Table 3.

Association with any tendon rupture and Achilles tendon rupture and other potentially confounding variables and co-morbidities

Variable	Any tendon rupture		Achilles tendon rupture
	Adjusted IRR	Adjusted p value	Adjusted IRR	Adjusted p value
Prior tendon rupture	4.60 (3.51–6.04)	< 0.001	7.48 (4.53–12.35)	< 0.001
Oral corticosteroid	2.25 (1.99–2.54)	< 0.001	3.60 (2.89–4.48)	< 0.001
Injectable corticosteroid	5.47 (3.36–8.91)	< 0.001	1.82 (0.40–8.29)	0.435
Fluoroquinolone	1.61 (1.25–2.09)	< 0.001	3.14 (2.11–4.65)	< 0.001
Co-amoxiclav	1.02 (0.79–1.31)	0.900	1.00 (0.64–1.57)	0.989
Body mass index	1.01 (1.01–1.02)	< 0.001	1.01 (1.00–1.03)	0.008
Statin therapy	1.06 (0.98–1.16)	0.129	0.96 (0.81–1.14)	0.650
Hypothyroidism	1.03 (0.90–1.17)	0.693	0.91 (0.70–1.18)	0.469
Hyperthyroidism	0.89 (0.51–1.55)	0.676	1.08 (0.41–2.89)	0.873
Charlson co-morbidity	0.99 (0.97–1.01)	0.279	1.00 (0.96–1.05)	0.975
Connective tissue disease	2.03 (1.66–2.49)	< 0.001	1.02 (0.63–1.65)	0.942
COPD	1.07 (0.99–1.17)	0.096	1.24 (1.08–1.44)	0.003
Cancer	0.97 (0.88–1.06)	0.473	0.98 (0.81–1.19)	0.854
Chronic kidney disease	0.96 (0.86–1.07)	0.452	1.02 (0.82–1.28)	0.865
Dementia	0.47 (0.34–0.66)	< 0.001	0.34 (0.14–0.79)	< 0.001
Diabetes mellitus	1.01 (0.91–1.11)	0.854	1.03 (0.85–1.25)	0.758
Heart failure	0.85 (0.71–1.01)	0.062	0.87 (0.64–1.25)	0.459
Liver disease	0.87 (0.56–1.34)	0.521	1.04 (0.49–2.23)	0.916
Myocardial infarction	1.07 (0.92–1.23)	0.404	0.96 (0.71–1.30)	0.796
Peptic ulcer disease	1.09 (0.94–1.27)	0.263	1.01 (0.76–1.36)	0.921
Peripheral vascular disease	0.90 (0.65–1.25)	0.543	0.85 (0.46–1.57)	0.606
Stroke	1.04 (0.90–1.21)	0.579	1.03 (0.75–1.41)	0.878
Smoking
Ex-smoker	1.04 (0.96–1.12)	0.360	0.85 (0.74–0.98)	0.029
Current smoker	0.85 (0.78–0.94)	0.001	0.72 (0.61–0.85)	< 0.001

Variables included separately in the model without interactions

IRR incident rate ratio, COPD chronic obstructive pulmonary disease