Skip to main content

Table 2 Days on sick leave and frequency of episodes—by years on study and days on sick leave per episode

From: Porphyria cutanea tarda and patterns of long-term sick leave and disability pension: a 24-year nationwide matched-cohort study

Social benefit type/group

Total number at risk

Predicted count divided by years on study (95% CI)

Yearly difference (95% CI)

Incident rate ratio (95% CI)

Annual LTSL days

    

Reference

21,360

23.7 (22.7, 24.7)

0.0

1.0

PCT (total)

534

30.7 (26.6, 34.9)

7.0 (2.7, 11.3)

1.3 (1.1, 1.5)

 Reference

9120

25.8 (24.3, 27.3)

0.0

1.0

 Sporadic PCT

228

36.7 (29.8, 43.5)

10.9 (3.8, 17.9)

1.4 (1.2, 1.7)

 Reference

9600

20.9 (19.8, 22.0)

0.0

1.0

 Familial PCT

240

23.7 (18.0, 29.4)

2.8 (− 3.0, 8.6)

1.1 (0.9, 1.5)

 Reference

2640

26.9 (22.6, 31.2)

0.0

1.0

 Unclassified

66

35.8 (25.1, 46.4)

8.9 (− 2.6, 20.3)

1.3 (0.9, 1.9)

Pre-PCT

    

 Reference

19,359

24.8 (24.1, 25.4)

0.0

1.0

 PCT (total)

484

35.7 (30.1, 41.4)

11.0 (5.3, 16.6)

1.4 (1.2, 1.7)

  Reference

8884

23.4 (22.7, 24.2)

0.0

1.0

  Sporadic PCT

222

34.7 (28.4, 41.1)

11.3 (4.9, 17.7)

1.5 (1.2, 1.8)

  Reference

8280

25.1 (24.1, 26.2)

0.0

1.0

  Familial PCT

207

31.0 (23.7, 38.3)

5.9 (− 1.5, 13.3)

1.2 (1.0, 1.6)

  Reference

2195

28.7 (26.0, 31.3)

0.0

1.0

  Unclassified

55

57.6 (25.7, 89.4)

28.9 (5.2, 61.3)

2.0 (1.1, 3.5)

During-PCT

    

 Matched cohort

15,916

6.1 (5.6, 6.6)

0.0

1.0

 PCT (total)

392

12.4 (7.8, 16.9)

6.3 (1.7, 10.8)

2.0 (1.4, 3.0)

  Reference

6060

4.7 (4.0, 5.3)

0.0

1.0

  Sporadic PCT

142

12.5 (5.1, 19.8)

7.8 (0.3, 15.2)

2.7 (1.4, 4.9)

  Reference

7735

6.2 (5.5, 6.9)

0.0

1.0

  Familial PCT

201

10.2 (4.4, 16.1)

4.0 (− 1.8, 9.9)

1.7 (0.9, 3.0)

  Reference

2121

9.9 (8.2, 11.5)

0.0

1.0

  Unclassified

49

20.9 (3.8 (3.8, 37.9)

11.0 (− 6.1, 28.1)

2.1 (0.9, 4.9)

Post-PCT

    

 Matched cohort

13,868

15.9 (11.2, 20.6)

0.0

1.0

 PCT (total)

335

4.4 (1.9, 6.8)

− 11.6 (− 16.8, − 6.4)

0.3 (0.1, 0.5)

  Reference

5102

3.7 (3.1, 4.4)

0.0

1.0

  Sporadic PCT

115

1.5 (− 1.1, 4.0)

− 2.3 (− 4.9, 0.4)

0.4 (0.1, 2.3)

  Reference

6969

16.7 (10.1, 23.3)

0.0

1.0

  Familial PCT

100

4.5 (1.0, 8.0)

− 12.2 (− 19.7, − 4.7)

0.3 (0.1, 0.6)

  Reference

1797

47.4 (22.3, 72.5)

0.0

1.0

  Unclassified

40

12.3 (1.4, 23.2)

− 35.1 (− 62.4, − 7.8)

0.3 (0.1, 0.7)

Annual LTSL episodes

    

Matched controls

21,360

0.30 (0.29, 0.31)

0.0

1.0

PCT (total)

