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Motivated by the recent inclusion of potatoes in U.S. government guidelines for healthy meals, a study in The BMJ looked for -- and found -- higher hypertension risk with spud consumption.
In pooled data from the Nurses' Health Study, the Nurses' Health Study II, and the Health Professionals Follow-up Study, people who ate at least four servings of any type of potatoes each week had about an 11% higher adjusted risk of hypertension than people who had less than one serving each week.
But potato consumption was measured using a dietary questionnaire, the reliability of which has been questioned. And an accompanying editorial by Australian authors also questioned the focus on individual foods or nutrients. "The overall pattern of foods offered in school lunch programmes may be more important than the isolated inclusion or exclusion of potatoes," they wrote.
Epidemiologic nutrition study skeptic John Ioannidis, MD, of Stanford University, called the findings unconvincing. "Nutritional observational effects of small magnitude are very tenuous. Personally, I will continue to eat both potatoes and vegetables and not worry about how much of each (within logical range)."
Silent Heart Attacks
Clinically-silent myocardial infarction (MI), found on ECG only, accounted for 45% of all MIs during 8.9 years of follow-up in the ARIC study.
The silent heart attacks were associated with a three-fold elevation in risk of death from coronary heart disease and 34% elevated all-cause mortality compared with no MI, which the researchers wrote in Circulation is "a magnitude that is relatively comparable to myocardial infarctions with clinical manifestations."
The implication is that, once discovered, these silent events should be treated as aggressively as those that do cause recognizable symptoms, senior author Elsayed Z. Soliman, MD, of Wake Forest Baptist Medical Center in Winston-Salem, N.C., suggested in a press release.
"The modifiable risk factors are the same for both kinds of heart attacks," he said. "Doctors need to help patients who have had a silent heart attack quit smoking, reduce their weight, control cholesterol and blood pressure and get more exercise."
Weekend Effect Biases
Inaccurate coding may account for the apparent "weekend effect" of higher stroke mortality in patients admitted over the weekend, a U.K. analysis suggested in The BMJ.
Comparing hospital administrative coding data against that collected for the same individuals as part of the Oxford Vascular Study of nine general practices, the researchers found that about a quarter of acute strokes were not correctly identified by the administrative coding.
False positives as coded by the hospital were more likely to be admitted on weekdays than on weekends, "partly because of weekday elective admissions after previous stroke being miscoded as new stroke episodes." And those elective admissions had lower 30-day case fatality.
"Consequently, relative 30 day case fatality for weekend versus weekday admissions differed (P<0.001) between correctly coded acute stroke admissions and false positive coding cases," the researchers noted.
Looking only at the study data, there was no imbalance in baseline stroke severity between weekdays and weekends and no significant difference in 30-day case fatality or functional outcome.
Inaccurate coding may undermine "weekend effect" studies by introducing "biases that cannot be reliably dealt with by adjustment for case mix," the researchers concluded.
In Other News
And finally, the large cardiovascular outcomes safety trial for diabetes drug canagliflozin (Invokana) turned up a possible amputation risk, although the FDA has said it's not yet certain the drug is to blame for the difference in event rates. Meanwhile the trial will continue.