Keywords
Aged - Dementia - Pain - Pain Assessment - Cognitive Impairment - Pain Measurement
Palavras-chave
Idoso - Demência - Dor - Avaliação da Dor - Comprometimento Cognitivo - Medição da
Dor
INTRODUCTION
Due to the major demographic transition in the form of an aging population, the number
of dementia cases is set to rise.[1] Currently, there are an estimated 30 million persons living with dementia worldwide,
a figure projected to reach 100 million by 2050.[2]
Pain is highly prevalent in the older population, especially among demented persons.
It has been estimated that 50% of people with dementia and pain are not correctly
diagnosed or treated.[1] Individuals experiencing potentially painful situations can develop other symptoms,
such as mood (anxiety and depression) and sleep disorders, aggression, agitation and
even psychosis, which negatively Impact quality of life and predispose these individuals
to disabilities.[2]
Some pain-related behaviors in demented persons can be treated inadequately, e.g.,
with use of antipsychotics for agitation or mechanical restraints which can have serious
adverse effects.[3]
Evaluating and measuring pain in older people can often be challenging. Traditional
tools designed for this purpose depend on the ability of the individual to self-report
pain. For instance, the visual analogue scale (VAS), used to determine the intensity
of pain, is problematic in the aging population, where around 33% of older person
proved unable to answer the VAS.[4] Thus, new tools for pain assessment have been developed for individuals with impaired
verbal communication, in an effort to improve treatment and quality of life.[2]
Instruments for assessing pain in older adults who are unable to express this verbally
have been translated and validated for use in Brazil, such as the PACSLAC,[5] PAINAD[6] and IADIC.[7] These tools assess body language, facial expressions and vocalizations, but which
behaviors suggest the intensity of pain have yet to be clearly defined. In fact, there
is no single instrument that serves to assess all pain dimensions in the older population
and therefore health professionals use those that best suit their place of work.[8]
The meta-instrument PIMD was developed to pool a limited set of best items for assessing
the intensity of pain in individuals with dementia and some degree of impairment of
expression when experiencing potential pain. The PIMD consists of 7 indicators that
best correlate to the presence and intensity of pain comprising 3 for facial expressions
(highly sensitive and reliable indicators for predicting pain); 1 for positioning,
1 for muscle stiffness, 1 for sighing, and 1 for verbal complaints.[9] The PIMD is a “meta-instrument,” i.e., a tool to “assess the assessments” of pre-existing
behaviors indicating pain in dementia.[3] This kind of instrument is used to aggregate findings from a series of evaluations,
it also involves an evaluation of the quality of this series of evaluations and its
adherence to established good practice in evaluation.
The PIMD was originally developed and validated in English in North America. No publications
related to the translation and cross-cultural adaptation of the PIMD in other languages
and countries were found. Recently, the PIMD was translated and cross-culturally adapted
(PIMD-p) for use in Brazil and was shown to be a very straight forward and practical
instrument for measuring pain in demented older individuals).[10] The PIMD-p can be found in the [Supplementary Material] (https://www.arquivosdeneuropsiquiatria.org/wp-content/uploads/2023/07/ANP-2023.0020-Supplementary-Material.docx).
The evaluation of PIMD's psychometric properties in other languages and cultures can
yield more details about this new tool.
METHODS
A methodological, descriptive analytical study was conducted to validate the PIMD-p
instrument. All procedures conformed to the ethical standards of the Research Ethics
Committee (permit approval number: 0188/2021).
The participants were selected by convenience sampling, a type of non-probability
method collecting data for members of the population who are conveniently available
for the study. According to some authors, samples of at least 50, and at most 100,
individuals are sufficient to assess the psychometric properties of construct measurement
instruments.[11] This study involved older adults aged ≥60 years of both sexes recruited from a geriatrics
outpatient clinic and a long-term care facility (LTCF), both situated in Sao Paulo
city. The inclusion criteria were: participants with dementia of any cause, diagnosed
according to the Diagnostic and Statistical Manual - V (DSM-V),[12] with impaired verbal communication, and currently exposed to potentially painful
situations (dislocations, bruises, sprains, infections, inflammation, fractures, operations,
etc.). Dementia was diagnosed by experienced geriatricians using the Mini Mental State
Examination and functionality in daily life (basic and instrumental activities, respectively
according to the Katz and Lawton scales). The Clinical Dementia Rating (CDR) scale
to measure the degree of dementia was also obtained by those professionals. Exclusion
criteria were patients undergoing dialysis, chemotherapy or radiotherapy treatments.
The legal representatives of participants selected signed a Free and Informed Consent
Form. Data collected included sociodemographics (age, sex, race); information on degree
of dementia measured by CDR scale; and etiologies of potential pain. Also, information
on pain intensity reported by participants' caregivers and LTCF nurses was collected
using the verbal numeric pain scale (classified as mild, moderate or high).
The PIMD-p was applied independently by two researchers (E1 and E2) on the same day.
