Panel data analysis in medical research

Abstract

Introduction: A longitudinal study involves repeated observations of the same items over long periods oftime. Panel studies are longitudinal studies of batch which combine cross-sectional and time- series data inobservations on a number of over time that play special role in medical research or clinical trials. In thispaper, we primarily discuss about the panel data and various modeling of panel data. It is not possible to useordinary regression methods due to inter- correlation of observation related to one unit. Generalizedestimation equation (GEE) for estimation of panel regression coefficient by considering inter correlationwas used among observations.Materials and Methods: We considerd the importance of panel data modeling with GEE in real paneldata samples as applications in the effect of estrogen patches on the postnatal depression.Results: In the estimation of panel regression coefficients on real data, starting treatment effect(b(pre)=0.428, p<0.001), treatment group effect (b(group)=4.025, p<0.001) and treatment period effect(b(visit)=1.218,p<0.001 with use of robust method to misspecification of the correlation structure weresignificant.Conclusion: According to the important role of panel data inter- correlation structure in analyzing inmedical research, we propose to estimate the coefficients of panel via GEE metho