Cohort Profile: The Dementia Registry in Macao

Introduction

Dementia is a chronic neurodegenerative disease with loss of memory, problem-solving and other cognitive abilities that are severe enough to interfere with daily life of older people. According to Alzheimer’s Disease International, ¹ there were about four thousand people living with dementia in Macao and it was expected that the number of people living with dementia would increase rapidly, resulting of increases in life expectancy at birth over the past years. ² In response to the significant health and social burden incurred by dementia, Macao Special Administrative Region Government had launched Macao Dementia Policy which included a 10-year strategic framework to build dementia friendly community and integrated health and social services in 2016, ³ of which the Macao Dementia Registry (MDR) was a powerful tool for monitoring of clinical care to facilitate population-level surveillance over time. Methods of identifying cases of dementia differentiated between registries but usually included reporting from clinics and hospitals. However, diagnosis occurred in a variety of settings and inclusive of the whole population could be challenging for a dementia registry. Therefore, understanding and studying the cohort with dementia captured within the registry could significantly contribute to the understanding of health service use, medicines, hospitalizations, mortality and other information. ⁴ The current evaluation had examined (1) the demographic and clinical characteristics of people living with dementia and (2) the comparability of data captured in the MDR dementia registry with selected established international dementia registries. This would allow for better understanding of the characteristics and limitations of this MDR cohort for monitoring the quality of care and outcomes for people living with dementia in Macao.

Cohort Description

Design and Data Sources

The study presented the results of a cross-sectional evaluation of the people with dementia identified by assessment data in the Dementia Medical Center and all the eleven Health Centers between September 21st, 2016 and July 22nd, 2021 in Macao. The entry point to the MDR cohort was in the Dementia Medical Center and all the eleven Health Centers where assessment and a recording of dementia were conducted and a person was identified from dementia medication prescribing records.

Dementia Ascertainment

Dementia was determined through eligibility assessments in the Macao Dementia Medical Center. During assessments, assessors made records of major diseases or disorders along with documented evidence of a diagnosis from doctor, which all had an impact on the person’s need for assistance with activities of daily living and social participation. Assessors could record one or more types of dementia or had the option to classify the dementia as ‘unspecified’ based on the medical record. In addition, medicines prescribed for the treatment of Alzheimer’s disease were not dispensed for any other reason, therefore, any person with who had been dispensed Donepenzil, Galantamine, Rivastigmine or Memantine could be classified as having dementia. ⁵

Data Set

The data available for the MDR cohort were presented in Table 1, with comparable data from other established international dementia registries. Registries included for comparison were chosen based on their broad coverage and the availability of data for comparison here. They included the Registry of Senior Australians ⁶ and the Swedish Dementia Registry. ⁷ The MDR dementia registry covered comprehensive demographic data and information about aged and health care service use. All dementia-related medicine dispensing was recorded, facilitating monitoring of medicine dosage, duration and polypharmacy. Information about medical history, diagnosis procedures or other clinical details was also available.

Table 1.

Comparison of Dataset Available of Macao Dementia Registry Cohort and International Dementia Registries.

Country/Region	Macao	Australia	Swedish
Demographics	Date of birth Gender Marriage status Education Carer co-residency	Date of birth Gender Marriage status Socioeconomic status Country of birth Living arrangement Language Region Carer availability Carer relationship	Age Gender Living arrangement Driver’s license Weapons license
Clinical characteristics	Types of dementia BMI Blood pressure Diagnostic tests Time for diagnosis Referral way	Types of dementia	Types of dementia Family history BMI Diagnostic tests Time for diagnosis Diagnostic workup
Diagnostic system	ICD-10	ICD-10-AM a	ICD-10
Cognitive testing	MMSE score	PAS-CIS score	MMSE score
Care use	Residential care Home care	Government funded care	Respite care Home care
Medications	Anti-dementia Antidepressants Antipsychotics Total number of drugs	All drugs	Anti-dementia Antidepressants Antipsychotics Anxiolytics Cardiovascular Number of drugs
Health & well-being	GDS-15 score	Comorbidities Cornell scale for depression	Fall, ulcers, malnutrition, Oral health Links registries
Function	Barthel Index score	Activity limitations	IADL score
Death	Date of death Time to death	Date of death Causes of death	Time to death

^aInternational Classification of Diseases, version 10, Australian Modification.

While most dementia registries included the Mini-Mental Status Examination (MMSE), the copyright restrictions had precluded its widespread clinical use. Instead, the Montreal Cognitive Assessment (MoCA) was scheduled to be conducted where cognitive impairment was suspected or known. A Geriatric Depression Scale (GDS-15) was conducted where symptoms of depression and dysthymia were present. Functional dependence was rated across domains, including nutrition, mobility, personal hygiene, toileting, continence, home maintenance and transport, though a validated measure as Barthel Index (BI) used in other registries was also included in the MDR dementia registry.

Cohort Characteristics

There were 2623 people with dementia in the MDR cohort over the capturing period and the detailed demographic data on the cohort were demonstrated in Table 2. The cohort was representative of the geographical spread of the Macao population with the majority living in Macao, Taipa, and Coloane islands. While comparing on demographic characteristics, the MDR cohort were similar sex and age distributions with other registries and also included less people living in nursing home.

