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Adler et al.

Seasonal variation in diverticulitis: evidence from both hemispheres

Joel T. Adler, MD, MPH, David C. Chang, PhD, MBA, MPH, Andrew T. Chan, MD, MPH, Omar Faiz, BSc(Hons), MBBS, MS, Lillias H. Maguire, MD

Supplement Table 1: Included diagnostic codes

562.11: diverticulitis of colon without hemorrhage

562.13: diverticulitis of colon with hemorrhage

K57.20: diverticulitis of large intestine with perforation and abscess without bleeding

K57.21: diverticulitis of large intestine with perforation and abscess with bleeding

K57.22: diverticulitis of large intestine with perforation and abscess, without mention of hemorrhage

K57.23: diverticulitis of large intestine with hemorrhage, perforation and abscess

K57.32: diverticulitis of large intestine without perforation or abscess without bleeding

K57.33: diverticulitis of large intestine without perforation or abscess with bleeding

K57.90: diverticulosis of intestine, part unspecified, without perforation or bleeding

K57.91: diverticulosis of intestine, part unspecified, without perforation or abscess with bleeding

K57.92: diverticulitis of intestine, part unspecified, without perforation or abscess without bleeding

K57.93: diverticulitis of intestine, part unspecified, without perforation or abscess with bleeding

Supplement Table 2: Excluded diagnostic codes

562.00: diverticulosis of small intestine

562.01: diverticulitis small intestine without hemorrhage

562.02: diverticulosis small intestine without hemorrhage

562.03: diverticulitis small intestine with hemorrhage

562.10: diverticulosis of colon without hemorrhage

562.12: diverticulosis of colon with hemorrhage

K57.00: diverticulitis of small intestine with perforation and abscess without bleeding

K57.01: diverticulitis of small intestine with perforation and abscess with bleeding

K57.02: diverticulitis of small intestine with perforation and abscess, without mention of hemorrhage

K57.03: diverticulitis of small intestine with hemorrhage, perforation and abscess

K57.10: diverticulosis of small intestine without perforation or abscess without bleeding

K57.11: diverticulosis of small intestinewithout perforation or abscess with bleeding

K57.12:diverticulitis of small intestine without perforation or abscess without bleeding

K57.13:diverticulitis of small intestine without perforation or abscess with bleeding

K57.30: diverticulosis of large intestinewithout perforation or abscess without bleeding

K57.31: diverticulosis of large intestine without perforation or abscess with bleeding

K57.40: diverticulitis of both small and large intestine with perforation and abscess without bleeding

K57.41: diverticulitis of both small and large intestine with perforation and abscess with bleeding

K57.42: diverticulitis of both small and large intestine with perforation and abscess, without mention of hemorrhage

K57.43: diverticulitis of both small and large intestine with hemorrhage, perforation and abscess

K57.50: diverticulosis of both small and large intestine without perforation or abscess without bleeding

K57.51: diverticulosis of both small and large intestine without perforation or abscess with bleeding

K57.52: diverticulitis of both small and large intestine without perforation or abscess without bleeding

K57.53:diverticulitis of both small and large intestine without perforation or abscess with bleeding

K57.80: diverticulitis of intestine, part unspecified, with perforation and abscess without bleeding

K57.81: diverticulitis of intestine, part unspecified, with perforation and abscess with bleeding

K57.82: diverticulitis of intestine, part unspecified, with perforation and abscess, without mention of hemorrhage

K57.83: diverticulitis of intestine, part unspecified, with hemorrhage, perforation and abscess

Supplemental Table 3: Logistic regression for month trends in diverticulitis admission incidence

Australia / England / United States
Month / OR (95% CI) / P value / OR (95% CI) / P value / OR (95% CI) / P value
January / 1.33 (1.16 - 1.53) / <0.001 / 0.84 (0.76 - 0.93) / 0.001 / 0.86 (0.74 - 0.98) / 0.03
February / 1.29 (1.13 - 1.48) / <0.001 / 0.82 (0.74 - 0.91) / <0.001 / 0.80 (0.70 - 0.93) / 0.003
March / 1.27 (1.11 - 1.45) / 0.001 / 0.87 (0.79 - 0.96) / 0.007 / 0.91 (0.79 - 1.04) / 0.18
April / 1.35 (1.19 - 1.55) / <0.001 / 0.87 (0.78 - 0.96) / 0.007 / 0.91 (0.79 - 1.04) / 0.16
May / 1.21 (1.06 - 1.39) / 0.005 / 0.88 (0.80 - 0.98) / 0.02 / 0.95 (0.83 - 1.08) / 0.42
June / 1.07 (0.93 - 1.23) / 0.37 / 0.88 (0.79 - 0.97) / 0.01 / 0.95 (0.83 - 1.09) / 0.48
July / 1.00 (0.87 - 1.15) / 0.99 / 0.9 (0.82 – 1.01) / 0.05 / 0.95 (0.83 - 1.08) / 0.42
August / Ref / . / Ref / . / Ref / .
September / 1.13 (0.99 - 1.30) / 0.08 / 0.95 (0.86 - 1.04) / 0.28 / 0.99 (0.87 - 1.14) / 0.93
October / 1.16 (1.01 - 1.33) / 0.04 / 0.95 (0.86 - 1.04) / 0.28 / 0.9 (0.78 - 1.03) / 0.12
November / 1.14 (0.99 - 1.31) / 0.06 / 0.86 (0.77 - 0.95) / 0.003 / 0.89 (0.78 - 1.03) / 0.12
December / 1.29 (1.13 - 1.48) / <0.001 / 0.77 (0.69 - 0.85) / <0.001 / 0.81 (0.7 - 0.94) / 0.004

Odds represent the ratio of probabilities that any given month will contain an admission in comparison to August, which represents winter in Australia and summer in England and the United States. Odds ratios adjusted for age, gender, and year of admission. OR, odds ratio. CI, confidence interval.