ABSTRACT
BACKGROUND: The response to antihypertensive drugs is predictable. The absence of precise prescription recommendations to treat arterial hypertension (HT) lead to use drugs unable to reduce blood pressure (BP) to target values.We published ATOM study, in which we found significant differences in the ability to reduce BP between the different drugs.The objective of the study was to determine the expected decrease in blood pressure with the use of commercialized doses of the drugs commonly used in the treatment of HT in clinical practice, to avoid the use of drugs or combinations that even with the best response, are unable to obtain the necessary BP decrease to reach the goal. METHODS: The analysis was based on the results of the ATOM study. To convert the mean doses of the different drugs and combinations in commercialized doses, the conclusions of the study by Law et al have been applied. RESULTS: Based on the results, two tables were drawn, one for systolic BP and the other for diastolic BP, where the doses of the different drugs and combinations are classified according to the BP decrease that can be expected from them. In order to favor the use of the tables in clinical practice, the different drugs have been grouped in intervals of 10âmillimeters of mercury (mmHg) for the decrease of the systolic BP and of 5 mmHg for the diastolic BP. CONCLUSIONS: Recommendations for the use of antihypertensive treatments should not be limited to pharmacological families. They should also consider differences between drugs or specific combinations. From the data of the ATOM study we have implemented tables that express the effect of the drugs commonly used in clinical practice and that should allow the clinicians to choose with care the treatment to use.
Subject(s)
Antihypertensive Agents/administration & dosage , Clinical Trials as Topic , Drug Therapy, Combination , HumansABSTRACT
Phase-shifting is one of the most useful methods of phase recovery in digital interferometry in the estimation of small displacements, but miscalibration errors of the phase shifters are very common. In practice, the main problem associated with such errors is related to the response of the phase shifter devices, since they are dependent on mechanical and/or electrical parts. In this work, a novel technique to detect and measure calibration errors in phase-shifting interferometry, when an unexpected phase shift arises, is proposed. The described method uses the Radon transform, first as an automatic-calibrating technique, and then as a profile measuring procedure when analyzing a specific zone of an interferogram. After, once maximum and minimum value parameters have been registered, these can be used to measure calibration errors. Synthetic and real interferograms are included in the testing, which has thrown good approximations for both cases, notwithstanding the interferogram fringe distribution or its phase-shifting steps. Tests have shown that this algorithm is able to measure the deviations of the steps in phase-shifting interferometry. The developed algorithm can also be used as an alternative in the calibration of phase shifter devices.
ABSTRACT
BACKGROUND: The relative efficacy of antihypertensive drugs/combinations is not well known. Identifying the most effective ones and the patients' characteristics associated with best performance of the drugs will improve management of hypertensive patients. OBJECTIVE: To assess the blood pressure (BP) reduction attributed to antihypertensive drugs and identify characteristics associated with BP decrease. DATA SOURCES: MEDLINE, Cochrane Central Register of Controlled Trials from inception through July 2012 and selected papers. STUDY ELIGIBILITY CRITERIA: Double-blind, randomized clinical trials whose main result was the reduction in BP by antihypertensive treatment, with study population ≥50 or ≥25 if the study was a crossover, follow-up of at least 8 weeks, and available required data. STUDY APPRAISAL AND SYNTHESIS METHODS: Study data were independently extracted by multiple observers and introduced in an electronic database. Inconsistencies were resolved by discussion and referral back to the original articles. Meta-analysis was performed according to PRISMA statement and using a Bayesian framework. MAIN OUTCOME(S) AND MEASURE(S): Mean decrease in systolic (SBP) and diastolic blood pressure (DBP) achieved by each drug or combination. RESULTS: Two hundred eight trials including 94,305 patients were identified. In monotherapy, most drugs achieved 10 to 15âmm Hg SBP and 8 to 10âmm Hg DBP decreases.Olmesartan/amlodipine, olmesartan/hydrochlorothiazide, felodipine/metoprolol, and valsartan/hydrochlorothiazide were the combinations leading to the greatest mean SBP reductions (>20âmm Hg). Female sex and body mass index >25âkg/m were associated with more pronounced SBP and DBP reductions, whereas Afro-American ethnicity was associated with BP reductions smaller than the median. Results were adjusted by study duration, cardiovascular disease, and diabetes mellitus. Still, the estimation was performed using the mean administered doses, which do not exactly match those of the available drug formats. LIMITATIONS: Data corresponded to those obtained in each of the included trials; the analysis of the combinations was limited to the most recent ones; estimations were performed using the mean administered doses. CONCLUSIONS AND IMPLICATIONS: Certain drug combinations achieve BP reductions ranging from 20 to 25/10 to 15âmm Hg. Sex, ethnicity, and obesity are associated with antihypertensive response. This information can contribute to better selection of the antihypertensive drug, depending on the magnitude of pretreatment BP elevation. Guidelines should be revised.
