Demographic and clinical data
The study included 119 BD patients in AS and 77 in RS and included 95 UD patients in AS and 61 in RS as well as 180 subjects in the HC group. Differences of sex among 3 groups were not significant (AS, c2=0.837, P=0.658; RS, c2=0.326, P=0.850). There were significant differences in age (AS, F=10.786, P<0.001; RS, F=5.131, P=0.006) among BD, UD and HC groups. Significant differences were also found in duration of illness (AS, t=2.195, P=0.029; RS, t=2.179, P=0.030). The differences in smoking history (AS, c2=0.192, P=0.661; RS, c2=0.001, P=0.982) and family history (AS, c2=1.042, P=0.307; RS, c2=0.615, P=0.433) between BD group and UD group were not significant. Additional information about demographics and clinical characteristics is presented in Table 1.
Differences in UA levels among BD, UD, and HC group in AS
There were significant differences in UA levels among three groups. Post-hoc analysis showed that UA levels of the BD group were higher than UD (P<0.001) and HC (P<0.001) group, while differences in UA levels between UD and HC group were not significant (P=0.453). Similar results were detected when analyzing separately by sex. (Table 2, Figure 1)
Afterward, the BD group was divided into bipolar mania/hypomania (BD-M, n=64) subgroup and bipolar depression (BD-D, n=55) subgroup to be compared with the UD group and HC group. There were significant differences among the four groups. The post-hoc test showed that differences of UA levels between BD-M subgroup and BD-D subgroup were not significant (P=0.213), as well as between UD group and HC group (P=0.895); UA levels of BD-M (UD, P<0.001; HC, P<0.001) and BD-D (UD, P<0.001; HC, P=0.003) subgroups were higher than UD group and HC group. When analyzed stratified by sex, similar results were detected in female patients, there was no significant difference on UA levels between subgroup BD-M and BD-D subgroup, so did to UD group and HC group; UA levels of BD-M (UD, P<0.001; HC, P<0.001) and BD-D (UD, P=0.039; HC, P=0.048) subgroups were higher than UD group and HC group. In male patients, the differences of UA levels between BD-D group and HC group were not significant, so did to UD group and HC group; UA levels of BD-M subgroup were higher than the other groups (BD-D, P<0.001; UD, P<0.001; HC, P<0.001), UA levels of BD-D subgroup were higher than UD group (P=0.028). (Table 2, Figure 1)
Differences in UA levels among BD, UD and HC group in RS
Significant differences in UA levels were spotted among three groups. The post-hoc test showed that UA levels of the BD group were higher than UD (P<0.001) and HC (P<0.001) group, while differences in UA levels between UD and HC group were not significant. The similar results were detected when analyzed stratified by sex. (Table 3, Figure 1)
Effects of treatment on UA levels
Drug-use subgroup vs. drug-naïve/free subgroup
Patients were divided into drug-use subgroup and drug-naïve/free subgroup (mania and depression unmedicated first episode or no treatment was used within eight weeks). Only in the UD group, there were significant differences in UA levels between drug-use subgroup and drug-naïve/free subgroup, and the differences disappeared when analyzed stratified by sex. (Table 4)
BD-M vs. BD-D vs. UD in the drug-use subgroup
In the drug-use subgroup, the differences among 3 groups were significant (F=10.547, P <0.001), the post-hoc test showed there were no significant differences in UA levels between BD-M and BD-D (P=0.846) groups, while UA levels of both groups were higher than UD group (BD-M vs. UD, P<0.001; BD-D vs. UD, P=0.012). When analyzed stratified by sex, no matter in male patients or female patients, UA levels of BD-M group were higher than UD group (P<0.001), there were no significant differences in UA levels between BD-M group and BD-D group as well as BD-D and UD group. (Figure 2)
BD-M vs. BD-D vs. UD in drug-naïve/free subgroup
In drug-naïve/free subgroup, the differences among 3 groups were significant (F=11.632, P<0.001), there were no significant differences in UA levels between BD-M and BD-D (P=0.301) groups, but UA levels of both groups were higher than UD (BD-M vs. UD, P<0.001; BD-D vs. UD, P=0.021) group. In male patients, UA levels of BD-M group were higher than BD-D group (P=0.025) and UD group (P=0.001), however, the differences of UA levels between BD-D group and UD group were not significant. In female patients, UA levels of BD-M group were higher than UD group (P<0.001), there were no significant differences in UA levels between BD-M group and BD-D group as well as BD-D and UD group. (Figure 2)