Table 4 Hypothetical example demonstrating the relative impact of smoking status on the risk of heart failure (HF) in 1000 rheumatoid arthritis (RA) and 1000 non-RA subjects

	Non-RA subjects with heart failure, n = 150		RA subjects with heart failure, n = 250
Factor X†	No	Yes	No	Yes
Current smoking	100	0	100	50
No smoking	50	0	50	50
Hazard ratio (HR) smoking/no smoking	100/50 = 2.0		150/100 = 1.5

*All data are hypothetical
†Factor X = other mechanism of disease?