. 2014 Feb 18;9(2):e88753. doi: 10.1371/journal.pone.0088753

Table 1. Newcastle–Ottawa quality assessment scale^*.

Selection

(1) Representativeness of the exposed cohort

(a) Truly representative of the average ‘GC patient’ in the community (1 star)

(b) Somewhat representative of the average ‘GC patient’ in the community (1 star)

(d) No description of the derivation of the cohort

(2) Selection of the non-exposed cohort

(a) Drawn from the same community as the exposed cohort (1 star)

(b) Drawn from a different source

(3) Ascertainment of exposure

(a) Secure record (e.g. surgical records) (1 star)

(b) Structured interview (1 star)

(d) No description

(4) Demonstration that outcome of interest was not present at start of study

(a) Yes (1 star)o

(b) No

Comparability

(1) Comparability of cohorts on the basis of the design or analysis

(a) Study controls for ‘ age, sex, BMI’ (1 star)

(b) Study controls for any additional factor (1 star) (ASA, tumor size, stage etc.)

Outcome

(1) Assessment of outcome

(a) Independent blind assessment (1 star)

(b) Record linkage (1 star)

(d) No description

(2) Was follow-up long enough for outcomes to occur?

(a) Yes (‘2 years’) (1 star)

(b) No

(3) Adequacy of follow-up of cohorts

(a) Complete follow-up – all subjects accounted for (1 star)

(b) Subjects lost to follow-up unlikely to introduce bias – small number lost ‘5%’ or description provided of those lost (1 star)

(d) No statement

^*A study can be awarded a maximum of one star for each numbered item within the Selection and Outcome categories. A maximum of two stars can be given for Comparability. Underlined and quoted phrases are provided in the scale to allow for adjustment to particular studies. Italicized phrases indicate our interpretation of the question relevant to this study.

GC, gastric cancer; ASA, American Society of Anesthesiology classification; BMI, body mass index.

Table 1. Newcastle–Ottawa quality assessment scale*.

Table 1. Newcastle–Ottawa quality assessment scale^*.