Treatment failure of patients using topical acne treatments: an observational retrospective cohort study

Figures & data

Table I. Demographic and treatment duration information by exposure group.

	One combination product initially (n = 61)	One monotherapy initially (n = 160)	Multiple products initially (n = 114)	p Value^†
Age (years)	22 ± 12	26 ± 15	25 ± 13	0.11
Sex – Female % (n)	66 (40)	71 (113)	74 (84)	0.54
Race % (n)				0.14
White	41 (25)	42 (67)	42 (48)
Black	57 (35)	50 (80)	46 (52)
Other	2 (1)	8 (13)	12 (14)
Failures % (n)	49 (30)	46 (73)	41 (47)	0.58
Mean follow-up time to event or right-censoring	250 ± 139	257 ± 139	277 ± 123	0.36
Mean time to treatment failure (days)*	133 ± 109	129 ± 111	152 ± 98	0.51

^†Calculated using Fisher's Exact test or ANOVA test.

*Among those who failed treatment.

Continuous data reported as mean ± SD; categorical data reported as % (n)

Figure 1. Kaplan–Meier curves of the proportion of patients not failing treatment over time for patients initially prescribed one combination product (solid line), one monotherapy product (long-dashed line), or two or more monotherapy products (dotted line).

Table II. Cox proportional hazards estimates for hazards of changing acne treatment.

Initial medication(s) prescribed	Crude hazard ratio (95% CI)	Adjusted^† hazard ratio (95% CI)
Primary analysis
Model 1
One combination product	Ref	Ref
One monotherapy	0.91 (0.60, 1.40)	0.91 (0.59, 1.39)
Multiple products	0.77 (0.49, 1.21)	0.73 (0.46, 1.15)
Subgroup analyses^‡
Model 2
Adapalene/BPO	0.86 (0.45, 1.61)	0.85 (0.45, 1.59)
Model 3
Clindamycin/BPO	1.22 (0.74, 2.01)	1.29 (0.78, 2.12)

^†Adjusted for patient age, sex, and race; ‡Insufficient samples for clindamycin/tretinoin and erythromycin/BPO; *p < 0.05.