Treatment training manual

8. 9 Grading evidence in clinical guidelines

Treatment guidelines make recommendations for treatment and care based on the best available evidence.

This also involves commenting on the quality of the evidence that is used.

For example, UK HIV treatment guidelines produced by BHIVA, are based on the GRADE system.

This involves a rating for the strength of the recommendation.

  • 1 is a strong recommendation.
  • 2 is a weak recommendation.

The quality of the evidence is also rated.

  • A = High quality evidence. This include consistent results from well conducted studies including RCTs.
  • B = Moderate quality evidence. This could be where results from studies are not always consistent and when additional research is still needed.
  • C = Low quality evidence. For example, if evidence is from observational studies of limited reviews.
  • D = Very low quality evidence. This can be when evidence is only limited to case reports or based on expert opinion (which is not evidence).

For example, a recommendations rated A1 should be followed as standard-of-care and has been proven in substantial clinical research.

BHIVA guidelines on antiretroviral treatment for adults living with HIV-1 2022. Appendix 1. Summary of the modified GRADE system. (2022). (PDF)

Last updated: 1 January 2023.