Potassium intake and cardiovascular outcomes and other stories . . .

BMJ 2016; 353 doi: https://doi.org/10.1136/bmj.i2294 (Published 28 April 2016) Cite this as: BMJ 2016;353:i2294

Dengue: the billion dollar question

The global cost of dengue is $3.7-19.7bn, concludes a study on its economic burden across 141 countries and territories (Lancet Infect Dis doi:10.1016/S1473-3099(16)00146-8). The study was funded by Sanofi Pasteur, which has marketed the first dengue vaccine, Dengvaxia. It is currently available in the Philippines at about £270 a course. Given that half the world’s population is at risk, mostly in low-to-middle income countries, there seems to be a mismatch.

Palliative gap for Parkinson’s

Parkinson’s disease can shorten life, have a high symptom burden, and require structured support, but patients seldom receive palliative care. A qualitative study (Neurol Clin Pract doi:10.1212/CPJ.0000000000000233) shows that most patients are highly receptive to palliative care to help them cope with psychosocial problems, adjustment to illness, non-motor symptom control, and advance care planning.

Dippers, surgers, and heart failure

Ambulatory blood pressure monitoring (ABPM) can tell us a lot about individual patterns of variation. Raised blood pressure is known to play a part in the development of heart failure, both with reduced systolic ejection fraction (HFREF) and preserved ejection fraction (HFPEF). Lifelong ABPM studies are needed for fuller understanding. In the meantime, a cross sectional study of 1191 elderly treated patients with hypertension provides new insights, such as an association between a morning surge in blood pressure and HFREF, and between a lack of nocturnal dipping and HFPEF (Am J Hypertens doi:10.1093/ajh/hpw015).

Potassium: not the good electrolyte?

Potassium intake does not affect cardiovascular outcomes, according to a cohort study of 7795 people followed for 10.5 years (Am J Clin Nutr doi:10.3945/ajcn.115.106773). Potassium excretion over 24 hours, which might be a more objective measure than food diaries, was measured at the start and middle of the study. After adjustment for multiple risk factors, potassium excretion was not associated with total cardiovascular disease, ischaemic heart disease, stroke, or new onset heart failure.

Stemming myasthenia gravis

Custom demands that the words “stem cell” should be followed by “breakthrough.” The latest is the use of autologous hematopoietic stem cell transplantation for treatment resistant myasthenia gravis. This approach did break through the disease in seven severely affected patients in a Canadian pilot trial (JAMA Neurol doi:10.1001/jamaneurol.2016.0113), with sustained benefit at a median of 40 months.

Testing for amoxicillin allergy

Lots of febrile children who are given amoxicillin develop a rash. Most of them then have “allergic to amoxicillin” stamped on their notes for ever. But in Montreal Children’s Hospital they have developed a graded provocation test with excellent predictive characteristics, as tested by later full treatment with amoxicillin (JAMA Pediatr doi:10.1001/jamapediatrics.2016.0033).

Disease orphanage (shut until further notice)

From 2005 to 2007 the Italian Medicines Agency (AIFA) ran a programme of independent research on drugs for rare diseases, spending €13.7m on 64 projects. Such drugs are rarely profitable for industry, so were they sufficiently worthwhile to justify this expenditure? The AIFA decided not and suspended the programme, but a study of its outputs finds that 10% may represent breakthroughs in their field and more than 30% provided definite clinical answers (Orphanet J Rare Dis doi:10.1186/s13023-016-0420-4). The publication rate was high (77%). The case for reopening this orphanage seems strong.

Be a stimulating sham

Some people who work in medicine can stimulate for a few minutes and then turn out to be sham. A new device has managed to reduce this to 40 s while remaining convincing. A study recruited 75 subjects with chronic pain and tested a new device that delivers interferential current (IFC), but cuts out after 40 s, against another placebo device or active IFC (Pain Med doi:10.1093/pm/pnw039). For IFC, the new placebo method fooled the investigator in all cases and 60% of patients stimulated, whereas for inactive placebo, the figures were 0% and 34%.

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