Current issues of ACP Journal Club are published in Annals of Internal Medicine

Quality improvement

Clinical guidelines and medical practice: a review

ACP J Club. 1994 May-June;120:85. doi:10.7326/ACPJC-1994-120-3-085

Source Citation

Grimshaw JM, Russell IT. Effect of clinical guidelines on medical practice: a systematic review of rigorous evaluations. Lancet. 1993 Nov 27;342:1317-22.



To evaluate the effectiveness of clinical guidelines in improving the process and outcome of patient care.

Data sources

Relevant citations were identified by searching MEDLINE, the United Kingdom Department of Health's DHSS-DATA, Elsevier's Embase, GRATEFUL MED, and the Dutch EAGLE Technical Committee's grey literature system SIGLE (to the end of 1992) using the following key words: algorithm, consensus statement, controlled trial, health planning guidelines, health services research, medical audit, practice guidelines, process and outcome evaluation, quality assurance, quality of health care, and reference standard. Additional articles were identified by scanning relevant bibliographies and searching for key authors' names.

Study selection

Studies were included if they were designed for medical staff and evaluated the introduction of guidelines in terms of the process of medical care or the outcome for patients; if enough data were collected for meaningful statistical analysis; and if the study design was 1 or more of the following: balanced incomplete block, randomized crossover, simple randomized, controlled before and after, or interrupted time series.

Data extraction

Data pertaining to the study design, intervention, disease or service, and the effects on the process and outcome of patient care were extracted.

Main results

59 studies met the selection criteria (24 on specific clinical conditions, 27 on prevention, and 8 on prescribing or on laboratory or radiologic services). 55 of the 59 studies detected significant change in the process of care in the direction proposed by the guideline. The size of improvement varied considerably across studies. For example, a study evaluating the effects of attaching guidelines for preventive care to patients' notes found that compliance with the guideline increased by 32%. On the other hand, a study examining the effects of studying scientific papers by physicians on compliance with preventive care guidelines found only a modest increase. 9 of the 11 studies evaluating the effects on patient outcome found some significant improvement.


Explicit clinical guidelines improved the process and outcome of patient care when introduced in the context of rigorous evaluations. The size of the improvements, however, varied considerably.

Sources of funding: Wellcome Trust and the Scottish Home and Health Department.

For article reprint: Dr. J.M. Grimshaw, Department of General Practice, University of Aberdeen, Foresterhill Health Centre, Westburn Road, Aberdeen AB9 2ZD, United Kingdom. FAX 44-224-840-683. E-mail


Despite the intense interest in the development and use of clinical practice guidelines, investigators have only recently begun to study how guidelines should be developed and evaluated (1, 2). As a result, several critical questions about guidelines have not been answered. Perhaps the most central questions are: Are health outcomes improved? If so, at what cost?

In this careful, systematic review, Grimshaw and Russell produced one of the only rigorous overviews of studies that evaluated the effect of practice guidelines. The authors took particular care to include only evaluations with adequate study designs. Their results are important because beneficial effects were found from the implementation of guidelines that cover a broad variety of health interventions. This finding suggests that guidelines may be useful in many settings.

Most of the studies reviewed, however, examined the effect of guidelines on the process of care, rather than on health outcomes. Implicit in these studies is the assumption, often untested, that changes in process lead to better health outcomes. The magnitude of the effect of guidelines was substantial and clinically important in some studies but of questionable clinical importance in others.

This study provides convincing evidence that guidelines, when developed and implemented carefully, can result in better care for patients. The review also shows that guidelines occasionally fail to produce these outcomes. Further delineation of the factors that contribute to the success or failure of particular guidelines will be an important next step.

Douglas K. Owens, MD, MSc
Department of Veterans Affairs Medical Center Palo Alto, California, USA