Table 2. Incidence and Adjusted Hazard Ratio of Inflammatory Bowel Disease Based on Sex, Age, and Comorbidities for Patients With Appendectomy Compared With Controls
Appendectomy Appendectomy Appendectomy Appendectomy Appendectomy Appendectomy  Compared to Control  Compared to Control
Yes Yes Yes No No No
Variables
Events
PY
Rate#
Events
PY
Rate#
Crude HR (95% CI) Adjusted HR (95% CI)
All 255 1737942 14.7 87 1766861 4.92 2.98(2.33, 3.79)*** 2.78(2.17, 3.55)***
Ulcerative colitis (UC)
116
6.67
49
2.77
2.40(1.72, 3.36)***
2.23(1.59, 3.12)***
Crohn’s disease (CD)
139
8.00
38
2.15
3.71(2.59, 5.31)***
3.48(2.42, 4.99)***
Gender
Female 119 851339 14.0 38 863289 4.40 3.17(2.20, 4.57)*** 2.95(2.04, 4.26)***
Male 136 886602 15.3 49 903572 5.42 2.82(2.04, 3.91)*** 2.64(1.90, 3.67)***
Age, years
≤34 101 713152 14.2 29 704429 4.12 3.45(2.28, 5.21)*** 3.33(2.20, 5.04)***
35-49 64 553971 11.6 13 560303 2.32 4.98(2.74, 9.03)*** 4.63(2.54, 8.44)***
>50 90 470819 19.1 45 502128 8.96 2.13(1.49, 3.04)*** 1.81(1.26, 2.60)**
Comorbidity
No 175 1466719 11.9 63 1628953 3.87 3.09(2.32, 4.12)*** 3.12(2.34, 4.17)***
Yes 80 271222 29.5 24 137908 17.4 1.69(1.07, 2.67)* 1.75(1.11, 2.77)*
Rate#: incidence rate per 10 000 person-years; Crude HR: relative hazard ratio; Adjusted HR: adjusted hazard ratio after control for age, sex, and comorbidities of CAD, hypertension, diabetes, hyperlipidemia, CVA, heart failure, COPD, CKD, alcohol-related diseases, cirrhosis, and biliary stone; Comorbidity§: patients with CAD, hypertension, diabetes, hyperlipidemia, CVA, heart failure, COPD, CKD, alcohol-related diseases, cirrhosis, or biliary stone were classified as the comorbidity group. CAD, coronary artery disease; CI, confidence interval; CKD, chronic kidney disease; COPD, chronic obstructive pulmonary disease; CVA, cerebrovascular disease; PY, person years; SD, standard deviation *P < .05, **P < .01, ***P < .001 Rate#: incidence rate per 10 000 person-years; Crude HR: relative hazard ratio; Adjusted HR: adjusted hazard ratio after control for age, sex, and comorbidities of CAD, hypertension, diabetes, hyperlipidemia, CVA, heart failure, COPD, CKD, alcohol-related diseases, cirrhosis, and biliary stone; Comorbidity§: patients with CAD, hypertension, diabetes, hyperlipidemia, CVA, heart failure, COPD, CKD, alcohol-related diseases, cirrhosis, or biliary stone were classified as the comorbidity group. CAD, coronary artery disease; CI, confidence interval; CKD, chronic kidney disease; COPD, chronic obstructive pulmonary disease; CVA, cerebrovascular disease; PY, person years; SD, standard deviation *P < .05, **P < .01, ***P < .001 Rate#: incidence rate per 10 000 person-years; Crude HR: relative hazard ratio; Adjusted HR: adjusted hazard ratio after control for age, sex, and comorbidities of CAD, hypertension, diabetes, hyperlipidemia, CVA, heart failure, COPD, CKD, alcohol-related diseases, cirrhosis, and biliary stone; Comorbidity§: patients with CAD, hypertension, diabetes, hyperlipidemia, CVA, heart failure, COPD, CKD, alcohol-related diseases, cirrhosis, or biliary stone were classified as the comorbidity group. CAD, coronary artery disease; CI, confidence interval; CKD, chronic kidney disease; COPD, chronic obstructive pulmonary disease; CVA, cerebrovascular disease; PY, person years; SD, standard deviation *P < .05, **P < .01, ***P < .001 Rate#: incidence rate per 10 000 person-years; Crude HR: relative hazard ratio; Adjusted HR: adjusted hazard ratio after control for age, sex, and comorbidities of CAD, hypertension, diabetes, hyperlipidemia, CVA, heart failure, COPD, CKD, alcohol-related diseases, cirrhosis, and biliary stone; Comorbidity§: patients with CAD, hypertension, diabetes, hyperlipidemia, CVA, heart failure, COPD, CKD, alcohol-related diseases, cirrhosis, or biliary stone were classified as the comorbidity group. CAD, coronary