Persistence on prostaglandin ocular hypotensive therapy: an assessment using medication possession and days covered on therapy

Table 4 Regression analyses of persistence and days coverage on index drug

	Method of imputing days supply
	Unadjusted		2.0-2.1 variable factor^†		2.0 Constant Factor 45 Minimum^‡
Variable*	Odds ratio	P value	Odds ratio	P value	Odds ratio	P value
Logistic regression of persistence on index drug
Bimatoprost	0.66	< 0.001	0.74	< 0.001	0.71	< 0.001
Travoprost	0.66	< 0.001	0.64	< 0.001	0.66	< 0.001
Female	0.99	0.889	0.97	0.545	0.96	0.423
Age 55 to 64 years	1.12	0.088	1.19	0.003	1.17	0.010
Age 65 to 74 years	1.21	0.009	1.27	< 0.001	1.24	0.001
Age 75+ years	1.10	0.204	1.14	0.057	1.16	0.025
Ocular hypertension	0.99	0.886	1.00	0.920	1.00	0.933
Linear regression of days coverage on index drug
	Coefficient	P value	Coefficient	P value	Coefficient	P value
Bimatoprost	-21.60	< 0.001	-21.03	< 0.001	-28.85	< 0.001
Travoprost	-32.84	< 0.001	-42.11	< 0.001	-39.44	< 0.001
Female	0.33	0.866	-0.56	0.833	-0.42	0.873
Age 55 to 64 years	12.67	< 0.001	17.17	< 0.001	16.21	< 0.001
Age 65 to 74 years	22.40	< 0.001	26.50	< 0.001	26.09	< 0.001
Age 75+ years	10.87	< 0.001	11.18	0.004	14.49	< 0.001
Ocular hypertension	2.31	0.241	-0.01	0.997	-0.17	0.950
Intercept	128.94	< 0.001	226.28	< 0.001	235.24	< 0.001

*Reference case is latanoprost as index drug; male; age 40 to 54 years; diagnostic-coded medical visit for preglaucoma or ocular hypertension during 180-day preindex period.
^†Imputed days supply is unadjusted days supply multiplied by 2.0 (latanoprost, travoprost) or 2.1 (bimatoprost).
^‡Imputed days supply is unadjusted days supply multiplied by 2.0 (all prostaglandins), with a minimum imputed estimate of 45 days.

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