Delirium in hospitalized older adults: influence of sociodemographic and clinical factors in a longitudinal study

Cechinel, Clovis; Lenardt, Maria Helena; Rodrigues, João Alberto Martins

doi:10.1590/1981-22562026029.250159.pt

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ORIGINAL ARTICLES • Rev. bras. geriatr. gerontol. 29 • 2026 • https://doi.org/10.1590/1981-22562026029.250159.en linkcopy

Delirium in hospitalized older adults: influence of sociodemographic and clinical factors in a longitudinal study

Authorship SCIMAGO INSTITUTIONS RANKINGS

Objective To analyze the effects of sociodemographic and clinical characteristics on the occurrence of delirium in hospitalized older adults.

Method A prospective longitudinal study was conducted with 427 older adults aged ≥60 years without delirium at hospital admission, between March 2022 and July 2023. Delirium was monitored daily until discharge or death. Kaplan–Meier curves were used to estimate survival, and Cox proportional hazards regression was used to calculate hazard ratios (95% CI), assessed using the Wald test. The proportional hazards assumption was verified using Schoenfeld residuals.

Results The risk of delirium was 5.47 times higher in frail individuals, 2.5 times higher in those receiving palliative care, and 2.51 times higher in individuals with dementia. Income greater than 3.1 minimum wages was a protective factor, reducing the risk by 71% compared with the 0–1 minimum wage category. Older adults with hospitalizations in the previous 12 months had a 56% lower risk of delirium. Age ≥80 years (p=0.0007), widowhood (p=0.0142), low body weight (p=0.0002), frailty (p<0.001), dementia (p≤0.0001), and palliative care (p≤0.0001) were associated with shorter time to first delirium episode.

Conclusion Frailty, dementia, and the need for palliative care were the main risk factors for delirium in older adults, whereas higher income showed a protective effect. Recognition of these factors allow the implementation of targeted, individualized, and more effective preventive and therapeutic strategies for delirium in hospitalized older adults.

Keywords
Aged; Hospitalization; Delirium; Observational Study; Risk Factors.

Variables	Occurrence of delirium
	Yes		No
	(N=60)	Relative frequency (95% CI)	(N=367)	Relative frequency (95% CI)
Sex
Female	32	53.3% (40.9; 65.4)	194	52.9% (47.8; 57.9)
Male	28	46.7% (34.6; 59.1)	173	47.1% (42.1; 52.2)
Age
Mean (SD)	79.5 (9.79)		73.6 (8.25)
Median [Min, Max]	79 [60.100]		73 [60.95]
Race/ethnicity
White	38	63.4% (50.7; 74.4)	246	67% (62.1; 71.6)
Mixed-race	17	28.3% (18.5; 40.8)	99	27% (22.7; 31.7)
Black	5	8.3% (3.6; 18.1)	19	5.2% (3.3; 7.9)
Other	0	0% (0; 6)	3	0.8% (0.3; 2.4)
Marital status
Married / Common-law union	21	35.1% (24.2; 47.6)	184	50.1% (45; 55.2)
Widowed	29	48.3% (36.2; 60.7)	114	31.1% (26.5; 36)
Divorced	5	8.3% (3.6; 18.1)	49	13.4% (10.2; 17.2)
Single	5	8.3% (3.6; 18.1)	18	4.9% (3.1; 7.6)
Other	0	0% (0; 6)	2	0.5% (0.1; 2)
Education (years of schooling)
Illiterate	10	16.7% (9.3; 28)	65	17.7% (14.1; 21.9)
1 to 8 years	46	76.6% (64.6; 85.6)	280	76.3% (71.7; 80.4)
> 8 years	4	6.7% (2.6; 15.9)	22	6% (4; 8.9)
Occupational status / Income
Retired	42	70% (57.5; 80.1)	263	71.7% (66.8; 76.0)
Pension / LOAS / Social benefit recipient	17	28.3% (18.5; 40.8)	51	13.9% (10.7; 17.8)
Working	1	1.7% (0.3; 8.9)	21	5.7% (3.8; 8.6)
Unemployed	0	0% (0; 6)	32	8.7% (6.2; 12)
Living arrangement
Spouse and/or children	47	78.3% (66.4; 86.9)	266	72.5% (67.9; 77)
Parents and/or siblings	3	5% (1.7; 13.7)	8	2.2% (1.1; 4.3)
Relatives	1	1.7% (0.3; 8.9)	17	4.6% (2.9; 7.3)
Caregiver	1	1.7% (0.3; 8.9)	0	0% (0; 1)
Homes for the Aged	2	3.3% (0.9; 11.4)	3	0.8% (0.3; 2.4)
Living alone	6	10% (4.7; 20.1)	72	19.6% (15.9; 24.1)
Not informed	0	0 (0%)	1	0.3% (0.1; 0.8)
Older adult income (MW)
0 – 1	27	45% (33.1; 57.5)	101	27.5% (23.3; 32.4)
1.1 – 3	27	45% (33.1; 57.5)	166	45.2% (40.3; 50.5)
3.1 – 5	2	3.3% (0.9; 11.4)	61	16.7% (13.2; 20.8)
5.1 – 10	1	1.7% (0.3; 8.9)	4	1.1% (0.4; 2.8)
No income	0	0% (0; 6)	20	5.4% (3.6; 8.3)
Not informed	3	5% (1.7; 13.7)	14	4.1% (2.3; 6.3)

