Turkiye Klinikleri Journal of Biostatistics

.: ORIGINAL RESEARCH
A Methodological Study on Estimating Propensity Scores with Missing Semi-Continuous Covariate Data: Application to Maternal Drinking and Childhood Cognition
Eksik Kısmi-Sürekli Kovaryat Verileri ile Eğilim Puanlarının Tahminine Yönelik Yöntemsel Bir Çalışma: Anne İçkisi ve Çocukluk Bilişi Üzerine Uygulama
Tuğba AKKAYA HOCAGİLa , Richard J. COOKb , Sandra W. JACOBSONc , Joseph JACOBSONc , Louise M. RYANd,e
aAnkara University Faculty of Medicine, Department of Biostatistics, Ankara, Türkiye
bDepartment of Statistics and Actuarial Science, University of Waterloo, Waterloo, Ontario, Canada
cDepartment of Psychiatry and Behavioral Neurosciences, Wayne State University School of Medicine, Detroit, USA
dSchool of Mathematical and Physical Sciences, University of Technology Sydney, Ultimo, NSW, Australia
eHarvard T.H. Chan School of Public Health, Boston, MA, USA
Turkiye Klinikleri J Biostat. 2024;16(3):129-39
doi: 10.5336/biostatic.2024-105388
Article Language: EN
Full Text
ABSTRACT
 Objective: This study adapts propensity score methodology for estimating causal effects in observational studies, particularly addressing the challenges of missing semi-continuous covariate data in environmental epidemiology. Material and Methods: Data were drawn from the Detroit Longitudinal Cohort Study, which examines prenatal alcohol exposure's impact on child cognitive development. The dataset includes maternal self-reports of alcohol and drug use during pregnancy, alongside biological assay results. A significant portion of the covariates, such as maternal substance use, exhibit a semi-continuous distribution with excess zero values and a long tail. Missing data in these covariates pose a risk to valid causal inference. To address this, we used the R package MICE for multiple imputation, incorporating maternal characteristics, socioeconomic indicators, and child neurodevelopmental outcomes. Additionally, a two-part modeling approach accounted for the distinct zero-inflated nature of the covariates. Misclassification correction techniques reconciled discrepancies between biological assays and maternal self-reports, particularly for illicit drug use, by adjusting sensitivity and specificity during the imputation process. Propensity scores for gestational alcohol exposure were estimated using the imputed datasets to ensure balanced covariates across exposure groups. Results: Our method performed well, particularly in scenarios with high percentages of zeros and missing observations in the semi-continuous covariates. Conclusion: This approach provides robust estimates of propensity scores, enhancing causal inference in studies involving maternal behaviors and childhood cognition.

Keywords: Multiple imputation for semi-continuous covariates; propensity score with partially observed covariates; Detroit Longitudinal Cohort Study; two-part structure; misclassification
ÖZET
 Amaç: Bu çalışma, gözlemsel çalışmalarda nedensel etkilerin tahmin edilmesinde eğilim skor metodolojisini uyarlamaktadır, özellikle çevresel epidemiyolojide kısmi-sürekli kovaryat verilerinin eksikliği ile ilgili zorluklara odaklanmaktadır. Gereç ve Yöntemler: Veriler, gebelikte alkol maruziyetinin çocuk bilişsel gelişimi üzerindeki etkisini inceleyen Detroit Boylamsal Kohort Çalışmasından alınmıştır. Veri seti, gebelik sırasında anne tarafından bildirilen alkol ve ilaç kullanımı ile biyolojik test sonuçlarını içermektedir. Kovaryatların önemli bir kısmı, anne madde kullanımı gibi fazla sıfır değeri ve uzun kuyruklu dağılımlar sergileyen kısmi-sürekli bir dağılıma sahiptir. Bu kovaryatlarda eksik veriler, geçerli nedensel çıkarım için risk oluşturur. Bu durumu ele almak için anne özellikleri, sosyoekonomik göstergeler ve çocuk nörogelişimsel sonuçları içeren çoklu imputasyon için R paketi MICE kullanılmıştır. Ayrıca, kovaryatların sıfır şişirilmiş doğasını hesaba katmak için iki parçalı modelleme yaklaşımı uygulanmıştır. Yanıltıcı sınıflandırma düzeltme teknikleri, biyolojik testler ile anne raporları arasındaki uyumsuzlukları, özellikle yasa dışı ilaç kullanımı için, imputasyon sürecinde duyarlılık ve özgüllük ayarlamaları yaparak uyumlu hâle getirmiştir. Gestasyonel alkol maruziyeti için eğilim skoru, impute edilmiş veri setleri kullanılarak tahmin edilmiştir ve bu sayede maruziyet grupları arasında dengeli kovaryatlar sağlanmıştır. Bulgular: Yöntemimiz, özellikle kısmi-sürekli kovaryatlarda yüksek sıfır oranları ve eksik gözlemler bulunan senaryolarda iyi performans göstermiştir. Sonuç: Bu yaklaşım, maternal davranışlar ve çocuk bilişi ile ilgili çalışmalarda nedensel çıkarımı geliştiren sağlam eğilim skoru tahminleri sunmaktadır.

Anahtar Kelimeler: Kısmi-sürekli kovaryatlar için çoklu imputasyon; kısmi gözlemlenen kovaryatlar ile eğilim skoru; Detroit Boylamsal Kohort Çalışması; iki parçalı yapı; yanıltıcı sınıflandırma
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