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Table 3 Risk of relapse after the index substance use for related variables estimated by Cox proportional hazards model

From: Difference in long-term relapse rates between youths with ketamine use and those with stimulants use

Variables Relapse Unadjusted model Adjusted model
n/N (%) HR (95% CI) P-value aHR (95% CI) P-value
Age (years) 0.91 (0.72–1.16) 0.450 1.00 (0.77–1.28) 0.968
Gender
 Male 47/104 (45.2) 1   1  
 Female 11/31 (35.5) 0.83 (0.43–1.60) 0.577 0.89 (0.45–1.77) 0.735
Substance use
 Ketamine 32/92 (34.8) 1   1  
 Stimulants 26/43 (60.5) 1.58 (0.93–2.68) 0.090 1.86 (1.06–3.28) 0.032*
Previous conviction record
 Without 36/94 (38.3) 1   1  
 With 22/41 (53.7) 1.48 (0.87–2.51) 0.152 1.56 (0.91–2.67) 0.106
Academic or social status
 Employed 12/42 (28.6) 1   1  
 Attending school 22/43 (51.2) 2.23 (1.10–4.52) 0.025* 2.77 (1.28–6.02) 0.010*
 Dropout and unemployed 24/50 (48.0) 2.06 (1.03–4.12) 0.042* 1.99 (0.97–4.08) 0.061
Family status
 Double-parent families 26/61 (42.6) 1   1  
 Single-parent families 26/58 (44.8) 1.15 (0.67–1.97) 0.624 1.16 (0.66–2.02) 0.608
 Grandparent(s) 6/16 (37.5) 0.81 (0.33–1.97) 0.637 0.72 (0.28–1.86) 0.492
  1. Stimulants: methamphetamine or MDMA; HR: unadjusted hazard ratio; aHR: adjusted hazard ratio; 95% CI, 95% confidence interval; n, number of individuals who relapsed with substance use; N, number of total subjects; *p < 0.05