TY - JOUR

T1 - Incorporating Baseline Outcome Data in Individual Participant Data Meta-Analysis of Non-randomized Studies

AU - Syrogiannouli, Lamprini

AU - Wildisen, Lea

AU - Meuwese, Christiaan

AU - Bauer, Douglas C.

AU - Cappola, Anne R.

AU - Gussekloo, Jacobijn

AU - den Elzen, Wendy P.J.

AU - Trompet, Stella

AU - Westendorp, Rudi G.J.

AU - Jukema, J. Wouter

AU - Ferrucci, Luigi

AU - Ceresini, Graziano

AU - Åsvold, Bjørn O.

AU - Chaker, Layal

AU - Peeters, Robin P.

AU - Imaizumi, Misa

AU - Ohishi, Waka

AU - Vaes, Bert

AU - Völzke, Henry

AU - Sgarbi, Josè A.

AU - Walsh, John P.

AU - Dullaart, Robin P.F.

AU - Bakker, Stephan J.L.

AU - Iacoviello, Massimo

AU - Rodondi, Nicolas

AU - Del Giovane, Cinzia

AU - for the Thyroid Studies Collaboration

N1 - Publisher Copyright: Copyright © 2022 Syrogiannouli, Wildisen, Meuwese, Bauer, Cappola, Gussekloo, den Elzen, Trompet, Westendorp, Jukema, Ferrucci, Ceresini, Åsvold, Chaker, Peeters, Imaizumi, Ohishi, Vaes, Völzke, Sgarbi, Walsh, Dullaart, Bakker, Iacoviello, Rodondi and Del Giovane.

PY - 2022

Y1 - 2022

N2 - Background: In non-randomized studies (NRSs) where a continuous outcome variable (e.g., depressive symptoms) is assessed at baseline and follow-up, it is common to observe imbalance of the baseline values between the treatment/exposure group and control group. This may bias the study and consequently a meta-analysis (MA) estimate. These estimates may differ across statistical methods used to deal with this issue. Analysis of individual participant data (IPD) allows standardization of methods across studies. We aimed to identify methods used in published IPD-MAs of NRSs for continuous outcomes, and to compare different methods to account for baseline values of outcome variables in IPD-MA of NRSs using two empirical examples from the Thyroid Studies Collaboration (TSC). Methods: For the first aim we systematically searched in MEDLINE, EMBASE, and Cochrane from inception to February 2021 to identify published IPD-MAs of NRSs that adjusted for baseline outcome measures in the analysis of continuous outcomes. For the second aim, we applied analysis of covariance (ANCOVA), change score, propensity score and the naïve approach (ignores the baseline outcome data) in IPD-MA from NRSs on the association between subclinical hyperthyroidism and depressive symptoms and renal function. We estimated the study and meta-analytic mean difference (MD) and relative standard error (SE). We used both fixed- and random-effects MA. Results: Ten of 18 (56%) of the included studies used the change score method, seven (39%) studies used ANCOVA and one the propensity score (5%). The study estimates were similar across the methods in studies in which groups were balanced at baseline with regard to outcome variables but differed in studies with baseline imbalance. In our empirical examples, ANCOVA and change score showed study results on the same direction, not the propensity score. In our applications, ANCOVA provided more precise estimates, both at study and meta-analytical level, in comparison to other methods. Heterogeneity was higher when change score was used as outcome, moderate for ANCOVA and null with the propensity score. Conclusion: ANCOVA provided the most precise estimates at both study and meta-analytic level and thus seems preferable in the meta-analysis of IPD from non-randomized studies. For the studies that were well-balanced between groups, change score, and ANCOVA performed similarly.

AB - Background: In non-randomized studies (NRSs) where a continuous outcome variable (e.g., depressive symptoms) is assessed at baseline and follow-up, it is common to observe imbalance of the baseline values between the treatment/exposure group and control group. This may bias the study and consequently a meta-analysis (MA) estimate. These estimates may differ across statistical methods used to deal with this issue. Analysis of individual participant data (IPD) allows standardization of methods across studies. We aimed to identify methods used in published IPD-MAs of NRSs for continuous outcomes, and to compare different methods to account for baseline values of outcome variables in IPD-MA of NRSs using two empirical examples from the Thyroid Studies Collaboration (TSC). Methods: For the first aim we systematically searched in MEDLINE, EMBASE, and Cochrane from inception to February 2021 to identify published IPD-MAs of NRSs that adjusted for baseline outcome measures in the analysis of continuous outcomes. For the second aim, we applied analysis of covariance (ANCOVA), change score, propensity score and the naïve approach (ignores the baseline outcome data) in IPD-MA from NRSs on the association between subclinical hyperthyroidism and depressive symptoms and renal function. We estimated the study and meta-analytic mean difference (MD) and relative standard error (SE). We used both fixed- and random-effects MA. Results: Ten of 18 (56%) of the included studies used the change score method, seven (39%) studies used ANCOVA and one the propensity score (5%). The study estimates were similar across the methods in studies in which groups were balanced at baseline with regard to outcome variables but differed in studies with baseline imbalance. In our empirical examples, ANCOVA and change score showed study results on the same direction, not the propensity score. In our applications, ANCOVA provided more precise estimates, both at study and meta-analytical level, in comparison to other methods. Heterogeneity was higher when change score was used as outcome, moderate for ANCOVA and null with the propensity score. Conclusion: ANCOVA provided the most precise estimates at both study and meta-analytic level and thus seems preferable in the meta-analysis of IPD from non-randomized studies. For the studies that were well-balanced between groups, change score, and ANCOVA performed similarly.

KW - baseline imbalance

KW - cohorts

KW - continuous outcome

KW - individual participant data

KW - non-randomized studies

U2 - 10.3389/fpsyt.2022.774251

DO - 10.3389/fpsyt.2022.774251

M3 - Journal article

C2 - 35273528

AN - SCOPUS:85126238360

VL - 13

JO - Frontiers in Psychiatry

JF - Frontiers in Psychiatry

SN - 1664-0640

M1 - 774251

ER -