Reviewer’s report
Title: 
Trend Changes and Factor Analysis of Endometrial Hyperplasia in
Patients with Polycystic Ovarian Syndrome Based on the Korean National
Health Insurance Database
Version: 
0 
Date: 
12 Jan 2022
Reviewer's report:
The article attempts to describe the incidence and prevalence PCOS and EH as
reported on a database with national coverage and the relation between the two
conditions. The strength of the DB comes from its size. However, the DB is
established for insurance purposes, not as a scientific resource. Thus, it is unclear
if the diagnoses made here were based on unified agreed criteria and whether
these have changed over time.
In the discussion section the authors consider whether the increased incidence of
disease is due to increased reporting perhaps related to increased awareness, or
changes in the diagnostic criteria over the years of the study. These elements
cannot be assessed in this study as there is no indication as to the diagnostic
criteria used by the clinicians or services. The article itself refers to rather old
articles when describing PCOS. In relation to EH, one important weakness is
that endometrial assessment is not (and there is no evidence that is should be) a
routine requirement in those labelled as having PCOS. Thus, the true incidence
of EH in this cohort is unknow. There is no indication as to the outcomes
following the diagnostic labelling. Did the hyperplasia regress? Were any tests
for PCOS repeated or was the labelling adhered to once made?
The authors' conclusion is that it is important to test for EH when selecting OC
for PCOS. But it is not clear what the supported evidence for this is. It is well
recognised that the vast majority (95%) of cases of EH without atypia regress
spontaneously. This calls for caution when labelling this a 'precancerous. The
distinction here is between EH that contains atypia. There is no indication in this
article as to the proportion of cases that had atypia or indeed on the indications
why any of the women subject to this study underwent endometrial biopsy.
Thus, it is not clear if those without hyperplasia ever had a biopsy. If so, what
was the outcome and what were the criteria for EH diagnosis?
The methodology involved search for the diagnosis of PCOS or EH. It would be
informative to have clarity as the characteristics of those with EH and of the
temporal relation between the diagnosis of EH and PCOS beyond what might be
inferred from Suppl table 2.
Supplementary Table 1: why was estradiol or conjugated estrogens prescribed?
These are not contraceptives? Was MedroxyProgesterone administered as a
depot preparation?
With regards to prescriptions, it is unclear whether the prescription of OCP or
MPA were to treat hyperplasia or PCOS. OCP prescription has its own
considerations e.g. in relation to obesity and it is thus unclear how the authors
considered this when analysing the role of prescribing.
From the Supplementary table 2: the incidence of EH and PCOS differ in the
different age groups with a considerable age gap. It is thus possible that of some
of those with EH may have had an earlier diagnosis of PCOS than included in
this study. Also, there is no indication of the possible risk modifying factors such
as changes in BMI, pregnancy, smoking.
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