Table 3.

Odds ratios for effect of preventive dose reduction (PDR) and for (severe) overanticoagulation in users of co-trimoxazole compared with users of other antibiotics

	Odds ratios (95%CI)	P	Adjusted Odds ratios (95% CI)a	P
Effect of PDR on overanticoagulationb
Co-trimoxazole
PDR applied, INR >4.5	0.10 (0.02–0.50)	0.005*	0.06 (0.01–0.51)	0.010*
PDR applied, INR >6.0	0.10 (0.01–1.02)	0.051	0.09 (0.01–0.92)c	0.042*
PDR not applied	Reference		Reference
Other antibiotics
PDR applied, INR >4.5	0.70 (0.32–1.52)	0.37	N.A.d
PDR applied, INR >6.0	1.36 (0.47–3.93)	0.57	N.A
PDR not applied	Reference
Risk of overanticoagulation
PDR not applied
Co-trimoxazole, INR >4.5	4.52 (1.56–13.1)	0.006*	3.96 (1.33–11.8)	0.013*
Co-trimoxazole, INR >6.0	5.43 (1.53–19.2)	0.009*	3.86 (1.03–14.6)	0.046*
Other antibiotics	Reference		Reference
PDR applied
Co-trimoxazole, INR >4.5	0.68 (0.17–2.73)	0.59	N.A.
Co-trimoxazole, INR >6.0	0.41 (0.04–3.66)	0.42	0.30 (0.03–3.05)e	0.30
Other antibiotics	Reference		Reference

*Statistically significant difference at P ≤ 0.05

^aAdjusted for differences in fever as indicated by patient, age, sex, target therapeutic range, unless otherwise indicated

^bPDR, Preventive dose reduction

^cAdjusted for differences in age and sex

^dN.A., Adjustment not applied because the inclusion of covariates in our model did not result in a change of at least 5% in the odds ratios (see text)

^eAdjusted for differences in age, sex and fever as indicated by patient