Fig. 2
Repetition rates. Repetition rates of acute poisoning by substances of abuse at the Oslo Accident and Emergency Outpatient Clinic (OAEOC). Kaplan–Meier plots of repeated poisoning before and after implementation of the intervention program, patients in target age (left panel), and patients just older than target age (right panel). Left panel younger pre-intervention group (blue; n = 422, 27 events, 393 censored at end of study, two censored due to emigration), and younger post-intervention group (green; n = 366, 31 events, 335 censored at end of study). No significant difference between groups, log rank test (Mantel–Cox) gives Χ2 = 1.597 (p = 0.21). Cumulative repetition probability (95 % CI) in younger pre-intervention group estimated at 9 % (6–13 %), and in younger post-intervention group at 12 % (7–16 %). When the last repetition occurred, 62 patients were still under observation. Time under observation ranged from 1 to 365 days in both groups. Right panel Older pre-intervention group (blue; n = 288, 36 events, 252 censored at end of study), and older post-intervention group (green; n = 247, 29 events, 217 censored at end of study, one censored due to death). No significant difference between groups, log rank test (Mantel–Cox) gives Χ2 = 0.0014 (p = 0.91). Cumulative repetition probability (95 % CI) in older pre-intervention group estimated at 16 % (11–22 %), and in older post-intervention group at 19 % (10–28 %). When the last repetition occurred, 20 patients were still under observation. Time under observation ranged from 1 to 362 days in older pre-intervention group, and from 1 to 365 days in older post-intervention group