Test accuracy
Due to heterogeneity in methodology and study quality, meta-analysis was
performed on studies from each group separately.
The accuracy of index tests to predicting endometriosis was variable,
although results across groups were consistent. Each index test gave a
positive likelihood for the presence of pelvic endometriosis, apart from
a BMI ≥30kg/m2, which decreased the likelihood of
disease. The positive likelihood ratio (LR+) for disease was highest in
investigation tests and there was a trend towards a greater specificity
than sensitivity. The summary results of bi/univariate meta-analysis are
shown in Figure 3. An assessment of confidence in individual sensitivity
and specificity of each test is displayed by a visual pentagon model,
the methodology for this assessment is described in the discussion and
legend shown in Figure 4.
Investigation category tests were the best performing overall and TVUSS
finding of endometrioma gave the highest summary LR+ at 21.6, at
sensitivity and specificity of 77.2% and 96.4% respectively. Serum
CA-125 >35U/mL showed sensitivity and specificity of 55.8%
and 92.7% respectively, with LR+ of 7.63. TVUSS finding of DIE had
showed sensitivity and specificity of 86.5% and 80.2% with LR+ of
4.39.
Symptom based tests showed LR+ within a similar range: 1.47
(dysmenorrhoea) to 1.93 (dyspareunia). Symptoms showed a generally
higher specificity than sensitivity. Dyspareunia showed the highest LR+
at 1.93 with a sensitivity and specificity of 36.3% and 81.1%
respectively.
Family history of endometriosis showed a LR+ of 6.25 with a high
specificity (98.5%) but low sensitivity (9.25%). The finding of BMI
≥30kg/m2 showed a decreased likelihood of diagnosis of
endometriosis (LR+ 0.44).
Hierarchical Summary Receiver Operating Characteristics (HSROC) curves
for index tests in each group are shown in Figures S6-8. The HSROC
curves show the greatest area under the curve (AUC) for investigation
category tests.
In the partial verification group, symptom index tests showed a greater
LR+ than the complete verification group, range 2.47 (dysmenorrhoea) to
7.13 (dyschezia). Specificity was also higher, range 69%
(dysmenorrhoea) to 92% (dyschezia).
In the database/self-reporting group symptom-based index tests performed
similarly to other groups. In partial verification and
database/self-reporting groups BMI ≥30 kg/m2 showed no
correlation with disease and had 95% CI crossing 1.0. In all other
index tests across all groups the 95% CI was >1.0.
The greatest inter-study variability in confidence intervals was shown
in Forest plots for the symptom-based tests, notably pelvic pain. The
inter study variance for specificity was generally lower than that for
sensitivity, as was the overall width of confidence intervals. Forest
plots for each index test in each group are shown in Supplementary
Figures S9-15.
Sensitivity analysis performed for studies without any high-risk
features is shown in Table 1. All studies included are from the complete
verification group. Summary accuracy measures are consistent with those
in this group for the majority of index tests, although sensitivity for
TVUSS finding of endometrioma and DIE reduced to 69.8% and 73.4%
respectively.