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By Louis Kuritzky, MD, Clinical Assistant Professor, University of Florida, Gainesville. Dr. Kuritzky is an advisor for Endo, Kowa, Pricara, and Takeda.
More Salt, Fewer Deaths in Diabetes: Who Would Have Thunk It?
Source: Ekinci EI, et al. Dietary salt intake and mortality in patients with type 2 diabetes. Diabetes Care 2011;34:703-709.
In the general population, there is a linear and reversible relationship between salt intake and blood pressure (BP): more salt in begets higher BP, and salt restriction lowers BP. Although it is generally accepted that BP lowering through antihypertensive medications in hypertensive diabetics improves cardiovascular outcomes, whether BP reduction attainable through lifestyle measures, such as salt restriction, might produce similar improvements has not been well documented. Indeed, salt restriction has the capacity to activate neurohumoral systems that are potentially particularly detrimental to diabetics; for instance, salt restriction can activate the sympathetic nervous system and the renin-angiotensin-aldosterone system, and can reduce insulin sensitivity each of which can be problematic particularly for diabetics.
Ekinci et al performed a prospective cohort study on diabetics attending a single diabetes clinic (n = 638). Salt intake was ascertained by 24-hour sodium excretion at baseline and each follow-up visit for the ensuing 10-year period of observation.
After adjustment for other risk factors, the relationship between salt intake and mortality was INVERSE. Specifically, for every 100 mmol INCREASE in sodium excretion, all-cause mortality DECREASED by 28%! Arguments about salt have raged for decades; the authors point out that other previous studies (but none previously specifically in diabetics) have NOT consistently found an association between salt intake and mortality.
Bisphosphonates and Femoral Fractures
Source: Park-Wyllie LY, et al. Bisphosphonate use and the risk of subtrochanteric or femoral shaft fractures in older women. JAMA 2011;305:783-789.
Although bisphosphonates (BIS) have a proven track record for reduction of osteoporotic fracture, reports of so-called "atypical" femoral fracture associated with BIS use have called for re-examination of the risk-benefit ratio of BIS. To do so, a case-control study of more than 200,000 Canadian women who had received BIS was performed. In this population, 716 atypical fractures occurred, and 9,723 typical osteoporotic fractures occurred.
BIS treatment of osteoporosis has been shown to reduce typical fractures by about one-fourth. Since typical fractures are 15-20 times more common than atypical fractures, approximately four times as many more atypical fractures than have been reported would have had to occur to make the risk-benefit ratio unfavorable. Additionally, not all atypical fractures are attributable to BIS use. Finally, the increased risk for atypical fracture was much more common in subjects who used BIS for more than 5 years.
Atypical fractures are an appropriate concern. Nonetheless, the typical fracture risk reduction far outweighs risk of atypical fracture induction. Risk for atypical fracture might be reduced by suggesting a drug holiday after 5 years of BIS use, particularly in women at the lower end of the spectrum of risk.
Can Antihypertensive Treatment Benefit Persons Without Hypertension?
Source: Thompson AM, et al. Antihypertensive treatment and secondary prevention of cardiovascular disease events among persons without hypertension: A meta-analysis. JAMA 2011;305:913-922.
Clinical trial data have shown that more than one-third of persons with prehypertension (130-139/86-89 mm Hg) will develop frank hypertension over a 4-year interval. Indeed, the lifetime risk of developing hypertension in the U.S. general population is approximately 90%. Although treatment of hypertension provides important risk reduction, clinicians rightfully wonder whether providing antihypertensive treatment to high-risk individuals (e.g., diabetics, persons with manifest cardiovascular disease) at the stage of prehypertension or even before might be beneficial.
Thompson et al performed a meta-analysis of 25 clinical trials that treated persons with prehypertension or normotension (total n = 40,395). Antihypertensive treatment classes included beta-blockers, ACE inhibitors, ARBs, calcium channel blockers, and diuretics, either alone or in combination.
Outcomes consistently favored antihypertensive treatment. The relative risk of stroke was reduced by 23%, MI by 20%, CHF by 29%, and all-cause mortality by 13%, all of which were statistically significant. These results suggest that patients at high risk of cardiovascular disease may benefit from use of antihypertensive pharmacotherapies at lower blood pressure than traditionally used as a threshold.