Table 4.

Models for binary logistic regression of factors associated with initial ED visit (N = 16 543)

	ED visit
	Bivariate	Model 1	Model 2	Model 3
	OR (95% CI)	OR (95% CI)	OR (95% CI)	OR (95% CI)
Individual factors
Demographics and health
Age	1.08 (1.07 to 1.09)*	1.09 (1.08 to 1.09)*	1.06 (1.05 to 1.06)*	1.06 (1.05 to 1.07)*
Gender
Female	Ref
Male	1.04 (0.97 to 1.11)
No of chronic diseases	1.22 (1.20 to 1.25)*	1.24 (1.21 to 1.26)*	1.12 (1.10 to 1.15)*	1.12 (1.10 to 1.15)*
Home help and healthcare use
Home help
No	Ref		Ref	Ref
Instrumental services	1.74 (1.51 to 2.01)*		1.31 (1.13 to 1.52)*	1.26 (1.08 to 1.46)*
Personal care	2.00 (1.71 to 2.34)*		1.49 (1.26 to 1.76)*	1.55 (1.31 to 1.83)*
Instrumental and personal care	3.38 (3.10 to 3.68)*		2.49 (2.27 to 2.74)*	2.48 (2.26 to 2.73)*
No of primary care visits	1.05 (1.04 to 1.05)*		1.03 (1.03 to 1.04)*	1.03 (1.03 to 1.04)*
No of specialist care visits	1.02 (1.01 to 1.02)*		1.00 (1.00 to 1.01)	1.00 (1.00 to 1.01)
No of hospital admissions	1.37 (1.32 to 1.42)*		1.01 (0.96 to 1.05)	1.00 (0.96 to 1.05)
Contextual factors
Annual social care cost per person 80+	1.00 (1.00 to 1.00)
Response, trust and safety	1.00 (0.99 to 1.00)
Influence and adequate time	1.00 (1.00 to 1.01)
Median days in residential care	0.99 (0.99 to 0.99)*			1.00 (0.99 to 1.00)
Proportion of 80+ in the population	0.94 (0.91 to 0.98)*			1.09 (1.05 to 1.13)*
Distance to the nearest ED	0.99 (0.99 to 0.99)*			0.99 (0.98 to 0.99)*
Deviance (−2LL)		20 624.749	19 883.865	19 701.645
Cox and Snell R2CS		0.062	0.103	0.113
Nagelkerke R2N		0.085	0.142	0.155

Note: The negative bivariate association for proportion of 80+ in the population with initial ED visit becomes a positive association and increases in magnitude in the multivariable model, indicating negative suppression. Through trial variable removal from the model,³⁰ it was determined that distance to the ED and median days in residential care both acted as suppressor variables for proportion 80+ in the population.

*Significant on values estimated from 95% CI.

ED, emergency department.