Tag: health

Updating practitioners as knowledge changes: the (discouraging) case of dietitians

I’ve become increasingly interested in the mechanisms through which health systems bring about practice changes among frontline providers. Pharmaceutical companies appear to do much of the work to reach and educate providers, if the practice change involves deploying a new pharmaceutical product. For the many other changes, I’ve yet to identify any approach which reliably and rapidly works across health systems. Health systems rely heavily on practitioner retirement and new entry – where the new entrants are educated on the new practice in their professional education. As the rate of medical knowledge accumulation accelerates, dissatisfaction with existing mechanisms is sure to grow.

 

Among medical knowledge domains, nutrition science has experienced relatively rapid change in the past 15 years. Naturally, this makes me curious about dietitians. How is the profession dealing with the changes? More to the point (for those of us interested in health systems): how well are different countries’ mechanisms for deploying practice change responding to this particular challenge?

 

A July 2017 paper by McArdle et al in the Journal of Human Nutrition and Dietetics presented some alarming answers to this question in the UK. McArdle and co-authors studied dietitians’ practice – focusing on what they advise diabetic patients with regard to carbohydrate consumption. NB: this is a domain where the appropriate advice has changed substantially in the past few years; in a nutshell, dietitians should be advising carbohydrate restriction.

 

The inestimable Zoe Harcombe synthesized the key findings thus:

This article shows that dietitians generally are confident in their advice – diabetes specialists especially so. Yet, fewer than one third (29.4%) of dietitians would recommend carbohydrate restriction even 50% of the time. More, (32.2%), would never, or hardly ever, recommend carb restriction. In the uncommon circumstances when carb restriction is supported, 92% of dietitians would advise type 2 diabetic patients to consume more than 30% of their total energy in the form of carbohydrate. Only 1 in 320 would advise the therapeutic level of carbohydrate for the treatment of type 2 diabetes.

dietitian old photo
Let me just check my class notes…..

Health services research regularly confirms how difficult it is to change the practice of doctors. Apparently this applies to dietitians as well. Given how many people are suffering with diabetes, I’d say we can’t afford to rely on the “wait for retirement” mechanism to work.

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Dealing with (mis)alignment between public financial management & health finance

misalignment

I’ve worked on health services reforms in more than 20 developing and transition countries. I’ve learned that the soundness of the interface between health finance arrangements and public financial management structures and processes is critical to the effectiveness of service delivery. Yet, health policy practitioners in these countries are rarely very knowledgeable about this topic; and, they tend to focus on finance mechanisms ‘further down’ (e.g. provider payment; or, how funds are managed within facilities). If the expertise gap is identified, more often than not, a general public financial management expert is brought in. This rarely helps though, as sound practices and principles for managing finances in the core of the public sector frequently conflict with managing finances for service delivery. And few public financial management experts are familiar with the institutional arrangements health agencies use to ‘govern’ finance. Both in the field, and in my teaching, I have longed for a high-quality, accessible resource on this topic. And Hurray! A top-notch team (Cheryl Cashin, Danielle Bloom, Susan Sparkes, Helene Barroy, Joe Kutzin, and Sheila O’Dougherty) at the WHO has developed one: “Aligning Public Financial Management and Health Financing: Sustaining Progress Toward Universal Health Coverage”. I heartily recommend it to any and all health policy practitioners and educators.

Time to rethink fat consumption, if you haven’t already

A study “Association of Dietary, Circulating, and Supplement Fatty Acids With Coronary Risk; A Systematic Review and Meta-analysis” published March 18 in the Annals of Internal Medicine should be the “nail in the coffin” of the lipid hypothesis (linking saturated fat consumption to coronary heart risk). I want to help out, to hammer one tiny nail in the coffin of this zombie idea. Herewith, my hammer swings.

The study is a systematic review of all available evidence on the lipid hypothesis, including observational studies, prospective cohort studies and RCTs. Taken together, the evidence does not support any link between consuming saturated fat and coronary heart risk. Its “surprising” results have come up in several conversations this week; one friend (you know who you are) speculated that the research may have been funded by a nefarious, self-interested funder (the beef industry perhaps?). This is not the case – as you can see if you follow the link above.

My friends, and many others, are suspicious because the finding conflicts with so much existing evidence. Except, they do not; rather, the finding confirms the balance of existing evidence. The findings are at odds with current dietary guidelines and conventional wisdom. This is a very different issue altogether.

