9 Interpreting the evidence and writing the guideline

Using the evidence

Evidence reviews summarise the evidence selected from the results of evidence searches. Depending on the topic and type of evidence, they may include GRADE tables, GRADE-CERQual tables or evidence statements. These describe the number, type and quality of the studies for each review question.

Developing evidence-based recommendations involves:

When discussing the evidence, the committee should consider the following:

A key element in reviewing the evidence is weighing up the magnitude and importance of the benefits and harms of an intervention, and the potential for unintended consequences. This may be done qualitatively (for example, 'the evidence of a reduction in medicines errors in care homes outweighed a small increase in staff workload and resources') or quantitatively (using a decision model).

The committee should assess the extent to which the effects observed in any clinical trials are representative of what would happen in the real world.

The committee should ensure that the evidence reviews are a fair summary of the evidence and should discuss any uncertainties in the evidence.

They also need to consider whether the evidence review has addressed equality issues.

Economic evidence

The committee should discuss cost effectiveness at the same time as clinical effectiveness when formulating recommendations. This may be done informally or may be more formal and include economic modelling (see chapter 7 on incorporating economic evaluation).

If several interventions are being considered that are equal in terms of clinical effectiveness, the committee should sequence them in terms of their cost effectiveness.

Indirect evidence

Sometimes, when there is no evidence directly relevant to a specific population or setting, indirect evidence from other populations or settings may be considered. For example, a review of systems for managing medicines in care homes for people with dementia may identify good practice that is relevant in other care home settings.

The use of indirect evidence must be considered carefully by the committee, with explicit consideration of the features of the condition or interventions that allow extrapolation to a different context or population.

This also applies when extrapolating findings from evidence in different care settings (for example, between primary and secondary care). The committee should consider any similarities in case mix, staffing, facilities and processes, and any limitations.

Other factors to consider

In addition to the evidence included in the evidence review, the committee should take account of other types of information, including:

They should also ensure that it will be feasible to put the recommendations into practice. As well as the sources above, committees can use other approaches to do this - see chapter 10 on the validation process for draft guidelines, and dealing with stakeholder comments and appendix B on approaches to additional consultation and commissioned primary research.

The committee should consider the extent to which a change in practice will be needed to implement a recommendation. They should consider the need for staff training, policy levers and funding streams, and the possible need for carefully controlled implementation with, for example, training programmes. This should be summarised in the guideline and documented in any resources to support implementation.

They should take account of the principles that guide the development of NICE guidance and standards and be explicit about the value judgements they make. The report on ethical issues in public health by the Nuffield Council on Bioethics provides useful guidance.

There are additional considerations when making recommendations about medicines, such as licensing and national medicines safety advice. The NICE medicines optimisation team can advise on any medicines-related issues. See the section on recommendations on medicines for further details.

Deciding what recommendations to make

The committee works with a multidisciplinary team at NICE, to agree the recommendations and write the guideline content.

Sometimes recommendations are made because of a legal duty or because the consequences of not following a course of action are extremely serious. If there is a legal duty, the recommendation should build on the law or statutory guidance rather than simply recommending users to follow it or repeating it.

The committee should use its judgement to decide what the evidence means in the context of the guideline and decide what recommendations can be made to practitioners, commissioners of services or others.

They should decide what action to recommend and keep in mind which sectors (including which practitioners or commissioners within those sectors) should act on the recommendations.

They should consider whether recommendations can be formulated to advance equality in health outcomes (for example, by making access more likely for certain groups, or by tailoring the intervention to specific groups). At the very least, they should ensure new recommendations will not worsen health inequalities. This means ensuring everyone who needs to access a service can do so.

See table 1 for a list of areas where NICE does not usually make recommendations.

See also the section on recommendations on medicines.

Conceptual framework or logic model

When the committee is developing its recommendations, it should consider any relevant conceptual frameworks or logic models because these may help to identify practical issues for recommendations that will change practice.

Deciding on the strength of recommendations

The concept of the 'strength' of a recommendation (Guyatt et al. 2008) is key to translating evidence into recommendations. This considers the quality of the evidence but is conceptually different.

If the committee concludes, based on the evidence, that the benefits of an intervention clearly outweigh the harms and the intervention is likely to be cost effective, they should make a strong recommendation in favour of the intervention.

If the committee concludes, based on the evidence, that there is a closer balance between benefits and harms, and believe some people would not choose an intervention whereas others would, they should make a weak recommendation.

NICE reflects the strength of the recommendation in the wording (see the section on wording the recommendations).

What to do if there is little evidence of difference between interventions

There might be little evidence of differences in effectiveness or cost effectiveness between interventions. In this case, all effective or cost-effective interventions may be recommended.

Interventions that are not cost effective should not usually be offered.

Considerations about equity may affect whether to recommend the intervention (see the section on approaches to original economic evaluation in the chapter on incorporating economic evaluation).

What to do if there is insufficient evidence

If published evidence of efficacy or effectiveness for an intervention is lacking, low quality, or uncertain, the committee may use its clinical experience and knowledge to do 1 of the following:

The principles in the section on wording the recommendations should be used.

When to remove recommendations

The committee should also assess whether, when recommending an intervention, they are able to remove recommendations for other interventions because they have been superseded by the new one.

