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Table 1 Methodological Profile - Meta-Analysis (MethProf-MA). Three part profile with (top) general information about available data, (middle) description of data and main effect of CT, (bottom) analyses to investigate interactions of treatment with a predictor

From: Investigating treatment-effect modification by a continuous covariate in IPD meta-analysis: an approach using fractional polynomials

A: General information about available data

Data sources

Breast Cancer DataMart (Provided by NCI)

Contains IPD from 14 published NCI-sponsored breast cancer studies.

8 studies assessed effect of adding chemotherapy (CT-Y/N) to tamoxifen. Here we include only tamoxifen treated patients. For details see section 4 in Wang et al.

Study question

Does effect of CT depend on estrogen receptor (ER) values?

Data

CT-N: N = 2982, No ER = 401, in study 2581

CT-Y: N = 3586, No ER = 440, in study 3146

Outcome: disease free survival (DFS)

Events: Ct-N = 1342, CT-Y=1601, overall. See Table 2 for more details.

We use ER+1 (see “General issues of the three-stage metaTEF approach”) and we truncate all ER values at 1000, which made little difference (see “Estrogen receptor”).

Variables

Treatment: CT (Y/N); Outcome: recurrence free survival (RFS); Predictor: ER

B: Description of data and main effect of CT

D1 – per study

Patients, Follow-Up, Events, p-values (CT-Y/N)

Table 2

D2 – per study

Estimates of DFS rates, combined for CT

Fig. 1

D3 – per study

Effect of CT in each study

Fig. A1, p-values in Table 2, check of PH assumption from the Cox model.

D4: ER – per study

Distribution

Table 3, Fig. A2, Estrogen receptor

C: Analyses to investigate interactions of treatment with a predictor

A1 – per study

Interaction of CT with ER?

Table 2, Preliminary analyses

A2 – ER subgroups

studywise and pooled estimate

Effect of CT in 4 ER subgroups

Table A2, Fig. A3, Preliminary analyses

A3 – TEF – studywise and pooled estimate

Treatment effect function (TEF) for log ER

Power 0 (log ER) in each study (see Fig. A4), Preliminary analyses

A4 – studywise FP1

TEF (FP1, flex3) separately per study

Fig. 2a, metaTEF

A5 – metaTEF for A4

Main analysis - Variances, weights per study and metaTEF

Fig. 2b – f

A6 – studywise and pooled FP2

As A4 but with FP2 (flex1)

Fig. A5, Table A3

sensitivity analysis FP1 or FP2?

A7 – metaTEF

Comparison of FP1/FP2 and fixed/random effect

Fig. 3

A8 – CI of metaTEF

Pointwise 95% CI for FP1/FP2 and fixed/random effect

Fig. A6

  1. The profile MethProf-MA, providing an overview of studies, patients, main effect of chemotherapy and conducted analyses to investigate interactions of chemotherapy with estrogen receptors
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BMC Medical Research Methodology

ISSN: 1471-2288

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