Evidence Table 3Patient Risk Factors - age

Bibliographic referenceStudy TypeEvidence levelNo. of patientsPatients characteristicsExposureLength of follow up/exposureOutcome measuresEffect sizeComments
Edmonds et al., 2004169Systematic review

6 cohort studies
2+1927Patients undergoing general, gynaecological, elective hip replacement and 1 study did not specify the type of surgery.

Other inclusion criteria:
2 studies - >40 yrs
1 study – 40–80 yrs
3 studies – no other specific patient group
Age

Different age bands used for different studies
Varied 6 to 8 postoperative days or for duration of hospitalisationPercentage of population with postoperative DVT40 to 60 year olds
24.4%
61 to 80 year olds
45.7%
significant
(1 study)
Pooled risk estimate not possible because of different categorisation of age

3 studies had reported no prophylaxis used, 3 studies did not report the prophylaxis used, 1 study did not control for prophylaxis.

Diagnosis of DVT: 5 studies fibrinogen uptake test
1 study bilateral ascending venography.
Percentage of population with postoperative DVTUnder 60 year olds
19%
Over 60 year olds
36%
p<0.0005
(1 study)
Mean ±SD age (years) groups with and without postoperative DVTWith DVT 58 ±3
Without DVT: 44 ±2
Significant
(1 study)
Mean ±SD age (years) groups with and without postoperative DVTWith DVT 71.7 ±9.8
Without DVT: 59.5 ±10.8
Significant
(1 study)
Incidence of postoperative DVT. (continuous range of age)Constant risk below 45 years, increases with each year older
(1 study)
Risk estimate for postoperative DVTOdds ratio: 1.21
CI: 1.04 to 1.42
(1 study)
Rocha et al., 2007556Systematic review

5 studies

3 cohort 2 registry studies
2+UnclearGeneral population, immobilised hospital population

Other inclusion criteria:
1 studies >65 yrs
1 study >75 yrs
1 study >80 yrs
1 study >85 yrs
Age

Different age bands used for different studies
UnclearRelative risk of VTE (no further description)Relative risk of 1.75 for age >65 no 95%CI given
Significant
(1 study; general population)

Relative risk of 1.51 for age >75
no 95%CI given
significant
(1 study; immobilised general population)

Relative risk of 2.0 for age > 85
no 95%CI given
significant
(1 study; general population)

Doubled at each decade from the 5th decade (RR = 1.9)
Pooled risk estimate not possible because of different categorisation of age

1 study reported on the use of prophylaxis.

No other studies reported prophylaxis use
Prevalence of asymptomatic DVT
(Doppler ultrasound)
(n=234)
Medical patients >80 years 17.8% (95% CI: 8.5–32.6)
(1 study)
Incidence of asymptomatic DVT
(Doppler ultrasound)
(n=234)
Medical patients >80 years 6 per 1000 patients (95% CI: 0–12.7)
(1 study)

From: Appendix D, Evidence tables

Cover of Venous Thromboembolism
Venous Thromboembolism: Reducing the Risk of Venous Thromboembolism (Deep Vein Thrombosis and Pulmonary Embolism) in Patients Admitted to Hospital.
NICE Clinical Guidelines, No. 92.
National Clinical Guideline Centre – Acute and Chronic Conditions (UK).
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