Development of a Method for Converting Visual Analogue Scale (VAS) Scores for Pain and Mobility to EQ-5D Answers

• The distribution of answers to EQ-5D-3L sub-questions on a 100mm VAS for each sub-question. [ Time Frame: Approximately five days postoperatively ] [ Designated as safety issue: No ]
  The investigators wish to investigate how patients scoring "no pain or discomfort", "moderate pain or discomfort" and "extreme pain or discomfort" on the EQ-5D questionnaire score their pain on a 100mm VAS of pain. The same is done for the four other sub-questions in the EQ-5D, eg. how do patients score their mobility on a 100mm VAS of mobility if they score "no problems in walking about", "some problems in walking about" or "confined to bed" on the EQ-5D. (see citations for similar study setups)
  
  

• Quality of life (Qol) [ Time Frame: approximately 30 days ] [ Designated as safety issue: No ]
  The investigators will obtain 3 measurements from each patient and are therefore able to evaluate the change in Qol from baseline to approximately 30 days postoperatively in a group of elective bypass patients. Investigators hereby aim to find the incremental Qol. The patient group will be segmented on whether they underwent endoscopic or open vein harvest during their surgery.
  
  

Many health economic researchers prefer that a treatments effect is measured in the quantity and quality of life (Qol) the treatment provides. This enables them to calculate effect in the generic Quality Adjusted Life-Years (QALYs). Patients' Qol can be estimates by having patients' answer the EQ-5D-3L questionnaire. However, when performing a post hoc health economic evaluation, data is often incomplete. Often there is no information available regarding the patients' Qol and some health economic researchers therefore resort to various conversions of other measurements of effect to Qol. Such conversions thereby enable them to calculate effect in QALYs even though they had incomplete information. However, no method has been developed for converting eg. VAS pain scores to Qol and the methods currently used are arbitrary. With this study the investigators wish to develop such a method and in the process evaluate our own arbitrary Qol conversion from a prior study by asking the same type of patients. The study is an observational study with no intervention.