Diagnostic performance analysis of the ICOPE screening tool for identifying decline in intrinsic capacity

doi:10.21203/rs.3.rs-2802132/v1

Background: Intrinsic capacity (IC) is a comprehensive indicator of an individual's positive attributes. The World Health Organization (WHO) recommends a two-step approach to assess IC decline among older people. The first step involved using the Integrated Care for Older People (ICOPE) screening tool to identify potential issues, and the second step involved using detailed assessments for confirmation. This study aimed to assess the diagnostic performance of ICOPE screening tool as a simple preliminary screening to identify IC decline among community-dwelling older adults, which was rarely reported in China.

Methods: This cross-sectional study included 228 community-dwelling older individuals aged ≥75 (mean age, 84.0±4.4 years; 131 [57.5%] females) who completed the IC evaluation according to the WHO IC assessment pathway. The diagnostic performance of the ICOPE screening tool were calculated using a 2 × 2 table and a receiver operating characteristic curve.

Results: The proportion of possible IC decline identified by the ICOPE screening tool was 79.4%, whereas the actual IC decline assessed by the detailed assessment was 73.2%, mainly in locomotion. The ICOPE screening tool showed a sensitivity of 94.6% and specificity of 62.3% for identifying IC decline, with an overall diagnostic accuracy of 86.0%. With the exception of the sensory dimension, the sensitivity of the ICOPE screening tool for diagnosing impairments in each dimension of the IC was highest in the cognition domain (100%) and lowest in the vitality domain (51.3%), whereas the specificity was highest in vitality (94.7%) and lowest in cognition (55.6%).

Conclusions: The ICOPE screening tool has high sensitivity and can be used as an IC screening tool in community-dwelling older people. However, further improvements are needed in the vitality dimension of the ICOPE screening tool to enhance its sensitivity in identifying individuals at risk of malnutrition.

Diagnostic performance

Intrinsic capacity

ICOPE screening tool

Older people

The aging global population is constantly increasing. As a populous country, China faces a severe aging situation. According to the National Bureau of Statistics of China's 2022 investigation on population changes [1], the proportion of people aged 60 years and above has reached 19.8%, with those aged 65 years and above accounting for 14.9%, indicating that China has become an aging society. Those born during the second baby boom, between 1962 and 1975, will gradually enter retirement by 2022, further increasing the burden of aging in China. In 2022, the Lancet published a report on China's path to healthy aging [2], which showed that its life expectancy has gradually approached that of other developed countries.

In 2021, the World Health Organization (WHO) proposed the "Decade of Healthy Aging 2020–2030" [3], which involves four areas: (1) providing person-centered integrated care to meet the needs of older people, (2) changing attitudes and behaviors towards aging, (3) supporting community interventions to maintain the intrinsic capacity (IC) of older people [4] and promote functional ability, and (4) providing long-term care for older people in need. The concept of healthy aging means that the medical model for older people should shift from a disease-centered to a function-centered approach [5]. WHO has proposed the construct of IC [6], which includes five dimensions: locomotion, vitality, cognition, psychology, and sensory (vision and hearing). Therefore, a two-step approach to assess IC decline among older people is recommended. The first step involved using the Integrated Care for Older People (ICOPE) screening tool to identify potential issues, and the second step involved using detailed assessments to confirm individuals with actual IC decline. Based on this assessment, personalized interventions can be provided to older people with IC decline.

However, what is the diagnostic performance of the ICOPE screening tool in detecting IC decline? There are two published studies, one from Hong Kong, China [7], and the other from Spain [8], both of which indicate that the ICOPE screening tool had high sensitivity but varying screening effectiveness across different dimensions. In addition, only a few such studies have been conducted in mainland China. This study aimed to evaluate diagnostic performance which contains the sensitivity, specificity, and diagnostic accuracy of the ICOPE screening tool to determine whether the screening tool is suitable for community-dwelling older people using step 2 of the detailed assessment of IC as the gold standard.

Study Design and Participants

This study is the baseline data of the previous study cohort [9], which included residents of an independent living area in the Beijing Taikang Yanyuan Community who were continuously included in the physical examination from July to September 2018. The inclusion criteria were: individuals aged ≥ 75 years and those who have completed the IC assessment. The exclusion criteria were as follows: individuals with acute illness within 1 month before enrollment, including but not limited to acute coronary syndrome, pulmonary infection, and stroke; and those who refused to participate in the study.

Measurements

Sociodemographic data, such as age, sex, height, weight, and education level, were collected. The Cumulative Illness Rating Scale for Geriatrics (CIRS-G) [10] was used to assess comorbidities. Basic activities of daily living (ADL) were evaluated using the physical self-maintenance scale (PSMS) [11].

