Scoring methodology

The PROMs programme utilises well-established methodologies to enable patients to rate their health status. All patients, are asked to complete a common set of questions about their health status, including sections about the patient’s circumstances, pre-existing conditions. Post-operative questionnaires also contain additional questions about the surgery, such as how the patient perceives the results of the operation and whether there were any post-operative complications.

The EQ-5D^TM health questionnaire consisting of a five-dimensional descriptive system and a visual analogue scale (EQ-VAS) developed by the EuroQol Group are included for all patients along with questions from the Oxford hip/knee scores.

EQ-5D^TM is a standardised measure of health status developed by the EuroQol Group to provide a simple, generic measure of health for clinical and economic appraisal. It provides a simple descriptive profile and a single index value for health status that can be used in the clinical and economic evaluation of healthcare as well as in population health surveys.

There are two distinct he EQ-5D^TM descriptive system and the EQ-5D^TM visual analogue scale (EQ-VAS).

The EQ-5D^TM descriptive system comprises the following five dimensions

• mobility
• self-care for example washing and dressing
• usual activities for example work, study, housework, family or leisure activities
• pain or discomfort
• anxiety or depression

Each dimension has three levels: no problems, some problems, severe problems. This results in a one-digit number expressing the level selected for that dimension. The digits for five dimensions can be combined in a five-digit number string describing the respondent’s health state, also referred to as the EQ-5D^TM ’health profile’.

EQ-5D^TM health states are converted into a single summary index by applying a formula that attaches values (also called ‘social preference weights’) to each of the levels in each dimension. The index can be calculated by deducting the appropriate weights from one, the value for full health (i.e. state 11111).

EQ-VAS consists of a simple scale, from 0 to 100, presented in a simple linear format. Respondents are asked to rate their health state by marking the scale at the relevant point, with zero being the worst and one hundred being the best state.