteric Subtrochanteric / reverse oblique Other / unknown |
1.3 (95% CI: 1.1–1.5) 1.1 (95% CI: 0.8–1.5) 0.9 (95% CI: 0.7–1.0) Reference 1.6 (95% CI: 1.0–2.5) |
0.007 0.53 0.10 – 0.040 |
1.5 (95% CI: 1.2–1.9) 1.2 (95% CI: 0.9–1.7) 1.1 (95% CI: 0.9–1.4) Reference 1.4 (95% CI: 0.8–2.3) |
<0.001 0.31 0.26 – 0.22 |
| Haemoglobin <12g/dl ≥12g/dl |
Reference 1.6 (95% CI: 1.4–1.8) |
– <0.001 |
Reference 1.2 (95% CI: 1.1–1.3) |
– 0.001 |
ADLs = activities of daily living; AMTS = abbreviated mental test score; CI = confidence interval; DHD = direct home discharge; OR = odds ratio