Health service costs and clinical gains of psychotherapy for personality disorders: a randomized controlled trial of day-hospital-based step-down treatment versus outpatient treatment at a specialist practice

Table 5 Estimated differences in costs for patients in step-down and outpatient treatment

		∆ costs: first trial period (0–8months)		∆ change in costs per month during trial				∆ costs: entire trial period (36 months)			Model fit
		∆ mean estimate (SE)	P	∆ initial slope (SE)	P	∆ curvature (SE)	P	∆ grand mean (SE)		P	AIC
Costs per patient
(A) Monthly costs of treatment	∆ (SDC-OPC)	720 (69)	.00	−86 (7)	.00	2 (0.2)	.00	281 (33)		.00	4814
	Predictor effects within OPC
	∆ (APD - other PDs)	264 (101)	.01	−19 (12)	ns	0.4 (0.3)	ns	136 (43)		.00	4813
	∆ (BPD - other PDs)	−11 (101)	ns	−8 (11)	ns	0.2 (0.3)	ns	61 (41)		ns	4819
(B) Monthly costs of emergency services	∆ (SDC-OPC)	−797 (500)	ns	45 (64)	ns	−0.4 (1.9)	ns	−331 (28)		.00	5541
	Moderator effects
	∆ (SDC_APD - OPC_APD)	−2411 (829)	.005	179 (109)	ns	−3.4 (3.3)	ns	−956 (120)		.00	5547
	∆ (SDC_{BPD -} OPC_BPD)	−1451 (749)	ns	199 (95)	.04	−4.9 (2.8)	ns	−303 (86)		.00	5546
(C) Sum of all monthly costs	∆ (SDC-OPC)	10 (504)	ns	−53 (65)	ns	2 (2)	ns	7 (44)		ns	5625
	Moderator effects
	∆ (SDC_APD - OPC_APD)	−1717 (829)	.04	92 (109)	ns	−1.3 (3.5)	ns	−905 (147)		.00	5626
	∆ (SDC_{BPD -} OPC_BPD)	−639 (755)	ns	94 (96)	ns	−2.1 (3.0)	ns	−37 (88)		ns	5632
								*Mean estimate (SE)*			*Incremental costs (SE)*
								*SDC*	*OPC*		*Incremental costs (SE)*
(D) Sum of all costs over 36 months	All patients							31823 (479)	31607 (956)	ns
	Moderator effects
	Predicted change: APD (not BPD)							35524 (381)	49728 (525)	.00	−14204 (633)
	Predicted change: BPD (not APD)							29709 (1275)	21309 (2482)	ns

Table 5 shows mixed-model estimates of (A) treatment, (B) emergency, and (C) total (all health service) costs (€) in models with treatment included as a predictor (SDC: the step-down condition, OPC: the outpatient condition). Monthly costs in the first trial period, change per month for the 0–36 month trial period, and grand means for the whole trial period are presented as: (1) ∆ (SDC-OPC): Differences (∆) between SDC and OPC. (2) Predictor effects within OPC: Cost differences for subgroups within OPC. (3) Moderator effects: Cost differences between SDC and OPC for subgroups of patients with (a) avoidant PD, APD: ∆ (SDC_APD - OPC_APD) and (b) borderline PD, BPD: ∆ (SDC_BPD - OPC_BPD). Estimates are presented as means with standard errors (SE). Akaikes Information Criterion (AIC) indicates goodness of fit for each model. Table 5 also shows (D): The sum of all costs over 36 months: Estimations of total 36-month costs and incremental costs (if significant SDC-OPC difference) based on mixed-model predicted values for all patients and subgroups with (a) avoidant and (b) borderline PD. P-values are presented if p < 0.05, ns indicates p > 0.05.

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