Characteristics of the studies describing the RAMs developed using individual patient data
| First author, year (quality score by authors of SR) . | Reference systematic review . | Study design and study type (sample size) . | Setting . | Data source . | Population (sample size) . | Outcomes and methods of diagnosis . | Follow-up time . |
|---|---|---|---|---|---|---|---|
| MEDENOX RAM | |||||||
| Alikhan et al, 2004 (82%)22 | Huang et al | • Double-masked RCT • Derivation (1102 enrolled, 866 without missing data) | • Countries, 9 • Sites, 60 • Time, 1996-1998 | Medical records (MEDENOX study) | Age >75 y, 51.7; male, 49.7%; cancer, 13.6%; major surgery within 3 mo, 0%; % of VTE, 12%; % of PE, 4/102 (4%); in-hospital VTE prophylaxis, 288 (placebo; 287 enoxaparin 20 mg; 291 enoxaparin 40 mg) | • DVT including below the knee DVT but not upper-extremity DVT (diagnosis based on venography of the legs or ultrasonography) • PE (diagnosis confirmed by lung scanning, pulmonary angiography, helical CT; or at autopsy) • Anticoagulant/ thrombolytic medication use was considered in model | 14 d since admission |
| Weill-Engerer RAM | |||||||
| Weill-Engerer et al, 2004 (85%)32 | Huang et al | Prospective case control- derivation (310:310) | • Countries, 1 (France) • Sites, 10 (university hospitals with long, intermediate, and short-term care facilities) • Time, 16 mo | Medical records | Geriatric and high-risk patients; mean age, 85.7 ± 7 y; male, 23.5%; cancer, 9%; major surgery within 1 mo, 4%; upper-limb DVT, ND; unknown site VTE, ND; in-hospital VTE prophylaxis, ND | • Clinically confirmed DVT including below the knee DVT but not upper-extremity DVT (diagnosis based on ray-scale and Doppler sonography or venography) • Anticoagulant/thrombolytic medication use was considered in model | In hospital |
| Yale RAM | |||||||
| Yale et al, 2005 (55%)34 | Huang et al | Case control- derivation (190:190) | • Countries, 1 (USA) • Sites, multiple • Time, 1995-2002 | EMRs | Medical patients discharged and rehospitalized; median age, ND; male, ND; cancer, ND; major surgery within 3 mo, 0%; upper-limb DVT, ND; unknown site VTE, ND; in-hospital VTE prophylaxis, ND | • DVT, location not described (not specified on diagnosis and definition) • Anticoagulant/thrombolytic medication use was considered in model | 60 d |
| IMPROVE RAM | |||||||
| Spyropoulos et al, 2011 (86%)31 | Huang et al and Stuck et al | Prospective cohort derivation (N = 15156) | • Countries, 12 • Sites, 52 • Time, 2002-2006 | Medical records review (IMPROVE Study) | Median age, 68 y; male, 50%; cancer, 22%; major surgery within 3 mo, 0%; % of VTE, 184 (1.2%); % of PE, ND; in-hospital VTE prophylaxis, 44% | • Symptomatic VTE excluding upper-extremity DVT • No description if below the knee DVT was included (diagnosis based on diagnosis test result and treatment information) • Anticoagulant/thrombolytic medication use was considered in model | 92 d |
| Mahan et al, 2014 (ND)20 | Stuck et al | Case control- external validation (ND) | • Countries, ND • Sites, 3 • Time, ND | Not described | Not described | Not described | Not described |
| Rosenberg et al, 2014 (ND)28 | Stuck et al | Retrospective study-external validation (ND) | • Countries, ND • Sites, 2 • Time, ND | Not described | Not described | Not described | Not described |
| Multivariable RAM | |||||||
