Glossary

Treatment using radium or other radioactive matter.

A process by which treatments are allocated to patients in a clinical trial on the basis of chance alone. This means that the characteristics of the people receiving each treatment should be similar at the start of the trial, so if there are any differences in outcomes at the end of the trial, it can be assumed that these are due to the treatment itself.

The most reliable type of clinical trial. In a trial comparing drug A with drug B, patients are split into two groups, with one group receiving drug A and the other drug B. After a number of weeks or months, the outcomes of each group are compared. See also ‘randomisation’.

The spread of values, from the smallest to the largest. The inter-quartile range (IQR) only includes the middle 50% of values and measures the degree of spread of the most common values.

An undetectable hepatitis C RNA viral load within 4 weeks of starting treatment. An extended rapid virological response (eRVR) is when viral load is undetectable within 4 weeks and remains undetectable until at least week 12.

The number of events that we would expect to occur during a specified period of follow-up (e.g. 100 person-years). Particularly useful when follow-up periods vary from person to person in a study, or where a person may experience more than one event.

Genetically reconstructed.

Mixing something which is in powder form (for example a drug) with water or another liquid to make a liquid form of the substance.

The last part of the large intestine just above the anus.

A drug or treatment combination and the way it is taken.

Improvement in a tumour. Also, a mathematical model that allows us to measure the degree to which one of more factors influence an outcome.

After dropping to undetectable levels, hepatitis C RNA is detected again in blood after treatment has ended. Different from ‘breakthrough’.

Comparing one group with another, expresses differences in the rate at which something occurs. A relative rate above 1 means the rate is higher in the group of interest; a relative rate below 1 means the rate is lower. Similar to ‘relative risk’.

Comparing one group with another, expresses differences in the risk of something happening. For example, in comparison with group A, people in group B have a relative risk of 3 of being ill (they are three times as likely to get ill). A relative risk above 1 means the risk is higher in the group of interest; a relative risk below 1 means the risk is lower. See also ‘absolute risk’.

Partial recovery from an illness, an alternative word for regression.

Relating to the kidneys.

The process of viral reproduction.

Studies aim to give information that will be applicable to a large group of people (e.g. adults with diagnosed HIV in the UK). Because it is impractical to conduct a study with such a large group, only a sub-group (a sample) takes part in a study. This isn’t a problem as long as the characteristics of the sample are similar to those of the wider group (e.g. in terms of age, gender, CD4 count and years since diagnosis).

The proportion of people asked to complete a survey who do so.

In which the length of treatment is individualized. Viral load at 4, 8, 12, or 24 weeks will determine for how long treatment should be continued.

Damage to the retina, the light-sensitive surface at the back of the eye.

A type of longitudinal study in which information is collected on what has previously happened to people - for example, by reviewing their medical notes or by interviewing them about past events. See also ‘prospective study’. 

Family of viruses to which HIV belongs, that are distinguished by their use of RNA.

A retroviral enzyme which converts genetic material from RNA into DNA, an essential step in the lifecycle of HIV.

An antiviral drug that is used to treat hepatitis C in combination with other drugs.

See ‘absolute risk’.

An aspect of personal behaviour or lifestyle, an environmental exposure, or a personal characteristic that is thought to be associated with an infection or a medical condition.

Ribonucleic acid, the form in which a virus stores its genetic material.In hepatitis C, RNA (viral load) testing is used for diagnosis, to help predict treatment outcome and to monitor response to treatment.