Tripodi 2015.

Study characteristics
Patient sampling	All 5 publications cited under the reference ID Tripodi 2015 (Included studies section) were based on the database we received by email from Valeria Tripodi (see notes). Case‐control, prospective, single centre study. Between January 2004 and June 2005, all pregnant women attending 1 hospital in their second half of pregnancy were screened for inclusion. Cases: 45 woman diagnosed with ICP for having pruritus, elevated aminotransferases, total serum bile acids > 11 µmol/l, absence of other known diseases (infectious, autoimmune, or skin diseases, alcohol intake, biliary obstruction). They all received UDCA treatment. Controls. 30 women among those clinically defined as healthy, were enrolled as controls. The calculated prevalence of ICP was 1.04%.
Patient characteristics and setting	Setting: Hospital JM Penna, Argentina (2596 yearly deliveries, thus meaning about 3894 estimated deliveries in the 18 months considered) Characteristics of patients in case group: 27.3 ± 1.0 years old, pre‐selected for having total serum bile acids > 11 µmol/L Characteristics of patients in control group: 26.1 ± 1.4 years old
Index tests	Total serum bile acid, lithocholic acid (LCA), chenodeoxycholic acid (CDCA), deoxycholic acid (DCA), cholic acid (CA), ursodeoxycholic acid (UDCA), total tauro‐conjugated/total glyco‐conjugated bile acids (T‐c/G‐c). For TSBA, we received individual participant data (see notes). Laboratory technique: micellar electrokinetic chromatography with UV detection, on fasting serum sample Predefined diagnostic cut‐off values Total serum bile acids > 11 µmol/l Not provided for the other index tests
Target condition and reference standard(s)	ICP and clinical evaluation including assessment of normalisation of symptoms and liver tests after delivery. Reference standard assessed by obstetricians, who were not blind for the index test as it was part of their evaluation
Flow and timing	Assessment of total serum bile acids after onset of symptoms in all patients. Follow‐up assessing normalization of symptoms and liver biochemistry abnormalities after delivery in all patients.
Comparative
Notes	We received further information on the study and a complete database from which all participant data were taken by email from Valeria Tripodi (see Included studies). One of the publications defined the study design as 'cross‐sectional' but, following its design description and data received from authors, CM and TS agreed in defining it as 'case‐control'.
Methodological quality
Item	Authors' judgement	Risk of bias	Applicability concerns
DOMAIN 1: Patient Selection
Was a consecutive or random sample of patients enrolled?	Yes
Was a case‐control design avoided?	No
Did the study avoid inappropriate exclusions?	No
		High	High
DOMAIN 2: Index Test Total serum bile acids
Were the index test results interpreted without knowledge of the results of the reference standard?	Yes
If a threshold was used, was it pre‐specified?	Yes
		Low	Low
DOMAIN 2: Index Test Component(s) of serum bile acid profile
Were the index test results interpreted without knowledge of the results of the reference standard?	Yes
If a threshold was used, was it pre‐specified?	No
		Low	Low
DOMAIN 3: Reference Standard
Is the reference standards likely to correctly classify the target condition?	Yes
Were the reference standard results interpreted without knowledge of the results of the index tests?	No
Was the index test not part of the reference standard?	No
		High	Low
DOMAIN 4: Flow and Timing
Did all patients receive the same reference standard?	Yes
Were all patients included in the analysis?	Yes
		Low

ALT: alanine aminotransferase; AST: aspartate aminotransferase: CA: cholic acid; CDCA: chenodeoxycholic acid; CM: Cristina Manzotti (study author); DCA: deoxycholic acid; fCA: free (non‐conjugated) cholic acid; fCDCA: free (non‐conjugated) chenodeoxycholic acid; fDCA; free (non‐conjugated) deoxycholic acid; fLCA: free (non‐conjugated) lithocholic acid; G‐c: total glyco‐conjugated bile acids; GCA: glycocholic acid; GCDCA: glycochenodeoxycholic acid; GDCA: glycodeoxycholic acid; GLCA: glycolithocholic acid; GUDCA: glyco‐conjugated ursodeoxycholic acid; LCA: lithocholic acid; RCOG: Royal College of Obstetricians and Gynaecologists; T‐c Total tauro‐conjugated bile acids; TCA: taurocholic acid; TCDCA: taurochenodeoxycholic acid; TDCA: taurodeoxycholic acid; TLCA: tauro‐conjugated lithocholic acid; TS: Tea Stimac (study author); TSBA: total serum bile acids; TUDCA: tauro‐conjugated ursodeoxycholic acid; UDCA: ursodeoxycholic acid.