Socioeconomic status as a moderator between frailty and mortality at old ages

BMC Geriatrics

Table 3 Mortality hazard ratios for frailty, socioeconomic vulnerability, and interactions based on including those lost to follow-up, CLHLS 2008/2009-2011/2012

	Model I	Model II	Model III	Model IV	Model V	Model VI	Model VII	Model VIII
Main terms
Frailty index (×100)	1.029***	1.043***	1.041***	1.037***	1.112***	1.110***	1.105***	1.104***
SEVI (×100)	1.006***	1.013***	1.011**	1.049**	1.010***	1.009***	1.040***	1.036***
Interaction terms
SEVI*frailty index (×100)		0.980***	0.982***	0.989**	0.986***	0.988**	0.992*	0.993+
SEVI*age				0.960***			0.967***	0.969***
Frailty index*age					0.930***	0.930***	0.932***	0.932***
Controls
Age	1.059***	1.058***	1.054***	1.087***	1.078***	1.074***	1.102***	1.096***
Men (women)	1.493***	1.494 ***	1.548***	1.483***	1.478***	1.522***	1.469***	1.510***
Han ethnicity (non-Han)	0.844***	0.847***	0.867**	0.842***	0.851**	0.871**	0.848**	0.867**
Coresidence with family (no)			1.106**			1.112**		1.132**
Currently married (no)			0.772***			0.788***		0.797***
Currently smoking (no)			1.043			1.064		1.068+
Doing regular exercise (no)			0.872***			0.866***		0.868***
N	16,563	16,563	16,563	16,563	16,563	16,563	16,563	16,563
Wald Chi square	5544.1***	5570.0***	5525.4***	5401.5***	4986.1***	4947.5***	4853.2***	4843.6***

Relative hazards were estimated based on inclusion of those lost to follow-up whose survival status and days survived from the interview in 2008 to the interview in 2011 were imputed. The imputation assumed that those who were lost to follow-up had the same survival status and survival length with those who were not lost to follow up given the same demographics, frailty index score, SEVI score, family/social support and health practice
Score of frailty index ranges from 0 (no deficits, the healthiest) to 1 (all deficits, the worst), while the score of the socioeconomic vulnerability index ranges from 0 (the least vulnerable) to 1 (the most vulnerable)
The reference category for each control is in parentheses
A model that includes the interaction between SEVI and age, main terms, and controls is similar to Model IV. A model that includes the interaction between frailty index and age, main terms and controls is similar to Model V. Therefore, these two models are not presented to save the space
+p <0.1, *p <0.05, ^**p <0.01, ^***p <0.001

ISSN: 1471-2318