Prevalence and Incidence Rates of Dementia: A Nationwide Population-Based Study of Electronic Health Records in Israel

Abstract

Background:

Data on the rate of dementia is essential for planning and developing appropriate services at the national level.

Objective:

We report the prevalence and incidence of dementia, based on electronic health records available for the whole population.

Methods:

This national dementia dataset was established as a part of the National Program to Address Alzheimer’s and Other Types of Dementia. Data from medical health records for all persons aged 45+ in Israel, for 2016, were extracted from the databases of the four health maintenance organizations. Dementia cases were identified based on either recorded dementia diagnosis, through International Classification of Diseases (ICD-9 and ICD-10) or dispensation of anti-dementia drugs. The date of first diagnosis was determined by the earliest recording.

Results:

A total of 65,951 persons with dementia, aged 45+, were identified from electronic health data. Based on both ICD codes and anti-dementia drugs, the prevalence rates of dementia among individuals aged 45+ and 65+ in 2016 were 2.5%and 6.4%, respectively, and the incidence rates were 0.49%and 1.3%, respectively. Based on ICD codes alone, the prevalence rates of dementia among individuals aged 45+ and 65+ in 2016 were 2.1%and 5.4%respectively, and the incidence rates were 0.36%and 0.96%respectively. The rates were higher among females compared to males and paradoxically lower in lower socioeconomic status compared to higher statuses.

Conclusion:

This data collection reflects the present access of dementia patients to medical care resources and provides the basis for service planning and future dementia policies.

Keywords

Dementia early-onset dementia electronic health data incidence national dataset prevalence

INTRODUCTION

The increase in life expectancy leads to population aging worldwide. The proportion of persons aged 65 and older in Israel has increased from 4%in 1948 to 12%at the end of 2019 [1]. Dementia is the most common neurodegenerative disorder in the older population and represents one of the most significant public health challenges [2, 3]. Early-onset dementia, defined as dementia occurring before age 65, is significantly less well studied than the late-onset despite early-onset dementia often presenting with a more aggressive disease progression [4]. In a systematic review of the global literature on the prevalence of dementia (1980–2009) and meta-analysis, the estimated age-standardized prevalence for those aged ≥60 years was 5%–7%in most world regions [5]. In a large meta-analysis of 160 studies including Europe and the US the pooled point prevalence of dementia in 23 community-setting studies among individuals 60 and over was 4.9%(CI95%: 4.2–5.6), while the pooled incidence rate of dementia was 17.2 per 1,000 person-years (CI95%: 13.9–21.2) [6]. In a large systematic review of 114 studies in the US among people aged 65 and over, the prevalence rate of dementia ranged from 6.3%in Japanese Americans to 20.9%in African Americans [7]. In this review the annual incidence rate of dementia was 1.4%to 5.5%for African American, 2.3%to 5.3%for Caribbean Hispanic populations, and 0.8%to 2.7%for non-Latino white populations [7]. The 2015 global cost of dementia was estimated to be 818 US$ billion, reflecting high medical and societal costs [8].

Data on the incidence and prevalence of dementia is essential for planning and developing appropriate services at the national level. Yet, only a few countries have established national registries (e.g., Sweden, Argentina, Austria, France, and South Korea) and a few others have regional dementia registries (e.g., United States, England, Scotland, Denmark, and Spain) [9].

In Israel, some studies have examined the prevalence of dementia among particular geographical or cultural subgroups [10 –14], but national-level dementia data have not been previously studied. The National Program to Address Alzheimer’s Disease and other Dementias in Israel has been led by the Ministry of Health, Division of Geriatrics, and its partners since 2013 [15]. One of the program goals is to establish national-level data on dementia. The objectives of this study, using electronic health records (EHRs), were: 1) To estimate the national incidence and prevalence of dementia among people aged 45 and older, according to age, sex, and socioeconomic status (SES); 2) To examine dementia-related medication use among prevalent and incident people with dementia.

MATERIALS AND METHODS

Subjects and study design

To develop a national dementia data, the Israel Ministry of Health, through the Geriatric Division and the Israel Center for Disease Control, collaborated with the four health maintenance organizations for Israel (HMOs), which provide health care services for all Israeli citizens and permanent residents, as stipulated by the National Health Insurance Law (1995). A wide range of health care services are covered through the universal health insurance scheme, including outpatient primary and specialist services, medications, laboratory tests, imaging, inpatient services, and more [16].

