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Table 1 Primary outcomes (with 95% CI) by DHB pair, Study Arm and Time Period. Rates of intentional self-harm presentations to Emergency Departments/death by suicide; rate ratio for change in rate within each DHB by from pre-intervention to intervention period; rate ratio for difference in these changes in rate within each DHB pair

From: Preventing suicidal behaviours with a multilevel intervention: a cluster randomised controlled trial

  Intentional self-harm/death by suicide
DHB Study Arm Period*1 Events (deaths*2) PYAR *3 Rate per 100,000 PYAR Rate ratio for period*4 Rate ratio for intervention*5
(95% CI)   (95% CI)   (95% CI)
A Intervention Baseline 231 (13) 52,139 443 (389–504) 0.94 (0.81–1.08) 0.95 (0.87–1.26)
Intervention 902 (33) 217,244 415 (389–443)
Control Baseline 392 (13) 79,422 494 (447–545) 0.98 (0.88–1.10)
Intervention 1605 (61) 330,925 485 (462–509)
B Intervention Baseline 689 (11) 133,329 517 (480–557) 0.86 (0.79–0.94) 0.93 (0.94–1.23)
Intervention 2477 (53) 555,538 446 (429–464)
Control Baseline 426 (21) 89,697 475 (432–522) 0.93 (0.83–1.03)
Intervention 1642 (68) 373,738 439 (419–461)
C Intervention Baseline 342 (10) 97,467 351 (316–390) 0.92 (0.81–1.03) 1.09 (0.77–1.09)
Intervention 1305 (64) 406,113 321 (304–339)
Control Baseline 325 (11) 74,124 438 (393–489) 0.84 (0.74–0.95)
Intervention 1135 (49) 308,850 367 (347–390)
D Intervention Baseline 230 (6) 74,219 310 (272–353) 0.96 (0.83–1.10) 1.34 (0.63–0.87)
Intervention 916 (46) 309,244 296 (278–316)
Control Baseline 925 (24) 216,542 427 (401–456) 0.71 (0.66–0.77)
Intervention 2739 (111) 902,256 304 (292–315)
  1. Footnotes for Table 1:
  2. *1 Baseline period 6 months; Intervention period 25 months duration
  3. *2 Events count is number of ISH events and suicide deaths combined (number in parentheses is number of deaths in period)
  4. *3 PYAR = Person Years At Risk (based on population derived from 2006 Census, multiplied by duration of period)
  5. *4 Rate ratio within each DHB for rate of outcome (intentional self-harm/death) during intervention period relative to baseline period
  6. *5 Ratio in intervention arm (relative to control) within each DHB pair for the intervention to baseline ratio for change in outcome (intentional self-harm/death)