Demographic and comorbidity predictors of adherence to diagnostic colonoscopy in the Danish Colorectal Cancer Screening Program: a nationwide cross-sectional study

Figures & data

Figure 1 Flowchart of study population.

Table 1 Characteristics of the study population overall and by adherence and nonadherence to diagnostic colonoscopy (n=8,112)

Characteristics	All, n	Adherence proportion, row %	Adherent (n=7,187), %	Non-adherent (n=925), %
Gender
Women	3,627	88.3	44.6	45.7
Men	4,485	88.8	55.4	54.3
Age, years
<55	1,935	90.4	24.3	20.0
55–59	702	89.7	8.8	7.8
60–64	945	89.8	11.8	10.4
65–69	1,476	89.4	18.4	16.9
70–74	1,551	88.9	19.2	18.7
75	1,503	83.8	17.5	26.3
Region of residence
North Denmark Region	1,035	92.5	13.3	8.4
Central Denmark Region	1,960	91.6	25.0	17.8
Region of Southern Denmark	2,067	90.2	25.9	21.8
Capital Region of Denmark	2,131	82.6	24.5	40.0
Zealand Region	919	88.0	11.3	11.9
CCI score
0	5,283	90.3	66.4	55.4
1–2	2,137	87.2	25.9	29.6
≥3	692	79.9	7.7	15.0
In-hospital staysa
0	6,722	89.5	83.7	76.2
1–2	1,170	86.2	14.0	17.5
≥3	220	73.6	2.3	6.3

Note:

a Number of in-hospital stays within the last year preceding the positive screening test result.

Abbreviation: CCI, Charlson Comorbidity Index.

Table 2 PPDs with 95% CIs for predictors of adherence to diagnostic colonoscopy

	Unadjusted		Adjusteda,b
	PPD	95% CI	PPD	95% CI
Gender
Women	0.00	–	0.00	–
Men	0.47	−0.92; 1.86	1.07	−0.23; 2.37
Age, years
<70	0.00	–	0.00	–
70–74	−1.09	−2.86; 0.68	−1.24	−2.96; 0.47
75	−6.10	−8.14; −4.07	−4.20	−6.19; −2.20
Region of residence
North Denmark Region	0.00	–	0.00	–
Central Denmark Region	−0.88	−2.91; 1.14	−0.31	−2.27; 1.66
Region of Southern Denmark	−2.24	−4.29; −0.18	−1.08	−3.07; 0.90
Capital Region of Denmark	−9.83	−12.10; −7.55	−8.22	−10.50; −5.97
Zealand Region	−4.43	−7.08; −1.79	−2.70	−5.28; −0.12
CCI score
0	0.00	–	0.00	–
1–2	−3.13	−4.76; −1.50	−2.30	−3.87; −0.74
≥3	−10.40	−13.50; −7.31	−9.24	−12.30; −6.19
Cardiovascular diseasea
No	0.00	–	0	–
Yes	−7.68	−10.00; −5.37	−6.64	−8.91; −4.36
Chronic pulmonary disease
No	0.00	–	0.00	–
Yes	−6.35	−9.46; −3.23	−5.42	−8.48; −2.37
Diabetesb
No	0	–	0	–
Yes	−5.14	−8.28; −1.99	−4.68	−7.74; −1.62
Cancerc
No	0.00	–	0.00	–
Yes	−2.57	−5.05; −0.10	−1.57	−3.96; 0.83
In-hospital staysd
0	0.00	–	0.00	–
1–2	−3.36	−5.47; −1.25	−2.41	−4.43; −0.39
≥3	−15.90	−21.70; −10.00	−14.50	−20.30; −8.74

Notes:

a Includes “myocardial infarction”, “congestive heart failure”, “peripheral vascular disease”, and “cerebrovascular disease”.

b Includes “diabetes I+II” and “diabetes with end organ damage”.

c Includes “any tumor”, “leukemia”, and “metastatic solid tumor”.

d Number of in-hospital stays within the last year preceding the positive screening test result.

e In the model of the association between adherence to diagnostic colonoscopy and gender, age, region, and CCI, these are mutually adjusted for each other, in addition to response time.

f The models of the association between adherence to diagnostic colonoscopy and cardiovascular disease, chronic pulmonary disease, diabetes, cancer and in-hospital stays, respectively, are adjusted for gender, age group, region of residence, and response time.

Abbreviations: PPD, prevalence proportion difference; CI, confidence interval; CCI, Charlson Comorbidity Index.

Table 3 PPDs with 95% CIs for adherence to diagnostic colonoscopy for men and women by CCI score and stratified by age

	<70 years, n=5,058		70–74 years, n=1,551		75 years, n=1,503
	PPDa	95% CI	PPDa	95% CI	PPDa	95% CI
Women
CCI score 0	0.00	–	0.00	–	0.00	–
CCI score 1–2	1.56	−1.17; 4.28	−0.46	−5.48; 4.55	−5.18	−10.30; −0.06
CCI score ≥3	−12.7	−20.90; −4.40	−0.94	−8.56; 6.67	−18.9	−29.50; −8.26
Men
CCI score 0	0.00	–	0.00	–	0.00	–
CCI score 1–2	−2.68	−5.29; −0.08	−6.42	−10.80; −1.98	−4.26	−9.64; 1.12
CCI score ≥3	−10.2	−15.90; −4.39	−9.40	−16.20; −2.60	−6.6	−14.00; 0.78

Note:

a Adjusted for region of residence and response time.

Abbreviations: PPD, prevalence proportion difference; CI, confidence interval; CCI, Charlson Comorbidity Index.

Table 4 Reasons for no diagnostic colonoscopy among 370 individuals, as recorded in hospital records in the Capital Region of Denmark

	n	Proportion, %	95% CI
The participant wanted no further diagnostic work-up	142	38.4	33.4; 43.5
Colonoscopy later than 2 months after positive iFOBT or in private practice not yet reported to the DNPR	114	30.8	26.1; 35.8
Unable to contact patient or other/unknown	46	12.4	9.2; 16.2
In surveillance program for inflammatory bowel disease or other risk factors	21	5.7	3.5; 8.5
Benign comorbidity prevents further diagnostics	19	5.1	3.1; 7.9
Colonoscopy within 18 months before positive iFOBT	17	4.6	2.2; 6.0
Malignant comorbidity prevents further diagnostics	7	1.9	0.8; 3.9
Deceased before diagnostics	4	1.1	0.3; 2.7

Abbreviations: CI, confidence interval; iFOBT, immunochemical Fecal Occult Blood Test; DNPR, Danish National Patient Registry.