Diabetes in pregnancy: are we providing the best care ... - HQIP

Methodology
4.10 Limitations
All data collected during this enquiry were derived from review of the medical records. Findings of this
report are therefore based on documentation in the medical records of demographic factors, social and
lifestyle issues and clinical care, and are not based on direct questioning of clinicians or women.
In many cases it was not possible to complete all questions on the pro forma with reference to the
medical notes provided. The proportion of missing information was even more pronounced for information
pertaining to the pre-pregnancy period, where missing data ranged from less than 5% to more than 50%
for specifi c data items.
Throughout the report, numbers are reported with reference to the total number of records where
information was recorded i.e. excluding all missing data. In general, there was no systematic difference
in the number of missing responses dependent on whether a pregnancy was a case or a control.
With regard to panel assessment of women’s behaviour and clinical care, it should be noted that the
enquiry sample is not fully representative of the whole population of pregnant women with diabetes, as
approximately half of women in the enquiry had a poor pregnancy outcome due to the sampling process.
It is therefore possible that the issues identifi ed by enquiry panels represent the worse end of the spectrum
of suboptimal behaviour and care. However, for many factors examined there was no difference between
cases and controls.
One of the potential limitations to the panel enquiry approach is variation of assessments between
different regional panels. Panel guidance notes were provided in order to minimise variation, and the
panel chairs and regional managers had an important role to play in directing the discussion and ensuring
that all factors were taken into consideration during assessments. Panel chairs attended a training day
(as described above) in order to standardise the approach to the enquiry assessment, and guidance
was provided in the enquiry pro forma (see appendix B) to aid in its completion. Despite this training and
guidance there remains a degree of subjectivity in the panel assessment process which cannot
be completely eliminated.
A source of bias that has been previously experienced in some confidential enquiry programmes is that
knowledge of the pregnancy outcome may affect the panel assessment of care. The Project 27/28 study 3
which enquired into standards of care for babies born at 27 and 28 weeks gestation, blinded assessors to
the outcome of the case up to the point of delivery. In this study, as one of the outcomes was congenital
anomaly which could be diagnosed antenatally, it was not possible to blind the panels to pregnancy outcome
in all cases. For this reason, it was agreed that assessors would not be blinded to any outcomes for the
pregnancies being reviewed. This may have led to an element of bias in this study particularly with respect to
the questions which asked for panel assessment of the standard of care received or the woman’s approach
to managing her diabetes. This bias could have led to an overestimate of the extent of the association of
panel assessment of suboptimal care with adverse pregnancy outcome. Results relating to panel assessment
are clearly identified throughout the report and should be interpreted with a degree of caution.
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