DEMQOL and DEMQOL-Proxy: a Rasch analysis

Hendriks, A. A. Jolijn; Smith, Sarah C.; Chrysanthaki, Theopisti; Cano, Stefan J.; Black, Nick

doi:10.1186/s12955-017-0733-6

Health and Quality of Life Outcomes

Table 5 Diagnostic statistics for the smaller item set of DEMQOL-Proxy (26 items)

From: DEMQOL and DEMQOL-Proxy: a Rasch analysis

Item	Location	Fit Residual	ChiSq	p	DIF	Item residual correlations
Item	Location	Fit Residual	ChiSq	p	DIF	r	Correlation with item
2. Worried or anxious	0.637	0.278	3.76	0.93	ns	0.33, 0.32, 0.29, 0.23, 0.16, 0.08	3, 7, 5, 10, 9, 12
3. Frustrated	0.574	−0.677	4.27	0.89	ns	0.34, 0.33, 0.33, 0.29, 0.26, 0.04	9, 2, 10, 7, 5, 12
5. Sad	−0.330	−1.455	7.01	0.64	ns	0.42, 0.32, 0.29, 0.26, 0.20, 0.06, 0.01	10, 7, 2, 3, 9, 28, 31
7. Distressed	−0.425	−2.095	6.48	0.69	ns	0.32, 0.32, 0.29, 0.27, 0.24	2, 5, 3, 10, 9
9. Irritable	0.052	0.919	3.07	0.96	PWD sex PWD age Relation	0.34, 0.32, 0.24, 0.20	3, 10, 7, 5
10. Fed-up	0.287	−1.249	3.05	0.96	ns	0.42, 0.33, 0.32, 0.27, 0.23, 0.08, 0.02	5, 3, 9, 7, 2, 28, 31
12. Memory in general	0.664	1.529	6.49	0.69	ns	0.13, 0.08, 0.04, 0.04, 0.03	14, 2, 3, 15, 31
13. Forgetting happened long ago	−0.467	4.704	19.16	0.02	ns	0.13, 0.04, 0.01	15, 16, 27
14. Forgetting happened recently	1.462	0.373	4.66	0.86	ns	0.26, 0.22, 0.22, 0.14, 0.13, 0.05	15, 17, 18, 19, 12, 16
15. Forgetting people’s names	0.684	2.627	8.42	0.49	ns	0.26, 0.14, 0.13, 0.10, 0.04, 0.04, 0.03, 0.03	14, 17, 13, 16, 12, 18, 19, 20
16. Forgetting where he/she is	−0.866	−0.539	5.87	0.75	ns	0.23, 0.16, 0.10, 0.07, 0.05, 0.04, 0.03	17, 18, 15, 19, 14, 13, 20
17. Forgetting what day it is	0.451	2.045	4.86	0.85	Severity	0.27, 0.23, 0.22, 0.14, 0.14	18, 16, 14, 15, 19
18. Thoughts being muddled	0.604	−3.813	25.07	0.00	Age	0.36, 0.27, 0.22, 0.16, 0.14, 0.04	19, 17, 14, 16, 20, 15
19. Difficulty making decisions	0.458	−3.475	15.15	0.09	ns	0.36, 0.16, 0.14, 0.14, 0.07, 0.05, 0.03	18, 20, 14, 17, 16, 26, 15
20. Making him/herself understood	−0.201	2.456	3.60	0.94	ns	0.16, 0.14, 0.03, 0.03, 0.01	19, 18, 15, 16, 27
21. Keeping him/herself clean	−0.744	2.423	7.96	0.54	ns	0.64, 0.10, 0.06, 0.04, 0.02, 0.02	22, 23, 24, 31, 26, 29
22. Keeping him/herself looking nice	−0.702	2.008	9.74	0.37	ns	0.64, 0.11, 0.05, 0.05, 0.02	21, 23, 29, 31, 24
23. Getting from the shops	−0.501	−0.922	3.61	0.94	ns	0.23, 0.11, 0.10, 0.07, 0.06, 0.03	24, 22, 21, 25, 27, 26
24. Using money to pay	−0.578	−1.365	5.59	0.78	ns	0.47, 0.23, 0.08, 0.06, 0.04, 0.02	25, 23, 27, 21, 26, 22
25. Looking after finances	−0.304	0.915	9.25	0.41	ns	0.47, 0.13, 0.07	24, 27, 23
26. Things taking longer	0.402	−2.987	13.39	0.15	ns	0.13, 0.11, 0.07, 0.07, 0.05, 0.04, 0.03, 0.02	30, 27, 29, 31, 19, 24, 23, 21
27. Getting in touch with people	−0.472	−1.684	6.39	0.70	ns	0.13, 0.11, 0.11, 0.08, 0.08, 0.06, 0.03, 0.01, 0.01	25, 26, 29, 24, 27, 23, 30, 13, 20
28. Not having enough company	−0.352	2.197	7.79	0.56	PWD sex Carer age Relation	0.10, 0.08, 0.08, 0.08, 0.06, 0.01	30, 10, 27, 29, 5, 31
29. Not able help other people	−0.472	1.136	5.80	0.76	ns	0.39, 0.14, 0.11, 0.08, 0.07, 0.05, 0.02	30, 31, 27, 28, 26, 22, 21
30. Not playing useful part	−0.231	−2.067	8.27	0.51	ns	0.39, 0.18, 0.13, 0.10, 0.03	29, 31, 26, 28, 27
31. His/her physical health	0.369	2.762	9.22	0.42	ns	0.18, 0.14, 0.07, 0.05, 0.04, 0.03, 0.02, 0.01	30, 29, 26, 22, 21, 12, 10, 5

Fit residuals in bold are outside the acceptable range of +/− 2.5. Location = average item threshold location (logit). ChiSq = chi square value; p = chi square probability. DIF = differential item functioning; ns = non-significant. None of the chi square tests is statistically significant at p < 0.01 (Bonferroni corrected)

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