The differential mediating effects of pain and depression on the physical and mental dimension of quality of life in Hong Kong Chinese adults

Table 2 Regression models testing the Pain-Depression-QoL mediation chain^a

Model	Std β	SE	95% CI	P value
Model 1: Pain mediates the Depression-QoL (Mental) ^b link
Depression (Predictor) → QoL (Outcome)	-0.154	0.078	-0.381, -0.074	0.004
Pain (Mediator) → QoL (Outcome)	-0.201	0.119	-0.689, -0.222	<0.001
Depression (Predictor) → Pain (Mediator)	0.271	0.033	0.113, 0.243	<0.001
Depression (Predictor) → QoL (Outcome)\|Pain (Mediator)^c	-0.111	0.081	-0.628, -0.143	0.002
Sobel test	z = -3.124		P = 0.002
Model 2: Pain mediates the Depression-QoL (Physical) ^d link
Depression (Predictor) → QoL (Outcome)	-0.311	0.121	-0.982, -0.504	<0.001
Pain (Mediator) → QoL (Outcome)	-0.106	0.195	-0.769, -0.004	0.048
Depression (Predictor) → QoL (Outcome)\|Pain (Mediator)^c	-0.304	0.127	-0.981, -0.480	<0.001
Sobel test	z = -1.929		P = 0.054
Model 3: Depression mediates the Pain-QoL (Mental) ^b link
Pain (Predictor) → QoL (Outcome)\|Depression (Mediator)^e	-0.170	0.123	-0.324, -0.006	0.042
Sobel test	z = -1.853		P = 0.064
Model 4: Depression mediates the Pain-QoL (Physical) ^d link
Pain (Predictor) → QoL (Outcome)\|Depression (Mediator)^e	-0.026	0.195	-0.479, 0.286	0.620
Sobel test	z = -4.045		P < 0.001

Note: QoL: Quality of life; Std β: Standardized beta coefficient; SE: Standard error; CI: Confidence interval.
^aFour separate regression models were generated to test the pain-depression-QoL mediation chain.
^bQoL was indexed by SF12-MCS.
^cPain, as mediator, was controlled in the regression equation.
^d QoL was indexed by SF12-PCS.
^eDepression, as mediator, was controlled in the regression equation.

ISSN: 1477-7525