Table 2.

Parameter estimates of mixed models for mental component summary (MCS) fitted in four polypharmacy strata for people with stable/decrease in comorbidities over four years

	No polypharmacy N = 914			Baseline only polypharmacy N = 87			Incident polypharmacy N = 130			Persistent polypharmacy N = 280
	β (SE)	P value	95% CI	β (SE)	P value	95% CI	β (SE)	P value	95% CI	β (SE)	P value	95% CI
Fixed effects
Intercept	52.2 (0.3)	< 0.001	51.6, 52.8	49.2 (1.5)	< 0.001	46.2, 52.2	51.7 (0.8)	< 0.001	50.2, 53.3	48.5 (1.0)	< 0.001	46.6, 50.4
Slope (per year)	0.03 (0.06)	0.645	− 0.1, 0.2	− 0.3 (0.2)	0.257	− 0.8, 0.2	− 0.8 (0.2)	< 0.001	− 1.1, − 0.4	0.02 (0.2)	0.912	− 0.4, 0.4
Random effects
Variance in intercept	48.3 (2.6)	< 0.001	43.4, 53.7	105.8 (17.9)	< 0.001	75.9, 147.4	53.3 (8.1)	< 0.001	39.6, 71.7	82.1 (7.9)	< 0.001	68.0, 99.2
Variance in slope	0.3 (0.1)	0.006	0.2, 0.7	0.3 (0.6)	0.682	0.002, 30.7	1.6 (0.6)	0.005	0.8, 3.1	0.7 (0.4)	0.061	0.2, 2.0

Intercepts and slopes for all models are adjusted for age, sex, education, social life, marital status, Socio-Economic Indexes for Areas decile, physical activity, smoking and alcohol intake, and baseline comorbidities; All covariates were mean centred and included as intercept and slope predictors; MCS: Mental component summary; Polypharmacy defined as ≥ 5 medications. Covariate estimates are reported in Table S10