Intrinsic capacity

This study was based on the WHO IC assessment pathway [4] (Table 1), and first conducted an IC screening evaluation of the participants using the ICOPE screening tool. The total score ranges from 0 to 9 points, and a score of ≥1 indicates possible IC decline. Step 2 involved a detailed evaluation [12-15] of IC to identify older people with actual IC decline. Total score ranges from 0 to 6 points, and a score of ≥1 indicates actual IC decline. In this study, visual and hearing impairments were defined as impairments with an impact on daily life during screening and detailed assessment.

Table 1. 2-Step IC assessment: ICOPE screening tool and detailed assessment¹

IC dimensions	ICOPE screening tool	Detailed assessments
Locomotion	Five times sit-to-stand test ＞14s	SPPB ＜9 score
Vitality	Loss more than 3 kg of weight in the past 3 months	MNA-SF ≤11 score
Vitality	Loss of appetite in the past 3 months	MNA-SF ≤11 score
Cognition	Cannot recall three words	MMSE ＜24 score
Cognition	Disorientation in time or space	MMSE ＜24 score
Psychology	Depressed or hopeless in the past two weeks	GDS-15 ＜5 score
Psychology	Lost interest in activities in the past two weeks	GDS-15 ＜5 score
Sensory (vision)	Vision deteriorated and affected daily life	Same
Sensory (hearing)	Hearing deteriorated and affected daily life	Same

Abbreviations: ¹If any problem in the table satisfied is scored 1. Total score of ICOPE screening tool ranges from 0 to 9 points, and a score of ≥1 indicates possible IC decline. Total score of detailed IC assessments ranges from 0 to 6 points, and a score of ≥1 indicates actual IC decline. IC, intrinsic capacity; SPPB, short physical performance battery; MNA-SF, short-form mini-nutritional assessment; MMSE, mini-mental state examination; GDS-15, 15-item geriatric depression scale

Statistical Analysis

Baseline data were collected, and normally distributed data were expressed as mean±standard deviation (x±s), while non-normally distributed data were expressed as median (interquartile range) [M (IQR)]. Qualitative data were presented as constituent ratios, rates, and absolute numbers. The validity of the ICOPE screening tool for detecting IC decline was calculated using a four-fold table. P <0.05 was considered statistically significant. All data were analyzed using SPSS26.0 for Windows (IBM Corp. Armonk, NY, USA).

Baseline Characteristics

A total of 228 older people were included (Table 2), with a mean age of 84.0±4.4 years. Of these participants, 131 (57.5%) were female, and 225 (98.7%) had an education level of high school or above. The CCI score was 5 (3–7) points. The ADL score was 6 (6–6) points, indicating a good functional status. The ICOPE screening tool score was 2 (1–4) points, and 181 (79.4%) participants were identified as having a possible IC decline. In the detailed evaluation of step 2 IC, the score was 1 (0–2) point, indicating that 167 (73.2%) older people had an actual IC decline.

Table 2. Baseline characteristics of 228 participants.

Variable	Total
Variable	n=228
Age, mean (SD), years	84.0±4.4
Female, n (%)	131 (57.5)
BMI, mean±SD, kg/㎡	24.2±3.4
High school or above, n (%)	225 (98.7)
CIRS-G, M (IQR)	5 (3–7)
ADL¹, M(IQR)	6 (6–6)
ICOPE screening tool	2(1–4)
Possible IC decline, n(%)	181(79.4)
IC detailed assessment	1 (0–2)
Actual IC decline, n(%)	167(73.2)

Abbreviations: SD, standard deviation; BMI, body mass index; CIRS-G, the cumulative illness rating scale for geriatrics; ADL, activities of daily living; ICOPE, integrated care for older people

Intrinsic capacity

In step 1, the ICOPE screening tool was used to identify possible IC decline among older people, and the proportion identified was 79.4%. The proportions of participants with impaired locomotion, vitality, cognition, psychology, vision, and hearing were 50.0%, 13.2%, 53.9%, 35.1%, 19.7%, and 20.2%, respectively. In Step 2, a detailed evaluation method was used to assess the proportion of older people with actual IC decline (73.2 %). The proportions of patients with impaired locomotion, vitality, cognition, and psychology were 60.1%, 17.1%, 17.1%, and 16.2%, respectively (Table 3).

Table 3. IC decline and impairment of each domain in 2-step assessment

	Step1 ICOPE screening tool	Step 2 detailed IC assessments
IC decline, n (%)	181（79.4）	167（73.2）
IC domain impairment
Locomotion, n (%)	114（50.0）	137（60.1）
Vitality, n (%)	30（13.2）	39（17.1）
Cognition, n (%)	123（53.9）	39（17.1）
Psychology, n (%)	80（35.1）	37（16.2）
Sensory (vision), n (%)	45（19.7）	45（19.7）
Sensory (hearing), n (%)	46（20.2）	46（20.2）

Abbreviations: IC, intrinsic capacity.

