Page 4 - Cannabis for the Management of Pain: Assessment of Safety Study

1236 The Journal of Pain Cannabis for the Management of Pain
Protocol Modifications Baseline characteristics are presented in Table 1. Pa-
tients in the cannabis group were younger, with a
The original protocol was modified during the study
implementation to reduce the burden on the study par- larger percentage of male, disabled, and tobacco or
alcohol users compared with the control group. Socio-
ticipants and aid recruitment. Details of these modifica-
tions are found in the Supplementary Materials (S-3). economic status did not differ between the groups.
The average pain intensity score at baseline was signif-
icantly higher in the cannabis group than in the control
Ethics and Regulatory Approvals group. Compared with cannabis users, more control pa-
The study was approved by the research ethics board tients were using opioids (55% in cannabis group vs
of each participating hospital and Health Canada. An in- 66% in the control group), antidepressants (47% vs
dependent Safety Monitoring Advisory Committee was 59%), or anticonvulsants (44% vs 55%) at baseline.
formed to ensure consistency for objectively and system- Three (1.4%) cannabis users reported ‘‘intermediate
atically categorizing the seriousness, severity, and causal- severity’’ addiction problems as judged by the DAST-20
ity of AEs (Supplementary Materials S-4). score.
Regulatory approval to use the herbal cannabis sup- Sixty-seven patients receiving study cannabis and 34
plied was obtained from the Therapeutic Products Direc- control patients discontinued the study before the full
torate of Health Canada. year of follow-up; data from all patients were included
in the safety analysis.
There were no significant differences in baseline mea-
Results sures between patients who completed the study and
From January 2004 to April 2008, 431 patients were re- those who did not (Supplementary Table 2). However,
cruited, 215 in the cannabis group and 216 controls in the cannabis group, ‘‘cannabis-naive users’’ (9 [56%])
(Fig 1). Median duration of follow-up was 11.9 months or ‘‘ex-cannabis users’’ (26 [45%]) were more likely to
(range = 7–551 days) in the cannabis group and withdraw from the study than ‘‘current cannabis users’’
12.1 months (range = 28–567 days) in the control group (32 [23%]) (c 2 [DF = 2] = 14.46, P < .001)
(outliers in follow-up time were due to late final visits; (Supplementary Table 2).
Supplementary Table 1). The cannabis group included The median daily dosage among cannabis-using par-
141 (66%) ‘‘current cannabis users’’, 58 (27%) ‘‘ex- ticipants was 2.5 g/d (range = .1–13.4; interquartile range
cannabis users’’, and 16 (7%) ‘‘cannabis-naive users’’. = 1.5–3.0); 11 (5%) patients received doses of >3 g/d.
Controls included 70 (32%) ‘‘ex-cannabis users’’ and 146 Fifty-eight participants (27%) used smoking as the only
(68%) ‘‘cannabis-naive users’’. route of administration, 130 (61%) used a combination

Figure 1. COMPASS CONSORT flow diagram.