Over the study period, the PDI recruited 36% more subjects than did the TOI (317 subjects versus 233). The effectiveness of prevention education as measured by the mean score of subjects on a knowledge test was 6.4 correct answers for PDI and 4.8 for TOI, (p<0.001). The programmes were also compared on the self-reported reduction of risky behaviours by subjects in each intervention. For the PDI site, the results were reported separately for the town centre (Middletown) and for an area outside the town (Meriden). Results included:
the reduction in percentage of subjects who reported sharing syringes was 48% to 6.7% in Middletown, (p=0.007); 12% to 20.4% in Meriden, (p=0.852); and 22% to 13.3% in the TOI site, (p=0.035);
the reduction in mean number of cooker or filter sharings during the previous 30 days was 76% to 1.26 in Middletown, (p=0.009); 6% to 18.49 in Meriden, (p=0.944); and 11% to 11.90 in the TOI site, (p=0.103);
the change in the mean number of rinse water sharings during the previous 30 days was a 60% reduction to 1.42 in Middletown, (p=0.011); a 2% increase to 13.98 in Meriden, (p=0.161); and a 28% reduction to 8.61 in the TOI site, (p=0.299);
the change in the mean number of injections during the previous 30 days was a 64% reduction to 27.22 in Middletown, (p<0.001); 5% increase to 90.53 in Meriden, (p=0.119); and a 6% increase to 91.26 in the TOI site, (p<0.001);
the reduction in the mean number of unsafe sex acts during the previous 30 days was 20% to 7.09 in Middletown, (p=0.427); 45% to 4.49 in Meriden, (p=0.053); and 42% to 9.12 to the TOI site (p=0.010).