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Table 5 IRR between the two abstractors, and validity against the “gold standard” for select variables, (N=30)

From: The University of Texas Houston Stroke Registry (UTHSR): implementation of enhanced data quality assurance procedures improves data quality

Categorical variables

Dichotomous variables

IRR = Kappa (95% LCL)a

Abstractor 1 vs. “gold standard”

Abstractor 2 vs. “gold standard”

  

N

Abstractor 1 vs. Abstractor 2

Bias Index

 

N

Agreement (%)

Sensitivity (%)

Specificity (%)

Bias Index

N

Agreement (%)

Sensitivity (%)

Specificity (%)

Bias Index

Stroke type

Infarct

30

1.00

0

 

30

100

100

100

0

30

100

100

100

0

ICH

30

1.00

0

 

30

100

100

100

0

30

100

100

100

0

TIA

30

0.65 (0.02)

−0.03

 

30

100

100

100

0

30

96.7

100

96.6

0.03

tPA therapy

Yes

30

1.00

0

 

30

100

100

100

0

30

100

100

100

0

Symptomatic hemorrhage

Yes

30

1.00

0

 

30

100

100

100

0

30

100

100

100

0

Disposition

Death

30

1.00

0

 

30

100

100

100

0

30

100

100

100

0

Home

30

1.00

0

 

30

93.3

100

91.3

0.07

30

93.3

100

91.3

0.07

Inpatient rehabilitation

30

1.00

0

 

30

100

100

100

0

30

100

100

100

0

Skilled nursing facility

30

1.00

0

 

30

96.7

100

96.6

0.03

30

96.7

100

96.6

0.03

Initial presentation

MHH

30

0.92 (0.76)

0.03

 

30

100

100

100

0

30

96.7

95.4

100

−0.03

Continuous variables

 

IRR = ICC d (95%LCL) a

Abstractor 1 vs. “gold standard”

Abstractor 2 vs. “gold standard”

 

N

Abstractor 1 vs. Abstractor 2

MD c (95%CI) b

N

Agreement (%)

Correlation (95%CI) b

MD c (95%CI) b

N

Agreement (%)

Correlation (95%CI) b

MD c (95%CI) b

Age (years)

30

1.00

0 (0, 0)

30

96.7

0.83 (0.65, 0.91)

1.4 (−1.5, 4.4)

30

96.7

0.83 (0.65, 0.91)

1.4 (−1.5, 4.4)

Onset time (minutes)

16

1.00

4.7 (−14.5, 5.3)

16

93.8

1.00

9.4 (−10.6, -29.4)

16

87.5

1.00

14.1 (−7.7, 35.8)

Arrival time (minutes)

29

1.00

0 (0, 0)

30

86.7

1.00

−0.2 (−1.9, 1.5)

29

89.7

1.00

−0.2 (−2.1, 1.6)

tPA time (minutes)

7

−0.48 (−0.89)

NR

7

100

1.00

0 (0, 0)

7

57.1

−0.49 (−0.90, 0.45)

NR

INR

25

0.98 (0.96)

0.02 (−0.02, 0.06)

25

80

0.98 (0.97, 0.99)

−0.01 (−0.04, 0.02)

26

73.1

0.39 (−0.00, 0.67)

0.1 (−0.2, 0.4)

mRS on discharge

23

1.00

0 (0, 0)

23

95.6

0.98 (0.96, 0.99)

−0.04 (−0.13, 0.05)

26

96.2

0.98 (0.96, 0.99)

−0.04 (−0.12, 0.04)

  1. a 95% LCL = 95% Lower Confidence Limit; b 95% CI = 95% Confidence Interval; c MD = Mean difference for reliability study is calculated based on abstractor #1 minus abstractor #2; for validity study the difference is based on abstractor #1 or abstractor #2 minus the “gold standard”; d ICC = Intra-class correlation; NR = Not reported because calculations were misleading due to an error in re-abstraction by abstractor #2 who reported 3 wrong dates (i.e., a wrong day, month or year) out of 7 dates for patients who received tPA therapy, which resulted in a misleading mean difference.