Table 2. Pretreatment Clinical Characteristics of Oral Naltrexone Users in Relation to Persistence Status.

	Patients		P-value
	Non-persistent (n=976)	Persistent (n=162)
CCI, Mean (SD)*	0.53 (1.01)	0.59 (1.00)	0.5
CDS, Mean (SD)*	1.43 (1.88)	1.56 (1.99)	0.4
Substance abuse-related claims**
Alcohol-related claims	806 (83%)	122 (75%)	0.03
Drug-related claims	258 (26%)	32 (20%)	0.07

^*For the Charlson Comorbidity Index (CCI) and the Chronic Disease Score (CDS), higher scores indicate a greater burden of comorbidity.

^**For the 6 months prior to the start of treatment; groups not mutually exclusive, so that patients could have had both alcohol- and drug-related claims