Decades long decline in Dementia

A study by Satizabal et al published in the NEJM found that dementia rates fell steadily over the past three decades, likely due to declining rates of heart disease.

The study analyzed data collected since 1975 from the Framingham Heart Study and included 5205 persons 60 years of age or older.  The authors compared interactions between epoch and age, sex, apolipoprotein E ε4 status, educational level, as well as the effects of vascular risk factors such as cardiovascular disease on the prevalence of dementia.

The 5-year age-and sex-adjusted cumulative hazard rates for dementia were 3.6 per 100 persons during the first epoch (late 1970s and early 1980s), 2.8 per 100 persons during the second epoch (late 1980s and early 1990s), 2.2 per 100 persons during the third epoch (late 1990s and early 2000s), and 2.0 per 100 persons during the fourth epoch (late 2000s and early 2010s). Relative to the incidence during the first epoch, the incidence declined by 22%, 38%, and 44% during the second, third, and fourth epochs, respectively. This risk reduction was observed only among persons who had at least a high school diploma. The prevalence of most vascular risk factors (except obesity and diabetes) and the risk of dementia associated with stroke, atrial fibrillation, or heart failure have decreased over time, but none of these trends completely explain the decrease in the incidence of the disease.

The authors concluded that the incidence of dementia has declined over the course of three decades.

N Engl J Med 2016; 374:523-532

SPRINT trial redefines blood pressure targets

More than 70 million people in the United States suffer from hypertension – which presently is defined by a systolic blood pressure of higher than 140 mm Hg and a diastolic of higher than 90 mm Hg.  A landmark study called SPRINT (Systolic Blood Pressure Intervention Trial) challenges the accepted guidelines of optimum level for systolic blood pressure and provided information about benefits and shortcomings of intensive pharmacotherapy. The study was published in NEJM was interrupted nearly two years early, when it became apparent that lower blood pressure for most people over 50 prevented heart problems and deaths.

In the SPRINT trial, 14,692 patients were assessed for eligibility, and 9361 individuals with a systolic blood pressure of 130 mm Hg or higher and an increased cardiovascular risk, but without diabetes, were randomly assigned in two groups; a systolic blood-pressure target group of less than 120 mm Hg (intensive treatment) or a target group of less than 140 mm Hg (standard treatment).

The primary outcomes were myocardial infarction, other acute coronary syndromes, stroke, heart failure, or death from cardiovascular causes.

At 1 year, the mean systolic blood pressure was 121.4 mm Hg in the intensive-treatment group and 136.2 mm Hg in the standard-treatment group. The mean number of blood-pressure medications was 2.8 in the intensive-treatment group and 1.8 in the standard-treatment group.  The intervention was stopped early after a median follow-up of 3.26 years owing to a significantly lower rate of the primary composite outcome in the intensive-treatment group than in the standard-treatment group (1.65% per year vs. 2.19% per year; hazard ratio with intensive treatment, 0.75; 95% confidence interval [CI], 0.64 to 0.89; P<0.001). All-cause mortality was also significantly lower in the intensive-treatment group (hazard ratio, 0.73; 95% CI, 0.60 to 0.90; P=0.003).

Investigators found that there were 27% fewer deaths (155 compared with 210) and 38% fewer cases of heart failure (62 compared with 100) among patients who achieved the systolic pressure target of 120 mm Hg than among those who achieved the current 140 mm Hg target.

The lower relative risk of major cardiovascular events observed across subgroups defined according to age, sex, race, medical history, and baseline blood pressure among patients who achieved the systolic pressure target of 120 mm Hg in comparison to those who achieved the currently recommended level of 140 mm Hg.

Rates of serious adverse events of hypotension, syncope were 67% and 33% higher in the intensive therapy group.   Electrolyte abnormalities, and acute kidney failure were noted but injuries due to falls surprisingly were not more common, as had been feared among the elderly in the intensive-treatment group.

The research indicated that among patients over 50 at high risk for cardiovascular events who are not diabetics, targeting a systolic blood pressure below the current guidelines of 140 or 150 mm Hg to less than 120 mm Hg, prevented heart disease and strokes and thus save lives.

DOI: 10.1056/NEJMoa1511939