Table 2

DVT frequency by compression ultrasonography and univariate association with demographic, clinical and risk factors

DVT n/N (%)OR (95% CI)P value
Total population50/901 (5.5)NA
Gender
 Female36/632 (5.7)1.1 (0.15 to 2.2)0.768
 Male14/269 (5.2)REF
Age mean±SD41.8±15.9NA
Age group
 20–3930/513 (5.9)1.5 (0.69 to 3.7)0.269
 40–599/231 (3.9)REF
 ≥6011/157 (7)1.9 (0.68 to 5.2)0.174
BMI (kg/m2) (n=863)
 <186/96 (6.3)1.3 (0.43 to 3.2)0.571
 18–2534/694 (4.9)REF
 25.1–304/60 (6.7)1.4 (0.34 to 4.1)0.548
 >302/13 (15.4)3.5 (0.36 to 17)0.088
Admitting service
 Medical32/587 (5.5)0.91 (0.50 to 1.8)0.856
 OBS-GYN18/314 (5.7)REF
Hospital department
 CHUK_OB12/151 (8.0)2.3 (0.75 to 7.5)0.104
 CHUK_IM17/308 (5.5)1.5 (0.56 to 4.8)0.379
 CHUB_IM15/279 (5.4)1.4 (0.53 to 4.8)0.419
 CHUB_OB6/163 (3.7)REF
Pregnancy
 Yes5/44 (11.4)2.3 (0.66 to 6.4)0.09
 No31/588 (5.3)REF
Postpartum period <6 weeks
 Yes6/185 (3.2)0.47 (0.15 to 1.2)0.09
 No30/447 (6.7)REF
Clinical features
 Pain/tenderness of the lower limb
  Yes35/88 (39.8)35 (17 to 73)≤0.001*
  No15/813 (1.9)REF
 Calf asymmetry†
  Yes15/26 (57.7)33 (13 to 84)≤0.001*
  No35/875(4)REF
 Entire limb swollen
  Yes40/119 (33.6)39 (18 to 90)≤0.001*
  No10/782 (1.3)REF
 Unilateral limb pitting oedema
  Yes27/41 (65.9)70 (31 to 163)≤0.001*
  No23/860 (2.7)REF
 Dilated collateral superficial veins
  Yes5/14 (35.7)10 (2.6 to 36)≤0.001*
  No45/8875.1)REF
 Tenderness along line of femoral or popliteal veins
  Yes16/34 (47.1)22 (9.4 to 49)
  No34/867 (4.0)REF
Risk factors
 Bedridden‡
  Yes28/314 (8.9)2.5 (1.4 to 4.5)≤0.001*
  No22/587 (3.8)REF
 Lower limb trauma§
  Yes0/30 (0)NA0.177
  No50/871 (5.7)
 Recent smoking (in last 4 weeks)
  Yes4/37 (10.8)2.2 (0.73 to 6.4)0.153
  No46/864 (5.3)REF
 Recent travel >6 hours
  Yes3/6 (50)18 (2.3 to 137)≤0.001*
  No47/895 (5.2)REF
 Congestive cardiac failure
  Yes6/80 (7.5)1.4 (0.48 to 3.5)0.425
  No44/821 (5.4)REF
 Respiratory failure
  Yes3/34 (8.8)1.7 (0.31 to 5.7)0.395
  No47/867 (5.4)REF
 Recent stroke (<3 months)
  Yes1/46 (2.2)0.36 (0.09 to 2.2)0.293
  No49/855 (5.7)REF
 Acute infectious disease
  Yes10/281 (3.6)0.53 (0.24 to 1.1)0.08
  No40/620 (6.5)REF
 History of confirmed VTE
  Yes2/5 (40)12 (1.9 to 72)0.03*
  No48/896 (5.4)REF
 Inflammatory bowel disease
  Yes0/2 (0)NA0.731
  No50/899 (5.6)
 ¶Malignancy
  Yes18/503.0 (1.51 to 5.60)≤0.001*
  32/851
 Nephrotic syndrome
  Yes0/7 (0)NA0.520
  No50/894 (5.6)
 Chronic venous insufficiency
  Yes0/5 (0)NA0.587
  No50/896 (5.6)
 OCPs (n=632)
  Yes0/7 (0)NA0.513
  No36/625 (5.8)
 Receiving DVT prophylaxis
  Yes14/57 (24.6)7.3 (3.4 to 15)≤0.001*
  No36/851 (4.3)REF
  • *Statistically significant (p<0.05).

  • †Calf more than 3 cm different in circumference, 10 cm below tibial tuberosity.

  • ‡Immobilisation (complete bed rest or inability to walk for >30 min per day) for >3 days.

  • §Lower limb trauma or surgery or immobilisation in a plaster cast (in last 4 weeks).

  • ¶Malignancy present or previous, on treatment or palliation up to 6 months previously.

  • BMI, body mass index;CHUB-IM, Internal Medicine Department of Centre Hospitalier Universitaire de Butare; CHUB-OB, Obstetrics and Gynecology Department of Centre Hospitalier Universitaire de Butare; CHUK-IM, Internal Medicine Department of Centre Hospitalier Universitaire de Kigali; CHUK-OB, Obstetrics and Gynecology Department of Centre Hospitalier Universitaire de Kigali; DVT, deep vein thrombosis; NA, not applicable; OBS-GYN, obstetrics and gynaecology departments; OCP, oral contraceptive pill; REF, referent group; VTE, venous thromboembolism.