Factors related to breast cancer detection mode and time to diagnosis in Alberta, Canada: a population-based retrospective cohort study

Table 3 Quantile regression estimates of the median and 90^th percentile of diagnostic interval by detection mode. The estimate associated with each category is the difference in days when compared to the reference variable category

Factor	Screen-detected (n = 4747)				Symptom-detected (n = 7280)
	Quantile 50 %		Quantile 90 %		Quantile 50 %		Quantile 90 %
	Days	P-value	Days	P-value	Days	P-value	Days	P-value
Intercept
	4.0	**	38.7	**	20.4	**	108.5	**
Demographic factors
Age
50–69 (Ref.)
39-	NA	NA	NA	NA	−1.0	0.29	−9.7	0.05
40–49	0	1.00	14	*	−0.8	0.19	1.6	0.72
70–74	0	1.00	4.9	0.26	1.2	0.42	−1.2	0.88
75+	1.0	0.19	−4.9	0.19	−1.4	0.07	−19.7	**
Neighborhood income quintile
> 80 % (Ref.)
60 % ~ 80 %	0	1.00	−3.3	0.52	1.6	0.06	−7.4	0.16
40–60 %	1.0	0.17	−6.9	0.15	0.6	0.44	−3.9	0.48
20 % ~ 40 %	2.0	**	−2.9	0.54	1.8	*	−7.4	0.20
< 20 %	2.0	**	−8.4	0.11	1.4	0.11	−9.4	0.10
Missing	16.0	0.19	63.0	0.52	5.4	0.42	−11.7	0.78
Clinical factors
Stage
I (Ref.)
In Situ	11.0	**	28.0	**	24.8	**	49.2	**
II	0.0	1.00	9.3	*	−6.4	**	−36.7	**
III	0.0	1.00	60.8	**	−7.0	**	−29.8	**
IV	−3.0	0.27	16.0	0.42	−12.2	**	−37.7	**
Missing	16.0	**	37.4	0.16	−5.6	*	−1.5	0.87
Charlson comorbidity index
0/1 (Ref.)
> =2	1.0	0.22	−3.1	0.56	−0.8	0.50	7.3	0.11
Healthcare factors
Regional Health Authority
6 (Ref.)
1	20.0	**	37.5	**	7.8	**	16.3	0.07
2	30.0	**	50.2	**	12.6	**	30.5	**
3	16.0	**	18.9	**	7.4	**	5.7	0.20
4	19.0	**	19.3	*	6.0	**	−2.5	0.71
5	10.0	**	21.4	0.12	2.8	0.17	4.7	0.70
7	6.0	*	9.6	0.22	1.2	0.47	−21.5	*
8	22.0	**	118.8	**	−3.4	0.06	−9.3	0.54
9	21.0	*	6.4	0.97	−3.0	0.27	−17.7	*
Time Period
2004–2006 (Ref.)
2007–2010	1.0	*	5.9	0.06	0.2	0.70	6.1	0.06
Usual Provider Continuity
High continuity (>0.75, Ref.)
Low continuity (<=0.75)	−0.0	1.00	5.4	0.12	0.4	0.50	2.9	0.46
Minimum doctor visits	−1.0	0.26	−2.77	0.62	−2.0	*	−19.2	**
Community Size and Metropolitan Influence Zone
Urban (Ref.)
Rural	3.0	*	−2.3	0.66	−1.2	0.20	1.7	0.75

ISSN: 1472-6963