| Rothberg et al, 2011 (88%)29 | Huang et al and Stuck et al | Retrospective cohort- derivation and internal validation (242 738: 194 198 [80%] derivation set; 48 540 [20%] validation set) | • Country, 1 (USA) • Sites, 374 • Time, 2004-2005 | Premier’s Perspective database (measuring quality and health care utilization) | Age ≥ 50 y, 87; male, 41%; cancer, 14%; major surgery before admission, ND; % VTE, 1052(0.4%); % of PE, ND; in-hospital VTE prophylaxis, 30% | • Symptomatic VTE including below the knee DVT, upper-extremity DVT was excluded (second diagnosis based on ICD-9-CM and confirmed with diagnosis test result and treatment information) • Anticoagulant/ thrombolytic medication use was considered in model | 30 d |
| 4-Element RAM | |||||||
| Woller et al, 2011 (68%)33 | Huang et al and Stuck et al | Retrospective cohort- derivation (143 975 + 46 856) | • Country, 1 (USA) • Sites, 22 • Time, 2000-2007 derivation; 2008-2009 validation | Intermountain health care administrative and EMR system | Mean age, 63 y; male, 44%; cancer, 44%; major surgery within 30 d, 1%; % of VTE, 3.7%; % of PE, ND | • Symptomatic VTE including below the knee and upper-extremity DVT (diagnosis based on ICD-9-CM) • No description whether anticoagulant/thrombolytic medication use was considered in model | 90 d post admission |
| Full logistic RAM | |||||||
| Woller et al, 2011 (68%)33 | Stuck et al | Retrospective cohort- derivation (143 975 + 46 856) | • Country, 1 (USA) • Sites, 22 • Time, 2000-2007 derivation; 2008-2009 validation | Intermountain health care administrative and EMR system | Mean age, 63 y; male, 44%; cancer, 44%; major surgery within 30 d, 1%; % of VTE, 3.7%; % of PE, ND | • Symptomatic VTE including below the knee and upper extremity DVT (diagnosis based on ICD-9-CM) • No description whether anticoagulant/thrombolytic medication use was considered in model | 90 d post admission |
| First author, year (quality score by authors of SR) . | Reference systematic review . | Study design and study type (sample size) . | Setting . | Data source . | Population (sample size) . | Outcomes and methods of diagnosis . | Follow-up time . |
|---|---|---|---|---|---|---|---|
| MEDENOX RAM | |||||||
| Alikhan et al, 2004 (82%)22 | Huang et al | • Double-masked RCT • Derivation (1102 enrolled, 866 without missing data) | • Countries, 9 • Sites, 60 • Time, 1996-1998 | Medical records (MEDENOX study) | Age >75 y, 51.7; male, 49.7%; cancer, 13.6%; major surgery within 3 mo, 0%; % of VTE, 12%; % of PE, 4/102 (4%); in-hospital VTE prophylaxis, 288 (placebo; 287 enoxaparin 20 mg; 291 enoxaparin 40 mg) | • DVT including below the knee DVT but not upper-extremity DVT (diagnosis based on venography of the legs or ultrasonography) • PE (diagnosis confirmed by lung scanning, pulmonary angiography, helical CT; or at autopsy) • Anticoagulant/ thrombolytic medication use was considered in model | 14 d since admission |
| Weill-Engerer RAM | |||||||
| Weill-Engerer et al, 2004 (85%)32 | Huang et al | Prospective case control- derivation (310:310) | • Countries, 1 (France) • Sites, 10 (university hospitals with long, intermediate, and short-term care facilities) • Time, 16 mo | Medical records | Geriatric and high-risk patients; mean age, 85.7 ± 7 y; male, 23.5%; cancer, 9%; major surgery within 1 mo, 4%; upper-limb DVT, ND; unknown site VTE, ND; in-hospital VTE prophylaxis, ND | • Clinically confirmed DVT including below the knee DVT but not upper-extremity DVT (diagnosis based on ray-scale and Doppler sonography or venography) • Anticoagulant/thrombolytic medication use was considered in model | In hospital |
| Yale RAM | |||||||
