Multi-morbidity
Symphony
One of the best data sources for multimorbidity is Symphony, a project which started in South Somerset and now covers the whole county. This brings together information about illness, treatment and care of individuals in a way that makes it possible to say how many people have what combination of conditions, rather than a simple how many cases of particular conditions exist. Symphony identifies the following eight priority long term conditions for their prevalence and seriousness:
· Depression
· Cancer
· Diabetes
· Coronary Heart Disease (CHD)
· Stroke
· Chronic Obstructive Pulmonary Disease (COPD)
· Dementia
· Chronic Kidney Disease (CKD)
Other sources of data on long term conditions exist. Differences in methodology mean that the numbers recorded are not wholly consistent between sources, but this is unlikely to invalidate the broad analysis here.
Symphony makes it possible to see whether the distribution of the various conditions is random – in other words that it is just bad luck to have three or four of them – or whether there are factors connecting them. The random distribution can be calculated and these figures can then be compared to the actually observed number of people with those combinations to see if there is clustering of conditions.
Clustering of Long Term Conditions
Below are the overall recorded prevalences in 2013/14. They show that there is definite clustering of conditions. There are slightly more people with no conditions than would be expected in a random distribution, fewer with just one condition but then progressively more and more with higher number of conditions than expected until there are several hundred times more with 5 or more conditions than would be expected.
Number of conditions out of 8 / Observed(number of people) / Expected
(number of people) given overall prevalences / Obs/Exp
0 / 447,727 / 429,243 / 1.0
1 / 79,909 / 110,708 / 0.7
2 / 19,187 / 11,799 / 1.6
3 / 4,519 / 671 / 6.7
4 / 953 / 22 / 43.5
5 or more / 149 / 0.4 / 356.8
A graph of the number of people with only a single condition shows that Depression is the most commonly occurring sole condition (and also that the observed number of people with a lone diagnosis of depression is close to what would be expected by chance). Chronic Kidney Disease is the least common andit occurs with other conditions much more often than would be expected by chance. All conditions occur alone less often than would be predicted by chance.
It is also possible to look at combinations of the conditions to see which are observed more often than expected by chance. The graph below looks at people in whom the two conditions listed on the horizontal axis occur together (some of those people will have other conditions as well).
All combinations occur more often than would be expected by chance. Depression occurs in the combinations on the left of the chart and where the observed value is getting more similar to the expected value, which fits with the observation above that depression appears almost to occur independently of other conditions.
There are almost 9 times more people with both dementia and stroke diagnosed than expected. Indeed groups of vascular conditions tend to show the greater excesses of observed numbers compared to expected numbers.
“Coronary Heart Disease and diabetes” is the most commonly observed combination of 2 conditions, despite them having the two lowest overall prevalences of the 8 conditions.
This can be extended to 3 conditions together - or even more – but numbers are getting smaller. All 3-condition combinations are observed more often than expected by chance and the same observations about vascular diseases and depression are still evident.
A straightforward count of observed combinations gives the following top 23 observed combinations (those with more than 500 people):
Condition(s) / Number / Proportion of population /None / 447,727 / 81.04%
Depression / 24,257 / 4.39%
Cancer / 16,769 / 3.04%
Diabetes / 15,420 / 2.79%
CHD / 10,550 / 1.91%
Stroke / 5,596 / 1.01%
COPD / 4,789 / 0.87%
CHD+Diabetes / 2,587 / 0.47%
Cancer+CHD / 1,886 / 0.34%
Dementia / 1,872 / 0.34%
Cancer+Diabetes / 1,837 / 0.33%
Diabetes+Depression / 1,525 / 0.28%
Cancer+Depression / 1,318 / 0.24%
CHD+Stroke / 1,208 / 0.22%
Cancer+Stroke / 1,049 / 0.19%
Diabetes+Stroke / 1,024 / 0.19%
CHD+Depression / 917 / 0.17%
CHD+COPD / 794 / 0.14%
Cancer+COPD / 699 / 0.13%
CKD / 656 / 0.12%
COPD+Depression / 623 / 0.11%
COPD+Diabetes / 606 / 0.11%
Depression+Stroke / 514 / 0.09%
The 23 combinations with the biggest excess observed number compared to the expected (and when there are at least 100 observed) are:
Condition(s) / Observed number / Proportion of population / Expected / Observed/Expected /CHD+Dementia+Stroke / 109 / 0.02% / 3 / 32.1
CHD+CKD+Diabetes / 121 / 0.02% / 4 / 31.5
CHD+Diabetes+Stroke / 381 / 0.07% / 22 / 17.5
CHD+COPD+Stroke / 114 / 0.02% / 8 / 14.9
CHD+COPD+Diabetes / 228 / 0.04% / 16 / 13.8
Cancer+CHD+Stroke / 291 / 0.05% / 22 / 13.3
Cancer+CHD+COPD / 180 / 0.03% / 17 / 10.9
Cancer+CHD+Diabetes / 477 / 0.09% / 47 / 10.1
Cancer+Diabetes+Stroke / 195 / 0.04% / 27 / 7.3
CHD+Depression+Stroke / 142 / 0.03% / 26 / 5.6
Cancer+COPD+Diabetes / 111 / 0.02% / 20 / 5.5
CHD+COPD+Depression / 100 / 0.02% / 19 / 5.2
CHD+Diabetes+Depression / 257 / 0.05% / 55 / 4.7
Dementia+Stroke / 362 / 0.07% / 81 / 4.5
Cancer+COPD+Depression / 104 / 0.02% / 24 / 4.4
Diabetes+Depression+Stroke / 100 / 0.02% / 31 / 3.2
CHD+Stroke / 1,208 / 0.22% / 427 / 2.8
CHD+Diabetes / 2,587 / 0.47% / 918 / 2.8
Cancer+CHD+Depression / 146 / 0.03% / 55 / 2.6
CHD+CKD / 195 / 0.04% / 75 / 2.6
CHD+COPD / 794 / 0.14% / 323 / 2.5
Cancer+CKD / 207 / 0.04% / 92 / 2.2
Cancer+Diabetes+Depression / 146 / 0.03% / 67 / 2.2