Table 3. Hazard Ratios and 95% Confidence Intervals for All-Cause Mortality by QRS Axis
Population Normal PR interval Prolonged PR interval Prolonged PR interval P for interaction
QRS axis >37° QRS axis ≤37°
Total 1 (Ref.) 0.78 (0.64-0.95) 1.18 (1.03-1.36)
Sensitivity analysis
P/PR ratio <0.7 1 (Ref.) 0.77 (0.62-0.95) 1.18 (1.00-1.38)
Exclude events within the 1st year 1 (Ref.) 0.77 (0.63-0.95) 1.18 (1.02-1.36)
Exclude patients taking AV node drugs 1 (Ref.) 0.79 (0.63-0.97) 1.23 (1.05-1.43)
Subgroup analysis
Sex 0.434
Men 1 (Ref.) 0.81 (0.62-1.04) 1.22 (1.01-1.47)
Women 1 (Ref.) 0.72 (0.52-1.00) 1.09 (0.87-1.36)
Race 0.156
Whites 1 (Ref.) 0.85 (0.67-1.08) 1.22 (1.04-1.45)
Others 1 (Ref.) 0.66 (0.46-0.94) 1.11 (0.84-1.46)
Age 0.489
<50 1 (Ref.) 0.87 (0.46-1.65) 1.23 (0.62-1.65)
≥50 1 (Ref.) 0.78 (0.63-0.96) 1.17 (1.01-1.35)
Diabetes mellitus 0.406
Yes 1 (Ref.) 0.93 (0.52-1.66) 1.21 (0.81-1.79)
No 1 (Ref.) 0.75 (0.61-0.93) 1.20 (1.03-1.40)
Antihypertensive medications use 0.189
Yes 1 (Ref.) 0.83 (0.62-1.12) 1.09 (0.89-1.35)
No 1 (Ref.) 0.74 (0.56-0.97) 1.31 (1.08-1.60)