Development of the PHASE-Proxy scale for rating drug-related signs and symptoms in severe cognitive impairment

Figures & data

Table 1. The time-line and population sizes for the various procedures used to evaluate the PHASE-Proxy psychometric properties.

Date	Nursing home	Property	Procedure	Statistics	Outcome
June 2012	1, 2	Criterion validity	Correlation between PHASE-20 and PHASE-Proxy (n = 30)	Spearman's rank correlation	Satisfactory
October 2012	3	Inter-rater reliability	Correlation between assessments of one resident by two informants (n = 18)	Spearman's rank correlation and intra-class correlation	Not satisfactory, four items revised
January 2013	4*	Inter-rater reliability of revised version	Correlation between assessments of one resident by two informants (n = 20)	Spearman's rank correlation and intra-class correlation	Satisfactory, no further revision
March--June 2013	5, 6, 7	Internal consistency, content validity	Additional data for 90 evaluable residents (of 110) tested	Cronbach's alpha and factor analysis	Satisfactory

*Data from nursing home 4 are included in the Cronbach's alpha and the factor analysis as these data are collected on the final version of PHASE-Proxy.

Table 2. The factor loadings of the seven-factor solution, and the Cronbach's alpha-coefficients for the seven factors.

Items	F I	F II	F III	F IV	F V	F VI	F VII
1. Appears dizzy/unsteady/high risk of falls	.167	.001	.105	.380	.768	.028	−.128
2. Poor sleep pattern	.726	−.034	.242	−.006	−.027	−.254	−.005
3. Tired/exhausted	.241	.030	.616	−.011	.321	.172	.051
4. Hallucinates	.696	.245	−.020	−.002	.238	−.39	−.136
5. Sounds or words that express discomfort/pain	.384	.784	−.107	−.115	.112	.096	.226
6. Facial expressions that express discomfort/pain	.301	.779	.036	−.083	.154	.257	.144
7. Low mood/wishes to be left alone	.543	.138	.135	.067	−.045	.127	−.115
8. Worried/restless/anxious	.541	.152	.092	.114	−.015	−.253	.327
9. Irritable/impulsive behavior/aggressive tendencies	.720	,039	−.190	.001	−.010	.207	.022
10. Stiff facial expression/body	−.094	.260	.095	−.100	.628	.186	.231
11. Poor appetite	−.004	.011	.837	−.031	.006	.115	.030
12. Dry lips/mouth/tongue	−.112	.119	.148	−.032	.022	.784	.076
13. Appears nauseous/vomits	−.164	.612	.310	.293	−.046	−.313	−.296
14. Diarrhea	.126	.301	.358	.431	−.397	.263	.163
15. Constipation	.196	.038	.193	.067	.326	.482	−.079
16. Swollen legs/ankles	.107	−.186	−.311	.665	.149	.263	−.173
17. Appears short of breath/breathes rapidly	.025	.023	.071	.766	.073	−.172	.183
18. Frequent urination/incontinent of urine*	.439	.063	.054	.144	.147	.097	.402
19. Itching/rash	−.117	.095	.043	.037	−.023	.011	.856
Alpha-coefficients	0.70	0.70	0.52	0.40	0.48	0.44	0.26

Note: Items with loadings above 0.4 shown in bold.

*Item 18 loaded in two factors, I and VII, and was chosen for factor VII since that solution was more logically interpretable.

Figure 1. The PHASE-Proxy scale.

Table 3. Assessment of the feasibility of the PHASE-Proxy instrument; opinions from carers (n = 33) and registered nurses (n = 4).

	Yes, definitely	Yes, to a moderate extent	Not really	Not at all
Does PHASE-Proxy provide useful information?	7/3	21/1	5/0	0/0
Does PHASE-Proxy ask for signs/symptoms that you are able to assess?*	9/3	18/1	4/0	1/0
Does PHASE-Proxy have reasonable response alternatives?**	15/1	12/3	4/0	0/0
Do you think that PHASE-Proxy should be used in your clinical setting?	13/4	16/0	0/0	4/0

*one response missing; **two responses missing.