The population base for this dataset included all persons insured by the HMOs aged 45 years and older who were alive by December 31, 2016. Data were extracted from individual computerized medical records, for persons who fulfilled the dementia case definition at some point between the year they turned 45 and December 31, 2016. The case definition of dementia included: at least one chronic diagnosis (ICD9 or ICD10) of dementia; or two or more recordings of visit diagnosis within one year, as recorded by a primary care physician or by a specialist in internal medicine, psychiatry, geriatrics, or neurology; or at least one purchase of medications for symptoms of cognitive decline (“anti-dementia” drugs). The lists of diagnoses and medications employed for case definition for the dataset are provided in Supplementary Tables 1 and 2. The drugs currently in use for symptomatic treatment of cognitive decline are acetylcholinesterase inhibitors (AChEIs), namely donepezil, rivastigmine, and galantamine; and the N-methyl-D-aspartate-antagonist (NMDA-antagonist), memantine. The first two (donepezil and rivastigmine) are covered by the universal health insurance plan in Israel, for patients diagnosed with dementia, depending on the patient’s disease severity and disability while the others are partially covered by supplementary plans offered by the health provider. In order to get reimbursement for dementia drugs by the health provider, the drugs should be prescribed by a specialist in psychiatry, neurology, or geriatrics for the treatment of dementia and not mild cognitive impairment; therefore, the potential for misclassification is low. Nevertheless, in order to allow comparison to other studies we added calculation of dementia rate by diagnosis codes only. Extracted data were de-identified to maintain patient anonymity. Persons who fulfilled the case definition were defined as prevalent dementia cases, and those who fulfilled it for the first time in 2016 were defined as incident dementia cases for 2016.

The Institutional Review Boards of Sheba Medical Center Ethics Committee approved this study (approval number 7789-20-SMC). As the data were anonymous, an individual consent form was not required.

Study variables

Demographic data obtained included age (categorized into four groups: 45–64, 65–74, 75–84, and 85 years and older) and sex. SES was determined according to the member’s census enumeration area (CEA), employing the Israeli Bureau of Statistics methodology [17]. For each CEA, a poverty index (PI) is assigned, ranging from 1 (lowest) to 10 (highest), based on parameters in the 2008 national census data collection, including household income, educational qualifications, crowding, material conditions, and car ownership [17]. SES status was classified into three groups, according to the PI: low (PI 1 to 3), intermediate (PI 4 to 7), and high (PI 8 to 10). Anti-dementia drugs and drugs for behavioral and psychological symptoms of dementia were defined based on the Anatomical Therapeutic Chemical (ATC) classification system (Supplementary Table 2).

Data analysis

Dementia prevalence rates per 100 persons were calculated by dividing the number of prevalent cases at the end of 2016 by the number of the general population at the end of 2016 and stratified by age and sex. Dementia incidence rates per 100 persons were calculated by dividing the number of incident dementia cases during 2016 by the number of the general population without dementia and stratified by age and sex. To allow comparison to the other studies, we also calculated dementia rates based on ICD codes alone (subtracting cases diagnosed based on anti-dementia drug treatment). Age-standardized rates for each SES status were calculated, using the Israeli general population at 2016 as the standard population. The 95%confidence intervals (CI) were calculated using the normal distribution. The rate of anti-dementia drug use among dementia cases in 2016 was defined as the number of people who were dispensed at least one of these drugs in that year. Similarly, the rate of treatment for behavioral and psychological symptoms of dementia in 2016 was defined as the number of people who were dispensed at least one of the behavioral and psychological symptoms drugs among dementia patients in that year. The demographic and clinical characteristics of the persons included were expressed as counts with percentages. Statistical analysis was performed using SAS Enterprise Guide 7.12.

RESULTS

The distribution of case definition of dementia

Based on both ICD codes and anti-dementia drugs, a total of 65,951 prevalent dementia cases among adults aged 45 years and older [23,688 (35.9%) male and 42,263 (64.1%) female] were identified at the end of 2016. Of dementia cases identified, 27,797 (42.2%) cases met the definition of having at least one “chronic” diagnosis of dementia; 9,123 (13.8%) cases had ≥2 “visit diagnoses” of dementia within one year and 16,276 (24.7%) met both case definitions. The remaining 12,755 (19.3%) cases were identified solely based on purchasing anti-dementia drugs.

