title: [Analysis on the trend of long-term change of blood pressure in hypertensive patients treated with benazepril].
abstract: OBJECTIVE
  To introduce the application of mixed linear model in the analysis of secular trend of blood pressure under antihypertensive treatment.
  
  
  METHODS
  A community-based postmarketing surveillance of benazepril was conducted in 1831 essential hypertensive patients (age range from 35 to 88 years) in Shanghai. Data of blood pressure was analyzed every 3 months with mixed linear model to describe the secular trend of blood pressure and changes of age-specific and gender-specific.
  
  
  RESULTS
  The changing trends of systolic blood pressure (SBP) and diastolic blood pressure (DBP) were found to fit the curvilinear models. A piecewise model was fit for pulse pressure (PP), i.e., curvilinear model in the first 9 months and linear model after 9 months of taking medication. Both blood pressure and its velocity gradually slowed down. There were significant variation for the curve parameters of intercept, slope, and acceleration. Blood pressure in patients with higher initial levels was persistently declining in the 3-year-treatment. However blood pressures of patients with relatively low initial levels remained low when dropped down to some degree. Elderly patients showed high SBP but low DBP, so as with higher PP. The velocity and sizes of blood pressure reductions increased with the initial level of blood pressure.
  
  
  CONCLUSIONS
  Mixed linear model is flexible and robust when applied to the analysis of longitudinal data but with missing values and can also make the maximum use of available information.
authors.affiliation: Department of Epidemiology and Biostatistics, School of Public Health, Peking University Health Science Center, Beijing 100083, China.
authors.forename: Jun
authors.initials: J
authors.lastname: Lu
authors.forename: Li-Ming
authors.initials: LM
authors.lastname: Li
authors.forename: Ping-Ping
authors.initials: PP
authors.lastname: He
authors.forename: Wei-Hua
authors.initials: WH
authors.lastname: Cao
authors.forename: Si-Yan
authors.initials: SY
authors.lastname: Zhan
authors.forename: Yong-Hua
authors.initials: YH
authors.lastname: Hu
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000806:Angiotensin-Converting Enzyme Inhibitors / Q000627:therapeutic use*; D000959:Antihypertensive Agents / Q000627:therapeutic use*; D001552:Benzazepines / Q000627:therapeutic use*; D001794:Blood Pressure / Q000187:drug effects*; D018660:Blood Pressure Monitoring, Ambulatory; D005260:Female; D006801:Humans; D006973:Hypertension / Q000188:drug therapy* / Q000503:physiopathology; D016014:Linear Models; D008137:Longitudinal Studies; D008297:Male; D008875:Middle Aged; D011358:Product Surveillance, Postmarketing
chemical_list: D000806:Angiotensin-Converting Enzyme Inhibitors; D000959:Antihypertensive Agents; D001552:Benzazepines; C044946:benazepril