Table 2 Association of risk factors with hazard of ventricular arrhythmias in patients who received allopurinol with no baseline ventricular arrhythmias before the index date of allopurinol episode

 65 to < 75

Ref

Ref

Ref

 75 to < 85

1.25 (1.15–1.36)

< 0.0001

1.19 (1.09–1.30)

< 0.0001

1.19 (1.09–1.30)

< 0.0001

  ≥ 85

1.43 (1.28–1.60)

< 0.0001

1.37 (1.22–1.53)

< 0.0001

1.37 (1.22–1.53)

< 0.0001

 Male

Ref

Ref

Ref

 Female

0.81 (0.75–0.87)

0.50

0.74 (0.68–0.80)

< 0.0001

0.73 (0.68–0.80)

< 0.0001

 White

Ref

Ref

Ref

 Black

1.32 (1.19–1.48)

< 0.0001

1.30 (1.16–1.45)

< 0.0001

1.29 (1.15–1.44)

< 0.0001

 Other

0.80 (0.69–0.94)

0.005

0.78 (0.67–0.91)

0.002

0.78 (0.67–0.90)

0.001

Charlson–Romano score, per unit change

1.15 (1.14–1.16)

< 0.0001

1.14 (1.13–1.16)

< 0.0001

1.14 (1.13–1.16)

< 0.0001

Diuretics

1.12 (0.94–1.33)

0.21

1.03 (0.86–1.24)

0.72

1.03 (0.86–1.24)

0.74

Statins

0.86 (0.70–1.05)

0.13

0.79 (0.64–0.97)

0.02

0.79 (0.64–0.97)

0.02

ACE inhibitor

1.09 (0.88–1.34)

0.43

1.11 (0.90–1.38)

0.32

1.11 (0.90–1.38)

0.33

Beta blockers

1.42 (1.20–1.68)

< 0.0001

1.41 (1.18–1.68)

0.0001

1.40 (1.18–1.68)

0.0001

Allopurinol use

0.86 (0.79–0.94)

0.001

0.82 (0.76–0.90)

< 0.0001

–

–

 0 days

Ref

–

–

Ref

 1 to 180 days

0.99 (0.88–1.12)

0.88

–

–

0.96 (0.85–1.08)

0.49

 181 days to 2 years

0.81 (0.72–0.90)

0.0002

–

–

0.76 (0.68–0.85)

< 0.0001

  > 2 years

0.74 (0.62–0.90)

0.002

–

–

0.72 (0.60–0.87)

0.001