Prevalence rates

Almost half of the prevalent cases (30,983/65,951) were 85 years and older, while adults aged 45–64 contributed only 3.5%of prevalent cases (2,284/65,951) when the case definition of dementia included ICD codes and purchasing anti-dementia drugs (Table 1). Forty-four percent of the prevalent cases (22,643/53,196) were 85 years and older, while adults aged 45–64 contributed only 3.6%of prevalent cases (1,943/53,196) when the case definition of dementia included ICD codes only (Table 1). Prevalent dementia cases by age and sex based on ICD codes and anti-dementia drugs (DR) and only on ICD codes are shown in Supplementary Table 3. Based on ICD codes and anti-dementia drugs, the overall prevalence rate of dementia among people aged 45 years and older was 2.52 (95%CI: 2.50–2.54) and among people aged 65 years and older was 6.38 (95%CI: 6.33–6.43). The prevalence rate of dementia increased with age, from under 0.2%among those under age 65 years to 22.1%among those aged 85 and older (Table 2). Similar trends were obtained in both sexes when the case definition of dementia included ICD codes only. Based on ICD codes only the overall prevalence rate of dementia among people aged 45 years and older was 2.07 (95%CI: 2.05–2.08) and among people aged 65 years and older was 5.35 (95%CI: 5.30–5.39) (Table 2).

Table 1

Demographic characteristics of individuals with dementia based on ICD codes and anti-dementia drugs (DR) and only on ICD codes. Number of cases and %

		Prevalent cases at the end of 2016		New cases during 2016
		ICD + DR	ICD	ICD + DR	ICD
		N = 65,951	N = 53,196	N = 12,233	N = 9,043
Age	mean±std	82.8±8.5	83.2±8.3	81.1±8.5	81.8±8.4
Age groups	45–64	2,284 (4.1)	1,943 (3.6)	581 (4.7)	372 (4.1)
	65–74	7,560 (12.8)	6,218 (11.7)	2,107 (17.2)	1,372 (15.2)
	75–84	25,124 (41.5)	22,392 (42.1)	5,550 (45.4)	4,090 (45.2)
	85+	30,983 (41.6)	22,643 (42.6)	3,995 (32.7)	3,209 (35.5)
Sex	Male	23,688 (35.9)	18,903 (35.5)	4,834 (39.5)	3,477 (38.5)
	Female	42,263 (64.1)	34,293 (64.5)	7,399 (60.5)	5,566 (61.5)
SES status	Low	6,309 (9.8)	5,462 (10.6)	1,321 (11.1)	1,057 (12.0)
	Intermediate	45,896 (71.5)	37,694 (72.8)	8,823 (71.5)	6,393 (72.7)
	High	11,958 (18.6)	8,636 (16.7)	2,069 (17.4)	1,346 (15.3)

Table 2

Prevalence and incidence rates of dementia (per 100) by age and sex based on ICD codes and anti-dementia drugs (DR) and rates based on ICD codes only

