Variable | Definition of categories | Equivalent ward variable | Confounder from literature on NHS Direct |
NHSDW call variables | |||
Type of call | For advice; only for information | Proportion of advice calls from ward | No |
Patient’s age | Age in completed years | Mean age of ward population from 2001 Census | Yes (refs 14 16 17) |
Patient’s gender | Male, female | Proportion of females in ward from the 2001 Census | Yes (refs 14 17) |
Patient’s main symptom | International Classification of Primary Care 228 | Proportion of patients with digestive symptoms (most common) in ward | No |
Patient’s ethnicity | White, other specified ethnicity, not specified | Proportion of ‘white’ residents in ward from 2001 Census | Not together with deprivation |
Relationship of patient to caller | Self caller, surrogate caller | Proportion of self callers in ward | No |
Day of week when call occurred | Sunday, Monday, Tuesday, Wednesday, Thursday, Friday, Saturday | Proportion of calls from ward on each day | No |
Advice given | Advice given by NHSDW | Not applicable (analysed in reference 20) | No |
Ward variables | |||
Call rate (dependent variable) | Not applicable | No of calls from ward divided by 2001 Census population | Not applicable |
Deprivation score (main explanatory variable) | Not applicable | Measured by Welsh Index of Multiple Deprivation26 | Yes (refs 14 16 18 19) |
Distance to ED | Not applicable | Measured by straight line from geographical centroid of ward to nearest ED | No |
Population density | Not applicable | No of people per hectare in ward from 2001 Census | No |
ED, emergency department; NHS, National Health Service; NHSDW, National Health Service Direct Wales.