Validation of smoking history in cancer patients

Figures & data

Figure 1.  Flow chart of the study.

Table I.  Proportion of responders (%) stratified by relationship to the patient and in relation to time since death of the patient.

	Responders (proportion%)	Able to give smoking information
Relationship to the patient
Spouse	n = 25 (93%)	n = 25
Children	n = 158 (90%)	n = 153
Sibling	n = 8 (67%)	n = 7
Other relation	n = 49 (88%)	n = 38
Total	n = 240 (89%)	n = 223
Time since death of the patient
<5 years	n = 42 (86%)	n = 40
5 ≤ years < 10	n = 54 (89%)	n = 52
10 ≤ years < 15	n = 49 (88%)	n = 48
15 ≤ years < 20	n = 38 (95%)	n = 34
20 ≤ years < 25	n = 25 (89%)	n = 21
≥25 years	n = 32 (91%)	n = 28

Table II.  Smoking data available at time of breast cancer diagnosis in patient records compare to information from the questionnaire from next-of-kin.

		Information from Next of-kin
		Smoker	Non smoker	Total
Patient records data	Smoker	73	3	76
	Non smoker	8	48	56
	Total	81	51	132
Overall agreement (%)		92
kappa (95%CI)		0.83 (0.73–0.92)
McNemar p-value		0.13

Table III.  Comparison of quantitative smoking information per day between patient records and next-of-kin.

		Information from Next-of-kin
		≤15 cigarettes	>15 cigarettes	Total
Patient records data	≤15 cigarettes	14	6	20
	>15 cigarettes	7	23	30
	Total	21	29	50
Overall agreement (%)		74
kappa (95%CI)		0.46 (0.21–0.71)
McNemar p-value		0.78