Age groups	Male		Female		Overall
	ICD + DR	ICD	ICD + DR	ICD	ICD + DR	ICD
	Dementia prevalence rate (per 100) at the end of 2016.
45–64	0.15 (0.14–0.16)	0.1 (0.12–0.14)	0.13 (0.12–0.14)	0.11 (0.10–0.12)	0.14 (0.14–0.15)	0.12 (0.12–0.13)
65–74	1.40 (1.37–1.43)	1.17 (1.13–1.20)	1.32 (1.29–1.35)	1.13 (1.10–1.17)	1.36 (1.33–1.39)	1.15 (1.12–1.17)
75–84	7.13 (7.04–7.23)	6.26 (6.13–6.37)	9.28 (9.18–9.39)	8.56 (8.43–8.67)	8.36 (8.26–8.46)	7.58 (7.48–7.66)
85+	18.15 (17.95–18.35)	15.38 (15.06–15.67)	24.54 (24.31–24.76)	20.64 (20.35–20.88)	22.10 (21.88–22.32)	18.67 (18.45–18.85)
≥45	1.94 (1.91–1.96)	1.57 (1.54–1.58)	3.04 (3.01–3.07)	2.51 (2.49–2.53)	2.52 (2.50–2.54)	2.07 (2.05–2.08)
≥65	5.10 (5.03–5.16)	4.21 (4.15–4.26)	7.40 (7.33–7.47)	6.25 (6.19–6.31)	6.38 (6.33–6.43)	5.35 (5.30–5.39)
	Dementia incidence rate (per 100) during 2016.
45–64	0.03 (0.03–0.04)	0.03 (0.02–0.03)	0.03 (0.03–0.03)	0.02 (0.02–0.02)	0.03 (0.03–0.03)	0.02 (0.02–0.03)
65–74	0.37 (0.35–0.39)	0.26 (0.24–0.28)	0.33 (0.31–0.35)	0.25 (0.23–0.27)	0.35 (0.33–0.36)	0.26 (0.24–0.27)
75–84	1.66 (1.59–1.72)	1.20 (1.15–1.26)	2.10 (2.03–2.16)	1.67 (1.61–1.73)	1.91 (1.86–1.95)	1.50 (1.45–1.54)
85+	4.47 (1.27–4.65)	2.52 (2.39–2.65)	5.11 (4.94–5.27)	3.47 (3.33–3.60)	4.86 (4.73–4.98)	3.25 (3.15–3.35)
≥45	0.41 (0.40–0.42)	0.29 (0.28–0.30)	0.56 (0.54–0.57)	0.42 (0.41–0.43)	0.49 (0.48–0.49)	0.36 (0.35–0.37)
≥65	1.13 (1.09–1.15)	0.78 (0.75–0.80)	1.43 (1.40–1.46)	1.08 (1.05–1.10)	1.29 (1.27–1.31)	0.96 (0.94–0.97)

Incidence rates

A total of 12,233 incident dementia cases were identified in 2016, among adults aged 45 years and older when the case definition of dementia in-cluded ICD codes and purchasing anti-dementia drugs (Table 1). A total of 9,043 incident dementia cases were identified in 2016, among adults aged 45 years and older when the case definition of dementia included only ICD codes (Table 1). Incident dementia cases by age and sex based on ICD codes and anti-dementia drugs (DR) and only on ICD codes are shown in Supplementary Table 3. Based on ICD codes and anti-dementia drugs, the overall incidence rate of dementia in 2016 was 0.49 (95%CI: 0.48–0.49) among people aged 45 years and older and 1.29 (95%CI: 1.27–1.31) among people aged 65 years and older (Table 2). The incidence of dementia increased with age, from 0.03%among those younger than 65 to 4.86%among those aged 85 and older. The incidence of dementia was significantly higher in females than in males, especially in people aged 75 years and older. Based on ICD codes, the overall incidence rate of dementia in 2016 was 0.36 (95%CI: 0.35–0.37) among people aged 45 years and older and 0.96 (95%CI: 0.94–0.97) among people aged 65 years (Table 2).

Prevalence and incidence by age and SES

The overall age adjusted prevalence rates of dementia were 2.17 (95%CI: 2.13–2.23), 2.61 (95%CI: 2.59–2.60) and 2.37 (95%CI: 2.33–2.42) for low, intermediate, and high SES, respectively. The overall age adjusted incidence rates of dementia were 0.08 (95%CI: 0.07–0.09), 0.54 (95%CI: 0.52–0.55), and 0.45 (95%CI: 0.43–0.47) for low, intermediate, and high SES, respectively. Lower SES status was associated with lower dementia rates compared to other SES groups (Table 3).

Table 3

Prevalence and incidence rates¹ of dementia (per 100) by age and SES status²

	Low		Intermediate		High
Age groups	Number	Rate (95%CI)	Number	Rate (95%CI)	Number	Rate (95%CI)
	Dementia prevalence rate (per 100) at the end of 2016.
45–64	439	0.15 (0.14–0.16)	1,811	0.17 (0.16–0.18)	357	0.13 (0.11–0.14)
65–74	1,141	1.80 (1.70–1.89)	5,765	1.61 (1.57–1.64)	1,258	1.19 (1.13–1.25)
75+	4,729	10.35 (10.08–10.59)	38,320	13.21 (13.09–13.31)	10,343	12.53 (12.30–12.72)
Overall age- adjusted rate	2.17 (2.13–2.23)	2.61 (2.59–2.60)	2.37 (2.33–2.42)
	Dementia incidence rate (per 100) during 2016.
45–64	105	0.04 (0.12–0.14)	375	0.04 (0.14–0.16)	83	0.03 (0.10–0.12)
65–74	304	0.48 (1.53–1.70)	1,450	0.41 (1.39–1.47)	288	0.27 (1.04–1.15)
75+	912	2.19 (2.06–2.31)	6,698	2.36 (2.31–2.41)	1,698	2.10 (2.01–2.19)
Overall age- adjusted rate	0.08 (0.07–0.09)	0.54 (0.52–0.55)	0.45 (0.43–0.47)

¹The case definition of dementia included ICD codes and purchasing anti-dementia drugs. ²Missing: 2.7%.