The ICOPE Screening Tool Validity

The ICOPE screening tool had a sensitivity of 94.6% and specificity of 62.3% for identifying IC decline, with a diagnostic accuracy of 86.0%. With the exception of the sensory dimension, the sensitivity for detecting impairment in each dimension of the IC using the ICOPE screening tool was the highest for cognition (100 %) and lowest for vitality (51.3 %). Regarding specificity, the vitality dimension performed the best at 94.7%, whereas cognition had the lowest specificity at 55.6% (Table 4).

Table 4. Sensitivity, specificity and diagnostic accuracy of ICOPE screening tool

Detailed IC assessment (IC domain impairment)		Possible IC decline by ICOPE screening tool		Sensitivity (%)	Specificity (%)	Diagnostic accuracy (%)
	Assessment result	Yes	No
IC decline	Yes	158	9	94.6	62.3	86.0
	No	23	38
Locomotion	Yes	108	29	78.8	93.4	84.6
	No	6	85
Vitality	Yes	20	19	51.3	94.7	87.3
	No	10	179
Cognition	Yes	39	0	100	55.6	63.2
	No	84	105
Psychology	Yes	27	10	73.0	72.3	72.4
	No	53	138

Abbreviations: IC, intrinsic capacity; ICOPE, integrated care for older people

To improve the sensitivity of vitality dimension screening, BMI <20 kg/㎡ [16] was added to the original ICOPE screening tool for vitality dimension. If any of the conditions in the vitality screening question are met, the vitality domain may be impaired. As shown in Table 5, the sensitivity and specificity of the modified ICOPE screening tool were 95.2% and 55.7%, respectively, and the sensitivity of the vitality domain screening increased to 69.2%, with a specificity of 90.5% and diagnostic accuracy of 86.8%.

Table 5. Sensitivity, specificity, and diagnostic accuracy of modified ICOPE screening tool

Detailed IC assessment (IC domain impairment)		Possible IC decline by ICOPE screening tool		Sensitivity (%)	Specificity (%)	Diagnostic accuracy (%)
	Assessment result	Yes	No
IC decline	Yes	159	8	95.2	55.7	84.6
	No	27	34
Vitality	Yes	27	12	69.2	90.5	86.8
	No	18	171

Abbreviations: IC, intrinsic capacity; ICOPE, integrated care for older people

Based on the WHO proposed assessment pathway for intrinsic capacity in older people, this study verified the feasibility of the ICOPE screening tool among community-dwelling older people in China. The ICOPE screening tool demonstrated a high sensitivity of 94.6%, specificity of 62.3%, and diagnostic accuracy of 86.0% in identifying older people with IC decline, and can be used as a simple and effective screening tool for promotion and application in the community.

The ICOPE screening tool demonstrated varying diagnostic effectiveness for different IC dimensions. The highest sensitivity was observed in the cognitive domain, reaching 100%, whereas the lowest sensitivity was found in the vitality domain, at 51.3%. One possible reason for the poor sensitivity in vitality is that, in the nutrition screening question, weight loss is defined as "unintentional weight loss greater than 3 kg in the past 3 months,” while some older people may have lost less than 3 kg. Furthermore, for some older people who are underweight, weight loss may not be significant, but they may still be at risk of malnutrition. These factors may increase the false-negative rate of the screening tool, leading to a decrease in sensitivity.

Because a screening tool should have high sensitivity, one way to improve it is to lower the weight threshold in the vitality dimension screening question, although the specific value requires further research and discussion. Additionally, adding BMI screening to the screening questions can increase sensitivity. Based on the Global Leadership Initiative on Malnutrition (GLIM) diagnostic criteria recommended for Asians [16] aged ≥70 years, a BMI <20 kg/㎡ indicates BMI reduction. In this study, the proportion of older adults with a BMI reduction was 10.1% (23 cases). By including BMI reduction in nutritional screening, the proportion of older adults who may be at risk of malnutrition increased to 19.7% (45 cases). Using the MNA-SF as the gold standard, the sensitivity of the vitality screening tool increased to 69.2% with a specificity of 90.5% (Table 5). This study provides a reference for future improvements in the ICOPE screening tools. In addition, the screening question used for the locomotion domain in the ICOPE screening tool was whether the time for the five-time sit-to-stand test (FTSST) was greater than 14 s. This study mainly involved older people of advanced age. We used an SPPB score of less than 9 points as the gold standard for impairment in the locomotion domain. ROC analysis was used to determine that the optimal threshold for the FTSST in this study population was 13.9s, which was consistent with the recommended threshold in the ICOPE screening tool. However, this threshold may be high in young age of older people, leading to a decrease in sensitivity. Different age groups may have different FTSST thresholds. Thus, further sample expansion is required to explore and establish appropriate screening thresholds for the locomotion domain.

