Table 2.

Time-at-risk for opioid misuse and overdose analyses by Morphine Daily Dose Equivalent, 2011–2014.^a

	Misuse analysis					Overdose analysis
Mean MDDE mgb	# Unique personsc	Person- years	Mean days opioid use per period	Mean days BZD use per period	% periods that were misuse	# Unique personsc	Person- years	Mean days BZD use prior 90 daysd	Total # opioid overdoses	Overdoses per 1k person- years
0	270,028	482,380	0	5	0.06	336,375	764,497	2	161	0.21
1 – <20	338,356	402,795	30	12	0.30	378,923	346,530	7	267	0.77
20 – < 50	37,509	53,709	131	31	2.27	72,884	71,005	16	190	2.68
50 – < 100	13,958	19,858	157	39	4.60	30,344	29,439	20	163	5.54
100+	7,825	14,124	168	43	7.43	15,217	26,465	24	263	9.94
All dose levels	361,785	972,866	25	10	0.48	396,168	1,237,936	5	1044	0.84

^aAll patients had at least one opioid fill in year 2011 in Kaiser Permanente Northern California. BZD: benzodiazepines; MDDE: morphine daily dose equivalent.

^bFor misuse analysis, daily dose is across 180-day periods. For overdose analysis daily dose is in the prior 90 days.

^cPersons could contribute time to one or more of the opioid dose categories. This sample is reduced due to exclusion of persons who had misuse in their first 180-day period (as there would be no prior period to use for prediction.)

^dOn each day a patient was at risk for an overdose, we measured the number of days the patient used benzodiazepines in the prior 90 days