Contingency management to reduce methamphetamine use and sexual risk among men who have sex with men: a randomized controlled trial

Table 2 Contingency management intervention metrics

Metric^a	Participants (n = 70)^b
% Visits attended, mean (SD); median (IQR)	37 (1.4); 25 (8-54)
% Visits attended, n (%)
0%	4 (6)
1-25%	32 (46)
26-50%	15 (21)
51-75%	10 (14)
75-99%	6 (9)
100%	3 (4)
% Metabolite-free urine samples out of those attended, mean (SD); median (IQR)	75 (3.6); 85 (0.5-1.0)
% Metabolite-free urine samples out of total possible visits, mean (SD); median (IQR)^b	29 (1.3); 18 (8-42)
% Metabolite-free urine samples, n (%)^c
0%	7 (10)
1-25%	37 (53)
26-50%	13 (19)
51-75%	5 (7)
75-99%	6 (9)
100%	2 (3)
Number of continuous metabolite-free samples, mean (SD); median (IQR)^c	4.2 (5.5); 2 (1-5)
Number of continuous metabolite-free samples, n (%)^c
Never submitted a metabolite-free sample	7 (10)
Submitted only single, non-consecutive metabolite-free samples	25 (36)
2-8	28 (40)
9-12	4 (6)
13-24	6 (9)
Earnings, US$ mean (SD); median (IQR)	112 (138); 50 (15-150)

IQR, interquartile range; SD, standard deviation.
^aData are n (%) unless otherwise noted.
^b63 participants had 24 possible visits, 5 participants had 36 possible visits, 1 participant had 33 possible visits, and 1 participant had 25 possible visits (mean = 25 visits).
^cWe assumed that during visits the participant did not attend, he would have submitted a urine sample positive for methamphetamine or cocaine metabolites.

ISSN: 1471-2458