The impact of non-medical cannabis legalization and other exposures on retention in longitudinal cannabis research: a survival analysis of a prospective study of Canadian medical cannabis patients

Table 2 Percent completing M6 and probability of retention at M3 and M6 by baseline prescription drug use and quality of life (QOL) in 1011 participants

Baseline prescription drug use and QOL	Completed M6 (%)	Kaplan–Meier estimator
		Probability of remaining in study
		M3	M6	P
Use of opioid				0.004
No	306/697 (43.9)	0.74	0.44
Yes	102/290 (35.2)	0.66	0.35
Opioid – defined daily dose (DDD)				0.321
< 0.57	44/108 (40.7)	0.64	0.41
≥ 0.57	34/108 (31.5)	0.66	0.31
Use of non-opioid pain medications				0.721
No	314/770 (40.8)	0.73	0.41
Yes	94/215 (43.7)	0.70	0.44
Non-opioid pain medications—defined daily dose (DDD)				0.245
< 0.43	37/76 (48.7)	0.72	0.49
≥ 0.43	36/89 (40.4)	0.64	0.40
Use of benzodiazepine				0.151
No	375/918 (40.8)	0.71	0.41
Yes	32/67 (47.8)	0.82	0.48
Benzodiazepine–defined daily dose (DDD)				0.151
< 0.38	13/29 (44.8)	0.71	0.41
≥ 0.38	15/27 (55.6)	0.82	0.48
Use of antidepressant				0.011
No	324/818 (39.6)	0.71	0.40
Yes	83/166 (50.0)	0.78	0.50
Antidepressant—defined daily dose (DDD)				0.342
< 1	14/35 (40.0)	0.74	0.40
≥ 1	45/90 (50.0)	0.78	0.50
Use of anti-seizure				0.003
No	326/827 (39.4)	0.71	0.39
Yes	83/159 (52.2)	0.79	0.52
Anti-seizure—defined daily dose (DDD)				0.542
< 0.5	24/46 (52.2)	0.80	0.52
≥ 0.5	34/72 (47.2)	0.75	0.47
WHOQOL—physical health (baseline)				0.671
< 36	218/526 (41.4)	0.74	0.41
≥ 36	199/481 (41.4)	0.70	0.41
WHOQOL—psychological (baseline)				0.042
< 54	166/442 (37.6)	0.71	0.38
≥ 54	251/565 (44.4)	0.73	0.44
WHOQOL—social relationships (baseline)				0.168
< 58	147/384 (38.3)	0.71	0.38
≥ 58	270/623 (43.3)	0.72	0.43
WHOQOL—environment (baseline)				0.166
< 66	222/556 (39.9)	0.70	0.40
≥ 66	195/451 (43.2)	0.75	0.43

ISSN: 2522-5782