Pharmacological treatment

Treatment for symptoms of cognitive decline

Table 4 presents the proportion of incident (first diagnosed in 2016) and prevalent (total) dementia patients receiving medications for cognitive decline, during 2016. A total of 45.5%of incident dementia cases and 42.2%of prevalent dementia cases patients received at least one of these drugs during 2016. The use of medications for cognitive decline was maximal in the 65–84 years age groups and males were more likely to receive these medications than females (Supplementary Table 4). In incident cases, use of memantine (NMDA-antagonist) was more common than AChEIs (53.9%and 11.4%respectively), whereas in prevalent cases this trend was reversed (14.0%and 35.5%, respectively).

Table 4

Proportion of dementia patients¹ treated with medications for symptoms of cognitive decline (anti-dementia drugs)² during 2016.

	Age groups
	45–64	65–74	75–84	85+	All
Incident patients
Overall medications for cognitive decline	245 (42.2)	1,142 (54.2)	2,744 (49.4)	1,437 (36.0)	5,568 (45.5)
AChEIs	88 (15.2)	307 (14.6)	665 (12.0)	333 (8.3)	1,393 (11.4)
NMDA-antagonist	313 (53.9)	1,364 (64.7)	3,210 (57.8)	1,702 (42.6)	6,589 (53.9)
Prevalent patients
Overall medications for cognitive decline	684 (30.0)	3,366 (44.5)	12,136 (48.3)	11,630 (37.5)	27,816 (42.2)
AChEIs	658 (24.5)	3,200 (38.0)	11,182 (40.8)	8,346 (30.4)	23,386 (35.5)
NMDA-antagonist	336 (12.5)	1,306 (15.5)	4,192 (15.3)	3,384 (12.3)	9,218 (14.0)

¹The case definition of dementia included ICD codes and purchasing anti-dementia drugs. ²AChEIs, Acetylcholinesterase inhibitors; NMDA-antagonist, N-methyl-D-aspartate-antagonist.

Treatment for behavioral and psychological symptoms

Table 5 presents the proportion of incident and prevalent dementia patients treated with medications for behavioral and psychological symptoms during 2016. The findings of the present study show that 56.5%of incident dementia cases and 61.2%of prevalent dementia cases patients received at least one drug for behavioral and psychological symptoms during 2016 (Table 5). The drugs most commonly used were anti-depressants (36%and 38%in incident and prevalent cases respectively), and other groups used relatively commonly were hypnotics and sedatives (26.5%and 30.1%respectively) and anxiolytics (20.4%and 23.1%respectively) whereas antipsychotics (both typical and atypical) were purchased by approximately 10%of the population. The use of anxiolytics and hypnotic and sedative medications increased with age, whereas this trend was less for antidepressants and absent for antipsychotics (Table 5). Females were more likely than males to receive medications for behavioral and psychological symptoms (Supplementary Table 5).

Table 5

Proportion of dementia patients¹ treated with medications for behavioral and psychological symptoms (BPS) during 2016

