Table 1 Baseline characteristics of subjects

Age

37.0 ± 14.6

40.4 ± 16.5

0.005

Sex (%)

 Women

134 (55.4)

276 (52.7)

0.536

 Men

108 (44.6)

248 (47.3)

Baseline hypertension (%)

23 (9.5)

42 (8.1)

0.605

Baseline diabetes (%)

10 (4.1)

17 (3.2)

0.683

Primary psychiatric diagnoses, ICD-10 (%)

 F20–29 (schizophrenia or psychotic disorders)

40 (16.5)

115 (21.9)

< 0.001

 F30–F31 (bipolar disorders)

173 (71.5)

252 (48.1)

 F32–F33 (depressive disorders)

29 (12.0)

157 (30.0)

eGFR  < 60 mL/min/1.73 m² (%)

2 (0.8)

8 (1.5)

0.733

Follow-up duration (year)

4.2 ± 4.2

5.3 ± 5.2

0.002

Cumulative years on lithium treatment

3.5 ± 3.5

–

–

Cumulative years on valproate treatment

–

4.3 ± 4.2

–

Average TDM

 Lithium TDM

0.6 ± 0.2

–

 Valproate TDM

–

56.7 ± 20.5

Episodes of lithium toxicity (≥ 1 episode)

 Lithium TDM  > 0.8 mmol/L (%)

112 (46.3)

–

–

 Lithium TDM  > 1.0 mmol/L (%)

54 (22.3)

–

–

 Lithium TDM  > 1.2 mmol/L (%)

17 (7.0)

–

–

Daily dosing schedule^a

 Lithium once-daily dosing

0.9 ± 0.2

–

–

 Valproate once-daily dosing

–

0.8 ± 0.4

–

Yearly median eGFR change (mL/min/1.73 m²)

− 1.3 (IQR − 6.8, 1.7)

1.1 (IQR − 4.5, 1.5)

0.389

Baseline eGFR (mL/min/1.73 m²)

103.9 ± 18.2

103.1 ± 18.4

0.533

Last eGFR (mL/min/1.73 m²)

100.9 ± 18.4

100.6 ± 19.0

0.851

Second to last eGFR (mL/min/1.73 m²)

101.9 ± 18.5

101.3 ± 18.2

0.629

Average eGFR values by year (mL/min/1.73 m²)

 Year 1 eGFR

104.6 ± 16.9

103.8 ± 18.1

0.549

 Year 3 eGFR

104.8 ± 15.6

101.4 ± 17.6

0.208

 Year 5 eGFR

99.5 ± 17.2

102.1 ± 17.7

0.507

 Year 7 eGFR

98.0 ± 16.1

98.0 ± 16.2

0.995

 Year 10 eGFR

96.4 ± 15.7

96.9 ± 18.1

0.945

 Year 12 eGFR

95.2 ± 11.5

96.5 ± 15.9

0.842

 Year 15 eGFR

73.7 ± 21.1

99.6 ± 15.6

0.085

 Year 20 eGFR

–

81.5 ± 21.9

–