3This meta-analysis compares health care resource use costs, adherence, and persistence between groups of patients taking antihypertensives as single-pill combinations (SPCs) vs free-equivalent components (FEC) based on a structured review of published studies. The search yielded 12 retrospective database studies included in analyses. The mean difference in combined total annual allcause and hypertension-related health care costs was $1357 (95% confidence interval [CI], $778-$1935) lower in favor of SPC than FEC groups. Adherence, measured as the mean difference in medication possession ratio, was estimated to be 8% higher for patients naive to prior antihypertensives and 14% higher for nonnaive SPC patients compared with corresponding FEC patients. Persistence in the SPC groups was twice as likely as the FEC groups (pooled risk ratio, 2.1; 95% CI, 1.1-4.1). Improved adherence and persistence may have contributed to the lower costs in the SPC groups via improved clinical outcomes. J Clin Hypertens (Greenwich). 2011;13:898-909. Ó2011 Wiley Periodicals, Inc.Hypertension is a chronic medical condition and recent estimates suggest that 76.4 million US adults 20 years or older have hypertension.1 Total costs (direct plus indirect) for hypertension in the United States were estimated at $73.4 billion in 2009. Pharmaceutical treatment of hypertension can be very successful, with the potential to reduce blood pressure (BP) to recommended levels in almost all patients (<140 ⁄ 90 mm Hg or <130 ⁄ 80 mm Hg for patients with diabetes or chronic kidney disease). However, recent data show that only 50% of patients with hypertension achieved BP control.2 Uncontrolled BP can result in significant morbidity and mortality, with increased risk of adverse cardiovascular (CV), cerebrovascular, and renal outcomes.3-5 Furthermore, uncontrolled BP can result in increased medication costs compared with costs for hypertension patients with appropriately controlled BP. 6Two of the main reasons for a lack of adequate BP control are lack of adherence (missing doses of an antihypertensive medication in the context of ongoing treatment) and lack of persistence (discontinuation of an antihypertensive medication). 7,8 Adherence to antihypertensive therapy is often very low, ranging from 15% to 35%.9 One major factor contributing to decreased adherence and persistence with antihypertensive medications is the complexity of treatment regimens. Many patients with hypertension require !2 medications to provide adequate BP control. Only one third of patients with hypertension require a single medication for BP control, one third require 2 medications, and the remaining one third require !3 medications. 10Strategies to improve adherence and persistence to prescribed antihypertensive medications are likely to improve BP control and thus can potentially have substantial medical and economic benefits. One such strategy is the use of fixed-dose single-pill combination (SPC) medications, which combine !2 active agents in a single pill. SPC medications simpl...

We report precision measurements of the refractive indices of dry air, N(2), O(2), Ar, and CO(2), performed by using a frequency comb as the light source in a Mach-Zehnder interferometer setup. Improved dispersion formulas for all gases are derived with a sensitivity level of 10(-9). These results are valid for a wavelength range from 740 to 860 nm and are in good agreement with measurements from other groups.

The phase instability induced during the transfer of radio frequency and optical clock signals through the turbulent atmosphere was measured in a rooftop experiment. Radio frequency intensity modulation of a laser to transmit signals over 100 m results in an Allan deviation of 1.31x10(-10) at 1 s. Optical transfer is more accurate at 1.68x10(-13) at 1 s. As a consequence, fiber links are more suitable for the transfer of optical frequencies over very long distances while free space transmission might find applications in short distances of less than 1 km.

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We report a new method in the precision measurement of the refractive index of air using a highly unbalanced Michelson interferometer with a femtosecond optical frequency comb as the light source. Standard dry air is filled into a 30 m multipass cell, serving as the long arm of the interferometer, while a short arm acts as the reference path. Both time and frequency domain interferograms are recorded to measure the refractive index of air. The deviation of our experimental results with Edlen's formula is 1.4x10(-9) at 800 nm. Our experiment has a standard error of 5.2x10(-9) at fixed parameters (pressure and temperature). This is achieved by putting the multipass cell into a temperature-stabilized box, and also by locking the interferometer path length with a He-Ne laser. We achieved a temperature stabilization of 0.8 mK for 25 h. This corresponds to 0.4 mu m multipass cell length change. The locking of the He-Ne interferometer enables us to achieve 7 nm path-length change outside the multipass cell. Combined with accurate measurement of temperature and pressure, we were able to achieve an accuracy of 7.7x10(-9). (c) 2006 American Institute of Physics