The cognitive domain had the lowest specificity among all the screening tools (55.6 %). In this study, among older people with abnormal cognitive screening results, 95.9% had a decrease in word recall ability, while only 39.0% had impairments in time and space orientation. This suggests that many older people may only experience a decline in word recall ability, whereas memory decline is common in older people and is not necessarily related to cognitive impairment. This may be one reason for the low specificity of the cognitive dimension-screening tool.

A study in Spain [8] included 207 older people aged ≥70 years, based on the WHO IC assessment pathway, including screening and detailed evaluation of vision and hearing. The study found that, among all dimensions, the cognitive domain had the highest sensitivity (0.889), with the other dimensions ranging from 0.438 to 0.557. Among them, vision (0.438), hearing (0.452), and vitality (0.455) domains showed poor sensitivity. The specificities of all dimensions were good, with the vitality domain being the best (0.960), and the other domains ranging from 0.682 to 0.953. Overall, their results were similar to those of our study, and some dimensional issues of the ICOPE screening tool require improvement. Another study [7] conducted in Hong Kong, China, included 304 community residents aged ≥60 years and found that the sensitivity and specificity of the ICOPE screening tool were 95.0% and 57.6%, respectively, which were consistent with the results of our study. However, the sensitivity of each IC dimension was highest in the vitality domain, reaching 100%. The reason for this difference may be that the study population was relatively younger, and there may have been fewer weight loss individuals, with a lower proportion of actual malnutrition risk or malnourished individuals and a lower false-negative rate.

Strength and Limitation

IC decline is commonly observed in older people and is associated with adverse outcomes [17-24]. Adopting a screening-before-assessment model can more efficiently utilize community resources. The main strengths of this study are that few studies have validated the diagnostic performance of the ICOPE screening tool. This enriches the research foundation in this field, provides theoretical references for promoting the ICOPE screening tool in the community, and suggests ways to improve its sensitivity. However, this study also has some limitations. This was a single-center, small-sample study, and further sample expansion is needed to validate and extrapolate the conclusions. In addition, the screening and detailed evaluation of sensory dimensions in this study were both self-assessment questionnaires. Considering the limitations of community resources, the evaluation of sensitivity and specificity for sensory screening may not be sufficient, and objective indicators should be used for further evaluation of the sensory domain in future studies.

The ICOPE screening tool has high sensitivity and can be used as an IC screening scale in community-dwelling older people. However, further improvements are needed in the vitality domain of the ICOPE screening tool to enhance its sensitivity in identifying individuals at risk of malnutrition.

ADL, activities of daily living; CIRS-G, the cumulative illness rating scale for geriatrics; FTSST, five-time sit-to-stand test; GDS, geriatric depression scale; ICOPE, integrated care of older people; IC, intrinsic capacity; MMSE, mini-mental state examination; MNA-SF, short-form mini-nutritional assessment; PSMS, physical self-maintenance scale; SPPB, short physical performance battery; WHO, world health organization.

Ethics approval and consent to participate

We confirm that all methods were performed in accordance with the Declaration of Helsinki and relevant regulations and guidelines. Ethical approval for this study was obtained from the Research Ethics Committee of Peking Union Medical College Hospital (PUMCH, JS2002). Informed consent was obtained from all participants.

Consent for Publish

Not applicable.

Availability of data and materials

The datasets analyzed in the current study are available from the corresponding author upon request.

Competing interests

The author reports no conflicts of interest in this work.

Funding

National High Level Hospital Clinical Research Funding (2022-PUMCH-B-132)

Author Contributions

All authors made a significant contribution to the work reported. The study design was performed by Fei Lu and Xiaohong Liu. Material preparation and data collection was performed by Fei Lu, Shuo Liu, Jiaojiao Li and Xueying Wang. Material analysis was performed by Fei Lu. The first draft of the manuscript was written by Fei Lu. The manuscript was revised by Xiaohong Liu and Xiaohong Sun. All authors commented on previous versions of the manuscript. All the authors have read and approved the final manuscript and agree to be accountable for all aspects of the work.

Acknowledgments

We are grateful to all the participants in this study. We thank Dr. Guifen Liu, Dr. Xinxiu Yu, Dr. Liang Han, Dr. Jin Zhang, and other medical workers from the Taikang Yanyuan community for their support.

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No competing interests reported.

Diagnostic performance analysis of the ICOPE screening tool for identifying decline in intrinsic capacity

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Abstract

Background

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Discussion

Conclusion

Abbreviations

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