Within 14 days, the instrument was reapplied by one of the researchers (E3), ensuring
no different analgesic interventions had been performed over the period.
All statistical analyses were performed using the Statistical Package for Social Science
(SPSS), version 17, Minitab 16 and Microsoft Excel 2010. The test of equality of two
proportions was used to characterize the distribution and relative frequency of the
qualitative variables.
The present study explored the psychometric properties of the PIMD-P including its
reliability and validation. Three measures of reliability were obtained: internal
consistency (correlation between items); test-retest reproducibility by the same observer
(intra-observer reproducability); and reproducibility by different observers (inter-observer
reproducibility).[13] Internal consistency was determined using Cronbach's α coefficient (E1), while reproducibility
was based on intraclass correlation coefficient (ICC). Convergent validity of the
PIMD-p was established using Spearman's test. Also, a ROC curve was plotted for reported
pain intensities and total PIMD scores. A 5% significance level was adopted.
RESULTS
The sample included 50 older individuals, mean age 86.1 years (range 68–100 years),
comprising 60% outpatients and 40% LTCF residents, predominantly female (80%) and
white (76%). For dementia rating, most participants had moderate (46%) or advanced
dementia (42%) (p = 0.687) ([Table 1]).
Table 1
Sample characteristics
|
Characteristics
|
N (%)
|
p-value
|
|
Age
|
Mean 86.1 years
|
|
|
|
Min-max 68–100 years
|
|
|
|
Sex
|
Female
|
40 (80)
|
< 0.001
|
|
Male
|
10 (20)
|
|
Race
|
White
|
38 (76)
|
|
|
Black
|
3 (6)
|
< 0.001
|
|
Brown
|
9 (18)
|
< 0.001
|
|
Dementia-CDR
|
1
|
6 (12)
|
< 0.001
|
|
2
|
23 (46)
|
|
|
3
|
21 (42)
|
0.687
|
|
Potentially painful conditions
|
Muscular
|
21 (42)
|
0.110
|
|
Arthritis
|
26 (52)
|
0.689
|
|
Vascular disease
|
4 (8)
|
< 0.001
|
|
Neurological disease
|
10 (20)
|
< 0.001
|
|
Ostomy
|
7 (14)
|
< 0.001
|
|
Pressure ulcer or painful skin condition
|
6 (12)
|
< 0.001
|
|
Trauma
|
4 (8)
|
< 0.001
|
|
Surgery
|
1 (2)
|
< 0.001
|
|
Others
|
4 (8)
|
< 0.001
|
|
Pain – intensity
|
Mild
|
23 (46)
|
|
|
Moderate
|
20 (40)
|
0.545
|
|
Intense
|
7 (14)
|
< 0.001
|
Abbreviation: CDR, clinical dementia rating.
Regarding pain conditions, osteoarticular (52%) and muscular pain (42%) predominated.
Pain intensity reported by caregivers and nurses was mainly mild (46%) ([Table 1]).
Reliability of the PIMD-p according to internal consistency was good, as measured
by Cronbach's α (coeff. 0.838). Reliability for intra and inter-observer reproducibility
was high and strong, according to the ICC (correlation coefficients 0.927 and 0.970,
respectively; p < 0.001) ([Table 2]).
Table 2
PIMD-p reproducibility according to ICC
|
Pain indicator
|
Interobserver
|
Intraobserver
|
Intraobserver
|
Intraobserver
|
|
ICC
|
p-value
|
ICC
|
p-value
|
|
Bracing
|
0.934
|
<0.001
|
0.958
|
<0.001
|
|
Rigid/stiff
|
0.927
|
<0.001
|
0.976
|
<0.001
|
|
Sighing
|
0.885
|
<0.001
|
0.957
|
<0.001
|
|
Complaining
|
0.926
|
<0.001
|
0.964
|
<0.001
|
|
Grimacing
|
0.758
|
<0.001
|
0.943
|
<0.001
|
|
Frowning
|
0.663
|
<0.001
|
0.930
|
<0.001
|
|
Expressive eyes
|
0.857
|
<0.001
|
0.951
|
<0.001
|
|
Score PIMD-p
|
0.927
|
<0.001
|
0.970
|
<0.001
|
Abbreviations: ICC, intraclass correlation coefficient; PIMD-p, pain intensity measure
for persons with dementia.
To analyze the psychometric property of the PIMD-p of convergent validity, pain indicators
were correlated with pain intensities reported by patients' caregivers and nurses.
Results for Spearman's test revealed a strong significant correlation, except for
“expressive eyes” (0.106; p = 0.462) ([Table 3]).
Table 3
Validity of PIMD-p according to Spearman correlation
|
Pain indicator
|
Pain intensity
|
Pain intensity
|
|
Correlation (r)
|
p-value
|
|
Bracing
|
0.439
|
0.001
|
|
Rigid/stiff
|
0.505
|
<0.001
|
|
Sighing
|
0.355
|
0.011
|
|
Complaining
|
0.605
|
<0.001
|
|
Grimacing
|
0.519
|
<0.001
|
|
Frowning
|
0.413
|
0.003
|
|
Expressive eyes
|
0.106
|
0.462
|
|
PIMD-p Score
|
0.726
|
<0.001
|
Abbreviation: PIMD-P, pain intensity measure for persons with dementia.