534

0.34 (0.30, 0.38)

0.04 (− 0.01, 0.08)

1.1 (1.0, 1.3)

 Matched controls

9120

0.31 (0.30, 0.33)

0.0

1.0

 Sporadic PCT

228

0.39 (0.30, 0.33)

0.07 (0.00, 0.15)

1.2 (1.0, 1.5)

 Matched controls

9600

0.27 (0.25, 0.28)

0.0

1.0

 Familial PCT

240

0.26 (0.21, 0.31)

0.01 (− 0.49, 0.48)

1.0 (0.8, 1.2)

 Matched controls

2640

0.38 (0.34, 0.43)

0.0

1.0

 Unclassified

66

0.41 (0.31, 0.51)

0.3 (− 0.08, 0.13)

1.1 (0.8, 1.4)

Pre-PCT

    

 Reference

19,359

0.24 (0.23, 0.24)

0.0

1.0

 PCT (total)

484

0.33 (0.27, 0.39)

0.02 (− 0.01, 1.05)

1.4 (1.2, 1.7)

  Reference

8884

0.24 (0.23, 0.25)

0.0

1.0

  Sporadic PCT

222

0.34 (0.26, 0.41)

0.10 (0.03, 0.17)

1.4 (1.1, 1.8)

  Reference

8280

0.23 (0.22, 0.24)

0.0

1.0

  Familial PCT

207

0.29 (0.20, 0.38)

0.06 (− 0.03, 0.15)

1.3 (0.9, 1.7)

  Reference

2195

0.25 (0.22, 0.27)

0.0

1.0

  Unclassified

55

0.42 (0.19, 0.66)

0.17 (− 0.06, 0.41)

1.7 (1.0, 3.0)

During-PCT

    

 Matched cohort

15,916

0.07 (0.06, 0.08)

0.0

1.0

 PCT (total)

392

0.09 (0.06, 0.12)

0.02 (− 0.01, 1.05)

1.3 (0.9, 1.8)

  Reference

6060

0.04 (0.04, 0.05)

0.0

1.0

  Sporadic PCT

142

0.08 (0.03, 0.13)

0.04 (− 0.01, 0.08)

1.8 (1.0, 3.3)

  Reference

7735

0.07 (0.06, 0.08)

0.0

1.0

  Familial PCT

201

0.07 (0.03, 0.11)

0.00 (− 0.04, 0.04)

1.0 (0.6, 1.8)

  Reference

2121

0.14 (0.11, 0.17)

0.0

1.0

  Unclassified

49

0.19 (0.05, 0.34)

0.05 (− 0.09, 0.20)

1.4 (0.6, 3.0)

After-PCT

    

 Matched cohort

13,868

0.17 (0.11, 0.22)

0.0

1.0

 PCT (total)

335

0.04 (0.01, 0.07)

− 0.12 (− 0.18, − 0.06)

0.3 (0.1, 0.5)

  Reference

5102

0.04 (0.03, 0.05)

0.0

1.0

  Sporadic PCT

115

0.01 (0.00, 0.02)

− 0.03 (− 0.05, − 0.02)

0.2 (0.0, 0.8)

  Reference

6969

0.20 (0.11, 0.29)

0.0

1.0

  Familial PCT

100

0.06 (0.01, 0.11)

− 0.14 (− 0.24, − 0.04)

0.3 (0.1, 0.7)

  Reference

1797

0.39 (0.16, 0.62)

0.0

1.0

  Unclassified

40

0.08 (0.00, 0.15)

− 0.32 (− 0.56, − 0.08)

0.2 (0.1, 0.6)

  1. Models and predicted counts based on a zero-inflated negative binominal model with robust standard errors. Day one of long-term sick leave is counted from the 17th day of consecutive sick leave absences. Sick leave days and episodes were divided by person-years on study, either for the entire study period, 2 years or more before (pre-PCT), within 2 years (during-PCT) and more than 2 after (post-PCT)—the age at the porphyria diagnosis. Estimates include 0 counts (i.e., no sick leave episode during period of study). Persons who accessed disability pension, retired, or died before these time periods were excluded from the time at risk cases. LTSL,  long-term sick leave
Back to article page

Orphanet Journal of Rare Diseases

ISSN: 1750-1172