Subject socio-demographics characteristics
Totally 204 participants complete the interview alone or by their relatives. The average time of interviewing is about 40–45 minutes. Not so clearly answers are not to be recorded. Table 1 and Table 2 summarize socio-demographics characteristics of participants and main characteristics of depression and schizophrenia.
The ages of the 135 (66.2%) patients with depression range from16 to 73 years, with an average of 39.17 ± 13.80 years; The ages of the 69 (33.8%) patients with schizophrenia range from16 to 74 years, with an average of 33.00 ± 14.09 years. Sixty (44.4%) male and seventy five (55.6%) female patients are in depression group, and thirty one (44.9%) male and thirty eight (55.1%) female patients are in schizophrenia group. Meanwhile, one hundred and thirty six healthy people are selected as control group, which were composed with 64 male and 72 female participants (Table 1 in detail).
Main characteristics of depression and schizophrenia
The duration of disease in depression group is ranged from 0.2 to 20.3 years, with an average of 4.44 ± 4.12, and the duration of disease in schizophrenia group is ranged from 0.1 to 39.8 years, with an average of 5.58 ± 7.31. There are seventy nine (58.5%) acute/sub-acute patients and fifty six (42.5%) chronic patients in depression group, and forty six (66.7%) acute/sub-acute patients and twenty three (33.3%) chronic patients in schizophrenia group. Nearly sixty (59.3%) patients of depression degree in depression group are in moderate level versus more than sixty six (66.7%) at the same severity of disease level in schizophrenia group. The treatment duration is in average of 3.30 ± 5.40 years and 4.20 ± 6.05 years in depression and schizophrenia groups respectively (Table 2 in detail).
Univariate statistical comparison of socio-demographic predictors: HRQOL of patients in depression and schizophrenia
The table 3 shows HRQOL dimension scores of patients with depression and schizophrenia compared among different relevant socio-demographic characteristics. The outcomes show that there are associations between socio-demographic characteristics of gender, ethnicity, education and marital status of patients and HRQOL of patients.
1) Comparison of HRQOL of dimension scores of patients with depression and Schizophrenia between male and female group
There is only difference in HRQOL of social functioning (SF) dimension score of patient with depression (t=-2.349, P = 0.020) and difference in HRQOL of physical functioning (PF) dimension score of patient with schizophrenia (t=-2.175, P = 0.033) respectively between male and female group. No differences in other dimension scores were found in both depression and schizophrenia patients (P > 0.050). The result indicates that the social function of female patients with depression is more likely to be better than that of male patients, whereas, the physical function of male patients with schizophrenia is more likely to be better than that of female patients, but there are not quite differences in HRQOL of other dimensions of all patients between male and female group.
2) Comparison of HRQOL of dimension scores of patients with depression and Schizophrenia in different ethnic groups
No difference in HRQOL of all dimension scores of patients with schizophrenia is found (P > 0.050) between Han and minority group. There are differences of total score and the dimension score of PF of patients with depression between Han and other minority groups (t=-2.067, P = 0.041; t=-3.323, P = 0.001). It is illuminate that the total HRQOL and the physical function of patients with depression in minority group is more likely better than that of patients in Han group.
3) Comparison of HRQOL of dimension scores of patients with depression and Schizophrenia at different educational level
In depression patients, there are differences of total score, the dimension scores of PF, bodily paining (BP) and SF in different educational level groups (F=-5.298, P = 0.006; F = 3.586, P = 0.030; F = 6.932, P = 0.001; F = 5.578, P = 0.005) and in schizophrenia patients, only difference of HRQOL of dimension of role emotional (RE) is found (F = 3.750, P = 0.029). The result indicates that the higher educational level of patients with depression, the better HRQOL would they have, especially in the dimension of PF, BP and SF, whereas, the higher educational level of patients with schizophrenia, the worse HRQOL of RE would they have.
4) Comparison of HRQOL of dimension scores of patients with depression and schizophrenia among different marital status groups
No difference of all dimension scores on HRQOL of patients with schizophrenia is found (P > 0.050). Whereas, there are differences of total score, the dimension score of PF, GH and RE of patients with depression among different marital status groups (F = 3.116, P = 0.048; F = 4.073, P = 0.019; F = 3.886, P = 0.023; F = 4.466, P = 0.013). The result manifests that compared with other groups, the dimension of PF, general health (GH), RE and the general HRQOL of patients with depression who are unmarried are more likely better.
Participants’ subjective health status
The participants’ subjective health status and the comparison of domain scores of SF-36 in patients with depression/schizophrenia to healthy group are shown in Table 2. The total score, PCS score and MCS score and all domain scores of SF-36 in three groups (patients with depression, schizophrenia and healthy population) are different each other through the S-N-K ANOVA analysis. The patients groups are both lower than those of general group and there are significant differences in all domains (P < 0.001). Compared with schizophrenia group, most domains scores of SF-36 in depression group are slightly higher besides of BP and SF, and there were differences in the domains of Role physical (RP) and Mental health (MT) between two groups (P < 0.001) (Table 4 in detail).
Correlation of the main predictors and HRQOL of patients with Depression and Schizophrenia using multiple linear regression analysis
The stepwise multiple linear regression models is used to analyze the correlation of potential impact factors and HRQOL of participated patients by manner of entering variable probability of 0.05 and the removing of 0.10. The predictors of HRQOL in PCS and MCS for patients with depression and schizophrenia are also analyzed respectively. As the HRQOL of PCS and MCS in patients with depression are the dependence 1 and dependence 2 respectively. The HRQOL of PCS and MCS in patients with schizophrenia are to be dependence 3, dependence 4 respectively. The potential impact factors in socio-demographic, socio-economic and medical level are selected to be the independence. The eighteen independence variables are selected, the quantization listed in the table 6.
Table 6 summarizes the results of stepwise multiple linear regression models to analyze predictors of HRQOL in PCS and MCS for patients with depression and schizophrenia. Concerning the stepwise multiple liner regression analysis on the Physical Component Summary (PCS) as the dependent variable Y, Mental Component Summary (MCS) as the dependent variable Y, respectively, the results indicate that HRQOL in PCS of depression is negative correlated to the change of health status and depressive degree and positive correlated to unmarried status, the regression equation model is 1(PCS) = 73.14–2.89X16-3.21X14 + 3.02 X4, this model explained twenty percent (20%) of the variance of HRQOL in PCS of depression with adjusted R Square = 0.20, F = 7.38, P = 0.00. The HRQOL in MCS of depression is positive correlated to unmarried status, ethnicity and duration of disease, the regression equation model is 2(MCS) = 42.55 + 4.04X4 + 4.50X3 + 0.35X13, this model explained eleven percent (11%) of the variance of HRQOL in MCS of depression with adjusted R Square = 0.11, F = 7.11, P = 0.00.
Annual family income, severity degree of patient is positive correlate with HRQOL in PCS of schizophrenia, change of health status, ethnicity, educational level are negative correlate, the regression equation model is 3(PCS) = 72.70-2.11X16 + 1.97X8-5.51X7 + 6.28X14-10.19X3, thirty six percent (36%) of the variance of HRQOL in PCS of schizophrenia can be explained with Adjusted R Square = 0.11, F = 7.11, P = 0.00, and only one parameter, ethnicity, is negative correlate to HRQOL in MCS with standardized beta coefficients of -0.28, the regression equation model is 4(PCS) = 57.97-6.80X3, the fourth model can explain six percent (6%) of the variance of HRQOL in MCS of schizophrenia with adjusted R Square = 0.06, F = 7.34, P = 0.02.