Table 2.

Hospital-Based Data—Dementia Frequency.

Author	Year	Country	Study design	Criteria used for dementia identification	Sample size	Setting/sampling tech	Study key findings
Ogunniyi et al. [26]	1998	Saudi Arabia	Hospital-based study	Dementia subtypes were made according to NINCDS-ADRDA, NINDSAIREN, and ICD 10	77	King Khalid University Hospital, Riyadh (KKUH) All Saudis with dementia at the university hospital from Jan 1985 to Dec 1996	Hospital frequency—19.3/100,000 Dementia subtypes: AD—51.9% VaD—18.2% Mixed cases—15.6% Dementia with Parkinson's disease—7.8% Treatable dementia—5.2%
Qureshi et al. [27]	2001	Saudi Arabia	Hospital-based study	Not mentioned	540	Hospital, random selection of 540 referrals to psychiatric hospital (1999)	Psychiatrists made more diagnoses of dementia than PHC or GH doctors (not significant) From 138 GH referrals: 9.4% of dementia patients were diagnosed by a psychiatrist 1.4% of dementia patients were diagnosed by the GH psychiatry doctors
Albugami et al. [3]	2018	Saudi Arabia	Hospital-based study	Medical records No standardized diagnostic protocol	418	Dementia patients in Saudi hospital from 1995 to 2010	Dementia subtypes: Mixed dementia—18.37% AD—15.87%. VaD—7.71% Parkinson dementia—3.85%
Hamad et al. [28]	2004	Qatar	Hospital-based study	MMSE, SMQ brain CT, MRI, blood tests	134	Dementia patients Hamad General Hospital, Doha 1997–2003	Dementia subtypes: AD—39 (29%) VaD—30 (22%) Mixed AD and VaD—20 (15%) Dementia with Parkinson's disease—8 (6%)