Accounting for Selectivity Bias and Correlation Across the Sequence From Elevated Blood Pressure to Hypertension Diagnosis and Treatment

• Published in: American journal of hypertension Vol. 31; no. 1; pp. 63 - 71
• Main Authors: Gordon-Larsen, Penny, Attard, Samantha M, Howard, Annie Green, Popkin, Barry M, Zhang, Bing, Du, Shufa, Guilkey, David K
• Format: Journal Article
• Language: English
• Published: US Oxford University Press 01.01.2018
• Subjects: Adolescent; Adult; Aged; Blood Pressure; China - epidemiology; Data Interpretation, Statistical; Disease Progression; Female; Humans; Hypertension - diagnosis; Hypertension - epidemiology; Hypertension - physiopathology; Insurance, Health - statistics & numerical data; Longitudinal Studies; Male; Middle Aged; Models, Statistical; Original Contributions; Prevalence; Reproducibility of Results; Selection Bias; Sex Factors; Socioeconomic Factors; Treatment Outcome; Urbanization; Young Adult; health infrastructure; health insurance; urbanization; China
• ISSN: 0895-7061; 1941-7225; 1879-1905
• DOI: 10.1093/ajh/hpx137

Abstract BACKGROUND It is unknown whether efforts to reduce hypertension burden in countries with very high prevalence, would be more effective if directed at hypertension diagnosis vs. treatment. Most analyses do not address bias and correlation across the sequence from elevated blood pressure (BP) to hypertension diagnosis and treatment, leading to potentially misleading findings. METHODS Using data spanning 18 years of the China Health and Nutrition Survey (n = 18,926; ages 18–75 years), we used an innovative 3-step, integrated system of equations to predict the sequence from: (i) elevated BP (systolic/diastolic BP ≥ 140/90 mm Hg) to (ii) diagnosed hypertension conditional on elevated BP, and to (iii) treatment (medication use) conditional on diagnosis, accounting for measured and unmeasured individual- and community-level confounders at each of the 3 steps. We compared results to separate traditional logistic regression models without control for unmeasured confounding. RESULTS Using our 3-step model, elevated BP increased from 12.6% and 8.5% (1991) to 36.8% and 29% (2009) in men and women, respectively, but diagnosis remained under 50%. We found widening disparities in hypertension diagnosis (higher hypertension at lower vs. higher education (difference of 2% in 1991 that widened to 5% in 2009)) and narrowing disparities in education (difference of 6% in 1991 to 4% in 2009) and insurance status (difference of 7% in 1991 to 2% in 2009) for treatment. CONCLUSIONS Our 3-step model improved model fit over traditionally used models. Our findings highlight serious barriers to hypertension diagnosis in Chinese adults, particularly among men and individuals of low attained education.