Skip to main content

Table 2 Rasch analysis: differential item functioning by etiology (NDO vs. OAB)

From: Psychometric properties of the incontinence utility index among patients with idiopathic overactive bladder: data from two multicenter, double-blind, randomized, Phase 3, placebo-controlled clinical trials

Item

NDO measure

NDO S.E.

OAB measure

OAB S.E.

DIF contrast

Welch t

p-value

1

I worry about getting to toilet in time

0.30

0.04

0.65

0.04

−0.35

−6.03

<0.001

2

I worry about coughing and sneezing

−1.17

0.04

−0.85

0.03

−0.31

−6.50

<0.001

3

I’m careful when standing up

−0.95

0.04

−0.71

0.03

−0.24

−5.07

<0.001

4

I worry about where toilets are located

0.36

0.04

0.61

0.04

−0.24

−4.33

<0.001

5

I feel depressed due to urinary problema

−0.35

0.04

−0.26

0.03

−0.08

−1.65

0.099

6

I don’t feel free to leave my home

−0.21

0.04

−0.35

0.03

0.14

2.94

0.003

7

I’m prevented from doing what I want

0.24

0.04

0.10

0.03

0.14

2.62

0.009

8

I worry about a urine smell on mea

−0.40

0.04

−0.33

0.03

−0.06

−1.33

0.184

9

Urine problems are always on my mind

0.50

0.05

0.50

0.04

0.00

0.00

1.000

10

I make frequent trips to the toilet

0.27

0.04

0.96

0.04

−0.69

−11.3

<0.001

11

Important to plan details in advance

0.30

0.05

−0.09

0.03

0.39

6.93

<0.001

12

I worry urine problems will worsen w/age

0.27

0.04

0.86

0.04

−0.59

−10.3

<0.001

13

I can’t get a good night of sleepa

−0.13

0.04

0.03

0.03

−0.17

−3.39

0.001

14

I worry about being embarrassed

0.41

0.04

0.39

0.03

0.02

0.42

0.674

15

I feel like I’m not a healthy person

−0.34

0.04

−0.56

0.03

0.22

4.45

<0.001

16

I feel helpless due to urinary problems

−0.52

0.04

−0.52

0.03

0.00

0.00

1.000

17

I get less enjoyment out of life

−0.16

0.04

−0.26

0.03

0.10

2.00

0.045

18

I worry about wetting myself

0.83

0.05

0.81

0.04

0.02

0.34

0.735

19

I feel I can’t control my bladdera

1.12

0.05

0.74

0.04

0.37

5.68

<0.001

20

I watch what and how much I drinka

0.51

0.05

0.36

0.03

0.15

2.61

0.009

21

My choice of clothing is limited

−0.53

0.04

−0.68

0.03

0.15

3.13

0.002

22

I worry about having sex

−0.55

0.03

−1.14

0.03

0.59

13.13

<0.001

  1. DIF: differential item functioning aItems which constitute the descriptive system of the IUI. DIF contrast in bold indicate items which exhibited differential item functioning
Back to article page

Health and Quality of Life Outcomes

ISSN: 1477-7525

Contact us