Table 4.

Logistic regression of CFU category.^*

	Location Crude OR (95% CI)	Dressing Crude OR (95% CI)
Recruitment site	n = 241	n = 72
Healthy volunteer	Referent	–
Intensive care	0.66 (0.41–1.06)	Referent
Medical/surgical	0.92 (0.50–1.68)	4.80 (1.51–15.3)†
Sample location ‡	n = 241	n = 72
Neck or lower arm	Referent	–
Chest or upper arm	0.40 (0.25-0.64)†	–
Around dressing	–	Referent
Under dressing	–	0.57 (0.22–1.45)
Length of stay§	1.02 (1.00–1.03)†	1.03 (0.99–1.08)
Length of device dwell§	–	1.13 (0.98–1.29)

^*Dependent variable (CFU count) set up as ordinal (0/1–29/30–299/⩾ 300) variable for ‘Location’, and dichotomous (nil/any) for ‘Dressing’ analysis.

^†Statistically significant at P < 0.05.

^‡Categories with similar effect sizes and directions were combined.

^§One-day increment.

OR, odds ratio; CI, confidence interval.