[R-sig-ME] diagnostic test meta analysis using glmer
Nathan Pace
n.l.pace at utah.edu
Tue Nov 14 07:04:24 CET 2017
Hi,
I am modeling the sensitivity and specificity of 7 diagnostic tests in a bivariate binomial model using glmer.
glmer(formula = cbind(true, n - true) ~ 0 + seM + spM + seMM + spMM + seMouth + spMouth +
seSM + spSM + seTM + spTM + seULBT + spULBT + seW + spW +
(0 + sens + spec | studyName), data = Compare_DL.df, family = binomial, nAGQ = 1)
The model without separating diagnostic tests is
glmer(formula = cbind(true, n - true) ~ 0 + sens + spec + (0 + sens + spec | studyName),
data = Compare_DL.df, family = binomial, nAGQ = 1)
The 7 test model assumes equal variances across tests.
The dataset includes sens, spec, seM, spM, etc as dummy index variables.
Both models can run and converge.
ANOVA shows improved fit:
Df AIC BIC logLik deviance Chisq Chi Df Pr(>Chisq)
Simple model 5 8987.8 9007.6 -4488.9 8977.8
Separate tests 17 6878.5 6945.8 -3422.3 6844.5 2133.3 12 < 2.2e-16 ***
I need to identify any separation of sensitivity and specificity properties among the 7 tests.
One possibility would be to jointly contrast seTesti – seTestj = 0 and spTesti – spTestj = 0 for all pairwise comparisons of the 7 tests (with multiplicity adjustment).
However, I am unable to construct such tests in lme4. Is this possible in lme4? If so, what is the code?
I have looked at other packages (multcomp) without success.
As usual, all help will be appreciated.
Nathan Pace, MD, MStat
University of Utah
Salt Lake City, UT
n.l.pace at utah.edu
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