Since this issue has come up in several conversations, I want to lay out what I  discovered when I examined the evolution of the evidence for this hypothesis, as well as the evolution of dietary guidelines.

The origin of the lipid hypothesis lay in poor handling of then-available observational data. To wit, Ancel Keys’ Seven Countries Study (1980), which examined observational data on changes in fat consumption and heart disease levels of different countries. It was named for the seven countries that saw an increase in heart disease cases correspond with increased fat consumption; the study ignored considerable additional observational data that was available at the time – which, taken together, supported the linkage – but weakly. Nevertheless, Time magazine covers, and sadly, national dietary guidelines based on the findings followed.There have been many more observational studies since then. Taken together, their findings do not support the lipid hypothesis. Check out this excellent overview of the evidence.

The mechanism? The concern over fat gathered steam when studies showed that saturated fat increases LDL cholesterol — the bad cholesterol — the artery-clogging stuff. They assumed this increased the risk of heart disease. When further studies did not confirm saturated fat elevated coronary heart risk, researchers started to dig more deeply into the mechanism. They found the more important predictor of risk is the ratio a person has of LDL to HDL, the good cholesterol. Note, compared with carbohydrates, saturated fat can increase HDL and lower fat deposits in the blood called triglycerides, which, is protective against heart disease. Heck, even the American Heart Assn admits this. In fact, more recent studies, such as those examining the health effects of consuming full-fat dairy – see here and here, suggest there are health benefits from eating higher saturated fat diets.

Nor do subsequent prospective, cohort studies (e.g. Framingham) support the lipid hypothesis. See this systematic review Siri-Tarino, P. W., Sun, Q., Hu, F. B., & Krauss, R. M. (2010). Meta-analysis of prospective cohort studies evaluating the association of saturated fat with cardiovascular disease. The American journal of clinical nutrition, 91(3), 535-546.  They foundno significant evidence for concluding that dietary saturated fat is associated with an increased risk of CHD or CVD”.

Many RCTs to measure the effects (in terms of fatal or non-fatal heart attacks) of saturated fat have been either inconclusive, poorly designed, or completely unsupportive of the hypothesis. A few such studies are (I could not find a systematic review of only RCTs):

  • Research committee. Low-fat diet in myocardial infarction. A controlled trial. The Lancet 1965;2:501-4.
  • Rose GA, Thomson WB, Williams RT. Corn oil in treatment of ischaemic heart disease. British Medical Journal 1965;i:1531-3.
  • Research committee to the medical research council. Controlled trial of soya-bean oil in myocardial infarction. The Lancet 1968;ii:693-700.
  • Dayton S, and others. A controlled clinical trial of a diet high in unsaturated fat in preventing complications of atherosclerosis. Circulation 1969;40(suppl 2):1-63.
  • Leren P. The effect of plasma cholesterol lowering diet in male survivors of myocardial infarction. A controlled clinical trial. Acta Medica Scandinavica 1966;suppl 466:1-92.
  • Woodhill JM, and others. Low fat, low cholesterol diet in secondary prevention of coronary heart disease. Adv Exp Med Biol 1978;109:317-30.
  • Burr ML, and others. Effects of changes in fat, fish, and fibre intakes on death and myocardial reinfarction: diet and reinfarction trial (DART). The Lancet 1989;2:757-61.
  • Frantz ID, and others. Test of effect of lipid lowering by diet on cardiovascular risk. The Minnesota Coronary Survey. Arteriosclerosis 1989;9:129-35.

This brings me back to the just-published systematic review of the available evidence from all three methods (observational, prospective cohorts; and, RCTs) Chowdhury, R., S. Warnakula, et al. (2014). “Association of Dietary, Circulating, and Supplement Fatty Acids With Coronary Risk: A Systematic Review and Meta-analysis.” Ann Intern Med 160(6): 398-406.

Which, unsurprisingly, found that “current evidence does not clearly support cardiovascular guidelines that encourage high consumption of polyunsaturated fatty acids and low consumption of total saturated fats”.

Let us hope government guidelines will finally be changed to reflect the evidence. We can’t take such a change for granted though. The folks involved with developing dietary guidelines have been ignoring the evidence they are wrong for quite awhile (see here and here).

I am not giving dietary advice. I am encouraging my many econometrically literate friends to take a look at the evidence themselves. Like me, I think you will be surprised what you find.