Recent Abstracts From Medical Literature for the Geriatric Practitioner

Risks of Untreated and Treated Isolated Systolic Hypertension in the Elderly: Meta-Analysis of Outcome Trials

Meta-analysis of outcome trials in hypertension has not previously focused on isolated systolic hypertension, nor has it shown the treatment benefit of reducing diastolic blood pressure. The authors initiated a quantitative overview of these trials in order to examine the risks associated with systolic blood pressure in treated and untreated older patients with isolated systolic hypertension.

Subjects included patients 60 years or older with a systolic blood pressure of 160 mm Hg or greater and a diastolic blood pressure of less than 95 mm Hg. Nonparametric methods and Cox regression were used to evaluate the risks connected with blood pressure, and to adjust for regression dilution bias. The investigators also calculated the pooled effects of treatment from stratified 2x2 contingency tables after applying Zelen’s test of heterogeneity.

A total of 15,693 patients with isolated systolic hypertension in eight trials were followed up for a median of 3.8 years. After adjusting for regression dilution bias, sex, age, and diastolic blood pressure, investigators found that the relative risks correlated to a 10-mm-Hg or higher initial systolic blood pressure were 1.26 for total mortality, 1.22 for stroke, and only 1.07 for coronary events. Results also showed that diastolic blood pressure (independent of systolic blood pressure) was inversely related to total mortality, emphasizing the role of pulse pressure as a risk factor.

Active treatment proved to reduce the total mortality by 13%, cardiovascular mortality by 18%, all cardiovascular complications by 26%, stroke by 30%, and coronary events by 23%. The number of patients needed to treat for five years to prevent one major cardiovascular event was lower in men age 70 years or older and in patients with previous cardiovascular complications.

The authors concluded that drug treatment is warranted in older patients with isolated systolic hypertension and a systolic blood pressure of 160 mm Hg or higher. The absolute benefit is much greater in men, in patients age 70 years or older, and in those with previous cardiovascular problems or wider pulse pressure. The treatment appeared to prevent stroke more effectively than coronary events, although there appears to be no relation between coronary events and systolic blood pressure in untreated patients, suggesting that the coronary protection may have been underestimated.

Staessen JA, Gasowski J, Wang JG, et al. Risks of untreated and treated isolated systolic hypertension in the elderly: Meta-analysis of outcome trials. Lancet 2000;355(9207):865-872.

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The Value of Routine Preoperative Medical Testing Before Cataract Surgery

Although routine preoperative medical testing is commonly performed in patients scheduled to undergo cataract surgery, its value is uncertain. The authors conducted a study to establish whether routine testing assists in reducing the incidence of intraoperative and postoperative medical complications. They randomly assigned 19,557 elective cataract operations in 18,189 patients at nine centers to be preceded or not preceded by various standard medical tests (electrocardiography, complete blood count, and measurement of serum levels of electrolytes, urea nitrogen, creatinine, and glucose), as well as a patient history and physical examination. Investigators recorded any adverse medical events and interventions on the day of surgery and during the seven days after surgery.

The medical outcomes were assessed in 9408 patients whose cataract operations were not preceded by routine testing and in 9411 patients whose operations were preceded by routine testing. In both groups of patients, the most frequent medical events were treatment for hypertension and arrhythmia. The overall rate of complications, including both intraoperative and postoperative events, was the same in both groups. The investigators found no significant differences between the nontested group and the tested group in the rates of intraoperative and postoperative events. They also found no benefit from routine testing in the analyses arranged according to age, sex, race, physical status, and medical history. Therefore, the authors concluded that routine medical testing before cataract surgery does not significantly increase the safety of the surgery.

Schein OD, Katz J, Bass EB, et al, for the Study of Medical Testing for Cataract Surgery. The value of routine preoperative medical testing before cataract surgery. N Engl J Med 2000;342(3):168-175.

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Glucosamine and Chondroitin for Treatment of Osteoarthritis: A Systematic Quality Assessment and Meta-Analysis

Glucosamine and chondroitin preparations are commonly praised in the lay press as remedies for osteoarthritis (OA), but the medical community remains uncertain about their efficacy. The authors sought to determine the benefit of these two drugs for OA symptoms by using meta-analysis in conjunction with systematic quality assessment of clinical studies of these preparations in OA of the knee and/or hip.

Investigators searched for human clinical trials in MEDLINE from 1966 to June 1999 and in the Cochrane Controlled Trials Register, using terms including and related to osteoarthritis. They also searched review articles, manuscripts, supplements from Rheumatology and other OA journals, and unpublished data (by contacting authors, experts, and manufacturers of glucosamine or chondroitin). The 15 studies included in the trial were either published or unpublished, double-blind, randomized, placebo-controlled trials of four or more weeks’ duration, which reported data on the effect of glucosamine or chondroitin on symptoms of knee or hip OA.

Reviewers performing the data extraction scored each trial using a quality assessment instrument. They computed an effect size from the intergroup difference in mean outcome values at the end of the trial, divided by the standard deviation of the outcome value in the placebo group, and applied a correction factor to reduce any bias. Heterogeneity and published bias were also tested and stratified for trial quality and size. Effect sizes were pooled using a random effects model.

Investigators uncovered quality scores ranging from 12.3% to 55.4% of the maximum with a mean of 35.5%. Only one study reported adequate allocation concealment, and two studies documented intent-to-treat analysis. The majority of studies were supported or performed by a manufacturer. Funnel plots revealed considerable asymmetry concurrent with publication bias. The tests conducted for heterogeneity proved nonsubstantial after eliminating one outlier trial. The accumulated effect sizes were 0.44 for glucosamine and 0.78 for chondroitin, but were decreased when only high-quality or large trials were considered. Effect sizes were also moderately consistent for pain and functional outcomes.

The authors concluded that trials of glucosamine and chondroitin preparations for OA symptoms exhibit average to extensive effects, but quality issues and publication bias indicate that these effects are amplified. Regardless, there appears to be some efficacy for these preparations.

McAlindon TE, LaValley MP, Gulin JP, Felson DT. Glucosamine and chondroitin for treatment of osteoarthritis: A systematic quality assessment and meta-analysis. JAMA 2000;283(11):1469-1475.

Annals of Long-Term Care - ISSN: 1524-7929 - Volume 8 - Issue 12 - December 2000