title: Comparison of the smoothness index, the trough : peak ratio and the morning : evening ratio in assessing the features of the antihypertensive drug effect.
abstract: OBJECTIVE
  To provide a direct comparison of the trough : peak ratio (TPR), the morning : evening home blood pressure ratio (MER) and the smoothness index (SI) in assessing the features of the antihypertensive drug effect.
  
  
  METHODS
  A total of 27 untreated hypertensives were randomized to receive lisinopril 20 mg o.d. or losartan 50 mg o.d. for 5 weeks and were subsequently crossed-over to the alternative treatment for a second 5-week period. Twenty-four hour ambulatory and 5-day home blood pressure were monitored before randomization and at the end of each treatment period. TPR, MER and SI were calculated for each drug for the total study population and for responders only.
  
  
  RESULTS
  When all patients were considered, lisinopril provided higher values of TPR [0.63/0.66 for systolic/diastolic blood pressure (SBP/DBP)], MER (1.02/0.77) and SI (1.01/0.87) than losartan (0.35/0.51, 0.60/0.60 and 0.64/0.53, respectively). Analysis of responders only, again showed a clear advantage of lisinopril over losartan in TPR (0.77/0.67 versus 0.44/0.47, respectively) and MER (0.86/0.87 versus 0.48/0.61), whereas there was no difference in SI (1.25/1.13 for lisinopril versus 1.11/1.12 for losartan).
  
  
  CONCLUSIONS
  These data suggest that the assessment of the duration of the antihypertensive drug effect provided by the MER is consistent to that by the TPR and that two drugs with different levels of TPR and MER may have the same level of SI. It appears that the SI is not simply a more reliable index of the features of the antihypertensive drug effect, but offers a different type of information complementary to that provided by the TPR and the MER, in regard to the homogeneity and the magnitude but not the duration of the antihypertensive effect.
authors.affiliation: Third University Deparment of Medicine, Sotiria Hospital, Athens, Greec. gstergi@med.uoa.gr
authors.forename: George S
authors.initials: GS
authors.lastname: Stergiou
authors.forename: Stamatis P
authors.initials: SP
authors.lastname: Efstathiou
authors.forename: Irini I
authors.initials: II
authors.lastname: Skeva
authors.forename: Nikolaos M
authors.initials: NM
authors.lastname: Baibas
authors.forename: Leonidas G
authors.initials: LG
authors.lastname: Roussias
authors.forename: Theodore D
authors.initials: TD
authors.lastname: Mountokalakis
mesh_terms: D000328:Adult; D000806:Angiotensin-Converting Enzyme Inhibitors / Q000627:therapeutic use; D000959:Antihypertensive Agents / Q000627:therapeutic use*; D001794:Blood Pressure / Q000187:drug effects*; D018660:Blood Pressure Monitoring, Ambulatory; D002940:Circadian Rhythm / Q000187:drug effects*; D018592:Cross-Over Studies; D003971:Diastole / Q000187:drug effects; D004341:Drug Evaluation; D005260:Female; D006801:Humans; D017706:Lisinopril / Q000627:therapeutic use; D019808:Losartan / Q000627:therapeutic use; D008297:Male; D008875:Middle Aged; D015203:Reproducibility of Results; D013599:Systole / Q000187:drug effects; D016896:Treatment Outcome
chemical_list: D000806:Angiotensin-Converting Enzyme Inhibitors; D000959:Antihypertensive Agents; D017706:Lisinopril; D019808:Losartan