So has QOF reduced death rates or not?

Martin Roland comments on a recent BMJ paper by Evan Kontopantelis and his colleagues (Investigating the relationship between quality of primary care and premature mortality in England: a spatial whole-population study BMJ 2015;350:h90)

Death rates have been declining for years, and a key question is whether this has anything to do with medical care. In this BMJ article, Evan Kontopantelis and colleagues try to answer the question in relation to QOF (the UK’s pay for performance scheme for primary care). The question they ask is whether there’s any relationship between GP practice performance on QOF and changes in death rates, and they find a clear answer: ‘No’.

Unfortunately their analysis is flawed and was always unlikely to give a clear answer to the question that they’re interested in. The reason is that they restricted their analysis to the period 2005 to 2011, but it’s well known that most of the improvements in care associated with the introduction of QOF had occurred by 2004 – after that improvements largely plateaued (See this NEJM paper for details)

So for this analysis to make sense, one has to postulate that effects of improved care on mortality were delayed by several years. While that’s quite plausible, the paper would have been much stronger if they’d examined mortality from, say, 2001. So the question is an important one, but this paper sheds little useful light on it.

This tests the first hypothesis, that variability in practice QOF scores might be associated with differences in mortality. The paper also looks in detail at the impact of deprivation, but again, previous work (by one of the authors of the BMJ paper) showed that the difference in QOF scores between affluent and deprived areas had all but disappeared by the third year of QOF. So again, analysis of data for later time periods may just not have had enough residual variability to show an effect.

The paper also asserts that there’s been no impact of QOF on emergency admissions apart from in diabetes. This ignores our recent BMJ paper which suggests a much wider impact of QOF on emergency admissions, slightly strange as one of the authors of this week’s BMJ paper was an author on our previous BMJ paper too!

The question of whether improving healthcare leads to improvements in health remains an important one, but not one to which this paper contributes a great deal. I’ve a lot of respect for this group of researchers, but I’m not sure this is their finest hour.

Parts of this blog were posted as a response on the BMJ website

 

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