Figure 2
From: Long term extension of a randomised controlled trial of probiotics using electronic health records
Trends in recruitment and retention of trial participants via fielder ork and electronic follow up. Our study was conducted in a population with a high percentage (28%. dotted horizontal line) of people in the lowest socio-economic fifth (defined by the Townsend Index), and low percentage in the highest socio-economic fifth (18%). Although recruitment to the trial from the most deprived group was excellent, this group was under-represented in field work follow-up at 2 years. The impact of this was explored elsewhere3. However, this loss was rectified in electronic records at both 2 years and 5 years (solid line). The trial over-recruited in the least deprived group; this discrepancy was exacerbated in field work, but improved by electronic follow up (dashed line). Deprivation (Townsend) fifths are based on geographical area of residence, using Lower Super Output Areas (LSOAs) defined by postcodes. This measure of material deprivation is calculated from rates of unemployment, vehicle ownership, home ownership, and overcrowding45.