artery disease; CI, confidence interval; CKD, chronic kidney disease; COPD, chronic obstructive pulmonary disease; CVA, cerebrovascular disease; PY, person years; SD, standard deviation *P < .05, **P < .01, ***P < .001 Rate#: incidence rate per 10 000 person-years; Crude HR: relative hazard ratio; Adjusted HR: adjusted hazard ratio after control for age, sex, and comorbidities of CAD, hypertension, diabetes, hyperlipidemia, CVA, heart failure, COPD, CKD, alcohol-related diseases, cirrhosis, and biliary stone; Comorbidity§: patients with CAD, hypertension, diabetes, hyperlipidemia, CVA, heart failure, COPD, CKD, alcohol-related diseases, cirrhosis, or biliary stone were classified as the comorbidity group. CAD, coronary artery disease; CI, confidence interval; CKD, chronic kidney disease; COPD, chronic obstructive pulmonary disease; CVA, cerebrovascular disease; PY, person years; SD, standard deviation *P < .05, **P < .01, ***P < .001 Rate#: incidence rate per 10 000 person-years; Crude HR: relative hazard ratio; Adjusted HR: adjusted hazard ratio after control for age, sex, and comorbidities of CAD, hypertension, diabetes, hyperlipidemia, CVA, heart failure, COPD, CKD, alcohol-related diseases, cirrhosis, and biliary stone; Comorbidity§: patients with CAD, hypertension, diabetes, hyperlipidemia, CVA, heart failure, COPD, CKD, alcohol-related diseases, cirrhosis, or biliary stone were classified as the comorbidity group. CAD, coronary artery disease; CI, confidence interval; CKD, chronic kidney disease; COPD, chronic obstructive pulmonary disease; CVA, cerebrovascular disease; PY, person years; SD, standard deviation *P < .05, **P < .01, ***P < .001 Rate#: incidence rate per 10 000 person-years; Crude HR: relative hazard ratio; Adjusted HR: adjusted hazard ratio after control for age, sex, and comorbidities of CAD, hypertension, diabetes, hyperlipidemia, CVA, heart failure, COPD, CKD, alcohol-related diseases, cirrhosis, and biliary stone; Comorbidity§: patients with CAD, hypertension, diabetes, hyperlipidemia, CVA, heart failure, COPD, CKD, alcohol-related diseases, cirrhosis, or biliary stone were classified as the comorbidity group. CAD, coronary artery disease; CI, confidence interval; CKD, chronic kidney disease; COPD, chronic obstructive pulmonary disease; CVA, cerebrovascular disease; PY, person years; SD, standard deviation *P < .05, **P < .01, ***P < .001 Rate#: incidence rate per 10 000 person-years; Crude HR: relative hazard ratio; Adjusted HR: adjusted hazard ratio after control for age, sex, and comorbidities of CAD, hypertension, diabetes, hyperlipidemia, CVA, heart failure, COPD, CKD, alcohol-related diseases, cirrhosis, and biliary stone; Comorbidity§: patients with CAD, hypertension, diabetes, hyperlipidemia, CVA, heart failure, COPD, CKD, alcohol-related diseases, cirrhosis, or biliary stone were classified as the comorbidity group. CAD, coronary artery disease; CI, confidence interval; CKD, chronic kidney disease; COPD, chronic obstructive pulmonary disease; CVA, cerebrovascular disease; PY, person years; SD, standard deviation *P < .05, **P < .01, ***P < .001 Rate#: incidence rate per 10 000 person-years; Crude HR: relative hazard ratio; Adjusted HR: adjusted hazard ratio after control for age, sex, and comorbidities of CAD, hypertension, diabetes, hyperlipidemia, CVA, heart failure, COPD, CKD, alcohol-related diseases, cirrhosis, and biliary stone; Comorbidity§: patients with CAD, hypertension, diabetes, hyperlipidemia, CVA, heart failure, COPD, CKD, alcohol-related diseases, cirrhosis, or biliary stone were classified as the comorbidity group. CAD, coronary artery disease; CI, confidence interval; CKD, chronic kidney disease; COPD, chronic obstructive pulmonary disease; CVA, cerebrovascular disease; PY, person years; SD, standard deviation *P < .05, **P < .01, ***P < .001