Reviewer's report
Title:Highly-cited estimates of the cumulative incidence and recurrence of
vulvovaginal candidiasis are inadequately documented
Version: 2Date:8 May 2013
Reviewer: Betsy Foxman
Reviewer's report:
The authors purport to trace the origin of commonly cited estimates of the
cumulative incidence of vulvovaginal candidiasis in the literature. After tracing
them to clinical opinion of two clinicians, they suggest that the existing
population-based studies (which they suggest but do not state are not commonly
cited) are fatally flawed because these studies depend on self-report of medical
history. They further assert that the cumulative incidence cannot be estimated
accurately from the existing population-based studies. They do not cite any
studies that estimated the incidence based on self-reported physician diagnosis
in a short time period (e.g., Sex Transm Dis. 2000 Apr;27(4):230-5.) where
effects of recall are likely to be low.
While listed as a ‘debate,’ I was unclear as to what were the terms of the debate,
and what the issues of interest are. Yes, physician diagnosis of VVC is a problem
- most US physicians do not have laboratory capability in their offices to confirm
diagnosis using a wet mount, and culture for VVC is not definitive as Candida is a
common inhabitant of the vaginal microbiota. However, the totality of all the
studies they reviewed suggest that VVC occurs and recurs frequently. The
estimates are undoubtedly imprecise, but they present no evidence to suggest
they are off by an order of magnitude.
On page 6 the authors state that women inappropriate diagnosis VVC, as do
their clinicians, because the literature cites erroneous estimates. However, the
estimates from a random digit dialing survey conducted shortly after treatment
was made available over the counter (in 2000) are essentially the same as from
a similar study published in 2013. This does not support their assertion that
women are over diagnosing as are physicians because of an erroneous
literature.
On page 7 the authors state “the commonly cited incidence and recurrence
figures were not derived from empiric investigation.” This is an issue not limited
to VVC, but why this is important is entirely unclear. There are empiric
investigations, such as those by Geiger et al., and Foxman et al., in the literature.
These the authors dismiss these as estimates are based on self-reported history
of physician diagnosis. One can argue that self-reported history of physician
diagnosis either over- or under- estimates the burden of VVC, as treatment is
available without prescription over the counter. However, the authors do not
make either of these arguments.
The proposed solution seems quite naïve: why would anyone fund such as study
unless there was already as suggestion of significant burden? How will they
obtain a representative population for study that is compliant for follow-up that
has a better response rate than the studies they dismiss? Further, why are more
accurate incidence and recurrence estimates required?
Level of interest: An article of limited interest
Quality of written English: Acceptable
Statistical review: No, the manuscript does not need to be seen by a
statistician.
Declaration of competing interests:
I have consulted on the epidemiology of VVC for two companies engaged in
developing a VVC vaccine.