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1.  Association between Ambient Temperature and Blood Pressure and Blood Pressure Regulators: 1831 Hypertensive Patients Followed Up for Three Years 
PLoS ONE  2013;8(12):e84522.
Several studies have suggested an association between ambient air temperature and blood pressure. However, this has not been reliably confirmed by longitudinal studies. Also, whether the reaction to temperature stimulation is modified by other factors such as antihypertensive medication is rarely investigated. The present study explores the relationship between ambient temperature and blood pressure, without and with antihypertensive medication, in a study of 1,831 hypertensive patients followed up for three years, in two or four weekly check ups, accumulating 62,452 follow-up records. Both baseline and follow-up blood pressure showed an inverse association with ambient temperature, which explained 32.4% and 65.6% of variation of systolic blood pressure and diastolic blood pressure (P<0.05) respectively. The amplitude of individual blood pressure fluctuation with temperature throughout a year (a 29 degrees centigrade range) was 9.4/7.3 mmHg. Medication with angiotensin converting enzyme inhibitor benazepril attenuated the blood pressure fluctuation by 2.4/1.3 mmHg each year, though the inverse association of temperature and blood pressure remained. Gender, drinking behavior and body mass index were also found to modify the association between temperature and diastolic blood pressure. The results indicate that ambient temperature may negatively regulate blood pressure. Hypertensive patients should monitor and treat blood pressure more carefully in cold days, and it could be especially important for the males, thinner people and drinkers.
PMCID: PMC3877276  PMID: 24391962
2.  Improved Doubly Robust Estimation when Data are Monotonely Coarsened, with Application to Longitudinal Studies with Dropout 
Biometrics  2010;67(2):536-545.
A routine challenge is that of making inference on parameters in a statistical model of interest from longitudinal data subject to drop out, which are a special case of the more general setting of monotonely coarsened data. Considerable recent attention has focused on doubly robust estimators, which in this context involve positing models for both the missingness (more generally, coarsening) mechanism and aspects of the distribution of the full data, that have the appealing property of yielding consistent inferences if only one of these models is correctly specified. Doubly robust estimators have been criticized for potentially disastrous performance when both of these models are even only mildly misspecified. We propose a doubly robust estimator applicable in general monotone coarsening problems that achieves comparable or improved performance relative to existing doubly robust methods, which we demonstrate via simulation studies and by application to data from an AIDS clinical trial.
PMCID: PMC3061242  PMID: 20731640
Coarsening at random; Discrete hazard; Dropout; Longitudinal data; Missing at random
3.  Improving efficiency and robustness of the doubly robust estimator for a population mean with incomplete data 
Biometrika  2009;96(3):723-734.
Considerable recent interest has focused on doubly robust estimators for a population mean response in the presence of incomplete data, which involve models for both the propensity score and the regression of outcome on covariates. The usual doubly robust estimator may yield severely biased inferences if neither of these models is correctly specified and can exhibit nonnegligible bias if the estimated propensity score is close to zero for some observations. We propose alternative doubly robust estimators that achieve comparable or improved performance relative to existing methods, even with some estimated propensity scores close to zero.
PMCID: PMC2798744  PMID: 20161511
Causal inference; Enhanced propensity score model; Missing at random; No unmeasured confounders; Outcome regression
4.  Postmarketing surveillance study of benazepril in chinese patients with hypertension: An open-label, experimental, epidemiologic study 
Benazepril hydrochloride is an angiotensin-converting enzyme inhibitor. Previous clinical trials show that antihypertensive treatment with benazepril provides effective blood pressure (BP) control and is generally well tolerated by patients with hypertension. However, the long-term antihypertensive effects and tolerability of benazepril remain to be established in Chinese patients with hypertension.
The aim of this study was to investigate the long-term efficacy and tolerability of benazepril in Chinese patients with essential hypertension.
This 36-month, community-based, open-label, postmarketing surveillance study was conducted in the Nanshi District (Shanghai, China). Chinese patients with essential hypertension were to receive 1 or more benazepril tablets PO QD in the morning for 36 months. Data for BP and pulse pressure (PP) were collected at baseline (month 0) and throughout the surveillance period. The rate of patients achieving BP targets (systolic BP [SBP]/diastolic BP [DBP], <140/<90 mm Hg) was determined, as was the rate of decrease in BP. Subanalyses by sex and age group also were conducted.
A total of 1831 patients (1090 men, 741 women; mean [SD] age, 55.8 [10.1] years [range, 35–88 years]) entered the study. After the 36-month treatment period, 75.7% of patients receiving benazepril as prescribed (1289 patients) had achieved the SBP target, 87.4% achieved the DBP target, and 71.5% achieved both targets. After 36 months of treatment, the mean (SD) decreases in SBP, DBP, and PP were 15.1 (0.4) mm Hg, 11.0 (0.3) mm Hg, and 4.2 (0.4) mm Hg, respectively, among compliers. In general, the rate of BP decrease slowed over time. No serious adverse drug reactions (ADRs) were detected during the 36-month follow-up period. All ADRs except cough (19.9%) occurred at a relatively low incidence rate (<3.0%). The cumulative incidence of benazepril related cough was statistically significantly higher in women than in men (23.6% vs 18.8%, respectively; P = 0.007). Of the 1831 patients studied, 1360 patients (74.3%) persisted in taking benazepril and were considered optimally compliant at 36-month follow-up.
In this study of Chinese patients with hypertension, benazepril was associated with prolonged, stable efficacy in lowering BP and relatively low incidence of ADRs.
PMCID: PMC3964560

Results 1-4 (4)