Somatic Symptoms of Depression Lose Association with Mortality upon Adjustment for Frailty: Analysis from the Fitness Haemodialysis Cohort

Table 4

Fractional regression coefficients of somatic and cognitive component PHQ-9 scores upon EQ summary index.

PHQ-9 component	Fractional regression model	Coefficient	Lower 95% C.I.	Upper 95% C.I.	P
Somatic	Univariable	−0.110	−0.146	−0.073	<0.001
	1	−0.093	−0.130	−0.056	<0.001
	2	−0.096	−0.135	−0.058	<0.001
	3	−0.102	−0.139	−0.064	<0.001
	4	−0.062	−0.104	−0.021	0.003
Cognitive	Univariable	−0.077	−0.102	−0.052	<0.001
	1	−0.071	−0.098	−0.043	<0.001
	2	−0.078	−0.106	−0.049	<0.001
	3	−0.084	−0.112	−0.057	<0.001
	4	−0.052	−0.081	−0.024	<0.001

Obtained by fractional regression. Coefficient:  change in the EQ fractional summary index score for each 1-point rise in PHQ-9 somatic or cognitive component scores. Univariable and adjusted models are shown. Model 1 included age, gender, ethnicity, education level, social support, IMD quintile, and employment status. Model 2 added to these haemodialysis vintage, Charlson comorbidity index (CKD omitted), haemoglobin, Kt/V, and current use of antidepressant medication. Model 3 added use of walking aids, slow walking (or inability to walk), and physical activity index. Model 4 added EQ self-rated health today (continuous score from 0 to 100) and self-rated health change.