| Yale et al, 2005 (55%)34 | Huang et al | Case control- derivation (190:190) | • Countries, 1 (USA) • Sites, multiple • Time, 1995-2002 | EMRs | Medical patients discharged and rehospitalized; median age, ND; male, ND; cancer, ND; major surgery within 3 mo, 0%; upper-limb DVT, ND; unknown site VTE, ND; in-hospital VTE prophylaxis, ND | • DVT, location not described (not specified on diagnosis and definition) • Anticoagulant/thrombolytic medication use was considered in model | 60 d |
| IMPROVE RAM | |||||||
| Spyropoulos et al, 2011 (86%)31 | Huang et al and Stuck et al | Prospective cohort derivation (N = 15156) | • Countries, 12 • Sites, 52 • Time, 2002-2006 | Medical records review (IMPROVE Study) | Median age, 68 y; male, 50%; cancer, 22%; major surgery within 3 mo, 0%; % of VTE, 184 (1.2%); % of PE, ND; in-hospital VTE prophylaxis, 44% | • Symptomatic VTE excluding upper-extremity DVT • No description if below the knee DVT was included (diagnosis based on diagnosis test result and treatment information) • Anticoagulant/thrombolytic medication use was considered in model | 92 d |
| Mahan et al, 2014 (ND)20 | Stuck et al | Case control- external validation (ND) | • Countries, ND • Sites, 3 • Time, ND | Not described | Not described | Not described | Not described |
| Rosenberg et al, 2014 (ND)28 | Stuck et al | Retrospective study-external validation (ND) | • Countries, ND • Sites, 2 • Time, ND | Not described | Not described | Not described | Not described |
| Multivariable RAM | |||||||
| Rothberg et al, 2011 (88%)29 | Huang et al and Stuck et al | Retrospective cohort- derivation and internal validation (242 738: 194 198 [80%] derivation set; 48 540 [20%] validation set) | • Country, 1 (USA) • Sites, 374 • Time, 2004-2005 | Premier’s Perspective database (measuring quality and health care utilization) | Age ≥ 50 y, 87; male, 41%; cancer, 14%; major surgery before admission, ND; % VTE, 1052(0.4%); % of PE, ND; in-hospital VTE prophylaxis, 30% | • Symptomatic VTE including below the knee DVT, upper-extremity DVT was excluded (second diagnosis based on ICD-9-CM and confirmed with diagnosis test result and treatment information) • Anticoagulant/ thrombolytic medication use was considered in model | 30 d |
| 4-Element RAM | |||||||
| Woller et al, 2011 (68%)33 | Huang et al and Stuck et al | Retrospective cohort- derivation (143 975 + 46 856) | • Country, 1 (USA) • Sites, 22 • Time, 2000-2007 derivation; 2008-2009 validation | Intermountain health care administrative and EMR system | Mean age, 63 y; male, 44%; cancer, 44%; major surgery within 30 d, 1%; % of VTE, 3.7%; % of PE, ND | • Symptomatic VTE including below the knee and upper-extremity DVT (diagnosis based on ICD-9-CM) • No description whether anticoagulant/thrombolytic medication use was considered in model | 90 d post admission |
| Full logistic RAM | |||||||
| Woller et al, 2011 (68%)33 | Stuck et al | Retrospective cohort- derivation (143 975 + 46 856) | • Country, 1 (USA) • Sites, 22 • Time, 2000-2007 derivation; 2008-2009 validation | Intermountain health care administrative and EMR system | Mean age, 63 y; male, 44%; cancer, 44%; major surgery within 30 d, 1%; % of VTE, 3.7%; % of PE, ND | • Symptomatic VTE including below the knee and upper extremity DVT (diagnosis based on ICD-9-CM) • No description whether anticoagulant/thrombolytic medication use was considered in model | 90 d post admission |
CT, computed tomography; EMR, electronic medical record; ND, not described; SR, systematic review.