A ROC curve was plotted to determine cut-off scores on the PIMD-p. To this end, reported
pain intensities were correlated with total pain intensity scores on the PIMD-p. Scores
≥7.5 (0–21) denoted moderate/intense pain intensity, with a sensitivity of 77.8% and
specificity of 95.7% (area under curve 0.931; p < 0.001) ([Table 4]). In this study, almost half of the sample had moderate/severe pain (44%).
Table 4
Sensitivity and specificity of PIMD-p for pain intensity on ROC curve
|
Total score PIMD-p
|
Sensitivity (%)
|
Specificity (%)
|
|
0.5
|
100
|
4.3
|
|
1.5
|
100
|
21.7
|
|
2.5
|
100
|
39.1
|
|
3.5
|
96.3
|
56.5
|
|
4.5
|
96.3
|
65.2
|
|
5.5
|
88.9
|
82.6
|
|
6.5
|
81.5
|
82.6
|
|
7.5
|
77.8
|
95.7
|
|
8.5
|
59
|
95.7
|
|
10.0
|
33.3
|
100
|
|
11.5
|
25.9
|
100
|
|
12.5
|
18.5
|
100
|
|
14.0
|
11.1
|
100
|
|
15.5
|
7.4
|
100
|
|
17.5
|
3.7
|
100
|
|
20.0
|
0
|
100
|
|
21.0
|
0
|
100
|
Abbreviations: PIMD-P, pain intensity measure for persons with dementia; ROC, Receiver
Operating Characteristic.
DISCUSSION
Pain assessment in older people with dementia and impaired verbal communication remains
a challenge for health professionals, since it is unclear which behaviors are most
suggestive of pain, unlike for psychological symptoms such as anxiety, agitation and
depression.
The present study is the first to analyze the reliability and validity of the PIMD
meta-instrument outside its country of origin. This type of investigation is important
because, when new measurement instruments are developed, they should undergo broad
assessment of their psychometric properties and be analyzed for different population
samples. More recently, a systematic review on pain assessment for individuals with
advanced dementia in a care home setting identified 17 different tools used worldwide.
These instruments included the PIMD, cited for having good psychometric quality and
for involving rigorous multidimensional pain assessment. The authors of the review
highlighted the need for more studies and tests of existing tools in larger and more
diverse samples to better determine their qualities.[14]
The present study sample comprised older people from the community and residents of
a LTCF. The mean age of the sample was 86.1 years, indicating older participants.
Also, individuals predominantly had moderate dementia (46%) and apparent joint and
muscular pain etiologies (52% and 42%, respectively). These potential pain etiologies
corroborate the data found by Lichtner et al., revealing a higher prevalence of musculoskeletal
and osteoarticular pain in older people with dementia.[15]
Analyzing the psychometric properties of the PIMD-p, primarily reliability, results
confirmed adequate internal consistency (Cronbach's α 0.838). This data corroborates
the findings for the original PIMD (Cronbach's α 0.72), while indicating even greater
reliability.[3]
For PIMD-P reproducibility, excellent results were observed both for intra and inter-observer
analyses (ICC 0.970 and 0.927, respectively, both with p < 0.001). This high reproducibility of the PIMD-p suggests its utility in clinical
practice. Convergent validity for the PIMD-p proved adequate, where the sum of pain
intensities calculated for each indicator correlated with the pain intensities reported
by caregivers. Strong significant correlation was confirmed, except for the indicator
expressive eyes (r 0.106 and p = 0.462), where higher PIMD-p scores correlated with greater pain intensities reported
by caregivers. In the absence of a gold standard for comparison, convergent validation
relative to reported pain intensity was used.
A cut-off point was determined for the PIMD-p due to the fact that pain intensity
is a key factor in the choice of analgesic therapy to be used. A ROC curve determined
that scores ≥ 7.5, with a sensitivity of 77.8% and specificity of 95.7%, indicated
moderate-severe pain (p < 0.001). It was opted for a cutoff point of 7.5 because it greatly optimized Specificity
with little reduction in the Sensitivity, thus obtaining a more specific instrument
to detect more intense pain.
Some limitations of the study should be noted such as the small sample size. However,
the sample did include many oldest-old (mean age 86 years), a group that is still
poorly studied, despite being a fast-growing stratum of the population.The PIMD-p
proved to be a reliable and valid tool for assessing the presence and intensity of
pain in demented older people with difficulties expressing themselves verbally. Therefore,
a meta-instrument for pain measurement is now available in Portuguese that has adequate
psychometric properties and is both simple and practical. This tool can help health
professionals improve care management in the older population with moderate or severe
dementia, a group that often includes individuals who are unable to verbally express
their pain.
