Table 1 Incidence rates (95% confidence intervals) of acute kidney injury stratified by two-year intervals, age, sex and comorbid illness from the Australia New Zealand Intensive Care Society Adult Patient Database 1996–2005

Age

   18–49 years

838

3.6 (3.3–3.8)

3.4 (2.8–3.9)

3.3 (2.8–3.9)

3.7 (3.2–4.3)

3.9 (3.4–4.4)

3.5 (3.0–3.9)

   50–64 years

1,026

4.5 (4.3–4.8)

4.3 (3.7–4.9)

4.3 (3.6–4.9)

4.0 (3.5–4.6)

5.1 (4.4–5.7)

4.9 (4.3–5.4)

   65–74 years

1,304

5.7 (5.4–6.0)

5.7 (5.0–6.3)

4.8 (4.2–5.5)

5.4 (4.7–6.0)

6.6 (5.9–7.3)

5.9 (5.2–6.5)

   ≥ 75 years

1,545

7.5 (7.2–7.9)

7.0 (6.1–7.9)

6.8 (5.9–7.7)

7.2 (6.4–8.0)

8.8 (8.0–9.6)

7.4 (6.7–8.1)

Sex

   Male

2,831

5.1 (4.9–5.3)

4.9 (4.5–5.4)

4.5 (4.0–4.9)

4.8 (4.4–5.2)

5.7 (5.3–6.1)

5.5 (5.1–5.9)

   Female

1,923

5.4 (5.1–5.6)

5.0 (4.5–5.5)

4.9 (4.3–5.4)

5.2 (4.7–5.8)

6.4 (5.8–6.9)

5.1 (4.7–5.6)

Comorbid illness

   None

3,335

4.7 (4.5–4.8)

4.2 (3.9–4.6)

4.1 (3.7–4.4)

4.3 (4.0–4.7)

5.5 (5.1–5.9)

4.9 (4.5–5.1)

   1 comorbidity

1,067

6.8 (6.4–7.2)

6.6 (5.7–7.4)

6.1(5.1–7.0)

6.8 (5.9–7.6)

7.6 (6.7–8.5)

6.9 (6.1–7.7)

   2 comorbidities

312

8.7 (7.7–9.6)

12.2 (9.6–14.8)

7.6 (5.3–9.9)

8.6 (6.7–10.6)

7.5 (5.8–9.3)

7.9 (6.1–9.8)

   ≥ 3 comorbidities

40

12.4 (8.8–16.0)

12.5 (4.1–20.8)

16.4 (6.8–26.0)

15.0 (7.0–23.0)

9.2 (2.6–15.9)

7.3 (0–15.6)

   Any comorbidity

1,419

7.2 (6.9–7.6)

7.6 (6.7–8.4)

6.5 (5.6–7.4)

7.3 (6.5–8.1)

7.6 (6.8–8.4)

7.1 (6.3–7.8)

Comorbid conditions

   Cardiovascular

553

6.3 (5.8–6.8)

7.7 (6.4–9.0)

5.0 (3.9–6.0)

6.3 (5.2–7.3)

5.7 (4.7–6.8)

6.7 (5.5–7.8)

   Respiratory

404

6.9 (6.3–7.6)

6.2 (4.9–7.6)

5.4 (3.9–6.9)

8.0 (6.4–9.6)

8.3 (6.8–9.9)

6.2 (4.9–7.5)

   Liver

230

12.1 (10.6–13.6)

12.1 (8.8–15.6)

12.8 (8.5–17.1)

12.1 (8.7–15.5)

13.2 (9.9–16.5)

10.9 (8.3–13.6)

   Metastatic cancer

143

8.2 (6.9–9.5)

8.4 (5.3–11.6)

9.4 (5.8–13.1)

7.7 (4.6–10.9)

8.6 (5.9–11.3)

7.3 (4.9–9.6)

   Haematologic malignancy

134

10.5 (8.8–12.2)

15.6 (10.5–20.7)

16.2 (10.3–22.1)

9.9 (6.3–13.6)

6.9 (3.9–9.9)

8.7 (5.9–11.6)

   Immunocompromised

351

8.2 (7.4–9.0)

8.9 (7.0–10.8)

8.7 (6.6–10.8)

8.3 (6.5–10.1)

7.9 (6.2–9.6)

7.1 (5.4–8.9)