February 2003 Bulletin

Table

Journal of Bone and Joint Surgery levels of evidence for rating the quality of clinical studies. Studies are classified as one of four study types with five possible levels. The criteria for assignment are contained within the cells of the table.

Types of Studies

Therapeutic Studies —

Prognostic Studies —

Diagnostic Studies —

Economic and Decision Analyses —

Investigating the results of treatment

Investigating the outcome of disease

Investigating a diagnostic test

Developing an economic or decision model

Level I

Randomized Trial Statistically significant difference. No statistically significant difference but narrow confidence intervals

Systematic Review2 of Level I RCTs (and studies were homogenous)

1. Prospective study1

2. Systematic Review2 of Level I studies

Testing of previously developed diagnostic criteria on consecutive patients (with universally applied reference "gold" standard) Systematic review2 of Level I studies

Clinically sensible costs and alternatives; values obtained from many studies, with multiway sensitivity analyses Systematic review2 of Level I studies

Level II

Prospective cohort study3 Poor quality RCT (e.g. < 80% follow-up)

Systematic review2(a) Level II studies(b) non-homogeneous Level 1 studies

Retrospective4 study Untreated controls from an RCT

 

Systematic review2 of Level II studies

Development of diagnostic criteria on consecutive patients(with universally applied reference"gold" standard)

Systematic review2 of Level II studies

Clinically sensible costs and alternatives; values obtained from limited studies; with multiway sensitivity analyses

Systematic review2 of Level II studies

Level III

Case control study5 Retrospective4 cohort study

Systematic review2 of Level III studies

Study of non- consecutive patients; without consistently applied reference"gold" standard

Systematic review2 of Level III studies

Analyses based on limited alternatives and costs; and poor estimates

Systematic review2 of Level III studies

Level IV

Case Series (no, or historical, control group)

Case series

Case-control study Poor reference standard

Analyses with no sensitivity analyses

Level V

Expert Opinion

Expert Opinion

Expert Opinion

Expert Opinion

 

1. All patients were enrolled at the same point in their disease (inception cohort) with a greater than or equal to 80% follow-up of enrolled patients
2. A combination of results from two or more prior studies.
3. Patients compared with a control group of patients treated at same time and institution.
4. The study was initiated after treatment performed.
5. Patients with a particular outcome called "cases"; e.g. failed total arthroplasty compared to those who did not have outcome called "controls", e.g. non-failed total hip arthroplasty.

Introducing Levels of Evidence to The Journal J Bone Joint Surg Am 2003 85: 1-3


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