When to make 'do not offer' recommendations

Reasons for the committee to make a 'do not offer' recommendation include:

When to make 'only in research' recommendations

The committee can make an 'only in research' recommendation if the necessary research can realistically be set up or is already planned, or people using services are already being recruited for a study. The following outcomes may also apply:

Prescribing information

Prescribing information includes dosage, duration of treatment, monitoring requirements, contraindications, cautions and adverse effects. NICE does not usually include prescribing information in its recommendations though there are some exceptions to this. See table 1 for details.

National medicines safety advice

National medicines safety advice includes national patient safety alerts and the MHRA's drug safety updates. NICE does not usually include patient safety information in its recommendations though there are some exceptions to this. See table 1 for details.

Antimicrobials and antimicrobial stewardship

Recommendations on antimicrobials should:

Guidelines that cover antimicrobial prescribing may include prescribing tables that detail choice of antimicrobials, dosages, duration of treatment and routes of administration (for an example of an antimicrobial prescribing table, see the section on choice of antibiotic in NICE's guideline on Clostridioides difficile infection).

Off-label use of licensed medicines

Recommendations are usually about using medicines within their licensed indications. However, there are clinical situations in which recommending an off-label use of a licensed medicine may be in the best clinical interests of the person, in line with the MHRA guidance (see appendix 2 of the MHRA guidance on the supply of unlicensed medicinal products). For example, this may happen if the clinical need cannot be met by a licensed product and there is enough evidence or experience of using the medicine to support its safety and efficacy.

Dosage information for off-label use of a licensed medicine is not usually included in the SPC. If off-label use is being recommended, NICE should check whether there is any relevant dosage information in the BNF or BNF for Children. If there is none, NICE should work with the BNF to add the necessary information.

Unlicensed medicines

The MHRA states that: If a UK licensed medicine can meet the person's clinical need (even if it is used off-label), it should be recommended instead of an unlicensed product. An unlicensed medicine should not be recommended if a product available and licensed within the UK could be used to meet the person's clinical need.

Committees should take account of the MHRA guidance (see appendix 2 of the MHRA guidance on the supply of unlicensed medicinal products) when making recommendations but consider each situation on its own merit.

Medical devices, including off-label use

Recommendations are usually about using devices within the terms of the instructions for their use. However, there are clinical situations in which the off-label use of a device may be in the best interests of the person. For example, when using a device outside the time period specified in the instructions for use.

Committees should take account of the MHRA guidance on the off-label use of medical devices.

Focus on the action and what readers need to know

Recommendations should be clear about what needs to be done, without the reader having to read the rationale or committee's discussion in the evidence review. When writing recommendations, keep in mind the following:

Include only 1 action per recommendation or bullet point unless it is clearer to include a closely linked action in the same recommendation.

Be specific about actions and use direct instructions in recommendations wherever possible because these are easier to follow. Recommendations should start with a verb such as 'offer' (or 'do not'), 'consider', 'measure', 'advise', 'discuss', 'ask about'.

Exceptions to this principle include:

Think carefully about how much detail to include. Recommendations should be clear and concise. Including a lot of detail can reduce the impact and make them harder to understand.

The content and measurability of any related NICE quality standard will be affected by the clarity and precision of recommendation wording. If possible, be clear when interventions should take place.

Reflect the strength of the recommendation

In recommendations on actions that should (or should not) be offered, use directive language such as 'offer' (or 'do not offer'), 'advise', or 'ask about'. In keeping with the principles of shared decision making, people may choose whether to accept what they are offered or advised.

If there is a closer balance between benefits and harms (activities or interventions that could be used), use 'consider'.

If there is a legal duty to apply a recommendation, or the consequences of not following a recommendation are extremely serious, the recommendation should use 'must' or 'must not' and be worded in the passive voice.

Use 'person-centred', precise, concise, clear English

Key principles include using language that is person-centred, using clear and consistent wording, and using bullet lists and tables if they make recommendations easier to follow.

Language that is person-centred acknowledges the experience of people who are directly affected by the recommendations (and family members, carers or advocates), and their role in decision making. For more information see the section on talking about people in the NICE style guide.

Identify preference-sensitive decision points

Guidelines should be written to support shared decision-making between people and their health or social care practitioners (see the recommendations on supporting people to make decisions about their care in the NICE guidelines on shared decision making, patient experience in adult NHS services, service user experience in adult mental health, people's experience in adult social care services, multimorbidity and babies, children and young people's experience of healthcare).

The committee should identify recommendations where someone's values and preferences are likely to be particularly important in their decision about the best course of action for them.

These 'highly preference-sensitive decision points' occur when the committee recommends 2 or more options that deliver similar outcomes but have different types of harms and benefits or different practicalities (such as a choice between medicine and surgery, or differing burden of treatment) that people may value differently.

Alternatively, a highly preference-sensitive decision point may occur if the choice between 1 or more investigation, treatment or care options and 'doing nothing new or different' is finely balanced.

These decision points may be identified as early as the guideline scoping stage, or when the committee reviews the evidence.

Summarise information to support decisions

When a highly preference-sensitive decision point is identified, create a summary of the evidence to make it easy for professionals and practitioners to discuss the options with the person.

Base the summary on the evidence reviews underpinning the recommendations, and using the BRAN (benefits, risks, alternatives, nothing) format explain the:

NICE medicines advisers can help with questions such as how to apply BRAN to a particular decision point, and how much information to include on adverse effects of treatments.

Occasionally, NICE will develop an additional decision aid (see chapter 12 on resources to support putting the guideline into practice and the NICE decision aid process guide).