Mark Merolli, Osman Ahmed, Karen McCreesh, Louisa Remedios, Kerryn Butler-Henderson
Are physiotherapists expected to be competent in digital health practice? Meta-synthesis of international physiotherapy practice competency standards
Physiotherapy theory and practice
imperfect followup longitudinal studies commonly leads missing outcome data potentially bias inference missingness nonignorable propensity missingness depends missing values data upstate kids study seek determine missingness child development outcomes nonignorable simple model assuming ignorable missingness would compare complicated models nonignorable mechanism correct nonignorable missingness shared random effects model srem jointly models outcome missing mechanism however computational complexity lack software packages limited practical applications paper proposes novel twostep approach handle nonignorable missing outcomes generalized linear mixed models first analyse missing mechanism generalized linear mixed model predict values random effects outcome model fitted adjusting predicted random effects account heterogeneity missingness propensity extensive simulation studies suggest proposed method reliable approximation srem much faster computation nonignorability missing data upstate kids study estimated mild moderate analyses using twostep approach srem similar model assuming ignorable missingness twostep approach computationally straightforward method conducted sensitivity analyses longitudinal studies examine violations ignorable missingness assumption implications relative health outcomes