Variables	Delirium		No delirium
Variables	(n=60)	Relative frequency (95% CI)	(n=367)	Relative frequency (95% CI)
Hypertension
No	15	25% (15.8-37.2)	88	24% (19.9-28.7)
Yes	45	75% (62.8-84.2)	278	76% (71.3-80.1)
Diabetes mellitus
No	40	66.7% (54.1-77.3)	228	62.1% (57.1-66.9)
Yes	20	33.3% (22.7-45.9)	139	37.9% (33.1-42.9)
Chronic obstructive pulmonary disease
No	49	81.7% (70.1-89.4)	309	84.2% (80.1-87.6)
Yes	11	18.3% (10.6-29.9)	58	15.8% (12.4-19.9)
Chronic kidney disease
No	50	83.3% (72-90.7)	307	83.7% (79.5-87.1)
Yes	10	16.7% (9.3-28)	60	16.3% (12.9-20.5)
Congestive heart failure
No	55	91.7% (81.9-96.4)	300	81.7% (77.5-85.4)
Yes	5	8.3% (3.6-18.1)	67	18.3% (14.6-22.5)
Dementia
No	41	68.3% (55.8-78.7)	329	89.6% (86.1-92.4)
Yes	19	31.7% (21.3-44.2)	38	10.4% (7.6-13.9)
Stroke
No	45	75% (62.8-84.2)	298	81.2% (76.9-84.9)
Yes	15	25% (15.8-37.2)	69	18.8% (15.1-23.1)
Depression
No	52	86.7% (75.8-93.1)	324	88.3% (84.6-91.2)
Yes	8	13.3% (6.9-24.2)	43	11.7% (8.8-15.4)
Cancer
No	54	90% (79.9-95.3)	336	91.6% (88.3-94)
Yes	6	10% (4.7-20.1)	31	8.4% (6-11.7)
Ischemic heart disease
No	56	93.3% (84.1-97.4)	320	87.2% (83.4-90.2)
Yes	4	6.7% (2.6-15.9)	47	12.8% (9.8-16.6)

		HR	95% CI	p-value	Adjusted
		HR	95% CI	p-value	HR	95% CI	p-value
Frailty	Non-frail	Ref.			Ref.
	Pre-frail	1.86	0.63; 5.47	0.26	1.57	0.52; 4.78	0.426
	Frail	7.22	2.57; 20.28	0	5.47	1.77; 16.84	0.003
Sex	Female	Ref.			Ref.
Sex	Male	0.98	0.59; 1.64	0.95	1.58	0.86; 2.91	0.141
Race/ethnicity	White	Ref.			Ref.
Race/ethnicity	Non-white	1.1	0.65; 1.87	0.71	1.02	0.57; 1.81	0.95
Age group	60–70	Ref.			Ref.
	70–80	1.5	0.73; 3.10	0.27	1.04	0.48; 2.24	0.926
	≥80	2.87	1.46; 5.63	0	0.98	0.45; 2.15	0.959
Marital status	Married / Common-law union	Ref.			Ref.
	Widowed	1.96	1.12; 3.45	0.02	1.7	0.86; 3.37	0.127
	Other	1.17	0.55; 2.50	0.68	1.11	0.49; 2.52	0.806
Older adult income (MW)	0 - 1	Ref.			Ref.
	1,1 - 3	0.75	0.44; 1.28	0.3	0.92	0.52; 1.61	0.764
	3,1 - 10	0.24	0.07; 0.80	0.02	0.29	0.08; 0.99	0.048
Palliative care	No	Ref.			Ref.
Palliative care	Yes	3.7	1.96; 6.99	0	2.5	1.11; 5.63	0.027
Hospitalization in the previous 12 months	No	Ref.			Ref.
Hospitalization in the previous 12 months	Yes	0.71	0.41; 1.23	0.22	0.44	0.24; 0.80	0.008
Fall in the previous 12 months	No	Ref.			Ref.
Fall in the previous 12 months	Yes	1.4	0.84; 2.33	0.2	1.4	0.80; 2.45	0.242
Nutritional status	Normal weight	Ref.			Ref.
	Underweight	2.39	1.30; 4.40	0.01	1.05	0.49; 2.23	0.897
	Overweight	0.82	0.43; 1.57	0.55	0.93	0.46; 1.91	0.851
Dementia	No	Ref.			Ref.
Dementia	Yes	3.76	2.18; 6.50	0	2.51	1.34; 4.70	0.004
Previous stroke	No	Ref.			Ref.
Previous stroke	Yes	1.47	0.82; 2.63	0.2	0.89	0.45; 1.74	0.726
Depression	No	Ref.			Ref.
Depression	Yes	0.99	0.47; 2.09	0.98	1.09	0.46; 2.58	0.837
Cancer	No	Ref.			Ref.
Cancer	Yes	1.28	0.55; 2.98	0.57	1.3	0.54; 3.11	0.561
Dyslipidemia	No	Ref.			Ref.
Dyslipidemia	Yes	0.76	0.42; 1.36	0.35	0.73	0.39; 1.39	0.343

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[tfnte1] LOAS: Brazilian Organic Law of Social Assistance; MW: Minimum Wage. Wilson score method.