	Age groups
	45–64	65–74	75–84	85+	All
Incident patients
Overall BPS treatment	292 (50.3)	1,058 (50.2)	3,091 (55.7)	2,465 (61.7)	6,906 (56.5)
Overall anti-psychotics	79 (13.6)	220 (10.4)	496 (8.9)	445 (11.1)	1,240 (10.1)
Typical anti-psychotics	45 (7.8)	83 (3.9)	200 (3.6)	190 (4.8)	518 (4.2)
Atypical anti-psychotics	51 (8.8)	154 (7.3)	334 (6.0)	280 (7.0)	819 (6.7)
Anti-depressants	191 (32.9)	752 (35.7)	2,010 (36.2)	1,453 (36.4)	4,406 (36.0)
Anxiolytics	82 (14.1)	332 (15.8)	1,100 (19.8)	981 (24.6)	2,495 (20.4)
Hypnotics and sedatives	94 (16.2)	366 (17.4)	1,430 (25.8)	1,346 (33.7)	3,236 (26.5)
Prevalent patients
Overall BPS treatment	1,356 (50.5)	4,613 (54.7)	16,566 (60.5)	17,805 (64.9)	40,340 (61.2)
Overall anti-psychotics	381 (14.2)	1,056 (12.5)	3,194 (11.7)	3,476 (12.7)	8,107 (12.3)
Typical anti-psychotics	168 (7.4)	413 (5.5)	1,369 (5.5)	1,988 (6.4)	3,938 (6.0)
Atypical anti-psychotics	210 (9.2)	638 (8.4)	1,806 (7.2)	2,184 (7.1)	4,838 (7.3)
Anti-depressants	702 (30.7)	2,660 (35.2)	9,579 (38.1)	12,087 (39.0)	25,028 (38.0)
Anxiolytics	390 (17.1)	1,409 (18.6)	5,429 (21.6)	8,034 (25.9)	15,262 (23.1)
Hypnotics and sedatives	372 (16.3)	1,472 (19.5)	7,030 (28.0)	10,987 (35.5)	19,861 (30.1)

¹The case definition of dementia included ICD codes and purchasing anti-dementia drugs.

DISCUSSION

In this Israeli national dementia dataset for 2016, based on routinely collected data in EHRs, the prevalence rates of dementia among individuals aged 45+ and 65+ in 2016 were 2.5%and 6.4%respectively, and the incidence rates were 0.49%and 1.3%, respectively, when the case definition of dementia included both ICD codes and purchasing anti-dementia drugs. The rates were paradoxically lower in lower SES compared to intermediate and higher SES statuses.

Consistent with other studies [6, 14], we found a significant increase in the prevalence and incidence of dementia with age, particularly among people aged 85 years and older. We found similar dementia rates in females and males aged 65 to 74 years; however, the rates were much higher in females than males for those aged 75 years and older. This may be explained by women’s longer life expectancy and higher level of seeking out healthcare providers [18].

Dementia prevalence and incidence rates reported for different countries show considerable variability [6, 7]. Comparisons among the different studies are difficult due to methodological differences in study design, dementia definition, and use of different standard population for calculation of standardized rates [19]. In addition, there is great variability in dementia detection rates between countries [6, 7]. There are many barriers for health care systems to identify the true prevalence and incidence rates of dementia, both from the side of the patient and his family and from side of the care providers and the healthcare system. On the one hand there may be a lack of public awareness, fear of stigmatization, misinterpretation, or denial of symptoms of dementia and of the severity of cognitive impairment. One the other hand there may be lack of professional awareness and expertise, insufficient access to specific diagnostic services, brief physician-patient encounters in the face of multiple comorbid conditions [20, 21]. Indeed, studies have demonstrated 31%to 69%of patients with dementia do not receive a documented diagnosis, especially among mild and moderate dementia cases [20 –22]. Previous Israeli survey found that only one fifth of the family caregivers of those older people identified by the study as having dementia reported that they had already been told by a physician that their older relative had dementia [10]. According to the recent World Alzheimer Report, standardized to the Western European population, dementia prevalence in people aged 60 years and older has substantial regional variation from 4.7%in Central Europe to 8.7%in North Africa and the Middle East [23]. Using Western Europe population as the standard population, we estimated that dementia prevalence in our study was 5.4%in people aged 60 years and older. A cut-off of 60 years is sometimes used arbitrarily and consequently the data on prevalence and incidence of early onset of dementia are much more limited [4].

Only a few studies were previously conducted in Israel on dementia prevalence, none on a national level [10 , 12–14]. Israeli studies in which the cognitive assessment was performed by trained medical workers, found a higher prevalence of dementia [10, 12], but these were small non representative samples. In a recent Israeli report based on data form one HMO, the prevalence of dementia, based on dementia diagnoses or dispensation of anti-dementia drugs more than once in EHRs, was 6.6%among people 60 and over [14].

Low SES status has been associated with cognitive decline, a negative impact on health and longevity [24] through less healthy lifestyles, poorer general health, and less access to appropriate medical care resources [25]. Unlike other studies, in our study the age-standardized rates of dementia prevalence and incidence were significantly lower for people who lived in low SES neighborhoods compared to intermediate and high SES groups. Possible explanations include decreased access to health care services or necessary medical procedures, reduced access to qualified medical personnel, or lower disease awareness [26]. All of these could lead to higher rates of undetected dementia among low SES groups. Indeed, studies conducted in Israel have shown inequalities in the use of health services between Jews and Arabs [27]. A recent meta-analysis [28] as a study from China [29] reported that the proportion of undetected dementia was high, particularly in populations with low SES status.

