Table 4:

Risk of ventricular arrhythmia associated with current, recent and past use of azithromycin and other antibiotics compared with nonuse of antibiotics (1-stage pooling)

Exposure*	No. (%) of cases† n = 12 874	No. (%) of controls n = 1 240 431	OR (95% CI)
			Crude‡	Adjusted§
Nonuse of antibiotics	5060 (39.3)	601 049 (48.5)	1.00 (ref)	1.00 (ref)
Use of azithromycin
Current use	30 (0.2)	1344 (0.1)	2.83 (1.97–4.08)	1.97 (1.35–2.86)
Recent use	109 (0.8)	8315 (0.7)	1.65 (1.36–2.00)	1.12 (0.92–1.37)
Past use	187 (1.5)	18 000 (1.5)	1.28 (1.10–1.48)	1.10 (0.95–1.28)
Use of other antibiotics¶
Current use	1026 (8.0)	52 543 (4.2)	2.43 (2.27–2.60)	1.83 (1.71–1.97)
Recent use	2617 (20.3)	193 154 (15.6)	1.69 (1.61–1.77)	1.32 (1.25–1.39)
Past use	3845 (29.9)	366 026 (29.5)	1.29 (1.23–1.34)	1.11 (1.06–1.16)

Note: CI = confidence interval, OR = odds ratio, ref = reference category.

^*Current = exposure period covered the index date (occurrence of ventricular arrhythmia) or ended within 7 days before the index date; recent = exposure period ended between 7 and 89 days before the index date; past = exposure period ended between 90 and 364 days before the index date.

^†Current users of both azithromycin and other antibiotics were not included in the analysis.

^‡The crude ORs are estimated for matched case-control pairs and cannot be calculated directly from the table above.

^§Adjusted for risk factors of ventricular arrhythmia: atrial flutter/fibrillation, cardiomyopathy, coronary artery disease, cerebrovascular disorders, chronic obstructive pulmonary disease, electrolytic imbalance, heart failure, hypertension, diabetes mellitus, lipid disorders, peripheral arterial disease, hypothyroidism, prior use of antiarrhythmic drugs, concomitant use of drugs known to cause hypokalemia, and concomitant use of drugs known to prolong QT interval.

^¶Does not include amoxicillin.