Table 2.

Comparison of Demographic Characteristics of Macao Dementia Registry Cohort and International Dementia Registries.

Country/Region	Macao (n = 2623)	Australia (n = 373 695)	Swedish
(n = 28 722)
Age at cohort entry (mean)	80.0	84.1	79.3
≥65 years	2413 (92.0%)	373 695 (100.0%)	NA
<65 years	210 (8.0%)	0 (.0%)	NA
Gender
Male	952 (36.3%)	137 943 (36.9%)	11 728 (40.8%)
Female	1671 (63.7%)	235 703 (63.1%)	16 994 (59.2%)
Living arrangementsa
Lives alone	294 (11.2%)	72 392 (19.4%)	25 492 (88.8%)
Lives with family	1991 (75.9%)	134 943 (36.1%)
Nursing home	338 (12.9%)	166 349 (44.5%)	3230 (10.2%)

^aIn proportion.

It was indicated that Alzheimer’s disease was the most common type of dementia in MDR dementia registry, similarly to other registries examined (Table 3). However, the results outlined in the Table 3 also suggested a greater proportion of persons diagnosed with vascular dementia (31.4%) in MDR dementia registry than the cohorts of other registries. This might be explained by the more common comorbidities among the people living with dementia in the MDR cohort, including hypertension (20.8%), diabetes mellitus (9.6%), heart diseases (4.1%), and hypercholesterolemia (3.4%), which were all under the cardiovascular diseases categories, likely to cause vascular dementia. Moreover, on cognitive assessment, the MDR cohort was more cognitively impaired than the cohorts of other registries. Individuals in the MDR cohort lived for an average of 16 months after they were first identified with dementia and 84 years old was an average age at the end of their lives. Similarly, a recent analysis of the Registry of Senior Australians identified that individuals had died at an average of 2-years follow-up period and were on average 88 years old. ⁶

Table 3.

Comparison of Clinical Characteristics of Macao Dementia Registry Cohort and International Dementia Registries.

Country/Region	Macao a (n = 2623)	Australia (n = 309 958)	Swedish (n = 28 722)
Dementia type
Alzheimer’s disease	1592 (60.7%)	229 104 (73.9%)	9248 (32.2%)
Vascular dementia	824 (31.4%)	33 638 (10.9%)	5199 (18.1%)
Other dementias	207 (7.9%)	45 202 (14.6%)	14 275 (49.7%)
Cognitive impairment score mean	MMSE	PAS-CIS	MMSE
	16	12	21

^aIn proportion.

Discussion

The only and largest sample and regional coverage provided by the Registry were key strengths of the MDR cohort. The MDR included the only and largest existing population-based sample of people with dementia in Macao and was acting as representative of the population in many ways, including demographic characteristics and clinical diversity. The MDR dementia cohort was, therefore, a powerful resource and could facilitate monitoring of clinical care and determinants of important outcomes including institutionalization and mortality over time. Furthermore, the MDR dementia cohort might inform the policymaking in Macao and future development of the Registry. Following a Chinese traditional culture of emphasis on family values and harmony interpersonal relationship in Macao, there was a greater proportion of persons with dementia who lived with their family members (75.9%), more than a double compared to those in Australia (36.1%). This might underscore the significant need for the strong effort to support the family caregivers in Macao Dementia Policy that was launched in 2016 as the 27th globally and was aligned with WHO Global Action Plan on the Public Health Response to Dementia 2017-2025. ⁸ Macao Dementia Policy, which included a 10-year strategic framework to establish dementia friendly communities across the region, had been highly praised by Alzheimer’s Disease International in 2018 as a positive model. ³

Despite these benefits, there were some limitations to the MDR dementia cohort. First, the MDR could not capture people with dementia who did not have a diagnosis in medical history. Approximately half of people with dementia in Macao were estimated to receive a diagnosis, ³ and delays in diagnosis were common.^9,10 People who received a diagnosis tended to have more severe impairment, have insight into their impairment, and be married. ¹¹ The MDR was not able to capture these individuals who had not been diagnosed and these factors introduced a sampling bias to the Cohort. Second, the data available in the MDR were not collected for research purposes and therefore might have limited internal validity. The accuracy of clinical and demographic data also relied on assessors who might not have been necessarily trained in research data collection or in dementia care. The accuracy of the dementia diagnosis recorded in the MDR was dependent on the skills and resources available to the clinician who made the diagnosis.

Conclusion

There were 2623 people living with dementia in the MDR and the MDR included the only and largest existing population-based sample of people with dementia in Macao and was representative of the population in many ways, including demographic characteristics and clinical diversity. The MDR was, therefore, a powerful resource and could facilitate monitoring of clinical care and determinants of important outcomes including institutionalization and mortality over time. Furthermore, the MDR dementia cohort might inform the policymaking in Macao and future development of the Registry.

Supplemental Material

sj-pdf-1-aja-10.1177_15333175211067124 – Supplemental Material for Cohort Profile: The Dementia Registry in Macao

Supplemental Material, sj-pdf-1-aja-10.1177_15333175211067124 for Cohort Profile: The Dementia Registry in Macao by Sio Mui Wong, Wen Zeng, and Iek Long Lo in American Journal of Alzheimer's Disease & Other Dementias®