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Table 3 Quantile regression estimates of the median and 90th 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

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

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
  1. **P-value < 0.005 *P-value < 0.05