In Israel, medical treatment for Alzheimer’s disease is included in the basic basket of services provided by the HMOs under the provisions of the National Health Insurance Law. In our study approximately 40%of people with prevalent dementia used anti-dementia medications in the last 12 months. In a multicenter European study, the authors found that the rate of AChEIs use for patients with dementia was 10.3%, varying from 3.0%in Holland to 20.3%in France [30]. The low anti-dementia treatment rate across the countries can be explained by the limited clinical efficacy of these medications and their lack of substantial impact on dementia course [30]. Moreover, there is no consensus on how long treatment with anti-dementia medications should last. Therapy is often stopped when side effects are not tolerated or when there is no perceived clinical response after a three to six-month trial.

In the present study the overall prevalence of the use of medications to treat the behavioral and psychological symptoms of dementia was 61.2%. Antidepressants were the most commonly prescribed medication (38%) in our study antipsychotic medications were prescribed in 12.3%. Patterns of antipsychotic medication use among people with dementia are variable across care settings and among countries. The prevalence of antipsychotic use among community dwelling older people with dementia ranged from 10.1%in the United Kingdom [31] to 29%in the US [32]. Depression is a common neuropsychiatric symptom of people with dementia affecting up to 43%of patients [33]. Recently published study of community-dwelling Medicare beneficiaries aged 65 years or older with a primary or secondary diagnosis of dementia, identified that a total of 49.8%filled an antidepressant prescription, followed by anxiolytics (26.8%), antiepileptics (21.9%), and antipsychotics (21.6%) [34].

Our study has several methodological strengths. Data were obtained from a non-selective nationwide population aged 45 and above, conferring good external validity. In our study, the case definition of dementia included, in addition to ICD diagnosis, also purchase of anti-dementia drugs. Although, the case definition of dementia based on dementia diagnosis in ICD-9 and ICD-10 codes may be highly specific to identifying people who actually have dementia. In addition, the positive predictive value for a dementia diagnosis in EHRs was reported up to be 90%[35]. However, because of the high rate of dementia under recording, ICD codes alone cannot serve as a gold standard for dementia diagnoses in the electronic health data [36]. General practitioners report barriers to formally recording dementia, so some patients may be known by general practitioners to have dementia but may be missing a diagnosis in their patient record [37]. Thus, using an algorithms which searches for anti-dementia medication prescriptions will be helpful for detection of true positive cases among unlabeled patients with dementia [37]. Some methodological limitations, however, should be considered. First, unlike registry, which obtains continuous online follow up for all dementia cases [38], our data was a one-time retrospective data collection including people with dementia who were alive at the end of 2016. Second, the uses of diagnoses of dementia in the EHRs were recorded mainly by primary care physicians, which may result in under-detection. Consequently, a recent meta-analysis of 23 studies, mainly from high-income countries, found the pooled rate of undetected dementia in primary care was 61.7%[28]. Third, dementia severity could not be ascertained as this data is not recorded in designated fields in the EHR. Forth, we have no valid data on dementia subtypes because in clinical practice the diagnostic criteria and the extent of workup vary substantially [39]. Finally, data on the indication for the use of medications for behavioral and psychological symptoms of dementia is not available; some of this medication use may reflect treatment for a previous psychiatric disease.

In conclusion, this national dementia data collection aimed, for the first time in Israel, to assess national prevalence and incidence rates of dementia using EHRs. This study provides the basis for a national dementia database that will help shape policy in the future including the promotion of early dementia detection, improving caregiver support, management of co-morbid conditions and behavioral problems and improving overall dementia management.

Footnotes

ACKNOWLEDGMENTS

The authors thank the health maintenance organizations in Israel (Clalit Health Services, Maccabi Health Services, Meuhedet Health Organization and Leumit Health Services) for their collaboration and providing the data on which this article is based.

This research was funded by the Ministry of Health, as part of the National Program to Address Alzheimer’s Disease and other Dementias in Israel. The authors received no financial support for the authorship, and/or publication of this article.

Authors’ disclosures available online ().

The supplementary material is available in the electronic version of this article: .

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