Report of the Canadian Hypertension Society Consensus Conference: 1. Introduction

Tables

Table 1: Levels of evidence for rating studies of diagnosis

I.
(a) Independent interpretation of test procedure (without knowledge of result of diagnostic standard).

(b) Independent interpretation of diagnostic standard (without knowledge of result of test procedure).

(c) Selection of patients or subjects who are suspected but not known to have the disorder of interest.

(d) Reproducible description of both the test and the diagnostic standard.

(e) At least 50 patients with and 50 without the disorder.

II. Meets four of the criteria in I.

III. Meets three of the criteria in I.

IV. Meets two of the criteria in I.

V. Meets one of the criteria in I.

VI. Meets none of the criteria in I.
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Table 2: Levels of evidence for rating studies of prognosis

I.
(a) Inception cohort.

(b) Reproducible inclusion and exclusion criteria.

(c) Follow-up of at least 80% of subjects.

(d) Statistical adjustment for extraneous prognostic factors (confounders).

(e) Reproducible descriptions of outcome measures.

II. Inception cohort but meets only three of the other criteria in I.

III. Inception cohort but meets only two of the other criteria in I.

IV. Inception cohort but meets only one of the other criteria in I.

V. Inception cohort but meets none of the other criteria in I.

VI. Meets none of the criteria in I.
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Table 3: Levels of evidence for rating studies of treatment, prevention and quality assurance

I. A randomized controlled trial (RCT) that demonstrates a statistically significant difference in at least one important outcome -- e.g., survival or major illness.

OR

If the difference is not statistically significant, an RCT of adequate sample size to exclude a 25% difference in relative risk with 80% power, given the observed results.

II. An RCT that does not meet the level I criteria.

III. A nonrandomized trial with contemporaneous controls selected by some systematic method (i.e., not selected by perceived suitability for one of the treatment options for individual patients).

OR

Subgroup analysis of a randomized trial.

IV. A before-after study or case series (of a least 10 patients) with historical controls or controls drawn from other studies.

V. Case series (at least 10 patients) without controls.

VI. Case report (fewer than 10 patients).
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Table 4: Levels of evidence for rating review articles

I.
(a) Comprehensive search for evidence.

(b) Avoidance of bias in the selection of articles.

(c) Assessment of the validity of each cited article.

(d) Conclusions supported by the data and analysis presented.

II. Meets only three of the criteria in I.

III. Meets only two of the criteria in I.

IV. Meets only one of the criteria in I.

V. Meets none of the criteria in I.
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Table 5: Grading system for recommendations

A. The recommendation is based on one or more studies at level I.

B. The best evidence available was at level II.

C. The best evidence available was at level III.

D. The best evidence available was lower than level III and inclued expert opinion.

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