Constant addition methods yielded valid and precise underlying blood pressure estimates, with medication class-specific addition performing best for systolic BP (0% relative bias for age coefficient) and simple constant addition performing best for diastolic BP.
Observational (n=10,283)
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Which missing data imputation method best estimates underlying blood pressure and its longitudinal association with age in patients taking antihypertensive medications?
Simple constant addition methods (class-specific for SBP, fixed for DBP) provide valid and precise estimates of underlying blood pressure and its longitudinal associations in cohort studies.
Antihypertensive medications complicate studies of blood pressure (BP) natural history; BP if untreated ("underlying BP") needs to be estimated. Our objectives were to compare validity of five missing data imputation methods to estimate underlying BP and longitudinal associations of underlying BP and age. We simulated BP treatment in untreated hypertensive participants from Atherosclerosis Risk in Communities (ARIC) in visits 1-5 (1987-2013) using matched treated hypertensive participants. The underlying BP was imputed: #1, set as missing; #2, add 10 mmHg for systolic, 5 mmHg for diastolic; #3, add medication class-specific constant; #4, truncated normal regression; and #5, truncated normal regression including prior visit data. Longitudinal associations were estimated using linear mixed models of imputed underlying BP for simulated treated and measured BP for untreated participants. Method 3 was the best-performing for systolic BP; lowest relative bias (5.3% for intercept at age 50, 0% for age coefficient) and average deviation from expected (0.04 to -1.79). Method 2 performed best for diastolic BP; lowest relative bias (0.6% intercept at age 50, 33.3% age <60, 9.1% age 60+) and average deviation (-1.25 to -1.68). Methods 4 and 5 were comparable or slightly inferior. In conclusion, constant addition methods yielded valid and precise underlying BP and longitudinal associations.
Balakrishnan et al. (Tue,) conducted a observational in Hypertension (n=10,283). Constant addition imputation methods (Method 3 for SBP, Method 2 for DBP) vs. Measured untreated blood pressure (gold standard) was evaluated on Relative bias for age coefficient and average deviation from expected blood pressure. Constant addition methods yielded valid and precise underlying blood pressure estimates, with medication class-specific addition performing best for systolic BP (0% relative bias for age coefficient) and simple constant addition performing best for diastolic BP.