Mapping the schizophrenia quality of life scale to EQ-5D, HUI3 and SF-6D utility scores in patients with schizophrenia

Figures & data

Figure 1. Distribution of generic utility scores.

Table 1. Characteristics of the sample (N = 251).

Demographics	Mean (SD)
Age	39.9 (10.2)
Gender, N(%)
Male	141 (56.2)
Female	110 (43.8)
Utilities
EQ-5D-3L	0.77(0.31)
EQ-5D-5L	0.81(0.22)
HUI3	0.65 (0.31)
SF-6D	0.68(0.14)
SQLS-total score	32.6(17.7)
Domain: Psychosocial	34.9 (22.7)
Domain: Energy/motivation	36.5(17.5)
Domain: Symptoms/side effects	26.5(19.8)

Table 2. Prediction performance of the preferred model within each class of models.

	OLS	Tobit	Betamix
EQ-5D-3L	(OLS6)	(Tobit4)	(BetamixM6e)
ME	0.0000	−0.1340	−0.0017
MAE	0.1458	0.2282	0.1455
RMSE	0.2083	0.2804	0.2148
R-squared	52.17	16.86	51.89
EQ-5D-5L	(OLS6)	(Tobit6)	(BetamixM6d)
ME	0.0000	−0.0702	−0.0004
MAE	0.1178	0.1429	0.1176
RMSE	0.1578	0.1847	0.1591
R-squared	49.04	30.19	48.21
HUI3	(OLS5)	(Tobit5)	(BetamixM1h)
ME	−1.41E–10	−0.0094	−0.107
MAE	0.1709	0.1688	0.175
RMSE	0.2283	0.2289	0.2310
R-squared	46.33	46.09	43.39
SF6D	(OLS5)	(Tobit5)	(BetamixM1d)
ME	1.50E–09	−0.0011	−0.0032
MAE	0.0697	0.0697	0.0704
RMSE	0.0922	0.0922	0.0927
R-squared	54.68	54.65	54.25

Note: Bold figures indicate the best performance among the three models.

Table 3. Summary statistics of the observed and simulated data sets predicted by the best model from each regression method.

		Predicted
		OLS	Tobit	Betamix
EQ-5D-3L	Observed	(OLS6)	(Tobit4)	(BetamixM6e)
Mean	0.771	0.771	0.905	0.773
Variance	0.094	0.512	0.109	0.057
Skewness	−1.772	−1.488	−0.480	−1.863
Kurtosis	5.979	5.246	2.646	6.370
Minimum	−0.568	−0.168	−0.100	−0.243
Maximum	1	1.066	1.512	0.989
Proportion at 1 (full health)	43.03	0	0	0
Proportion above 1	0	0	0	0
Proportion < 0	3.2	0.8	0.4	1.2
Percentiles
1%	−0.300	0.093	0.102	−0.088
5%	0.092	0.322	0.261	0.263
10%	0.285	0.458	0.430	0.424
25%	0.686	0.667	0.687	0.698
75%	1.000	0.926	1.142	0.928
90%	1.000	0.979	1.295	0.970
95%	1.000	1.006	1.365	0.981
99%	1.000	1.057	1.467	0.988
EQ-5D-5L		(OLS6)	(Tobit6)	(BetamixM6d)
Mean	0.812	0.812	0.882	0.812
Variance	0.049	0.240	0.209	0.019
Skewness	−1.818	−1.508	−0.814	−1.512
Kurtosis	7.322	5.303	3.402	5.585
Minimum	−0.367	0.170	0.198	0.210
Maximum	1	1.028	1.254	0.985
Proportion at 1 (full health)	36.5	0	0	0
Proportion above 1	0	3.6	31.1	0
Proportion < 0	0.4	0	0	0
Percentiles
1%	0.036	0.334	0.284	0.365
5%	0.328	0.478	0.478	0.505
10%	0.531	0.587	0.571	0.622
25%	0.740	0.744	0.755	0.754
75%	1.000	0.915	1.020	0.906
90%	1.000	0.951	1.118	0.951
95%	1.000	0.977	1.160	0.965
99%	1.000	1.023	1.248	0.984
HUI3		(OLS5)	(Tobit5)	(BetamixM1h)
Mean	0.647	0.647	0.657	0.658
Variance	0.098	0.045	0.049	0.037
Skewness	−0.850	−1.051	−0.908	−0.802
Kurtosis	2.582	3.858	3.528	2.900
Minimum	−0.151	−0.120	−0.102	0.095
Maximum	1	0.960	1.007	0.926
Proportion at 1 (full health)	6.37	0	0	0
Proportion above 1	0	0	0.40	0
Proportion < 0	4.4	0.8	0.8	0
Percentiles
1%	−0.109	0.053	0.053	0.167
5%	0.016	0.203	0.203	0.271
10%	0.148	0.332	0.332	0.351
25%	0.478	0.535	0.535	0.535
75%	0.905	0.814	0.814	0.804
90%	0.973	0.918	0.918	0.877
95%	1.000	0.933	0.933	0.898
99%	1.000	0.985	0.985	0.926
SF-6D		(OLS5)	(Tobit5)	(BetamixM1d)
Mean	0.680	0.680	0.681	0.683
Variance	0.137	0.010	0.011	0.009
Skewness	0.398	0.112	0.147	−0.031
Kurtosis	2.603	2.31	2.305	2.342
Minimum	0.383	0.466	0.470	0.465
Maximum	1	0.907	0.914	0.894
Proportion at 1 (full health)	2.79	0	0	0
Proportion above 1	0	0	0	0
Proportion < 0	0	0	0	0
Percentiles
1%	0.413	0.484	0.486	0.481
5%	0.474	0.515	0.515	0.514
10%	0.522	0.541	0.541	0.540
25%	0.579	0.602	0.601	0.609
75%	0.771	0.748	0.750	0.752
90%	0.887	0.824	0.828	0.822
95%	0.929	0.859	0.863	0.850
99%	1.000	0.897	0.905	0.897

Note: Bold values indicate the most resemble statistics of predicted value to observed value.

Data availability statement

The datasets used and/or analyzed during the current study are available from the corresponding author on reasonable request.