Table 1.
GRADE evaluation of interventions for thromboembolism
| Important outcomes | Mortality, rates of symptomatic recurrence, post-thrombotic syndrome, symptomatic pulmonary embolism, proxy radiological evidence of clot extension or pulmonary embolism; time spent in the target international normalised range | ||||||||
| Number of studies (participants) | Outcome | Comparison | Type of evidence | Quality | Consistency | Directness | Effect size | GRADE | Comment |
| What are the effects of treatments for proximal DVT? | |||||||||
| 3 (421) | Rates of symptomatic recurrence | Compression stockings v placebo or no treatment | 4 | 0 | 0 | 0 | 0 | High | |
| 3 (490) | Post-thrombotic syndrome | Compression stockings v placebo or no treatment | 4 | 0 | 0 | 0 | 0 | High | |
| 1 (169) | Post-thrombotic syndrome | Different durations of stockings v each other | 4 | –2 | 0 | 0 | 0 | Low | Quality points deducted for sparse data and poor reporting of data |
| 8 (4157) | Mortality | LMWH v unfractionated heparin | 4 | 0 | 0 | 0 | 0 | High | |
| 10 (5159) | Venous thromboembolism | LMWH v unfractionated heparin | 4 | 0 | –1 | 0 | 0 | Moderate | Consistency point deducted for conflicting results |
| 1 (120) | Rate of symptomatic recurrence (venous thromboembolism) | Acenocoumarol plus iv unfractionated heparin v acenocoumarol alone | 4 | –2 | 0 | 0 | 0 | Low | Quality points deducted for sparse data and poor follow-up |
| 9 (3804) | Mortality | Long-term v short-term anticoagulation | 4 | 0 | 0 | –2 | 0 | Low | Directness points deducted for wide inclusion criteria and assessment periods |
| 9 (3804) | Rate of symptomatic recurrence (during treatment) | Long-term v short-term anticoagulation | 4 | 0 | 0 | –2 | 0 | Low | Directness points deducted for wide inclusion criteria and assessment periods |
| 7 (1137) | Mortality | Long-term LMWH v long-term oral anticoagulation | 4 | 0 | 0 | 0 | 0 | High | |
| 14 (at least 2907) | Rate of symptomatic recurrence | Long-term LMWH v long-term oral anticoagulation | 4 | –1 | 0 | –1 | 0 | Low | Quality point deducted for incomplete reporting of results. Directness point deducted for variation in study duration |
| 8 (1239) | Adverse effects (haemorrhage) | Long-term LMWH v long-term oral anticoagulation | 4 | –2 | –1 | 0 | 0 | Very low | Quality points deducted for incomplete reporting of results and methodological flaws. Consistency point deducted for conflicting results |
| 1 (400) | Mortality | Vena cava filters v no filters | 4 | –1 | 0 | 0 | 0 | Moderate | Quality point deducted for lack of blinding |
| 1 (400) | Pulmonary embolism | Vena cava filters v no filters | 4 | –1 | –1 | 0 | 0 | Low | Quality point deducted for lack of blinding. Consistency point deducted for conflicting results |
| 1 (400) | Rate of symptomatic recurrence (thromboembolism) | Vena cava filters v no filters | 4 | –1 | 0 | 0 | 0 | Moderate | Quality point deducted for lack of blinding |
| 1 (41) | Rate of symptomatic recurrence (thromboembolism) | Abrupt withdrawal of heparin v additional warfarin for 1 month | 4 | –2 | 0 | 0 | 0 | Low | Quality points deducted for sparse data and incomplete reporting of results |
| 6 (1708) | Mortality | Home treatment with LMWH v hospital treatment with LMWH | 4 | –1 | 0 | –1 | 0 | Low | Quality point deducted for reported methodological problems. Directness point deducted for inclusion of different comparators |
| 6 (1708) | Rate of symptomatic recurrence (thromboembolism) | Home treatment with LMWH v hospital treatment with LMWH | 4 | –1 | 0 | –1 | 0 | Low | Quality point deducted for reported methodological problems. Directness point deducted for inclusion of different comparators |
| 5 (1522) | Mortality | Once-daily LMWH v twice-daily LMWH | 4 | 0 | 0 | 0 | 0 | High | |
| 5 (1522) | Rate of symptomatic recurrence (thromboembolism) | Once-daily LMWH v twice-daily LMWH | 4 | 0 | 0 | 0 | 0 | High | |
| 1 (96) | Rate of symptomatic recurrence (thromboembolism) | High-intensity oral anticoagulation v lower-intensity oral anticoagulation | 4 | –1 | 0 | 0 | 0 | Moderate | Quality point deducted for sparse data |
| 1 (96) | Adverse effects (haemorrhagic events) | High-intensity oral anticoagulation v lower-intensity oral anticoagulation | 4 | –1 | 0 | 0 | +2 | High | Quality point deducted for sparse data. Effect-size points added for RR <0.2 |
| What are the effects of treatments for isolated calf DVT? | |||||||||
| 1 (51) | Proximal extension of clot | Warfarin plus heparin v heparin alone | 4 | –1 | 0 | 0 | +1 | High | Quality point deducted for sparse data. Effect-size point added for RR >2 |
| 1 (197) | Rate of symptomatic recurrence (thromboembolism) | 6 weeks' warfarin v 12 weeks' warfarin | 4 | –3 | 0 | 0 | 0 | Very low | Quality points deducted for sparse data, no blinding, and inclusion of other populations in randomisation |
| What are the effects of treatments for pulmonary embolism? | |||||||||
| 1 (35) | Mortality | Heparin plus warfarin v no anticoagulation | 4 | –1 | 0 | 0 | 0 | Moderate | Quality point deducted for sparse data |
| 1 (326) | Rate of symptomatic recurrence (thromboembolism) | 3 months' oral anticoagulation v 6–9 months' oral anticoagulation | 4 | 0 | 0 | –1 | 0 | Moderate | Directness point deducted for broad inclusion criteria and length of treatment in the comparison |
| 13 (at least 1951) | Mortality | LMWH v unfractionated heparin | 4 | –1 | 0 | 0 | 0 | Moderate | Quality point deducted for sparse data |
| 13 (at least 1951) | Rate of symptomatic recurrence (thromboembolism) | LMWH v unfractionated heparin | 4 | –1 | 0 | 0 | 0 | Moderate | Quality point deducted for sparse data |
| 8 (679) | Mortality | Thrombolysis v heparin | 4 | 0 | 0 | 0 | 0 | High | |
| 5 (611) | Rate of symptomatic recurrence (thromboembolism) | Thrombolysis v heparin | 4 | 0 | 0 | 0 | 0 | High | |
| What are the effects of computerised decision support on oral anticoagulation management? | |||||||||
| 2 (5751) | Rate of symptomatic recurrence | Computer-assisted dosage v manual dosage | 4 | –1 | 0 | 0 | 0 | Moderate | Quality point deducted because data are subgroup analyses of 2 RCTs |
| What are the effects of patient self-management of oral anticoagulation? | |||||||||
| 1 (18,617) | Rate of symptomatic recurrence | Computerised decision support v manual dosage | 4 | –1 | 0 | 0 | 0 | Moderate | Quality point deducted because data are subgroup analysis of a larger RCT |
Type of evidence: 4 = RCT; 2 = observational; 1 = non-analytical/expert opinion. LMWH, low molecular weight heparin.Consistency: similarity of results across studies. Directness: generalisability of population or outcomes. Effect size: based on relative risk or odds ratio.